Author Topic: E36 M42 won't start/stals if cam sensor is plugged (Read 6738 times)

SwayArt · « **on:** August 31, 2010, 02:15:55 PM »

Hi, I've a weird one on a 93' M42 E36, so has been replaced knock sensor's, camshaft and crankshaft sensors, and the engine only starts with high idle and coming up and down between 1000rpm and 2000rpm with cam sensor unplugged, if I plug the cam sensor the engine stals and gives a missfire with a big bang on the exaust..! And won't start with cam sensor plugged, just gives a 1 second work and stals with missfire on the exaust. I've checked every sensors, injectors, fuel pump etc this is weird cause she was running pretty well and become like this with no explanation.. AFM replaced, Idle valve replaced, engine temp sensors on the head replaced, double checked everything and no solution yet..!

Any suggestion?

DesktopDave · « **Reply #1 on:** August 31, 2010, 06:03:04 PM »

Check the timing to see if you've possibly skipped a tooth. Sounds like timing is off for some reason.

SwayArt · « **Reply #2 on:** August 31, 2010, 06:44:40 PM »

Forgot to say, I've done that too and it's correct.. :p

DesktopDave · « **Reply #3 on:** August 31, 2010, 07:33:56 PM »

What resistance does the cam sensor have?

Maybe try continuity and resistance tests on the wiring harness back to the DME to eliminate chafed wires. I'd test continuity between each wire and to the DME ground as well.

Let me know what a stomp test tells you too. I'm not sure where you're from...but all US OBDI M42s can do that. Not the best test, but better than nothing.

nicknikolovski · « **Reply #4 on:** September 01, 2010, 06:02:47 AM »

Double check your timing like DesktopDave said. Stalling and backfire are a common symptom of this. Also check your vacuum lines and fuel pressure (Check pressure at pump and then at fuel rail)

SwayArt · « **Reply #5 on:** September 01, 2010, 01:01:04 PM »

Cam and crank sensors are brand new, cam has 1250 and crank has 550. Timing is correct checked it twice, stomp test says 1444 all the time even when plug the cam sensor and stals it records nothing... It's an euro e36. Vacuum lines all new already check with carb cleaner spray everything nice, fuel pressure at the pump it's good, installed a new FPR and hasn't changed nothing keeps the same

DesktopDave · « **Reply #6 on:** September 01, 2010, 02:05:42 PM »

You've hit all my favorites. Did you check static timing on the crank trigger wheel? I have heard that the woodruff key fails on occasion & permits the trigger to be off. The high idle speed really has me puzzled. If timing was a little off on the crank, the idle might be high. Plugging in the cam sensor might be correcting the timing or changing the advance, then that stalls the car & causes a backfire since the plugs aren't firing correctly.

Not to be a prick here, you sound like you know what you're doing, but you have the coil packs plugged in to matching cylinders...1-2-3-4, right? From rad to firewall? I'm just trying to eliminate causes - not trying to insult anyone.

SwayArt · « **Reply #7 on:** September 01, 2010, 06:51:51 PM »

hmm you give me an idea, I'll replace the crank pulley tomorrow, the idle it's puzzling me too, If unplug the ICV the idle goes down but keeps going up an down but between 1000rpm and 1500rpm.
Yes the coils are matching the cylinders, thats no insult sometimes we just check the complicated things and leave simple behind! I've checked:
intake manifold, unassembled it to the bone to check all the sensors plugs and signals between the plugs and ECU, replaced gaskets too to eliminate any micro air leak that could possible exist, next tested every sensors the cam and crank were bad bot working just to eliminate possibilites I've replaced them with brand new ones same way but same result. Fuel pump, FPR and relay check, engine main relay, DISA, Knock's (replaced both with brand new) TPS, AFM, lambda, injectors, coils, spark plugs, engine temp sensors were replaced with new ones too, and tested with another working ECU.
I've checked the distribution chain guides and chain tensioner.

At this time it sound's like something were wrong on the internals bended exhaust valve maybe, but she's not showing signs of that just looks something wrong with the electronic, a hell of a mistery here!

nicknikolovski · « **Reply #8 on:** September 02, 2010, 06:41:26 AM »

What about checking your wiring from the cam sensor back to the ecu pin. Also make sure your cam and crank sensors are plugged into the correct connectors. They sit very close together so they are easy to mix up. (Unlikely but its good to check).

Another question: with cam sensor unplugged, does the engine take longer to fire. I mean does it crank longer than normal?

SwayArt · « **Reply #9 on:** September 03, 2010, 02:49:59 PM »

Nothing new keeps doing the same, already checked every wire back to ecu, the crank and cam sensors plugs on the e36 only fit on teh correct place, not possible to plug the cam sensor on the crank plug.. with the cam unplugged the engine doesn't take longer to fire, looks the same as always, can't get out of this I'll pull the head next week to check valves and compression rings.

SwayArt · « **Reply #10 on:** September 15, 2010, 12:46:54 PM »

Pulled the cylinder head, confirmed, bended 4 intake valves and 2 on the exhaust, going to fix it and will report as soon as she's operational again, will make some improvements this time since the head's out. Her last run http://www.youtube.com/watch?v=ZoxvNgaDOKs
after this pull I've parked her on the garage and didn't start again :p on the video on 4� gear could see some power loss after 5000rpm guess she was warning me of the bended valves :p this run was versus an E36 318is, mine has a few mods I would describe with pictures later,

cheers