Is this a problem????

Buix893

Buick = $$$
Ummm I have a fuel pressure gauge on my rail, the guage reads accurate and the car runs strong, o2's are perfect and BL are 128 always... but after I shut down the car the guage needle on the fuel press guage goes down to zero in about 6 seconds. Is that normal??? I feel like a dummy asking this question..:tongue:
 
I am guessing it goes back to the tank...but when sitting for like 3 or 4 days it cranks in about 3 turns.

I have raced the car lots and never had a problem, just noticed it today..lol..but figured it just bleeded into the tank. Fuel pressure is steady 43and rises with boost I stuck it to the windshield...Injectors..FP reg and Walbro 340 are all new..maybe 2000 miles on em
 
Normally when the gauge shows that the pressure has gone down fast as in your case it means that you might have a stuck injector. I would start looking at the easy stuff first, look for any small fuel leaks. Look at the fitting for the gauge itself, then start looking at all the fuel connection points. Also try another gauge, lots of fuel problems have been traced down to a bad working gauge.
 
If the injector is stuck then how would I go about fixing it or diagnosing it?? Would the plug be fouled?? I don't think its a huge problem, not like the car is leaning out but want to try and fix this ASAP
 
Change out the plugs and inspect them. If you find a wet one, then thats your stuck injector. If they all look good, then start looking for leaks in the system, but like i said before, dont trust that gauge so much.
 
Ok...Im guessing by priming the fuel pump with key in ign is enough to check for stuck injector. Don't think I have to start the car, but will check either way.

I am also gonna OHm the injectors and plug tommarrow. I have the 60lbs from turbotweak so those are High flow injectors correct? Cause the high should be 16 ohms I belive
 
Ok...Im guessing by priming the fuel pump with key in ign is enough to check for stuck injector. Don't think I have to start the car, but will check either way.

I am also gonna OHm the injectors and plug tommarrow. I have the 60lbs from turbotweak so those are High flow injectors correct? Cause the high should be 16 ohms I belive
How do you ohm an injector? Just got done ohming coil packs!
 
I've never tried this, but maybe you can pull the fuel rail with the injectors attached and turn the ign. switch to the on position. My thoughts are that the injectors will not be open unless they get a signal from the ECM or if one is slightly stuck open.

Isn't there a check valve in the fuel pump that stops fuel from draining back into the tank?

I doubt it is the gauge leaking down. Gauges can leak, but that fuel and pressure has to go somewhere.....it will likely dribble down your intake.
 
It's pretty common. I see it on 90% of the cars. In most cases the fuel is draining back to the tank. Not a big deal.

In the case of a stuck injector, you would have a pretty good miss on startup if not all the time. That cylinder would be soaked with fuel.
 
I checked the plugs...all are dry but the last plug on the driver side had a little bit of gas on it...def not soaked but a little bit of gas. I checked the OHMS on the injector harness and they were all 18-19, but when checked on the plug that was a bit wet it was 14 OHMS???
 
I checked the plugs...all are dry but the last plug on the driver side had a little bit of gas on it...def not soaked but a little bit of gas. I checked the OHMS on the injector harness and they were all 18-19, but when checked on the plug that was a bit wet it was 14 OHMS???

The lower the resistance through the harness the better. Are you checking the resistance throught the injector as well? I hope so with those resistance readings. Excessive resistance will cause the injector not to fire, not hang open. You are thinking about it backwards.
My guess is that the pressure is being lost due to a faulty fuel pump isolater in the tank. Just something I have seen many times on these cars. Keycycle a few times and let the pressure blead down. Start the engine. Does it miss or smoke on initial start up? If not the fuel must be draining back to tank.
 
Yea my injector harness looks nasty...so I removed it today and gonna order a new one...I'm guessing the fuel is going to the tank cause my car has always been like this and never had fuel in the oil.
 
Yea my injector harness looks nasty...so I removed it today and gonna order a new one...I'm guessing the fuel is going to the tank cause my car has always been like this and never had fuel in the oil.

Caspers has a nice upgraded one.
 
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