Still trying to determine my slow start condition when the motor is warm. Fuel pump is building adequate pressure and the injectors and the filter are new.

Can a flakey FPR cause a slow start condition when the motor is warm? Cold start is not a problem.

 

yes. pull the vacum line off and if there is any sign of fuel on it...the FPR is bad

 

+1 on the test, if you see or smell fuel, likely the diaphragm for the fpr is faulty. Also what fuel pressure are you getting (prime, cranking, idle, WOT)? Does it hold or does it drop off to zero quickly?

 

Idle was around 39. WOT was around 43. Holds pressure steady for over an hour (engine off) but will bleed off overnight although that might be the gauge.

 

Sounds like fuel pressure is not your problem. Maybe get your ICM tested.

 

Update.
Pulled the vac line of of the FPR. No leaking gas or smell.
Checked the pressure again. Vac line on make 40#, vac line off makes 45#.
Pressure remains steady after the motor is turned off, no bleed off.

It would appear that the FPR is perfectly fine. I will look at the ICM.

 

Maybe check the temp sender. Last week I had one flake out on my wagon. Car actually acted like a fuel or spark problem, intermittent misses while running, HARD hot starts etc. When I hooked up the laptop the coolant temp was bouncing around faster than O2s.

Basically this caused the computer to command completely wrong fuel and spark.

 

Thanks for the advice. I have a scanmaster in the dash. If I monitor the coolant temp and it appears stable (not bouncing), would this indicate that it is likely working properly.

 

Long as the temp it is registering seems reasonable.

 

Okay the temp sensor appears fine. It checks out with the scanmaster and shows no ill behavior. Now what? Coil?

 

You could have a fuel pump going out, if ALL it does is takes longer to start in cold AND hot conditions. The check ball/valve inside could be stuck/bad and that lets fuel drain back into the tank. So when you goto start it, the system has to prime again each time. While driving though, it's fine since the pump is always running.

 

Cold motor starts immediately. Warm motor, after 20 minutes takes up to 5 seconds or so. If the check valve in the pump were bad, would it not want to bleed off the pressure at the rail. After even an hour or two, it still shows about 40#.

 

did you check the vacum elbow imediately after starting or cranking for signs of fuel?

 

Yeah did that to. It showed no signs of gas.

 

I know someone said it, but did you check the ICM yet?

D

 

No it wouldn't hold pressure.

 

Okay,
I am going to shift gears here a bit.

I left the fuel gauge on the fuel rail over night. It read 0# pressure this morning. I went to start it and it fired up immediately and ran perfect.

Yesterday I drove it for 20 minutes the parked it. Went out 30 minutes later and checked the gauge. The pressure dropped from 40# to 30# and when I went to start it cranked for about four seconds before starting.

I waited another 20 minutes, repeated the above procedure and got the same result.

I waited even another 20 minutes but this time I turned the key to on, off then on, off then on to prime the line three times. The motor fired up immediately. I think this rules out anything electrical.

HTF can it fire immediately cold with no rail pressure but not fire immediately when its warm and has 30# on the rail.

I am going to plum the fuel pressure gauge into the outlet side of the filter tonight and let it pressurize to see if it holds steady or bleeds off. This will rule out the FPR and the injectors and I can go from there.

 

Old thread I know, but did you ever figure out the issue? I have the same problem, but I have a different engine. Maybe I have a similar cause. Thanks.

 

Not really. Its just a minor annoyance that I deal with.

Cold start, fires fast with no drama.
Immediate hot re-start. No drama.
Hot restart after 20 minutes or so. It stumbles a couple times and then smooths out.

 

Did you ever replace your ICM as advised? If not, I would do the ICM mod (space the ICM off the cylinder head), I imagine it would clear up your hot start issue.