hard warm start

[owenjm]

Hi there
Hope someone can help, the problem is on an 89 325i starts right up cold, drive some where turn off let sit 30-45 mins cranks for 4 to 5 seconds before firing up. now if you turn it off and restart within say 5mins it fires right up.
checked temp sensor, changed coil and afm. did a scan on it, everything tests good and engine light has not come on at all. other than that car runs excellent.

Owen

[jlevie]

That could be leaking fuel injectors that are flooding the engine when it sits for a while. Pull the injector rail, jumper the fuel pump rely to pressurize the system and see if the injectors drip.

[owenjm]

thanks I will check that, however when it does start it doesn't smell rich.
I thought about just having the injectors cleaned to rule them out

Owen

[emi325i]

mine does that every now and then, and it has new injectors. All 3 e30's i had did that with good injectors. there's a check-valve fuel line retrofit you can perform to fix this problem, but I wouldn't call it a problem.. it's more of an annoyance.

[jlevie]

A bad check valve would also cause a problem on a cold start, which isn't happening here. So I doubt it is involved.

[backtrail69]

Leaky injectors.

[owenjm]

is that check valve fix a dealer item. I talked to the previous owner and she said it has been that way since she bought it 50k miles ago. the car now has 137k on it. they changed the dme, fuel pressure reg,coil,fuel filter and gas cap. and said it made no diff.

Owen

[owenjm]

ok fuel pressure is 39.5 psi running if you pull vac. line it goes to 44psi.
shut off and let sit an hour and it was still at 39 psi, still cranks about 5 seconds to start. pressure direct from pump was 75-79 psi.

Owen

[kamotors]

i had the same problem, it was because i had a broken thermostat(stuck open),i had good fuel pressure, i thought my fuel injectors were leaky but they weren't,bought a new thermostat for other reasons and it fixed all my problems.

[scabzzzz]

There is a section in the Bentley that lists numerous possibilities for hard warm starts. You should check that out. Its in section 3.

[Stanley Rockefeller]

lemme know how this goes, as I'm faced with the same prob on my e30

my car has had:
rebuilt injectors, new thermostat, fuel filter, air filter, starter...(you name it, it's got it) and still it suffers from the hard warm starts.

[owenjm]

Just installed new fuel pump had the injectors cleaned and flow checked
no leakage before or after cleaning, no change still starts hard warm.

recap, parts changed
coil
fuel pressure reg
thermostat
fuel pump
injectors
adj. valves
new breather hose


Owen

[DCColegrove]

Carbon build up on the intakes can do this...

also:

Funky O2 sensor
Intake Air Leaks
Worn or mal adjusted AFM

Then we get into to the weird shit...let me know if you need more info.

[owenjm]

tried another afm no difference. one thing changed when fuel pump was changed, now it starts the same cold or warm. cranks about 5 seconds
then starts up every time. tried a new bosch press. regulator installd when cold, system had no pressure. checked with bmw about inline check valve that use to be installed by dealer that could fix problem they said it is discontinued because they had problems with them failing and leaking gas.
anyone know of an inline one way valve that could be used for this.

[owenjm]

some progress ran car a few mins. turned off clamped pressure hose next to pump waited 2hrs turned to start at the same time released clamp. and it started instantly. now I will look for a check for sure.

Owen