Granitsilber Coupe: x-country warrior kicking it in SoCal

[thatphysicsguy]

I've had cats do that with switched-around plug wires, but your initial symptoms sound like CPS, not injectors

If it's CPS, wouldn't the car simply refuse to start? It goes through phases where it'll start and run without a prob.

[thatphysicsguy]

Ugh, Alex, I was a little worried when you said your car was wounded. This stuff can get fixed, but its also why you should have AAA plus membership. It really should be the first thing you buy when you have a E30 to daily.

Good luck getting it fixed. If the ignition side is good, then the other things to check is fuel and finally air. sounds like you're on the right track... though I would think the plugs would smell like gas

Yeah plugs were gassy but not coked or burned.

[thatphysicsguy]

Put on the green tops and the car seems to be running okay.

Going to change the oil and take it for an extended drive tomorrow to make sure everything's okay considering the worst of the problems come after driving for an extended period on the highway.

[thatphysicsguy]

well this morning the car refused to run well (again) with the same symptoms as before.

After more troubleshooting the suspects are:

-Fuel pump: replaced year or so ago when it was noisy. now possibly dying and not supplying enough pressure intermittently

-c191 connector under intake: I inspected the plug and both the leads and plugs were fine. I need to take the harness apart a bit more to see if there's any hidden corrosion.

-ECU: Might be this, but need to track down someone in the PHX area who can lend me a spare to find out if it's the culprit or not.

[thatphysicsguy]

Update:

Peeled apart the c101 and all the wires were fine: no corrosion.

Tested fuel pressure and everything is fine there

So all roads lead to ECU.

I sourced a unit and we'll see if it gets rid of the gremlin for good when I return to phoenix next week.

[TimKninja]

I had a similar issue on a customers M20 car.

ended up being an aftermarket CPS causing the ECU to freak out.

only install BMW CPSs

[thatphysicsguy]

I had a similar issue on a customers M20 car.

ended up being an aftermarket CPS causing the ECU to freak out.

only install BMW CPSs

CPS is original. I'll probably put a new one on too just to be sure.

[thatphysicsguy]

Boy am I glad I ordered that CPS.

It turns out that the wire coming off the CPS was rubbing against the Alt belt and it got frayed. This caused intermittent bad signal and thus my no-spark misfire issues.

Put in a 173 DME (I had a 251: They're interchangeable I guess) and still had the misfire. Looked at the CPS and saw the wire was frayed from rubbing and instantly knew what the problem was. Put the new one on, changed the oil and went on my way.

Car back to normal and driving great! Here's a couple shots I got on my way home. The best pics I've taken of my car so far IMO.





Now I have to leave it for 5 months while I go back to upstate NY to finish my undergrad. It will be a tough separation. If I have the financial resources, I'm planning on stiffening up the front end with a strut bar and thicker sway bar. Also in the market for a decent chip. But those projects are still a while away. For now my goal is to enjoy my car as much as I can before I leave on Thursday :[

[2mAn]

No cross country road trip this time?

[thatphysicsguy]

No cross country road trip this time?

No I don't want to bring my car to Troy for the Winter. I only have one more semester left so I'll make due.

[kronus]

told ya ;)

[thatphysicsguy]

I guess I'm still a after all...

:thankyou:

told ya ;)

[kronus]

eh, live and learn

glad you got it fixed!

[iwantspeed]

glad its fixed alex

[Kershaw]

Make sure you zip tie the CPS wires tight to the engine so it doesn't fray again. Glad you got it fixed.