Hey everyone, I've looked all over our forum, but I can't seem to find the actual specs for a leakdown test for my 1993 Jimmy. Lots of posters recommend doing this test, even where to attach the pressure tester. No one posts the actual pressure readings I should be looking for.

Here is what I have: at key on engine off, I get a spike in pressure to 60 psi. As soon as the pump stops after two seconds, the pressure starts dropping pretty quickly to 40 psi. From there the pressure starts dropping slowly to zero over a short period of time (3 minutes).

What do you think guys? What should my pressure readings be?

Inside of plenum is bone dry. New nut kit, all poppets spray, new FPR(Dorman brand).

 

60 is good, but it has to hold above 50 psi for at least 10 mins after you turn off the key.

You just replaced the fuel pump, didn't you? Did you replace just the pump or the whole hanger assembly?

 

Thanks for the response Leeann_B. I just replaced the pump. Is there something in the hanger plumbing like a check valve? If so, is it replaceable, or should I get a new hanger assembly? I have looked at the hanger, and other than the sender for the fuel gauge, the plumbing looks pretty simple. I do not see any sort of check valve in the line from the pump to the hanger outlet. Please let me know what I should be looking for or what I missed during my install.

 

There is a check valve in the pump, but I was asking because many people have had problems with the little piece of hose connecting the pump to the hanger - it deteriorates with ethanol.

 

That really sucks for me because this Delphi pump is less than a week old. Thank goodness I have a spare pump and hanger assembly that I harvested from the junkyard for the fuel gauge sender. Hopefully the pump is good. I will be taking this Delphi back to O'reilly tomorrow. Thanks for the info Leeann_Bravada, i was at my wits end.

 

Well, I replaced the pump and sender assembly. Good pressure readings: spike at 60psi, then it drops and holds at 50. Plus the fuel gauge reads correctly now. if i have this problem of a pressure drop because of the pump,again, I'm going to add a check valve to the fuel line. I saw a thread about it on a jeep site. If and when this happens, I'll post my modification.