My Hard Cold Start Dillema: Solved!

[bcrdukes]

So, I bought my E30 with the symptom of a hard cold start issue. I did everything from swap fuel injectors, cold start temp sensors, cleaned the dreaded C191 plug, charcoal canister, vacuum hoses, valve adjustment, timing belt, fuel pressure test, vacuum smoke test, fuel pressure regulator, ICV, AFM - the whole works.

But I forgot one thing: fuel filter!

Took it out today - it was installed the wrong way! I don't know which shop or who did it but the arrow was pointing away from the engine. Took it out, swapped in a new one - fixed!

What gives!

New fuel filter


Old fuel filter (It looks original?)


Moral of the story: When troubleshooting, go over all the basics. FML. :D

[evil_twin]

Hmmm, a backwards fuel filter would make a hard start when cold? Weird.

[bcrdukes]

That's what I thought too, hence why I overlooked the fuel filter.

[bcrdukes]

Come to think of it: I spoke too soon.

If I let the car sit for ~1 hour or so (give or take 15mins) it'll have a hard time starting. I get the feeling my injectors are leaking and flooding the cylinders. Pressure goes from 3bar to ~1bar after about 45mins to an hour.

Should the injectors be "rebuilt" or replaced with new ones?

[m20technik AZ]

Im still having the same problem.. I hope a new FPR will fix it, thats what i think it is.

[thereisnoyun]

guys I would like to share that I too had hard start issue on my cab. for the longest time I was thinking injectors, fpr, fuel filter etc. Needless to say, its none of the those. Two weeks ago I blew the house that goes into the throttle housing, and coolant spill over the gasket, I disassemblethe entire housing, and cleanout hte throttle. Well, now it fires up like a champ everytime. Check that just my own experience.

[m20technik AZ]

guys I would like to share that I too had hard start issue on my cab. for the longest time I was thinking injectors, fpr, fuel filter etc. Needless to say, its none of the those. Two weeks ago I blew the house that goes into the throttle housing, and coolant spill over the gasket, I disassemblethe entire housing, and cleanout hte throttle. Well, now it fires up like a champ everytime. Check that just my own experience.

Interesting. My car finally decided to not start at all, after I stopped to put some gas in it this morning. I dont think its a spark issue, and I can smell fuel when it cranks, so I was hoping there was some other issue that would cause a no-start... IIRC, there was some coolant around this area you speak of.. near the throttle body.. I got it towed to a garage nearby, I know the owner so he should be honest with me with whats going on... Im calling tomorrow to see whats up with it.

[evil_twin]

fuel pump?

[m20technik AZ]

I got a new fuel pump installed today. Its getting fuel but not starting still. Blah

[ahlem]

Got spark at all the plugs? How old are the plugs? Try changing them anyway. Once they go bad they stay bad. Harbor Freight spark checker is cheap.

[bcrdukes]

Problem is officially solved!

Swapped in the new Bosch Design III injectors from Five-O Motorsport - now the car starts up every time and is SO much more smoother.

Unless I get the original injectors ultrasonically cleaned, flow-tested and rebuilt, I'll never know what was wrong with them.