Chronic hard start condition

[IsaacHayes]

But why would it run fine after started?? ICM you mean?

[IanSzgatti]

ONLY when hot? ALWAYS a consistent time period before it fires up? How many seconds? EVRY single time when hot? NEVER when cold?

[gpse3400]

yeah the icm. i've been calling the dis for a 1000years... yeah it can really do some odd things. I'd go t othe junkyard and get one from the latest modle 3400 you can find and swap it and the coils over.

[JoeMechanic]

Crank Sensor and ICM work hand in hand.I would install a new crank sensor and ICM and some good platinum plugs..that should do it.

[JoeMechanic]

To change the 24X you will have to pull the harmonic balancer off with a puller I believe.I would change the crank sensor and your ICM and eliminate those before changing or removing the 24X sensor.The crank sensor can be removed without too much trouble..its bolted to your block either in front ,rear or top next to intake manifold(might have to remove PS pump and or Alt to get to it).

[jcob2]

Problem solved! Just wanted to report what I found.

I replaced the 24x sensor and it made no difference. I also had the cam sensor and low-res crank sensor, but didn't install them. I decided to check out a hunch about the fuel pressure regulator first, and I was right.

Car off, prime the fuel pump, gauge on schraeder valve read 41psi. Spec is 41-47. But... it didn't hold the pressure. Within 30 sec., it had bled down to 20 psi and then held there. It should have held at 40.

Then I tried starting the car. Hard long crank as usual, then fired up. Fuel pressure was STILL 41 psi, and it should have dropped 3-10 psi from the vacuum line on the fpr. So, I pulled the vacuum line off the fpr with the car running, and fuel came squirting out the vacuum connection. Obviously a bad diaphragm.

Replaced the FPR, and PROBLEM SOLVED!

[IsaacHayes]

Good info, I will check my friends car whenever I can to see if this is the same problem. Thanks!

[GT8]

I have a 1990 Pontiac TGP McLaren based 3.1 intercooled turbo motor that starts sometimes and sometimes it won't. Now here is the strange part. When I am turning it over cold it starts for second and shuts off. I pull a plug and the spark fires very erratically, I use a spark tester for this, looks like a spark plug. Now when the motor turns over and does not spark during rotation, it will spark when the engine stops turning over like a build up as a capacitor would have. Any ideas. Also where is the crank sensor for this motor? Do I have to take the whole thing apart, it is an automatic as well. Just wondering any ideas?

[IanSzgatti]

if you have an electronic ignition i'd be checking the ignition control modual.

can you even drive the car right now or are you a no start here? Does it happen hot? cold? both?