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View Full Version : Help me fix my car.....



jeds320i
11-30-2010, 11:38 AM
A couple weeks ago i posted a thread about my M50nv swap in my E21 and how its not running right. i decided to make a new thread to try and figure it out. If i cant seem to find an answer im gonna take it to bmw. Here are the things i've done so far:

All new vac lines secured and tight.
New intake boot
New crank sensor
New coils
New ecu temp sensor
Fuel pressure is perfect
TPS and intake temp sensors are good
New plugs

The problem still occurs and ive tried everything. When i first start it up cold, it idles at about 1k and seems to run fine. but after a couple minutes it starts to drop idle a bit and hesitate. It kind of hunts for the idle, goes between 750-1100 rpm by itself. it doesnt do this constantly, but once and awhile. otherwise its at like 800rpm and stumbles, sounds like its cammed. when driving in first gear barely on the throttle, it jerks real bad. After 2k rpms it seems to run perfect. But it doesnt pull quite like it should. My e21 only weighs like 2300 lbs and should be faster.

one thing i have to know is if i got the right ecu. im running a green label 405 but ithe engine originally came with a red label 402. Can this make a diffference?

Grantnz
11-30-2010, 04:40 PM
Oxygen sensor?

M Quick
11-30-2010, 04:56 PM
What engine does the green label 405 belong to? If it doesn't belong to that engine then i wonder why you haven't tryed with the red label 402 that you say is the original and came with?

Seems like you tryed everything, so why not get that off the list of things that's been tested, though i would hunt for all problems with that stock ECU.

How is your MAF? Have you tryed disconnecting it and then take the car for a drive? It should run on "safe mode" disconnected and run pretty much without jerkiness if that is the culprit.

CleanE34
11-30-2010, 05:07 PM
how are the coil packs? i know i used to have a loss of power when mine went.

M Quick
11-30-2010, 05:25 PM
how are the coil packs? i know i used to have a loss of power when mine went.


He has new coil packs :stickoutt

* New coils

To the OP; What plugs are you running btw?

lovinlyfe4dub
11-30-2010, 07:12 PM
EGR is were I would check.

jeds320i
12-01-2010, 12:25 AM
02 sensor is new. Im running E3 spark plugs. i would've used the red label 402 ecu but it didnt work for some reason. it was broke. so the guy i bought the m50 from had another ecu thats supposed to be for a nonvanos, so i traded him. Also, does anyone know what the cam sensor ohms is? my cam sensor reads 1.5 ohms. i just want to eliminate every possible cause.

NY Bimmers
12-01-2010, 12:32 AM
check the icv? definitely sounds electrical. +1 on the MAF also.