car jerks at randomly need help

[u3b3rg33k]

oh and i had ngk's in my car before i switched a week ago to the bosch platinums. my cars running so rich that in less then a month after putting the brand new ngk's in, they were coated with black stuff and were little wet from too much fuel. im running m50 injectors.

Do you have an M50? It doesn't sound like it. Perhaps you should be running 14# injectors?

[88e30dippin]

oh and i had ngk's in my car before i switched a week ago to the bosch platinums. my cars running so rich that in less then a month after putting the brand new ngk's in, they were coated with black stuff and were little wet from too much fuel. im running m50 injectors.

[88e30dippin]

the platinums all i could find at the moment around the local part stores. the recommended was bosch coppers but i couldnt find them. the gap of the spark plugs are fine right now. i have changed out my afm to a 325is one because its all i could find. i think my crank angle sensor is bad because the wire coming out of the sensor is lose and you can see the wires which they are not supposed to be showing. so im guessing i need the 2.7l 325 afm, a new crank sensor and the original 88 325 2.7l 5 speed ecu. if that doesnt fix it then im going to put a 2.5l head and run the 325is computer and afm.

[u3b3rg33k]

so i have replaced my afm with 325is one. i have replaced my spark plugs with bosch platinums and gapped it to .030 instead oem .028 because im running more fuel and air into the motor now. im starting to think my problem is either the idle control valve or the crank angle sensor. unless its because im using a e34 m20 ecu? im getting sick of this problem.

Why are you running platinums? Run recommended plugs at the recommended gap if you're having a problem.

Again, by what logic do you blame the ICV? it's after the AFM, so if it fails closed, you'll notice nothing while cruising. if it fails open, you'll have a high idle or less engine braking, it will not cause the car to buck or stall when you have your foot on the gas pedal.

[JLegleiter]

Long time...

Anything causing bucking and sputtering should drop a code. Have you mashed the pedal?

I have experienced these same symptoms from the following (Edit) four things in the past:
Bad Main Relay
Bad Fuel Pump Relay
Faulty Evaporative Purge Valve
A deteriorating C101 connector under the intake manifold.

AFM, DME or CPS as others have said are also culprits.

On a side note, those platinum plugs are shit. Go for NGK or ordinary Bosch coppers.

[hotballs]

With my experience of having a car that, for the most part, runs well and normal but on occasion, "bucks" or sputters slightly then goes away, it's either the main relay for the computer or the DME itself. Swap out both with working units and let us know what happens.

[88e30dippin]

so i have replaced my afm with 325is one. i have replaced my spark plugs with bosch platinums and gapped it to .030 instead oem .028 because im running more fuel and air into the motor now. im starting to think my problem is either the idle control valve or the crank angle sensor. unless its because im using a e34 m20 ecu? im getting sick of this problem.

[mkcman17]

okay, my problem has come back worse now. it seems like when i'm starting it cold, it will get stuck under about 1200 rpms until it's at full operating temp. it's really getting bad...esp if i have to cruise around driving like a goon for 20 until i get it hot enough. any help here? i have never experience any sputtering after full warm up, only when starting after sitting for more than a few hours. basically, it'll rev up to about 1200, then sort of revlimit itself out there.

[88e30dippin]

i haven put in a 325is afm in today. car runs great. no check engine light but i have the sputter thing still. i might have a bad crank sensor. im going to replace it and find out. if that doesn't fix it then my last try is the icv.

if that don't fix it what else could it be?

[88e30dippin]

i replaced the oem afm that was bad with an 87-93 525i afm. would it give me issues?

[88e30dippin]

i have replaced the oem 88 325 seta afm with a different afm and now it runs better and doesn't jerk (but its only been a day since i put it in so idk if it will jerer k still). but my check engine light is on. it came on after i put the afm on. i will look at the model number and post it up here incase im using the wrong year afm on my 88 325 s-eta.

[88e30dippin]

okay i will be giving the arm idea a try. hopefully it works. i have found a good used 325i afm and icv for 60 bucks for both. if i can get a for sure on the m20b25 and the m20b27 afm being different, then i will not buy the 325i afm. i will search for a b27 one instead to be sure that i have the right afm.

[scottinAZ]

I think the AFM is different between the types, so that does make it a bit more challenging. I would pop the black cover off of the AFM and check operation of the wiper. If the tracks are shot, adjust the height of the arm on the shaft up SLIGHTLY and this will get you to new carbon track. DONT GO TOO FAR as that will cause more problems than it solves, TRUST ME. Hope this helps

[StereoInstaller1]

Unlikely that would be the main.

AFM is what I would check first.

Swap with a known smooth car, only thing I can say is I don't know if it is the same as M20B25

[88e30dippin]

so the car is a stock 1988 bmw 325. its got the s-eta motor. m20b27 i believe. all stock besides 325is throttle body and 93 m50 vanos injectors.

i took the advice and cleaned the icv and afm. now my car jerks more. idk what this issue is but it just got worse. my throttle response is awesome. after cleaning, now it does a weird thing where after driving on the highway and it does the jerk thing, when i come to a stop the idle freaks out a little. jumps from 800 to 500 jerkingly like its about to die then goes back to 800 again. so could it be the relay that stereoinstaller1 is talking about or the icv?