M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: bigskyis on October 08, 2013, 10:12:05 PM
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Picked up an e30 is approx. 3 years ago. Bought it with the knowledge that there was something wrong with it. PO stated that there was a lot of steam/coolant leaking. She finally tired of the car so $600 and it was mine. Towed it home and there it sat. Did not even look at car. Until a month ago.
In the past 4 weeks I have spent a lot of time reading the posts on this forum. I would like to thank those that made/make it happen and those that contribute. I won't say I read every post but at times it seems like I did. Thanks to all.
So...here is where I am at with the car...put battery in and it fires right up. No theatrics. WTF? I let it warm up and take it for a drive. Definitely down on power but it runs. So I am pleasantly surprised. My intent with the car was to get the chassis, yank the drivetrain for a swap and call it a day. But now that it runs...I want to get the 4 banger going if possible.
First order of the day is to do the MUTI. Thank you M42 Club. All the hoses had the usual cracks at either end and were clearly leaking air. Removed those that needed to go and replaced the rest. New gasket between the TB and intake. CEL 1222 goes away but still not running right.
Pull plugs for compression test. Plugs look uniformly old. DVOM says 25kohms on each plug. New plugs purchased. Perform compression test. 190-195# across the board. Shocked me, too. So pretty sure HG is good and head is not cracked (yet). Should be noted at this time I notice coolant leaking. Turned out when doing the MUTI I cracked one of the nipples off of the plastic coolant pipe. Order one from BA....URO....Send back to BA with nastygram (thanks m42) I only want OEM. Thank you Turner Motorsports. Topic for another day is might have thoughts on why the URO stool pipe leaks. Anyways...new pipe/o-ring and leak solved. I wonder if this was problem for PO. Also original pipe was cracked at flange in the block.
Drop lower oil pan (thanks M42)...no bolts in pan. All bolts where they should be and they are snug. Button up the pan. Fill with oil, coolant bleed system and off we go. Also, no remnants of timing chain or guides. Happy happy, joy joy....
Car fires up...idle is fine. Give it some gas and it falls on its face. As if running on 2 and 3/4 cylinders.
Ignition??? Well...I DVOM the wires...6kohm pretty consistently. At least they are uniform from resistance standpoint. Check coils and they all come in at 0.8ohms per Bentley. Seemingly OK. Hook it all back up. Fire up the engine. Idle is OK. Give it some gas and it is the same thing. When idling...
the exhaust is clearly running rich. While idling...I start to pull plug wires...first at the plugs. Pull cyl 1 and 3 and the idle drops almost stalling the engine. Pull 2 and 4 and there is no drop in idle. (???). When I pulled each wire individually, I could get the boot close to any metal surface and I have an arc. Same for all four wires. Hook them back to the plugs and I do same thing at the coils. When I put the boot close to the respective coil tower I get and arc. Same for all 4 coil/wires.
Let engine cool off. Pull the plugs again...cylinder one is velvety black. Cylinders 2-3 actually look sort of normal. Cylinder 4 is wet with gas. Does not even look like it has fired. Scratch head and reinstall.
Fire up the engine...let it idle for 10-15 minutes. Temp gauge stays around 1/4. Put the IR temp sensor on the outlet and it is around 150F.
Put temp sensor on each headpipe....Cylinders 1 and 3 are at 600F. Cylinders 2 and 4 are at 300F.
Still scratching head. Shut it down. Pull fuel pump and the sock is clean (more or less). Reinstall fuel pump and it cycles like it should. I did install a new fuel filter (under car) which made no difference. Car fires up readily but still runs like a dog.
I should add that I did install a new blue top coolant temp sensor. No change. I checked CPS with DVOM and it is within specs. I have spark out the yingyang so the the CPS must be doing its thing.
I pull the valve cover to replace the gasket as it did have a slight oil leak. Everything under the valve cover looks reasonable. Yes...I know that the timing set can be suspect...but there are no noises right now to suggest chain slap from failed guides/tensioner. If I can solve my current dilemma the timing set will get replaced. First things first.
I sprayed a little starting fluid on anything that might have an air leak...no change. Pretty sure the MUTI thing took care of those issues.
At this point...this is where I am at. I don't believe it to be a spark/ignition issue. I have too much crisp,blue sparks when I checked the ignition. I also took a look at night time with engine running. No itinerant sparks anywhere.
