87IROC350HO

Hey Guys; Anyone had this problem (issue):

Fires right up first thing in the AM (Makes me proud). But i have to crank her over several times to start afterwards. ??? Where should i start? I've been thinking about a new Msd ignition. Does the cold start injector screw up warm starts?

Thanks in advance
Stan

heavy_chevy29

im not sure it i under stand what you are talking about. when you crank it several time to get it to start does it crank real so like you have a dead battery. if is that is a timing problem. hope this helps alittle.

Vader

Protracted cranking on warm/hot restart?

My first guess would be a leaking injector or pressure regulator that is flooding the intake. Allowing the engine too cool allows some of the excess fuel to evaporate. A cold engine also tolerates and needs the rich mixture more than a warm engine (thus, the cold start valve/injector).
You can test the injector theory with a fuel pressure gauge. Connect the gauge to the Schrader valve on the right side fuel rail, start the engine, read pressure, then shut the engine off. Pressure should remain for at least 15 minutes. If the pressure falls off before then, you may have a leaking injector or the fuel pressure regulator may be leaking through or internally.

If the pressure does leak down, you can isolate the pressure regulator by pinching the fuel return line shut and monitoring pressure drop. If pressure still drops, you have isolated the problem to the injectors, fuel pump check valves, and regulator internal leakage.

If the regulator is leaking internally, you can remove the vacuum line from the FPR and see fuel leaking through. If there is no apparent leakage, the regulator is probably O.K., and you're back to the pump check valves and injectors.

You can isolate the pump check valves by pinching the fuel supply line closed. If pressure still drops, you have a leaking injector.

At that point, determining which one is the leaking injector(s) is inconsequential, since they all need to be removed for service/cleaning. An '87 should have Rochester or Bosch injectors, which respond very well to cleaning.

87IROC350HO

Thanks Vader....really nice info. You certainly have a gift for verbal or written expression. And Chevy 29....She cranks real strong all the time. She simply fires right up on cold starts and cranks several times (aprox 2-3 seconds) before starting when warm. BTW, they are replacement injectors and one of the blue injector's tip was cracked during installation. Didn't think it would make much difference...hmmmm??

Stan

Vader

87,

Sorry. I missed the part about the Accel injectors in your list. The diagnosis would be the same, regardless.

If the FPR line isn't surging fuel when removed, I'm guessing you'll find an injector issue. Don't overlook the cold start valve as one of those possible leakers.

I doubt that a cracked protection cap on the injector tip would cause leakage, but I'm no expert. I know it shouldn't be a problem on GM injectors.

paulo57509

When my IROC starts (no pun intended) to exhibit long crank times when warm, changing the fuel filter solves the problem.

Very weird, but it works.

Akshay

It's the CTS (coolant temperature sensor). You'll have to replace that. Check it with a resistanc meter.

Akshay

87IROC350HO

CTS, Fuel filter, FPR and injectors....