Having been a loyal Volvo driver for 20 years, I have seen and done my share of shade tree mechanic work on them.My 93 940problems are exhausting me. The idle is surging, thepedal response frequently hesitates,and the car dies intermittantly when driving; especially when decelerating. It's beenvery difficultto find what the problem is.The cap, rotor, fuel pump relay, idle air controller, and fuel filter were changed with no effect. I installed bench cleaned injectors; still nothing. It is a Regina fuel system and the pump is the only one (primary).Now after replacing the fuel pump (no easy task), the car won't start. I can hear the pump operate and Idon't see or smell any leakswith the ignition switch on, but the system doesn't appear to be priming. Is there something I'm missing here, because even though the idle ran rough, it always started ok. Are there any "tricks" to helping the fuel line build up pressure?

 

Do youstill have spark and injector pulse?

 

I checked and there is spark. What's the best procedure to check for injector pulse?

 

You need to find a Noid light. It is a Led light that you plug into the injector plug. When you crank the motor over it will pulse.

 

I don't have access to a noid light right now, but I opened up the fuel rail and tried priming it a few times, but no fuel is pushing through. I'm beginning to believe that the 3rd partypump I bought from Autozone is not strong enough to pressurize the system.

 

one more thing; since the new pump was a different size, I removed a small black junction box with a metal "lid"from the sender unit pump assy and used a new piece of fuel hose to bypass it. Is this box just a connector or does it have a check valve in it?

 

I think that is a check valve but not sure.

With the fuel rail out if you crank it over there should be fuel coming out. The engine needs to be cranking for the injectors to fire.

 

Gremlins (occasional no-starts) are difficult to pin down. If your engine dies and stays dead, go to www.stepbystepvolvo.com for a free guide to 740/940 no-starts. Though that guide is for LH Jetronic fuel injection systems, you might find some useful info.


Also, a new air filter never hurts.

 

Thanks for the link; it definitely should prove useful in the future. I reinstalled the pump using the junction box from the oem pump, thinking it is a check valve. I can hear the pump kick in, but still no fuel to the rail. Since the in tank is the only pump, my gut feeling is that this smaller after market pump doesn't have the hp to prime the system. The old pump was replaced as a problematic suspect, but the vehicle started before it was changed. I guess I will put the old pump back in to test (groan).

 

Thats what I would do.

Some people also get a 850 fuel pump motor and install it in the 940's.