Pretty sure it is a fuel/ fuel delivery problem. I am assuming the fuel pump is ok (for now). I do have a fuel pressure gauge for EFI...but it is in my garage somewhere. I am ashamed to admit I have no idea where it is at. Will try to find it. but...I am still comfortable with the pump at this time.
This leaves me with FPR and injectors. Based on what I can figure out...I am leaning towards the injectors being the culprit. The good news is that I have a good friend who owns a wrecking yard and should have any number of Fords with 0-280-150-556's sitting in them. Soo....this weekends experiment is to get some injectors off of a Ford V-8 and give them a try. And try to find my fuel pressure gauge.
I am not sure if I left any pertinent info out...or forgot...I would really like to get the M42 running. If not...out it comes and I will proceed with original plan to install 2.4l TD/5 speed out my old 524td. Easy swap. Slap in the 2.93LSD I have and it is off to the races or at least back to 40mpg land but I would rather preserve the M42. Hell...even the AC works. Car has 152,xxx showing on the odometer.
Any help/thoughts/tips/insight you guys can provide would be greatly appreciated.
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I had a similar issue with my car post M.U.T.I. , Turned out i had the sensors hooked up wrong which really messes with how the car runs. It would idle but ran terrible until i fixed it proper and then everything worked again.
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Bald Eagle:
Thank you for that information. The only problem is that of the 3 connectors you posted, the only one that had been removed was off the blue top temp sensor to the ECU. Never moved/removed either of the other two. As my in dash coolant temp gauge is functioning and the oil pressure light goes off when the engines fires up...I suspect they are where they need to be. However, when I get home this weekend I will surely check each and every one of them.
Thanks again!
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Could be clogged or stuck injectors.
COntrary to what is posted in here, the 19# Ford injectors aren't going to work super well. The stock M42 ones are 21# units. I'd see about finding some used M42 ones from someone on here or r3vlimited.
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I had unhooked mine to clean. I also thought I had it hooked up right but it was so backwards. It took me a while to find that illustration identifying I had things improper. Best of luck!
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bmwman91:
I hear you about the Ford injectors. For me it is the quick and easy thing to do. I have been scratching my head over this one and am thinking the injectors are at fault. I can access the Ford injectors for nothing. If I slap them in and the car runs, then I have found my problem. If that is the case, I will probably send mine out to be cleaned, etc. I would agree that the Ford injectors are not the absolute answer, but they are the only thing I can get my hands on at the moment. Montana is not the absolute hot bed of BMW parts and pieces. I might have a set off of my 86 535i...but they are probably living with my fuel pressure gauge. Someplace.
Bald Eagle: where do you get those pics/info that you posted earlier?
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Got ya. Yeah, the car will at least run with them. As far as I recall (and according to real OEM), the M42 and M30 engines use the same injectors, so you may have a decent option there.
You did mention that plug #4 was wet with gas at one point. That seems like an ignition thing. Try opening up the ECU. Some people have had the ignition coil driver IC's die on them, in an often visible way. Other times the coils just poop out as the potting epoxy breaks down and you get internal shorts on the secondary coil, which you can't really test with a DVOM. Ignition may be fine since you could get sparks from all 4 coils, but it's also a lot harder on the system in a running engine than in free-air.
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I forgot to mention that I did pull the ECU and open it up to have a look at the coil drivers (per a post by Desktop Dave)( I think). Nothing in the ECU looked burned. If I was looking at the coil drivers correctly, all four of them looked as I would have expected them to. Like I said, I have spark from all 4 coils up to the plugs. Plug 4, when I pulled it, looked like it had been sitting in a puddle of gas. Plain, dripping wet. I would venture to say that the injector on #4 cylinder is firing like a fire hose. In all my years of schlepping cars I have never seen an plug that looked like this. I don't think it could have fired if it had wanted to. Frozen open? No idea. I had the car for almost 3 years prior to my even trying to turn the engine over. Maybe it is gummed up. But...Ford injectors as a test or if I can find my M30's. Will know this weekend.
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Yeah, sitting for 3 years could have gummed it up and stuck it open. Good luck, let us know how some fresh injectors work out!
