Wither a vacuum line is connected to the FPR or not does not cause sufficient fuel rail over pressure to blow an o-ring out. If the source of the fuel was an o-ring on an injector you screwed it up when you put it back together. Could also have been a fuel line break or even a crack in the fuel rail.

Even with so much fuel pressure that the injector pintals are held close (totally dead FPR) a properly assembled fuel rail with the clips on the injectors will retain an over pressure of almost 60 psi.

 

Sorry to hear about your incident and glad it turned out OK.

This is really good advice. Whenever I restart after having the fuel rail off I always follow the same routine.

Roll the car outside to start it so that in the event that it does catch on fire, it has less of a chance of taking my house with it, filling my garage w/smoke etc.

Have a fire extiguisher or water handy.

While starting the car, I have somebody check all the fuel connections for the first moments to make sure there are no leaks

It has saved me more than once. The last time it was a return line connection that was never touched while working on the car and it didn't really start leaking until after the car had been running for probably 20-30 seconds.

 

Also, make sure the screws that hold the fuel rail to the cam cover are on and tight. When I bought my car they were missing, just moving the rail around you could get the injectors to leak or worse the whole rail and injectors popping out.

It's good you and your car made it out fine.

 

i usually prime the pump by turning the key on to get pressure up, check lines, start, then keep an eye on it for a few minutes w/ the large 5lb halon extinguisher close by. Ive had the FPR vac line come off- all it did was run rich. Sounds like you had pinched some o-rings or something. A classic Rock move.

 

The pump only runs when the engine is cranking/running.

 

Unless someone has hacked the wiring to the pump and run it directly off of the ignition. Then they are just asking for an engine fire.

Engine fire = parts car.

 

when you turn the key on, the pump runs for a second to prime the fuel lines- then shuts off- then it only runs if the key is on.

 

Thanks for all of the advice, when i pulled the fuel rail out yesterday it's actually good this all happened in my driveway, two of the injector o-rings were bad. They've since been replaced and everything will be pressure tested before i actually run the engine.

Basically i'm going to disconnect the ignition coil and crank the engine a few times, immediately check for leaks, wait a few minutes, go back and check for any leakes that may have developed. If everything's okay, recconnect the coil, start the engine, run it for a minute or two, re-check for leaks, hit the throttle a few times and check for leaks again. Get in the car, drive it down the driveway and back up again a few times with the hood open, stop the car get out, check the engine, hit the throttle a few more times and check for more leaks. Meanwhile, this whole time i'll be keeping a fire extinguisher in hand, a hose, and a few buckets of water within a seconds distance.

Once thats done i'll take it for a spin around the neighborhood, go up and down a few hills so i can cycle the engine through the RPMs a little more, and if THATS all okay.. Well then i'll be happy.

 

Thats sounds like a safe course of action. Just dont try to impress any girls for a little while.

It would look mighty bad if you revved up your motor and dumped that smelly brown red smoke out again....

 

Pump runs (or should) only when you are cranking the engine. Then for a half second after you stop cranking. Once the engine starts the pump runs above about 400 rpm. Below that it is supposed to shut off even if the key is on. If the pump runs with just the key on then someone has monkey farted with the wiring.

On the early 944's you can jump between aux fuse 2 and 3 to run the pump with the key off.

On the later 944's you can pull the DME relay and jumper between pins #30 and 87b. Note that pin 30 is direct unswitched unfused current directly from the battery. Use pin #86 for power switched from the key.

 

i had some issues whith the injectors...when u put the key on the pump works it makes presurre on the rail..trust me i had one loose injector....and gas was gettin out .really quick..so is best to check before..leave the key on and take a look on the rail and injectors..iS SAFE... AND CONSIDER YOUR BEST FIEND A BUCKET..OF WATER ..WHEN DOING THIS IF U CRANK THE ENGINE

 

Yes, this fire had nothing to do with the vacuum lines. When vacuum is applied to the regulator pressure actually decreases. When pressure (from boost) is applied pressure will increase. With the vacuum line disconnected completely, you should see the pressure spec'd for the regulator (2.5 bar). Make sure you installed the o-rings with soem type of lubricant. I usually use a bit of ester or mineral oil.

 

Okay, following all of the steps mentioned above i repaired everything and replaced the fuel line which was charred a bit and looked pretty scary.. and.. the car runs great!

Only problem is once i hit the throttle after the engine had been on for about 30 seconds varying amounts of white smoke started coming out from around the camshaft housing, i'm hoping its a broken camshaft housing gasket as that can be easily replaced in about an hour or two. I first thought it was an exhaust leak but when i smelled the smoke it smelled like burnt oil, only thing is, aside from smoke coming from around the camshaft housing, looking down from the passenger side of the engine compartment the smoke seemed to be coming from lower down. Checked the oil, it was clean but it looks like i lost some of it since yesterday, coolant was clean as well. Not sure yet, but i'll be posting it in another thread..

Other than that the car started right up, checked everything fuel related and there were no leaks whatsoever.. Figure once i get that problem with the smoke fixed i'll baby the car for a couple of months until everything gets cycled through.

 

If you just replaced the head gasket it's probably just residual oil that dripped down the side of the block and grease from your hands on the headers that's burning off. I've had new rebuilds smoke for the first 20 minutes or so.

 

Thanks, thats what I'm hoping too, but another thing that seemed to be happening was that the smoke increased as I revved the engine. Then again hopefully I'm wrong and was just seeing the smoke from a different angle which made it seem like it had more volume to it.