car won't start cold

[LS1 TA]

My 1989 Formula 350 will not start after sitting for a few hours. It has spark and good fuel pressure. I've replaced the distributor( which was bad), the ICM, the ECM, as well as the coil. I have the static timing set at 8* BTC. It starts fine after its been running for a while. But 85% of the time after its been sitting, it gives no sign of wanting to start. Any input would be greatly appreciated as I am completely stumped.

[Injuneer]

Do the 3rd Gens use a "cold start injector"? Have you checked the coolant temp sensor?

[2firebirds]

Does it crank? if yes then It sound like a fuel or electrical problem.

If it the fuel then it could be leaky injectors hook up a fuel gauge to see if it hold presure with the car off.

If it the electrical possibly the coolant sensor. (any check engine lights)?

Here is the timing & fuel specs.

1989 Trans Am 350
TIMING SPECIFICATION 6 DEGREES
FUEL SYSTEM PRESSURE 30-44 PSI

Brian

[LS1 TA]

It's holding fuel pressure, and there are no check engine lights on. The only ses code I get is 12. It cranks over just fine, but it takes anywhere from 2-15 times to get it going. Why could the coolant temp sensor be the problem?

[Ken(Bone Breakin Chevy)]

I just went through the same problem with our 91 jimmy. we use it only in the winter for a plow. The problem ended up being with the fuel pump sending unit. Our problem started like yours, then after a while it just stopped starting all together.

[2firebirds]

The coolant sensor sends a (voltage resists) signal to the ECM which control the fuel on start up. When the sensor is cold the resist is differnent the when it warm. For $7.99 you can buy one from autozone and give it a try.

Brian

[LS1 TA]

The fuel pump engages everytime I turn the key, so I'm thinking the problem may not be there.

[Ken(Bone Breakin Chevy)]

ours was to, until it stopped starting all together. Im not saying its definately your problem, but thats what we ran into.

[LS1 TA]

From what I have been reading all day, and as also suggested above, it is probably my coolant temp sensor. It would apear that once again I've dumped alot of money into an $8.00 problem. Oh well.

[95TransAm]

From what I have been reading all day, and as also suggested above, it is probably my coolant temp sensor. It would apear that once again I've dumped alot of money into an $8.00 problem. Oh well.

Hey, at least you replaced a lot of things now that may go out later

You gotta always try and look at the bright side I suppose

[LS1 TA]

So I replaced the coolant temp sensor and still nothing, it took for ever to get it started. I hooked it up to my friends scanner and to my surprise..... No codes everything good, scanner said good to drive. Fuel pressure is 46lbs while trying to crank, but pressure bleeds off as soon as car is shut off. Fuel pressure regulator? or maybe the pump as suggested before?

[2firebirds]

If it not holding pressure to check the regulator diafram disconect the hose from the side regulator and plug it up with a bolt. have some one crank the car and see if fuel come out of the regulator it' leaking. But it sounding more like leaking injectors the fuel presure pushing the fuel past the injector closed valve in to the cylinder (too much gas leaks in the cylinder will fouling out the plugs). Have you checked the plugs? (black carbon = rich mixture)

Brian

[LS1 TA]

Nice, crisp, golden brown plugs.

[LS1 TA]

If it not holding pressure to check the regulator diafram disconect the hose from the side regulator and plug it up with a bolt. have some one crank the car and see if fuel come out of the regulator it' leaking. But it sounding more like leaking injectors the fuel presure pushing the fuel past the injector closed valve in to the cylinder (too much gas leaks in the cylinder will fouling out the plugs). Have you checked the plugs? (black carbon = rich mixture)

Brian

If its the injecotrs as opposed to regulator or the pump, what would cause it start off everytime when its warm? The problem only happens cold. Not enough fuel leaking to flood it in that short a time span maybe?