Have starting problems after 15 min....until 15 min no problems..
Pump and relay, running ok. Have mounted fuelgauge, and pressure is ok acc. to manual...
BUT pressure is dropping to none, within 15 min, is that to fast !!
Coud this be injectors leaking fuel...surely when turning the ign. back on, pressure is up right away...
Can injectors be renovated ??

 

RR,

Your symptoms may indicate a leaking injector, a leaking FPR, or a check valve in the pump that is failing.

If you pinch the fuel return line closed and repeat your pressure test, that will eliminate the possibility of fuel returning through the FPR. If pressure maintains during this test, the FPR is suspect. If pressure still drops, continue on to test the pump and injuectors.

You can isolate the pump by pinching off the fuel supply line after pressure has risen, then shut off the pump and monitor pressure at the fuel rail. If pressure maintains, the pump is probably leaking back to the tank. If that is your case, there isn't much to do other than change the pump or live with the "problem". If the pump leaks back to the tank but still maintains adequate pressure while running the engine, you can run it that way indefinitely, since it really isn't causing any operational problems. If pressure still drops off with the supply line closed during the test, there isn't much left but the injectors.

Injectors can often be salvaged and returned to original condition through cleaning. Since you are in Norhtern Europe, I have no suggestions about where to send your injectors for service. In North America, I'd suggest Cruzin' Performance. You may be able to find some helpful suggestions about where to send your injectors on the European Region Board on this site.

 

i just had this same problem on my 88 and i heard a couple different testing procedures that confused me so heres the easyest way. 1)pressurize the line 2)pinch off the return line. if the pressure leaks off the same then it is NOT the fuel pump check valve. now, 1)repressurize the line 2) now pinch off the feed line if the pressure drops it is an injector or several injectors if it doesn it is the fpr. if its an injector unbolt the rails from the manifold and pressurize again and watch for gas dropplets to form on the injectors.

 

Does it crank a long time before starting? When it does catch, does the motor fire right up, or does it choke and stumble a bit?

 

well mine cranks way to long and then fires up and will run fine but if i stab the gas it practically shuts off and then takes off kinda wierd? like it will completely die and then take off without problems. bad mpg too

 

I just replaced a few components on mine, and not specific to that problem, the new fuel pump cured the biggest ail, no start at all. Now I find I need to hold the key for about 6 seconds, I'd say, before it kicks over, and that seems consistant. If you hold the key to start too long, your doing damage and I see people do this out of frustration rather then wait the required time and try again.
Mine has had rough idle but the weather is a bit on the harsh side

 

IrocThe5,7L you are right on the spot......It chrank 5 sec. , and chockes a bit.......
Fuelpump valve will just return the pressure to tank....leaking injectors will overfill engine i guess (black fog at start)
How about fitting a electricsolenoid betvin in and outlet (over fuelpressureregulator ??) to rewile pressure instandly after stop ??

 

Thats what tipped me off my problem was injectors or the fuel pressure regulator, the motor would be flooded when I tried to start it, and stumble around for a few seconds until it cleaned itself out. The longer it sat, the harder it was to start. Vader pretty much covered it all in his post. I sent my leaky injectors to rich@cruzinperformance.com and he fixed them.