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A friend downloaded a whole bunch of manuals, most of which were in German. I found 1 that was useful and happen to have this info. Let me see if I can get it to you somehow. Its 106 MB, looks to be the CD portion of a repair manual. I will edit this post with a link if i can get it to you.
https://docs.google.com/file/d/0B0i7pdGuuoDTSGRQX25lMXZMem8/edit?usp=sharing
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JFC...went to the boneyard thinking I was going to score some Mustang injectors. No such luck. However, I did find some 943 injectors out of a 4.6l Ford. I figured they might work enough to confirm that my original 714's were the problem. Did not exactly go down that way...Slapped the 943's in and buttoned everything up. Hit the starter repeatedly to prime the fuel system. Go to start and...nada...zip...nix...Engine will spin till the cows come home but no start. I squirt some ether in to the intake and the engine will cough and turn over as long as there is a little ether. But will not start. Inject a little gas in the intake. Same story. Engine will cough/sputter/run as long as there are fumes. So...I double check my work. All connectors are where they ought to be. Gas in the tank. Etc. etc......So on to plan two. Time to root around the garage and see if I can find my 535i injectors. Also, I should have a set of injectors off of my e36 328is. All I want to do is confirm that my original problem is/was due to my factory 714's. I had hoped that 4 hole 943's might do the trick. But...there is no indication that they are firing at all. I would have figured that the 943's would have let the car run. But...What are the chances that all 943's are crapped out? Probably minimal. So I will assume that they 943's cannot work in the M42. Oh well...I will give it another try tomorrow.
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Weird. The 943's are almost exact replacements for the 714's in terms of flow rate and impedance. Seems unlikely that they all quit.
Have you checked the condition of the fusible link on the 12V supply to the injection electronics? There's the giant 12V wire that comes off of the battery in the trunk, and then there's the smaller (but still pretty sizable) black wire that runs parallel to it. That smaller one is dedicated to the injection stuff and it has a big inline fuse on it about 18" from the battery. VERY often the connection corrodes and causes all sorts of funky intermittent injection & ignition issues. Go take a look at it and give it the old 5lb tug test!
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bmw91man: I thought the exact same thing about the 943's as you did. They are "oh so close"...I wonder if any other forum member has actually used them. Anyways...it is a puzzler. I will check those items that you pointed out and see "wassup". As for my 535i injectors...I might be SOL. I found a set of injectors but they turned out to be a set of 200's from a mid 80's M106 745i. Low impedance. I have some injectors from old turbo t-bird (when I used to screw with those) and they also are low impedance. Can I find my old 535i's? Not in your lifetime. Note to self...mark these things and put in one location. Dammittall...As for the e36 stuff...they may have gone the way of the 535i. The only good news is I can get more injectors tomorrow from boneyard in the a.m. However, I am going to check the stuff you pointed out. Frustrating to say the least. But I am getting proficient at pulling the upper intake.
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I installed 943's and my car runs great, gained a few mpg and she fires right up like brand new. However it did take about 20 minutes to initially get the car running, I had to hook up a battery charger and kept checking the starter motor doesn't burn up. Between cranks I played around with the sensor wires and mysteriously blew a fuse, eventually I unplugged the ICV and finally the car started up! Well that's what worked for me but I wish there was another "trick", cranking for that long was painful.
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Slowered318: Thank you for posting. I feel a little more comfortable with the 943's after reading your post. However...I pulled the whole thing apart. With the fuel line dc'd from the fuel rail, I can hit the starter and I have got gas shooting out like a damn fire hose. Cleaned up my mess and figured that wasn't the problem. I have fuel and I have spark. I have a car that will not start. Unless I squirt some ether or gasoline in the intake. After reading your post it makes me think the thing is behaving like it is vapor locked. Before I put it back together I think I am going to hook up a longer line to the fuel return side of the fuel rail and keep priming until I have fuel at the outlet. I also now wonder if the fuel return line to the tank has a kink in it someplace....hmmmm.....you got me thinking. Guess I better put the battery on the charger tonite. Thanks again. I will keep at it. But maybe not until next weekend.
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It seems really odd your injectors are not functioning at all (by the sounds of it), are you sure you have the supply/return hoses connected properly?
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Good call. Yeah, make sure that the fuel line that exits the filter is the same one that connects to the middle nipple on the fuel rail. The rail nipple down by cylinder #4 is the return. Just recently a guy on r3vlimited accidentally connected his fuel return line to the evap / vapor return line and had basically pumped his whole evap system full of gas! So many black hoses, so little room to see!
