I have a 1988 corvette engine in my 84 monte using a 1987 trans am harness and computer. The car always started cold beautifully and had a hard time starting warm until i replaced the injectors with 8 new ford 24# injectors. That seemed to solve the hot start problem but cause a new cold start problem. Now the thing doesn't want to start cold at all. It takes at least 10 good seconds of cranking before she turns over. I have checked resistance at the 9th injector and get a good 4.2 ohms and I have confirmed that the 9th injector temp switch (front of intake) is functioning properly (closed when cold, open when hot) I haven't checked yet if the 9th injector is getting a good voltage signal or if it has good fuel pressure, but I think I am off to a good start. Any suggestions before I destroy my oil pump during a cold start?

Thanks

 

Check your fuel pressure....if you're not hitting ~45 or so when cold starting....you've got fuel pressure issues. My fuel pressure problems (also a cold start thing) ended when I installed a new fuel pump.

 

hmm. i have the pressure set to 39psi. I thought this was normal for unsing the ford 24# injectors because something to do with the way they are rated compared to the LUCAS ones. in any case, I'll check the pressure when cranking.

Could the cold start injector itself be bad even though it shows an impeadence of 4.2 ohms?

 

Well......I'm unsure on the ford injectors....but the cold start injector works when it's REALLY cold outside. In fact....if it's considered hot outside, the cold start isn't doing much. Have you tried using carb-cleaner to start the car (like spraying it inside the intake then going and cranking it over. That's what I had to do until the pressure problem was fixed. I don't know......those ford injectors change the whole equation.

 

This morning I just did a cold start using a little carb cleaner and it fired up great. Strongest cold start I have ever seen the car do in the 2 years I've had it. Does this suggest my fuel pressure is too low? I really dont want to turn up the pressure just for that. I'm very happy with the way the car runs and drives (once it's running)

 

It's too bad I'm the only one paying any attention to this thread...or you'd get some more ideas. I was of the same opinion before I replaced my fuel pump (which was causing the pressure to be too low) that my car ran great. Stock L98 cars came from the lot running rich...and mine never had. It was wonderful. The pump got replaced and now I run a tad rich. Big deal. For instant starts in whatever weather I feel like - It's worth it.

 

The car should start fine with 39 psi at the rail. You may want to check into making sure your fuel pump is priming the system when key is turned to "on" position before starter is cranked over. I had a car that took a couple turns of the key to the "on" position to get the fuel pump to build up enough static pressure to start the car. Also, has your engine been kept in good tune? It may be something other than a fuel problem.

 

I'm sticking by what I said. My fuel pressure meter read 39 psi at cranking with the old pump and no start. Go figure. Maybe mine's a mutant??????:lala:

 

Stock fuel pressures in TPI cars were known to vary by up to 10 psi from the factory due to inconsistencies with production regulators and so on. I have personally ran a Tuned port 350 with fuel pressures ranging from the mid 30s up to 55psi. Higher pressure generally produces better results so long as the pressure is not so high that the computer is not able to compensate the pulse width to the pressure.

 

My fuel pump is definately always priming when I start the car. I have always known to wait until it stops priming before I actually crank it. It's pretty loud and I hear it. The pump is a 3 year old delco unit for the vette application L98. I have a TPIS adjustable FPR but I have found it to definately burn less fuel when I keep the pressure lower. My plugs and wires have about 30k on them but the distributor cap and rotor are fresh. Since I got such a good cold start with the carb cleaner and it runs so healthy once it fires up I'm willing to ASSUME (there I said it) that they are not the main contributor the problem. I haven't checked the fuel pressure WHILE cranking but it should be pretty tight. I dont see where it could be leaking. The injectors are new. Thanks by the way for the replys guys.