E30 Starts Effortlessly When Cold, But Only Cranks Once Warmed

[hoodhippee]

I’ve recently finished installing the 325i Intake Manifold, 325i Throttle Body, a CAI, 3.0 Bar FPR, e30 325i injectors, and an eBay performance chip on my 87 325e. After having to replace some vacuum lines and gaskets, I was finally able to get the car started and running pretty well if I do say so myself. (Don’t Care if You Think these are “Useless Mods”, I can definitely feel a difference) but recently I ran into an issue where once the car is warmed up after driving it a while, I go back to start the car and it simply just cranks. Sometimes it will catch and surge to 1500rpms but stepping on the gas seems to do nothing in those situations. If I play with the screw on the ICV, I am usually able to get it started, but the ICV is functioning as its supposed to as far as I know. Any ideas what the issue may be ? I have already thrown enough money at the project and I don't want to be guessing anymore. Everything I read says it MIGHT be the fuel pump, or that it MIGHT be the check valve. Ive also been told it MIGHT be a leaky injector. My dad told me it may be the ICV, but when the key is in the “ON” position I can feel it buzzing. Any definite answers or do I have to just keep guessing ?

[TobyB]

You have to do some diagnosis.

You need to figure out WHY it's not hot- starting.

There's spark- do you have it, hot, and is it at the right time?
Diagnosis is with a timing light, cranking, when it won't start.

There's fuel- do you have it hot, and is it enough, or too much?
This one's a little harder. It starts with pressure: 3 bar, across the regulator hot?
Then injectors- getting signal? flowing fuel? NOT flowing fuel when NOT getting signal?
Then pulling plugs- are they getting drenched?

You're overfuelling the car- it's not a bad GUESS that it's flooding, hot.
It does the 'restart' fuelling based on stock pressures and flow rates.
A quick way to test that is to try to restart with the throttle floored.
And to see if it's drenching the spark plugs when it's not starting.

t

[ADEN]

If you moved from low impedance injectors to high impedance aren't you supposed to go v1.3 ecu?

[hoodhippee]

I will run some tests probably tomorrow. I really appreciate the feedback and you are more then likely right that I am over fueling the engine. I’ve already swapped back in the low impedance injectors and tommorow I will put the 2.5 Bar Regulator back to see if it makes a difference. This is my first project car so I obviously have a lot more to learn and understand.

[jeffnhiscars]

Your injectors and ecu have to match your harness, sensors etc. e has a cold start valve and thermotime switch etc etc.

[hoodhippee]

Update: I solved the problem and it turned out to be a bad fuel pump. The problem immediately went away after replacing in line pump for any future viewers. Also as mentioned make sure your injectors match up with your ecu.

[It's Soda Not Pop]

A Bad Main Relay will act up when hot and cause hot starting issues as well. Ask me how I know.