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Please confirm that the nipple that is towards the firewall is the fuel return line and the one in the middle is the feed line. If that is the case...there might be a problem there. I am certain that when I dc'd the fuel lines from the rail and primed the pump...the fuel shot out of the hard metal line that would connect to the rear most fuel rail nipple. It looked like somebody had been in at the pump as the fuel line clamps are American clamps not BMW. When I get home this weekend I will trace the lines from pump to filter; from filter forward and from fuel return back. Thanks.
Now let me add this...after Slowered318's post I hooked all back up and decided to crank it. This was with the 943's. Took upwards of 10 minutes of trying and a can of ether but it finally started. Rough at first. Crack throttle and it would die. Let it idle and it seemed to even out. Now...will fuel get through the FPR from the backside? It has an off idle stumble up to around 1700 but after that it smooths out and will rev to redline. So I am going to trace the lines when I get home.
I did take my original 714's to NAPA and they put them on the AZNU tester...nothing wrong there. Hmmmm......WTF?
943's are in the car and are going to remain there for now. I am tired of pulling the intake.
But now for something completely different...while on the ramps (where it has been for 2+ weeks) I note a fluid spill on concrete under bellhousing/block interface....I also noticed that my clutch pedal is now very "light" ( for lack of better term). Would appear that salve cylinder took a dump. New one on the way. At least it happened in my driveway and not in the middle of nowhere.
Please let me know on the fuel rail nipples/barbs/thing-a-ma-bobs. I will trace the lines when I get home.
Thank you for your patience and input.
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Fudge, sorry, I had it backwards for the nipples on the rail. A pic is worth a thousand words. Parts 12 & 13 have little arrows on them, as well as their names.
http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=13_0308&hg=13&fg=15
Then it is just a matter of making sure that the hoses from the fuel rail connect to the proper hard-lines on the chassis. That's easy enough to verify by seeing which one connects to the filter outlet! Did you mess with the hoses by the pump at all? As long as the pump output is going to the filter & not the return, you should be fine. The nipple toward the bottom of the pic is the outlet and the upper one is the return.
(http://i253.photobucket.com/albums/hh64/PC853/DIY%20Tech%20Write-Ups/TRE340%20Fuel%20Pump%20Install/IMG_4679.jpg)
This guy has a lot of good pics of his project which might be helpful.
http://www.r3vlimited.com/board/showthread.php?t=156902
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My vote is to keep using the 943 injectors. Although 20 year old 318's are not all the same from my observations. Always a slight variations from one car to another so it's hard to advise what injectors will work with a particular engine.
I will verify that the nipple on the far right (closest to the firewall) connects to the "supply" line from the fuel pump. I also used the same (unsafe) method of checking what line has fuel pressure, should have marked them previously.
If possible, you might need to take it out for a long drive to get everything "dialed-in".
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Fuel lines hooked up properly. Car fires up nicely but...same-o, same-o...still has the off idle stumble when you give it gas. Took it for a ride, clearly doing better than when I started. But it still is not running great. Clearly there is a "miss" through the RPM band up to 5k+. I don't expect this to set land speed records but...years ago I had a late 80's Saab 9000 with the 2 liter DOHC 4 cylinder. Ran great, very smooth and ran well. I expect this M42 to run as well. Anyways...I am fairly certain it is not fuel delivery. Which leaves ignition. Plug wires ohm out at 5.8k to 6kohms. I will double check the crank position sensor. I did check the coils and they all come in at 0.8 ohms as measured per the Bentley manual. I did swap in some individual e36 coils but made not much difference. On occasions I get what sounds like a back fire in the headpipe. The exhaust does smell "rich" at the tailpipe. What else..???...Not sure. Anyways...I am getting close to parking it for the winter. It is not a life or death thing if I don't get it running at the moment. If that were the case, the diesel and the 2.93 gearing would be in/running over the course of a weekend. I still debating about doing that and setting the M42 aside for now. Be that as it may, I would rather have the M42 hooking and cooking but crap happens. We shall see about BavAuto coils are COP. I don't really want to throw $$$ at the parts game crapshoot. Thanks for help!
