Engine failure/problem help, PROBLEM SOLVED on 9-2-11, thanks

[schtozo]

Hi, today i started the car and drove like 20 minutes without any signs of problems from anywhere, shut the engine for like 20 minutes to change a flat tire for my wife on her car and then when tried to fire my e30 it fired but kinda sputtering/stalling/shaky. All of a sudden. The car wouldn rev past 2-2.5k. I shut the engine and double checked on all plugs and sensors i the engine, everything seemed to be fine, i tried to fire the engine again but this time was successful, i drove like 20 minutes with no problems at all. All this with no check engine light at all. My ecu is ebay chipped/ spark plugs are less than a year old.
Any thoughts?

[LJ851]

Crank position sensor. My car had random symptoms just like you describe and eventually wouldn't rev past 2500 ever. I loosened up the sensor holder and shifted the sensor as close to the pulley as possible and then it revved to 3500. New sensor fixed it. Could be your problem.

[mrsleeve]

CPS would be my 1st guess. MAF and Temp sensors can do weird shit like too when they start to go and are sending outta range shit to the comp.

[schtozo]

Ok guys did some more testing, i changed between three different 173 ecus i have laying arround, it did the same in all of them, its reving fine however but aint holding at idle, it just die. Turning the AC on helps a lot and holds the rpms at idle and the engine wont die. Any help? Icv?

[KirkerBezerker]

Did u check the cps?

[Zasz]

Check the cable that goes from your AFM to the computer, that's what did that for me. Also, throttle cable.

[schtozo]

Did u check the cps?

i already ordered a new one, assuming its that but still did not get it, any ways it was cheap, but is there a way to check mine?

[AnimalE30]

Ok guys did some more testing, i changed between three different 173 ecus i have laying arround, it did the same in all of them, its reving fine however but aint holding at idle, it just die. Turning the AC on helps a lot and holds the rpms at idle and the engine wont die. Any help? Icv?

Turning the AC on raises your idle to compensate for the drag from the compressor. If this is helping your problem you may have an intake leak or bad icv. I'm not sure if the tps plays into this tho.

[schtozo]

Turning the AC on raises your idle to compensate for the drag from the compressor. If this is helping your problem you may have an intake leak or bad icv. I'm not sure if the tps plays into this tho.

Thats what i thought too, anyways im waiting for my new cps and tps that i ordered, might want to check the icv too. Thanks guys, all this happened very suddenly with no prior warning at all.

[E30_fiend]

I too think your icv could be the culprit. Usually, the crank sensors slowly get worse. They dont just stop working. I would also swap to a known good AFM.


Taylor

[schtozo]

I made some tests today.

1- starting the engine cold made the revs kinda jumpy from 600 to 1200 rpms. When engine warmed up it acted a bit better.
2- i disconnected the icv and the engine didnt notice it at all which leads into thinking that its the culprit part?
3- i disconnected the flowmeter and the engine started but with a huge failure. And the check engine light came on. So i assume thats because i have a working afm?
4- turning the AC on helped with the idling at low rpms and it held better.
5- turning the AC off make the engine die when i open the throttle and let go.
6- i have to play with the throttle position to maintain the engine running with the AC off.

What is it guys, ICV?

[F34R]

It sounds like the ICV, if the CPS was bad I doubt it would start. Check for cracked intake boot and vacuum lines.

[ZM Blue Devil]

try this...

pop hood
start car
while the car running
wiggle the injector wires while revving the engine

[schtozo]

try this...

pop hood
start car
while the car running
wiggle the injector wires while revving the engine

Ill try it tomorrow, but what should i look for doing that Levent?
Ill. See if luis have any icv i could borrow and check that too.
Thanks L.

[ZM Blue Devil]

wire crack and dont make good connection, if you wiggle and the engine revs differently you know to keep looking in that area.

call me tomorrow if you need help while doing it.