Running on 3 cylinders.. FML

[Lingurade]

so... i just got an 89 325is from an auction only knowing it had "mechanical issues" i got it and found out the timing belt snapped and the head was toast, after doing timing belt, water pump, pulley crank and cam seals thermostat, spark plugs and wires, cap and rotor new accessory belts the whole shebang the car wouldnt start.. after more tries it started and now it starts everytime but the catch is that is only runs on 1,3 and 5 i checked spark it gets spark on all plugs, the injectors are all pretty clean and in good shape but i used a test light and on the injector harness it showed that injectors 1, 3 and 5 get voltage and the culprit 2,4 and 6 don't.. sooooo the connector that plugs the whole harness to the injector harness had wires that were loose, reconnected them and still no good, ran a jumper wire across to see if it made a difference and still only running on 3 cylinders ive had people say it could be crank position sensor but that wouldnt make sense because i get spark all across, another friend said vacuum leak? still doesnt make sense the car runs good just only on 3 cylinders lol compression is around 150 all across as well.. any thoughts? could it just be a bad injector harness? thats the only thing i could think of thats left.. please help me figure this crap out i need a car to drive! :sad:

[whodwho]

Usually corrosion in the connector but sounds like you looked at that, could also be the ECU

[jlevie]

Either there is a wiring problem or the Bank 2 control circuit in the DME is bad.

C191, the round connector below the intake, is vulnerable to any coolant leaks from the throttle body heater. The problem could be there, in the injector harness, or in the engine harness.

All of the injectors have a common power lead. The injectors for each bank have one wire that the DME grounds to fire that bank. A bit of work with an ohmmeter should tell where the problem is. You'll also need the wiring diagrams from http://wedophones.com/BMWManualsLead.htm

[Lingurade]

Thanks for all the ideas, i checked the ECU today and it all checked out.. i also jumped wires straight across the C191 and still no bueno, im going to try to find an injector harness and hope for the best, if not i guess ill be changing the harness :/ ill see what happens and post my results

[Lingurade]

ok so today i pulled the injector harness and checked it all out with a test light and also checked resistance and its fully functional.. i checked the ECU yesterday and it all looked good no burned up terminals or anything like that. i hate this so much. anybody really good at electrical crap wanna figure it out for me? :)

[Lingurade]

someone suggested the entire distributor itself could be bad.. any thoughts? ive changed the cap and rotor..

[Komzorz]

You don't have a distributor.

Also, how did you check the ecu? Just looking at it isn't good enough. I'd try swapping a known good one in.

Failing that, I'd do what jlevie says as his troubleshooting was spot on for me, although it took me like a year to figure it out. Coincidentally, my ecu was bad, although I had a different issue.

[bmwguy325is]

You don't have a distributor......

Pretty sure they do. Its a cap and rotor its still called a distributor. The only difference is instead of timing retard/advance be controlled mechanically the ECU does it.
However yes Id swap in a ECU just to see if the one you have is bad. You dont have to have burned up stuff for chips to go bad.

[TobyB]

well, shit, someone ripped me off... just changed the cap and rotor last weekend...

You say 2,4,6 don't have voltage- but all 6 should have 12 v all the time, and
the computer pulls the other side to ground to fire them. If you trace the wire back to the
ECU, check there to see if it's grounding...

http://www.wedophones.com/BMWManualsLead.htm

looks like you should see alternating ground on both pins 16 and 17.
If not, bad ECU.
If so, bad wiring- you could even swap pins 16 and 17 to see if the problem
tracks the wiring or the ECU.

hth

t

[Komzorz]

Pretty sure they do. Its a cap and rotor its still called a distributor. The only difference is instead of timing retard/advance be controlled mechanically the ECU does it.

Yeah, but it's *only* a cap and rotor sitting on the end of the cam. Distributing is taking place there, but there's no physical distributor per se. Unless you've got one of these setups, but that's a whole other kind of deal.

[Lingurade]

Well damn i have no idea forget what i said about the distributor thing then haha as for the ECU yes i only gave it a visual inspection i will check it further tomorrow and try to find a good ecu to swap in and check if possible.

[Lingurade]

got a good working ECU/DME today and put it in, still no difference.. :(

[Bmwb]

it sounds like an electrical problems , you should still check the crank position sensor even if your getting spark.. mine was defective yet my car started and... sounded like shit and was torn and basically half apart contacting to other wires, just because something looks like good dosent meen it is working properly

[Lingurade]

Hmm.. Not a bad suggestion honestly, ill probably replace it just in case and if that fixes it you sir get a really high five. Haha no but seriously thanks for the suggestion at this point any ideas are much appreciated

[JBedo]

I'd take a quick look at the crank pulley and make sure there is no damage to the pickup teeth.