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Forgot to add...no CEL...stomp test 1444...road test...step on the gas, stumbles,gains RPM slowly and is like stepping on a wet sponge.
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Maybe you have a plugged catalytic converter? When you drive, does it get red hot or anything?
When the ignition craps out, you usually get misfires and jerky acceleration. If a coil or wire was somehow totally dead, it would run on 3 cylinders, which is sounds like it is not.
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So here is how it is hanging...obviously, many possibilities as to the ultimate fail point. Have not found it just yet. Pretty certain it is not fuel delivery. Trying to locate my fuel pressure testing set. The 943's seem working fine. Therefore...thinking ignition. After plying the pages here and at R3V I figured I would try swapping the coils. Bought the BavAuto upgrades...well...made no difference. Runs just like it did with the stock coils. (I am going to post a rant about the BA coils on a different thread). So far we have new coils. New plugs. New blue top H2O sensor....Although I have ohmed the CPS and it was within specs based on previous postings at M42, I am going to give Turner Motorsports some business next week and order the CPS. I will recheck everything over the weekend but the car (although it runs) is really not safely drivable. Could it be wires? Sure but they all ohm out between 5.8k and 6k. I think the uniformity tells me they are more or less "otay". I will put the DVOM on the TPS. Again. And the cam sensor. Again. But...I am getting towards the end point on this piece o'stool. The TD conversion is looking better all the time. I really do want the M42 to run as well as I think it should run...after all, that is why I jumped on it when I found it for sale. But there does come a time to cut ones losses...So...I will get the CPS ordered and on its way. I will cross my fingers and hope that the CPS does the deed. Otherwise...going to be selling a bunch of stuff...but I still tremendously appreciate all the help everybody has thrown my way.
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Uugh, throwing money at an issue is never fun, but at times it can be necessary. The ignition wires might Ohm out OK even with failed insulation. If the insulation is breaking down, you'll get arcing which can cause issues. It is hard to say what's going on though.
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I hear what you are saying. When you say arcing of the wires...I have had the thing running at night and taken a look at the wires...there is nothing. Now...I am referencing one of my earliest automotive experiences...my first car was a 62 Chevy Biscayne with a 235 inline 6. It ran. Not great but it ran. One night I had to open the hood with it running and you could see a great light show in various areas along all the wires...
Next day it had some new wires and it ran a whole lot better. I have had the 318 running in the night and specifically looked for anything similar and sure have not seen anything. I might fire it up today and lightly spray the wires with H2O and see if there are any changes. Is the 6k ohm resistance per wire that I measure, relatively normal? Regardless, I am going to get a CPS on its way.
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The GD CPS that was supposed to be here today won't be here till...which means I won't get around to this piece o'stool until next weekend,...
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Well...it wasn't the CPS. Needless to say, it is a bit of a downer. New coils and new CPS and still runs poorly. Tomorrow I have a few things to try and then I am done. New rear main seal for the diesel arrived and it is getting close to doing the deed. I am not happy about this but like I said in the beginning I am not going to go throwing parts at it until I hit something. I can't afford that. I really had high hopes to have this thing run as I had read such good reviews on the M42 powerplant. In the big scheme of things it is not that big of deal. If I had known I was going to go down this road I would have sought out a 323e/I with a dead engine. Well...that's my story and I am sticking to it. Another downer is that I have a cylinder head at the machine shop. Already pressure tested and is without leaks. It is going to get .007 shaved off of it to true it up and then to the chopping block. Thanks for everyone's input.
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Sorry to hear that you haven't had any luck sourcing the issue, yet. Where do you live? Maybe there's an M42 guy in the area who could lend you a hand? I'm sure you could lure him there with a six-pack. Might be worth poking around r3vlimited, as well.
