M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: Petebee on May 28, 2012, 08:22:08 AM
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Okay so back in December my little 318i starting acting funny, throwing CEL 1222 and generally running crappy. 1222 is Lambda so I thought it might be vaccuum related. After performing the "intake mess" fix and doing a full tune up still no good. Checked out the various sensors (cam, crank, throttle) narrowed it down to the AFM. Replaced that with a 100K mi used unit and ta-da...car was running good again!
Fast forward to about 8 weeks ago. Stopped to get fuel (engine hot), and when I started the car it stumbled, idle hunted and died. Took a few cranks to get her to fire, but she did, cleared her throat and away we went.
A week later I took the car to an auto-x (my daughter has lost my auto-x car keys - 81 Scirocco - the night before the event). I hadn't planned on running the BMW, but sinced I'd already paid, I figured what the heck.
After restarting the car after my first run, it acted like it did at the fill up. Then after the second run car would not fire at all. Crank, crank, trying to fire but it just wouldn't "catch". Had someone listen in the filler neck and verified that fuel pump was running. Pushed car out of the grid and it finally started - with a lot of throttle feathering to keep it running until idle settled.
Fast forward to this weekend. Went to a cool BMW show in Old Salem and on the way back decided to visit my buddies Adam and Mario to see Mario's turbo 318is. Hot day, driving somewhat hard (80-85 mph sustained for an hour). When we got to Adam's found out the turbo car broken a drive axle, so Mario needed a ride home (and my spare parts axle). Went to start the car and same thing as the auto-x. Took a good 20 attempts to get it to finally run. On the way to Mario's noticed that power was down. Idling at his house it threw 1222 code again.
Traded Mario for another AFM - figured what the heck? Before putting that in I decided to check the joints on the DME as I remember Desktop Dave mentioning that high engine temps can affect wiring on coils, which can then overheat and mess up the solder jioints on the DME. Pulled cased apart on DME but was afraid to break it so I didn't remove the bottom panel. Threw it back in the car. I noticed it was very warm even though the car had not been run since the day before. It was hot inside the car, and car is black but that seemed odd.
Tried to start the car and now it doesn't want to idle and is misfiring badly. Threw in the AFM I got from Mario, no difference. Threw in a used coil pack that I bought a while ago, no difference. Tonight I will swap out the plug wires that came with the used coil pack - maybe I'm lucky? Wires in the car are originals I believe (160K mi).
Also car has required quite a bit of cranking before firing (7-8 seconds). Been doing this since winter.
Might see if Mario has another DME - he is a bit of an M42 parts hoarder. Other than that, any suggestions? It is bumming me out...:(
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That could be lots of things. Could also be one (or both) of the temp sensors - if the DME thinks the motor is warmed up it'll run far to lean a mix on cold start.
Could be a weak fuel pump or FPR too - I'd test the fuel pressure. Should be about 40psi IIRC. If you can't properly tee into a fuel line, dead-heading the pump should read up to about 80psi.
The DME has this irritating plastic pin that keeps the shell together. I also tend to break the little metal tabs every time I open one up, no big deal. Internally, there are also these strong metal spring clips that secure a plastic spacer on the coil driver transistors - carefully pry them off. I'll post a pic or three if I get to it over the holiday.
Any stomp test codes?
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Tonight I will swap out the plug wires that came with the used coil pack - maybe I'm lucky? Wires in the car are originals I believe (160K mi).
I don't think I've ever let a set of wires go that long
If it's not Ignition/elec related, or injector/fuel related... it sound's like when I broke an exhaust cam on my DOHC nissan years ago
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Stomp code from when CEL flashed on Saturday was 1222 (when car was idling...I noticed it when I got in to drive). After messing around yesterday no codes just 1444.
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The DME has this irritating plastic pin that keeps the shell together. I also tend to break the little metal tabs every time I open one up, no big deal. Internally, there are also these strong metal spring clips that secure a plastic spacer on the coil driver transistors - carefully pry them off.
Okay so here's a pic. For the plastic pin I imagine it is the white piece of plastic right above the upside down "20" on the circuit board.
For the coil driver clips I imagine those are the bronze looking clips on the left and right sides - looks like they have a black magic marker mark on them. Am I correct? Do these just lift/pry off? If these are the driver transistors I should look for breaks in the solder joints on the back side of the board, right? If I have to solder should I somehow ground myself?
