Leaking Injector/s??

[Donne Trav]

If hard starting is a result of a leaking injector or injectors, will the
gas be noticeable on the manifold/engine. Or where would it leak to if
it cannot be seen? Thanks.

 

[G Winter]

Leaking injectors would leak to the inside of the intake.
Depending on how much they leak it might start very well cold but warmed up and sitting for awhile but not long enough to have a cold engine it will start hard and may give you a little black smoke from exhaust. There is a leak down test in the FSM to check it.
Other people will most likely have more info.

Welcome to the site. There are a lot of good people here.

Glenn

 

[Donne Trav]

Leaking injectors would leak to the inside of the intake.
Depending on how much they leak it might start very well cold but warmed up and sitting for awhile but not long enough to have a cold engine it will start hard and may give you a little black smoke from exhaust. There is a leak down test in the FSM to check it.
Other people will most likely have more info.

Welcome to the site. There are a lot of good people here.

Glenn

Glenn, what & where is the FSM for the "leak down test"?
Thanks for the reply.

 

[G Winter]

FSM = the service manual that the GM dealers use. It can be obtained from
http://www.helminc.com/helm/homepage.asp?r=


Quote from the 1990 helms manual.

An injector sticking open can best be determined by checking for fouled or saturated spark plugs. If a leaking injector can not be determined by a fouled or saturated spark plug the following procedure should be used.
Remove plenum and remove fuel rail bolts. Follow the procedures in the fuel control section of this manual , but leave fuel lines connected. Lift fuel rail out just enough to leave injector nozzles in the ports . pressurize the fuel system and observe injector nozzles. end of quote.
If you do this use caution not to have fuel spray all over. Might want to wear a face shield or safety glasses.

It seems to me without disassembling anything,that you can attach a fuel pressure gauge to the schrader valve on the fuel rail.Turn on the ignition to activate the fuel pump and bring the pressure up. Then turn key off and observe if pressure drops. If so you may have a leaking injector.This could also mean a leak somewhere else.

I would check the plugs first. That should show a leaking injector.

Hopefully someone will chime in and correct me if I have anything incorrect.

Glenn