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timothymcn: I live in Montana. Doubt there are many other running M42's running the state. Let alone anybody that knows how to troubleshoot/maintain them. It clearly is not a mechanical problem. I swapped the brain and it still runs the same. I backprobed all the grounds at the DME connector and they are all good. Swapped the TPS from an E36 throttle body I had laying around (same part number). No improvement. To add insult to injury my 89 325ix pinched a loaf last Monday. Which is a story for another day. I thought...maybe fuel pump. So I pulled the pump from the ix. It was a Walbro I swapped into the IX within the past 3 years. No change. Car starts and runs. I can drive it. Virtually all of the time, it feels like it is running on 3 cylinders. Any mild grade and the sucker can barely pull the hill. Have to drop a gear or two and rev the crap out of it, even then it just wants to lay down. The car can barely get out of its own way. My wife made an interesting comment last nite... "that car really stinks when you pull away"....hmmm.....crapped out convertor? I guess the best way I can describe the way that it runs is that it seems like it has a butt plug shoved up its ass. Never overheats. I don't know...I like challenges but it is 11 degrees out and I do all this crap in the driveway. Not today. I am not going to bail on the M42 just yet...It has got to be something simple. If/when I find it I am sure I am going to have one of those WTF moments. Thanks for the r3v tip. But...been there, done that. I scored the DME from a cat on r3v (Thanks Justin!). If anybody here reads this post and has had experience with a plugged cat, post up. I am ready to ream the thing. It would be a "no harm/no foul. The only cat I ever had fail was on an 88 Mustang GT. The cores fell apart and rattled like a sum bitch. Ford had a big recall on that one. But I have never had a "plugged convertor". Again, thank you.
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Sorry to hear about your troubles. If you decide to trash the M42, make sure you post some pics of the M21 swap. Always wanted to try that myself.
I know it sucks to track stuff like this down, but I'd be going through the system and methodically checking it part by part. Get a fuel pressure tester on it to verify fuel pressure at the rail, maybe do a volume test too to check the fuel filter.
Did you test the resistance of the CLT, cam & crank sensors? I'd be surprised if your AFM was working at 100%. Most of the ones I've seen are close, but a few were way off. A few have been worn resistor tracks, some have had clock springs loosened up too much. I'll see if I can track down the testing guide for those AFMs, it's not an obvious thing.
You replaced the crank sensor, the TPS and the injectors so far, right?
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Hi Dave: Thanks for weighing in. The M21 diesel swap is really rather easy. Did one a few years ago on an M10 318. With little exception it is more or less a bolt in. I can walk you through it if need be. But...back to the M42. Since I posted a few hours ago I have been researching failed catalytic convertors. I think the conventional way to test is to drill a hole in front of cat and insert pressure sensor and measure back pressure. Well...not going to do that today. Another suggestion was to use an IR temp gauge, measure temps at cat inlet and outlet. According to the site, assuming you have a functioning cat, the temp at the outlet should be HIGHER than that of the inlet. Well...after running my POS I measured the temps...clearly, the temp on my cat, at the inlet, is HIGHER, than at the outlet, by approximately 100 degree's F. If this is correct, it would appear (at face value) that I have a convertor that may have failed. The website I referenced said the temperature at the outlet should be higher than that of the inlet and be within 400 degrees F of each other. One thing I have noticed is that when the car is cold (especially today with an overnite low of 9 above) the car seems to run better, but after running up and down the road it just seems to get worse. Maybe the convertor is not completely plugged but is failing. Next weekend I am going to unbolt the exhaust behind the cat a take a look. I will most likely ream out the convertor. And that is this weekends installment.
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You can also check for a plugged cat using a vacuum gauge. I started a thread on that a few years ago.
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Keflaman: Thank you you for the tip. I read up and yes, you can use engine vacuum to aid in diagnosing bad cat. At this point, I am going to pull the cat and have a direct visual on the core. Based on what the PO told me when I bought the vehicle a couple of years ago (wish I had listened to her and asked her a few more questions) I am beginning to think the cat is shot. Would not be surprised if it is original to the car.
If it is...well...a 22-23 year old cat has probably out outlived its useful lifespan. No complaints. Believe it or not, I am hoping that it is the problem. Will know more on Saturday, Sunday at the latest.
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Time for the weekend update...I would like to thank the BMW engineers as it was rather easy to pull the catalytic convertor but...that was/is not the problem. Pulled the cat and was looking into from the outlet of the cat. Took me a few minutes...(little slow on the uptake) and then I realized...the cat had been cored already. Put it back together. Fired it up. No change/improvement. Different O2 sensor...no change/improvement. No CEL. No idea. Perplexing to say the least. At least I figured out why it sounded like one of the many rice grinders with a fart can that run around town. Oh well...there you have it.
