I am troubleshooting a cold start issue. I have already replaced the ECT and Fuel Pressure Regulator, hard starting continues. Symptom: If the engine has not been run immediately before testing, the fuel pressure comes up to 42 PSI when the key is turned to on. GM Specs say it should be 48 PSI. If the engine has just been run, shut off, then the key turned back to on, pressure comes up to 46 PSI. The pressure also drops 10 PSI within 10 minutes of pressurizing if the engine is not started, GM says it should drop no more then 5 PSI. This car will start fine unless it has set for more than 9 hours. It then requires excessive cranking.

I think the fuel pump module is not pressurizing to a high enough pressure for sufficient priming for cold starts. I cannot find anyone that sells shut off adapters that install on the quick connect fittings going to/from the engine fuel rails so that I can troubleshoot per the GM procedure. Does anyone know where I can purchase these?

If these are not available, can anyone give me a procedure so that I can be sure the pump module is the problem?

 

A pump or leaking injector could also be the issue but without the shutoff tool it's hard to isolate which.
A leaking injector will usually run rough and spit black smoke for a few seconds after starting.
The pump issue will just be extended crank.

Kent moore is the tool supplier for GM. I can get you the phone number and part # today at work.
Shoot me a PM if you don't here back from me in a day or too. I sometimes get sidetracked at work.

 

Kent Moore 1-800-468-6657

3/8" Fuel line shut-off J-37287-1
5/16" Fuel line shut-off J-37287-2

 

O.K., you got my attention.

Really interested to hear outcome.
Keep us posted please.