(http://i112.photobucket.com/albums/n200/petebee/SAM_0715.jpg)
I plan to test the spark plug wires (after returning coil pack and AFM to former pieces) and then check for continuity on the crank/cam sensors.
How many temp sensors do we have? I remember the one on the side of the head. Any specs for testing (continuity on the sensor, voltage on the wire)?
I'll try to get a fuel pressure gauge hooked up somehow, too.
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Yup, just pry those clips up and off. They're really on there as they provide a heat sink. There are a few, you're looking for four identical ones with three leads...those are the coil drivers. Bad coil drivers I had looked visibly burned out.
There are three temp sensors in the e30 M42. On the motor is the temp gauge sender, the DME temp sender and then the air temp sensor in the AFM.
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The more I think about it the more I begin to suspect the engine/coolant temp sensor. If that sensor is off, it will give a bad reading to the DME at different actual states of engine temperature:
- if engine is cold and sensor is giving a false warm state (lean) it would make it harder to start since the cold engine is not getting enough fuel; this might be why it cranks so long and why the car was running a bit crappy at initial cold start
- if the engine is super hot (a la auto-x or high speed highway run) same bad reading might be giving too much fuel and floods engine; once engine cools down it starts
- unfortunately right now engine doesn't want to run at all while cold; have to keep feathering throttle to keep it going as it won't hold an idle without stalling; revs crappy enough so that it really can't run
That darn second sensor is buried under the intake, making it impossible to test at various temp states. I can't find any real useful posts on the impact of a wonky coolant temp sensor.
Thanks for the tips on the DME and the coil drivers. I might see if someone has a spare DME and pop that in as a test before going forward with the temp sensor and fuel tests. Process of elimination!
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Going to test fuel pressures this weekend (cold, warm up and hot start)...some on R3V think it might be a wonky fuel pump.
If fuel checks out I'll start testing coil packs and digging into the DME.
Big bummer...found a bunch of rust in the tube that the fuel vent hoses run through :(
Other than the bottom of the battery box this is a rust free car. Now I'll have to drop the fuel tank to fix this rust. Yuck. First have to figure out why it's acting wonky.
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I have a spare DME if you need to swap it out. Problem is that the coils and driver tend to fail as a pair. If you replace the DME, the bad coil will kill the driver again.
I'm hoping it's a bad CLT sensor, they're cheaper than pumps.
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Tested fuel pressure. Initial setup I had the gauge hooked up to the return line...read zero pressure and no fuel in the line even though car run. Hmmm, suspected something.
So switched to the feed line and I have a whopping 11psi of fuel pressure. Guess it is time to bit the bullet on a new pump.
Worth it to try test/jumper the relay before I commit to a pump? Which plugs should I jump if so? (30 and 87 I think)...middle relay in the trio of relays under the cover, right?
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Yep, that's the drill - short 30 & 87 on the middle relay socket to power the pump.
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So jumper the relay and car performs the same, so it is off to buy a pump.
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There's also a substitute pump that you can wire in, I know that thread is around here somewhere...
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There's also a substitute pump that you can wire in, I know that thread is around here somewhere...
Found out one of my buddy's had a correct sized "wire in" unit from Airtex. Read that these are not the greatest quality, but what the heck...
Well installed it after soldering in new pump now it doesn't start at all :rolleyes:
I might have the wires crossed but felt guilty that I was putting a junk part in the car. So I bit the bullet and ordered the OEM VDO entire fuel assembly unit. I just don't like putting shady parts in my car.
Fingers crossed it works.
I am also sad because I found bad rust in the fuel vent line piping that runs from the rear fender into the car. Must have been from years of road crap accumulating under the cover. Now I have to cut this out and repair it, but will wait until the clutch job (will require dropping tank and removing vent lines to correct properly...oh well).
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Okay so the free Airtex pump was a big fail...so I bit the bullet and plunked down $250 for a brand new VDO OEM complete pump unit.
Put it in the car and vroom! Man the car must have been running crappy for a while because it feels like a rocket (okay so I might exaggerate).
I must have done something to my wiring as the tach now doesn't work (used to be jumpy) and the interior lights are not working. Everything else okay.
Plus put in a set of black vinyl sport seats I picked up from my buddy Adam and now I am a badass :p need to get a matching black bench for the rear...
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Glad to see it sorted. The tach is odd, I'd figure the speedo would be out instead if you were working in the back of the car. Mine tach was dead once & it ended up being a fuse (wish I could recall which one it was).