Little Help Please

[benbimmer357]

Hey All

New to forum but not new to BMW's. I have had my fair share of them over the years, 3 - 3series, 2 - 5 series and 1 - 740. I bought my first M42 1993 318is a few weeks ago as a project, it wasnt running when I got it and have had some trouble getting it started. Seems to want to start - turns over and back fires into the intake. Here is what I have done so far:

New Plugs and wires
Switched coils out with tested working coils
Both cam shaft sensors
Switched out ICV with working one
switched out DME and fuel relays with working ones
replaced all vacume hoses under intake
Used working ECM
Replaced fuel injectors with bosch
Fuel pump replaced by PO
Mann fuel filter
Drained the tank and put 4 gallons of fresh gas with octane boost
Checked compression in all cyl - good -even

All this and still no start....
My questions are....

ECM - do I need to switch out the chips in it to make it work on my car? Same part number same ecm...

When I replaced the cam and crank sensors I did it at the same time and they have the same plugs - can someone tell me which one plugs into what so I can verify I put them in the right way?

Can you really hear the fuel pump on starting on these cars? I cant seem to hear it work but I checked the lines before and after the filter to see if I had fuel coming out at start up which it did...

Thanks so much for your help! These boards keep me in the cars I love without them I would probably be driving a honda....

Ben

[DesktopDave]

I had to approve your post, sorry if you didn't see the changes right away.  Spam filter is tough here.  Welcome to the 'club!  Hopefully we can help get your car running!

Sounds like you're really close, you've already replaced all the right stuff.  IIRC, the fuel pump will pulse some fuel once but then will turn off until it gets a signal off the crank sensor.  If that signal is wrong (for instance if the sensor is in the wrong plug), the car won't start.  You can test that by jumping the fuel pump relay socket pins 30 to 87. With the jumper in and the key in ignition pos II you should hear the pump running.  I'd also test the resistance on both sensors.  Crank should be 580-ish ohms, cam about 1200-ish.  Do you have the ETM?

ECM/ECU/DME will work, I think they're all the same until BMW started with that idiotic EWS (late 94?).  I'm pretty sure the red label units all work.  Silver label units have to be "aligned" with the keys & chassis.

I don't recall offhand how to identify the wiring harnesses, but I know for sure on my car that the lower plug in the wiring plenum is for the crank sensor and the upper plug is the cam sensor.  BTW, when I got my car it wasn't running either.  I had to clean the crank sensor and the mount.  If it's a little too far away from the trigger wheel it won't work well.

You should also be sure you didn't swap the fuel lines into the rail.  They're easy to put in the wrong way.  IIRC the feed line is on top, and the return is underneath.  However, they're hidden by the intake manifold.  I'm not 100% on this, but the inner line should be the return line off the FPR.

There are a few other things I'd check:
Your key cylinder might be worn or broken.
Vac leaks are really common, and they can keep the car from running.  I put silicone lines in my car to solve the issue.
The early e36 had a problem with the DME getting flooded, BMW added another drain to resolve that problem as a dealer TSB.
Finally, is your cam timing right on?  The cam gears tend to strip from worn guides/weak tensioner & the chain can jump time, causing all sorts of havoc.

[benbimmer357]

Thanks so much for the added information. I will try that with the fuel pump and relay....

I forgot a few things....
New chain tensioner - other one was shot

Also pulled the VCG again to check cams - turned it to TDC and the cam lobes seemed to be allignes as well as the arrows - does anyone have a good picture of what this should look like. The bently picture is a little vague.

My ECU is a green label - Does that still hold true on the chip?
I pulled the original one and tore it apart found some minor issues and cleaned it, it did not look like it had gotten wet.

I am pretty sure I got reattached th ecoorect fuel lines into the rail - very little slack there... Could the PO not attached them correctly to the fuel pump? Is there a way to check that?

Dont know what "ETM" means, can you elaborate?

Thanks Again!!
Ben

[benbimmer357]

Checked the fuel pump for power through the relay worked fine, even found a small fuel leak. Switched out the chips in the DME just in case. Check the fusible link - good. NO start exactly the same thing wants to start backfires in the T Body and nothing....

It sounds to me like its timing but I pulled the VC off and checked it at TDC and it looked correct. I replaced or swapped about everything imaginable and still no start!

Any help would greatly be appreciated, this has been my MOST frustrating projects yet!:mad:

[DesktopDave]

OK, so fuel pump checks out, DME looks OK.  Green label is the same as the e30 IIRC.  