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One of the gurus on the S14 SIG mailing list posted something interesting last week where the ceramic insulator on a spark plug was slightly loose and was causing the electrode to be shielded when the plug was installed. Have you moved the plugs around to see if the misfire follows it to a new cylinder?
Obscure, but might be worth a shot.
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Yeah that was Don Fields at MrMCar posting that. When he showed me the plug I couldn't believe it. That's where I built my motors/cars and keep my track car. He taught me everything I know about BMW's. He came up with the S50/52 cam tray idea for me about 7 years ago. I would go the spark plug route and then go directly to the AFM like Dave had mentioned.
Cheers,
~Ralph
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Colin: New spark plugs were installed a couple of weeks ago.
Warsteiner: I hear you about AFM. Have a "new" (to me one on its way). But...I am not sold that this is the problem
new spark plugs. New BavAuto upgrade coils. Different O2 sensor. Different fuel pump. New blue top Coolant temp sensor. New crank position sensor. No catalytic convertor. None of which has made any difference in how the engine runs.
This weekend, I am going back to basics. Pull the plugs and inspect and re-accomplish compression check. Recheck all my vacuum lines. Recheck the IAC.
The latest fly in the ointment is that my oil pressure light comes on after running for a while. Engine makes no bad noises whatsoever and has not changed one bit in how "bad" it runs. I can rev it up to redline (in neutral) and it goes just fine. I can drive the car...I am able to do 60 in 3rd...slip it into 4th and it slows down. Try 5th and the car goes "backwards". Head for a mild incline/grade in the road and the car is a moving road hazard. Going downhill you would never know anything is wrong.
So...as for the AFM...I jump pins 1 and 2 (fluke DVOM)...with the flapper closed it shows 347ohms. Open the door and the resistance increases to 950 ohms but past a certain point it heads back to 347. At wide open it shows 347 ohms. Not certain as to what to make of it but it does parallel another forum members observations. Does this mean AFM bad? Dunno...won't have my replacement until next week.
So it is a back to basics weekend.
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Dave asked above if you had replaced/checked the injectors? Could be I missed it but have you pulled these to see if one or more is clogged?
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Sorry for my last, just looked at the first page on the thread on the injector saga.
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Boris: yes I did swap the stock injectors out for some Ford injectors. No difference in how the engine runs. It is just perplexing the crap out of me. That is why I am going to start at square one this weekend and try to check every thing one more time.
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Car sat for three years. You've replaced fuel pump, injectors, checked lines etc. What about the gas itself. Full tank when the car sat? Added any Stabil before you let it sit? Have you drained the tank or added a bottle or three of gasline dryer?
Other: valve bent, crack in main intake boot, timing off somehow (new to m42s so not sure what to look at here)...
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Since the Packers were taking it in the shorts today, I went out and started checking everything. Dc'd the fuel pump and checked compression..
187-195 across all 4 cylinders. Not great but at least uniform. I check all the electrical things and everything pretty much is in line with
the Bentley manual specs. Find the vacuum gauge...well...note to self...intake manifold vacuum should be one of the 1st tests one does. Period.
I have 10-11 inches of vacuum at idle. Snap throttle and it drops. Let throttle close...back to 10-11. Should be sitting in the 20" range.
If I have a vacuum leak one would think I should be able to hear it, loud and clear. But I have not heard one. I replaced all the hoses under the intake and used clamps on each one. Should be good there. The only place I have not checked is the intake gasket between the lower intake and the cylinder head. That is pretty much going to be the last thing I can check unless somebody else has any thoughts. I think what I really have is a
tired M42. Most likely in need of a rebuild. Wish I had the gauges to do a leakdown test but I will bet it would show tired rings. Not a big deal. When I bought the car I knew it was going to be work in progress. And I did buy it with the intent of doing an engine swap. No loss there. Looks like I will be doing the engine swap sooner than later. I will pull the M42 and set in on the engine stand and tear it down as time permits. But in the meantime...project "dwiesel" will be getting teed up. Will order the new clutch and get that ready to stab in. Thank you to everybody here.
I haven't used the vacuum gauge in a month of Sundays (years and years). A useful tool. And I knew this. Oh well....I had hoped it was something simple but in the back of my mind....
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Sorry to hear about that. I've been caught in the "has to be something simple" loop with some cars and bikes when I should have known better.
Fingers crossed you'll find the reason though.