87 intermittent fuel injector leak
Thread Starter
Intermediate
Joined: Mar 2011
Posts: 33
Likes: 0
87 intermittent fuel injector leak
My 87 appears to have an intermittent fuel injector leak since the fuel line pressure holds after engine turn off at times and not other times. It may also explain why the car idles at 800 rpm and at other times at 500 rpm. Is an intermittent fuel injector leak possible or is it from some other cause?
Burning Brakes
Joined: Feb 2009
Posts: 785
Likes: 3
From: Richmond Virginia
If the pressure drops off immediately or very quickly--the check valve in the pump may be faulty or you may have a leaking injector. The check valve should maintain pressure in the lines and fuel rail for a while after ignition is turned off. Out side chance the FPR may not be closing/sealing after the engine is off, but that's not a common issue.
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
ohm the injectors if you have doubts feel free to contact Jon he will always give
good advice and solve your problem !
Fuel Injector Connection, LLC
4966 Wade Valley Way
Cumming, GA 30040
Tel: 770-888-1662
Jon at FIC http://fuelinjectorconnection.com/shop/
SEND FICINJECTORS A PM HERE
good advice and solve your problem !
Fuel Injector Connection, LLC
4966 Wade Valley Way
Cumming, GA 30040
Tel: 770-888-1662
Jon at FIC http://fuelinjectorconnection.com/shop/
SEND FICINJECTORS A PM HERE
Team Owner
Joined: Jan 2003
Posts: 20,333
Likes: 262
From: Summerland B.C. Canada
Try and isolate the pressure loss area, probably not an injector.
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
Intermediate
Joined: Feb 2011
Posts: 47
Likes: 0
ohm the injectors if you have doubts feel free to contact Jon he will always give
good advice and solve your problem !
Fuel Injector Connection, LLC
4966 Wade Valley Way
Cumming, GA 30040
Tel: 770-888-1662
Jon at FIC http://fuelinjectorconnection.com/shop/
SEND FICINJECTORS A PM HERE
good advice and solve your problem !
Fuel Injector Connection, LLC
4966 Wade Valley Way
Cumming, GA 30040
Tel: 770-888-1662
Jon at FIC http://fuelinjectorconnection.com/shop/
SEND FICINJECTORS A PM HERE
Team Owner
Joined: Jul 2004
Posts: 28,495
Likes: 3,298
From: Hartford WI
How does that help? It tells you the condition of the solenoid but not the leaking or not leaking.
I don't understand why people seem to be resistant to the idea of having their injectors professionally cleaned and tested every few years. On my diesel vehicles, every 100K they are tested and cleaned. They always need work. Either one or several but something needs to be cleaned up. On my gas vehicles, I would take them out every few years or X miles and have them tested and cleaned. I don't bother with the snake oil cleaner in a can stuff and I can't remember the last time I did an ohm test on the injectors. Unless I suspect that we have one bad injector coil, I would not bother with the ohm test. You cannot tell the spray pattern or if it is leaking or not with the test.
I don't understand why people seem to be resistant to the idea of having their injectors professionally cleaned and tested every few years. On my diesel vehicles, every 100K they are tested and cleaned. They always need work. Either one or several but something needs to be cleaned up. On my gas vehicles, I would take them out every few years or X miles and have them tested and cleaned. I don't bother with the snake oil cleaner in a can stuff and I can't remember the last time I did an ohm test on the injectors. Unless I suspect that we have one bad injector coil, I would not bother with the ohm test. You cannot tell the spray pattern or if it is leaking or not with the test.
Team Owner
Joined: Jul 2004
Posts: 28,495
Likes: 3,298
From: Hartford WI
If you suspect the injectors, here is one simple test. IIRC, there should be 3 lines at the tank. Hose going to and hose going from and vent. If you clamp off the hose to the engine, you will get no fuel pressure. If you clamp off the vent, you will have no difference in pressure readings. Kinda narrows things down.
So, test the fuel pressure and see how long it holds pressure. This only works with the stock system. With my HSR using the Kirban FPR, it will leak down pretty quick so there is not a comparison.
Clamp off the return line to the tank, pressurize the fuel rail and see how long it holds pressure. If the pressure drops you have a bad injector. Still if you haven't, send the injectors off to be cleaned and tested.
So, test the fuel pressure and see how long it holds pressure. This only works with the stock system. With my HSR using the Kirban FPR, it will leak down pretty quick so there is not a comparison.
Clamp off the return line to the tank, pressurize the fuel rail and see how long it holds pressure. If the pressure drops you have a bad injector. Still if you haven't, send the injectors off to be cleaned and tested.
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Michael S. Palmer
Intermediate
Joined: Feb 2011
Posts: 47
Likes: 0
If you suspect the injectors, here is one simple test. IIRC, there should be 3 lines at the tank. Hose going to and hose going from and vent. If you clamp off the hose to the engine, you will get no fuel pressure. If you clamp off the vent, you will have no difference in pressure readings. Kinda narrows things down.
So, test the fuel pressure and see how long it holds pressure. This only works with the stock system. With my HSR using the Kirban FPR, it will leak down pretty quick so there is not a comparison.
Clamp off the return line to the tank, pressurize the fuel rail and see how long it holds pressure. If the pressure drops you have a bad injector. Still if you haven't, send the injectors off to be cleaned and tested.
So, test the fuel pressure and see how long it holds pressure. This only works with the stock system. With my HSR using the Kirban FPR, it will leak down pretty quick so there is not a comparison.
Clamp off the return line to the tank, pressurize the fuel rail and see how long it holds pressure. If the pressure drops you have a bad injector. Still if you haven't, send the injectors off to be cleaned and tested.
