Long start when warm?

[blacksport325]

I hate to keep bombarding the gen. tech. with questions, but on my 91 318is, I am getting a long crank when the engine is warm, it will start after about 5 seconds of cranking. The battery WAS bad, I just replaced it and I can hear the starter moving faster than before but it is still taking 5 seconds when the engine is warm. When it's cold it starts up as expected (<1 second), I have visually inspected for torn intake boots but didn't see anything, I will attempt to smoke test it this week to make sure but when I sea-foamed it a few weeks back I didn't have any smoke in the engine bay.

I can hear the fuel pump kick on for a second of less when turning the key but I don't smell gas. Could this be a fuel pressure regulator issue as well? The car has new plugs, I guess it could use plugs but something tells me this is a vacuum/fuel issue.

Thanks in advance.

[Balleristic31]

My guess is FPR. Mine did this same thing. Try putting the key in the "on" positon for like a second of two to let the pump fill the rail with fuel, this eliminated my long starts because I didnt have to wait for the rail to build pressure while cranking.

[urbancynic]

I had this in an 86 325e.

I replaced the fpr, both fuel pumps, and eventually the coil.

Turned out it was the coil.

To eliminate wasting money I would break out the bentley manual and start doing tests on the fuel system and the coil and replace whatever is questionable.

In my case the coil was still in spec, but only marginally.

[blacksport325]

I tried turning the key to let the fuel rail fill and start, no change. Maybe it is a coil/spark...

[Kershaw]

might be the starter dying. when its cold its fine, but when the engine bay heats up (and the starter with it) it wont work well.

[nando]

My guess is FPR. Mine did this same thing. Try putting the key in the "on" positon for like a second of two to let the pump fill the rail with fuel, this eliminated my long starts because I didnt have to wait for the rail to build pressure while cranking.

only 318is's with the M42 prime the pump. all other E30s only turn on the pump when the ECU sees an RPM from the crank.

[blacksport325]

only 318is's with the M42 prime the pump. all other E30s only turn on the pump when the ECU sees an RPM from the crank.

I've got a M42, so it should prime when the key is turned to ON and not START? Does this mean it is still possibly a FPR issue?

[blacksport325]

So, I can narrow it down to the point of when the engine is warm and turned off for only a few minutes it will start as normal (i.e. getting gas), but when its left for 10+ minutes or so it will take awhile to start. Does that rule out anything? Still sounds like a FPR, I might as well try it.

[kalib0y]

^ have you figured this out? I am curious

[blacksport325]

Not yet, i'm going to look at it today, probably check fuel pressure at the rail when its warm, i'm pretty sure its a FPR though.

[blacksport325]

I did find a cracked hose running from the intake hose to I'm guessing the crankcase or throttle body? I'm not sure if this would have an effect when warm, but i'm going to look around at the other hoses today to make sure I order all the parts I need.

[urbancynic]

Sounds like exactly the same problem I had. I had a long start when warm or cold. Only would fire right up if it had only been off for a few minutes.

I replaced the FPR to begin with with no change.

Replaced the in-tank pump with slight change, but not enough.

Replaced several hoses with no change.

Finally replaced the external pump and the coil and the problem was gone.

[kalib0y]

I found out it was my starter solenoid so I replaced my starter and its all good now on my s50 swap

[blacksport325]

The coil seems to be a recurring theme here, maybe I will try to swap some in to see if there is a difference.

[urbancynic]

The coil seems to be a recurring theme here, maybe I will try to swap some in to see if there is a difference.

If you have a Bentley manual follow the test procedures. Mine tested barely within the limits, but it was still a problem.

Had that issue on an 89 GTI too. The coil was part of the problem on that one.

If you can, test first. buy parts when they are confirmed bad.