I'd run a compression check on the motor if you haven't done that yet.

ETM is the electrical troubleshooting manual.  Priceless bit of work.  I have a copy of both the '89 325i and the '91 318i/is in my car.  You'll need both as the '91 is missing some info.  http://wedophones.com/BMWManualsLead.htm

[benbimmer357]

I will have to get the ETM book....

I did a compression check came out 150-160 on all cylinders.

I also cleaned the area around the new Crank Sensor

Any other suggestions?

Thanks again for the help!
Ben

[DesktopDave]

Sounds like you've covered all the bases.  Next thing I'd check is to be sure the timing is right.

I have a hunch that maybe the coil harnesses are incorrect.  Are you 100% sure the correct coil harnesses are plugged in 1-2-3-4 to the same wires to the same coils?  The stickers fall off the plugs and if they get swapped the car will not run.

[benbimmer357]

Yup on the spark plug wires - I even pulled them out of the channels to make sure I had the #1 plug wire from the front of the engine to #1 front of the coil - #2 wire to coil #2 and so forth... that is correct 1234 front to back on both coil and engine right?

Here is what I did today:

- Checked for spark - had it in all 4 coils - is there a way to check the strength of the spark or does that reallly matter?

- Pulled the plugs (new) to see if they were wet - they were

So it looks like I have spark and fuel but still no start....

Any other ideas - I think I may start reversing what I have done and check for any electrical connections or vacume hoses that I may have not plugged back in or hooked up properly.

I am utterly stumped and frustrated... any help would be greatly appreciated

[DesktopDave]

Yep, that's right...1-2-3-4 from rad to firewall.  All have to match.  What I was talking about is the wiring harness from the DME to the coil packs...are you sure those are the 1-2-3-4 harnesses to match the packs & cylinders?

[victor.askew]

Use a inspection mirror and check under the intake manifold to ensure it is seated correctly and is flat aginst the gasket and isnt cocked. The back firing into the intake leads me to think there may be a very large vacuum leak present in this area. Good luck.

[benbimmer357]

Okay... pulled the intake off AGAIN.... no loose vacume hoses all plugs seem to be plugged in properly, One thind I did notice was some gas in the lower intake - could that be a fuel pressure guage issue?

I installed the bosch (yellow) injectors - I am debating on putting the old ones back in and see what happens... Any thoughts - I am running out of things to do....

Thanks!
Ben

[benbimmer357]

Sorry. fuel pressure regulator...

[benbimmer357]

Replaced the fuel regulator sucked the extra gas from the bottom of the intake, put it all back together and............................. NOTHING! Still the same almost wants to start but doesnt - I guess if I have no other feedback I am going to start working backwards. Frustrating to say the least!!!

[DesktopDave]

Are you sure the coils are correct off the DME?  Not from coil to plug, but from DME to coils?  I'd do a continuity test just to be sure.  Here's a pinout...you can be sure the cam & crank sensors get to the correct connector as well:
http://www.m42club.com/forums/showthread.php?t=1622

Gas in the intake is a very odd symptom; I still think it's not timed correctly.  Your compression # look good and you said the cams are timed properly, so it's unlikely to be the motor.

[bmwman91]

You might be surprised at how much timing error the car will run with. Back in 2005 I was being a dumb 21 year old & rushed putting the timing case back together. The crank was 1 tooth off of TDC relative to the cams...let's just say that the car will run surprisingly well with pistons hitting valves!

Dave, if you are thinking that maybe the crank & cams are 180 degrees out of phase, I agree that benbimmer should check that. An easy way to check that is to:

- Pull valve cover
- Turn crank with ratchet / 22mm socket until cylinder 1 cam lobes face up & toward each other (the square ends of the cams by cylinder 4 will have two small holes drilled in them, and these faces should be up & approximately parallel)
- Pull out spark plugs for cylinders #1 & #2
- Get a small dowel and stick it in the holes until it hits the pistons. #2 should be >75mm lower than #1.

If you find that #2 is at the top & #1 is at the bottom, then the crank is 180 degrees off. You CAN remedy this without pulling the timing case covers, but you must be careful to not ram pistons into valves. Basically, remove the cam sprocket bolts & rotate the crank to #1 TDC & then get the cams aligned to TDC & bolt it back together. There's an access port in the back of the block where an 8mm bolt can be used to lock the flywheel at TDC.

Remember to only turn the crank in the direction that it goes when running (clockwise, when standing in front of the car looking at the engine). The chain can bind up and cause timing errors otherwise.