Question : 95 3.4 DOHC flooding (like noah's ark)

[pontiacoz]

I'm stumped. My 95 Pontiac Grand Prix Special Edition just shut down while I was driving. It would not restart or fire at all. The engine floods to the point the gas is literally running out of the intake. No exaggeration, I have dumped several cups of gas out of the air filter housing. The first thing I thought was that it had jumped timing. That is not the case. It has good spark too. If I disable the injectors it will fire and burn off the gas in the engine though I don't think this is particulary safe to do. I went to the local Pontiac dealer and spent some time talking to the maintenance manager who was very friendly. He asked serveral of his techs their opinions. (It seems that techs with knowledge of this engine are getting rare.) Several remember an issue with the fuel system dumping gas due to a short or something to that effect, but no magic bullet. Has anyone seen this issue?

[walterdude]

I'm gonna say check the Fuel Pressure Regulator. I have heard of someone having a problem with the intake filling with gas from a bad FPR. When the diaphragm gets a hole the vacuum could suck gas into the intake When you say you disabled the injectors did you disable the whole fuel system (fuel pump) or the injectors?? Well, a pressure check is easy enough...

http://60degreev6.com/forum/f100/troubleshooting-occasional-long-start-condition-t41789

Here's a link to the thread I'm talkin bout. #6 in particular. There are also details on checking the fuel pressure. I don't think 95 used a MAP sensor, so you'll have to trace the vac line from the FPR to where they pull vacuum if you wanna check for gas in the vac line..
Hopefully this helps and if it's something else,,, SORRY!!!
Tom.....
When you find whatever the problem is, GET THE RAW GAS OUT OF THE INTAKE!!! I personally wouldn't try to run it if there's as much gas as you say....

[GTP091]

I've never heard of anyone having your problem with this engine. Knowing how the top end goes together I can't think of any way for that much fuel to get into the intake, except by sucking in from the FPR like the other post suggested. If I remember correctly the fuel regulator is held down to the fuel rail with a screw. I believe it just twists off after the screw is removed and there's a small o-ring inside. You'll have to remove the plenum unfortunately. I would be cautious about taking it to a mechanic who doesn't 'know' your engine. If you take it to a smaller garage they might have a mechanic who's familiar with the 3.4. Phone first. i'd try the FPR yourself first It's quite easy to get the plenum off. Don't blow yourself up!!

[RedZMonte]

will put money on the Fuel Pressure Regulator.. pull the vac line for your Fuel pressure regulator and try priming the fuel pump. My FPR went bad and same deal. engine was FLOODED with fuel. the upper intake and oil was overflowing. CHANGE the oil, drain the intakes, check your vac lines. My oil change pan was almost overflowing because the engine was so full of fuel when i drained the oil. then do another oil change very shortly after (500-1000 miles) make sure you get as much of the gas out of the engine you can..

Got $.50 on the FPR.

[timg]

Ditto the FPR. When mine went, the intake filled with gas. Literally, it was pouring out of the throttle body once I removed the intake pipe.

Tim

[Emc209i]

Another vote for FPR.