Working on a 92 4.9. It is flooding badly. It will not run more than a minute before stalling. I went through the manual and checked out the great post in Tech on the FPR. The vacuum line is open. No fuel is evident at the nipple. Fuel pressure initially is 42 and slowly leaks to 0 over say 25 minutes. The injectors are new OEM. I did not get to try capping the return off and checking pressure drop. (We had a little car and air show in town and I ran out of time) But I did pull a vacuum on the FPR diaphragm. Or tried to. I noticed someone asked if the FPR was bad if the diaphragm would not hold a vac even with no fuel at the nipple. I didn't see an answer. This one won't even go into a vacuum! I can check the one on my car. But if someone knows offhand it'll save me some time. Thanks.
Another FPR question.
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69 Thunderbird | 90 Seville | 03 Corolla | 89 Marquis(scrapped) | 72 Torino(scrapped)
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Sounds like one or more injectors is stuck open/leaking.
If the FPR wont hold vaccum, the only place for the leak to be is the diaphragm itself which would allow fuel to pass through. Make sure that your vacuum pump seals well on the nipple. Its rather small. I had this problem when checking mine. I wrapped a zip tie around the hose end...
Also, cycle the fuel pump on and off with the nipple exposed to give the FPR enough time to fill with fuel and begin leaking at the nipple. When the engine is running, the fuel gets sucked out immediately and doesnt have time to build up in the unit.
You can also test by running the engine with the FPR hose capped at the TB. If flooding remains, this will rule out the FPR.
If the FPR wont hold vaccum, the only place for the leak to be is the diaphragm itself which would allow fuel to pass through. Make sure that your vacuum pump seals well on the nipple. Its rather small. I had this problem when checking mine. I wrapped a zip tie around the hose end...
Also, cycle the fuel pump on and off with the nipple exposed to give the FPR enough time to fill with fuel and begin leaking at the nipple. When the engine is running, the fuel gets sucked out immediately and doesnt have time to build up in the unit.
You can also test by running the engine with the FPR hose capped at the TB. If flooding remains, this will rule out the FPR.
Yeah, I suspected what you said about leaking around the hose and tried a smaller hose and the vacuum did hold. But when I capped the return off it held pressure, which according to the FSM means the regulator needs to be replaced. Still no fuel at the nipple. I'm an HVAC guy by trade, so hydro and thermodynamics are second nature. I can't figure why, if it is leaking through the regulator back to the tank the engine is flooding. It seems the motor would run lean. Unless the gas is just pouring through the reg. I can't keep the darn thing running long enough to do any "engine running" checks. I hate to throw parts at something. Especially with someone else's money. But I guess it can't hurt to replace a 20 year old part at any rate. He brought it to a shop and they put a new fuel pump and new injectors on it and the problem wasn't fixed. I doubt it needed either.
I was going to suggest a stuck open check valve at the pump, but having the pump replaced should rule that out. Your fuel pressure seems about right and I would not be too concerned about a 25 minute leak down.
How have you determined that it is flooding?
How have you determined that it is flooding?
The fuel system sounds ok to me from what I've read. Do you suppose there are any codes? a bad vacuum leak? A bad MAP sensor will make it blubber pretty bad; not sure it will stall but maybe.
I suppose it is flooding. The plugs are soaked. There is a strong fuel smell and rich exhaust output. No active codes showing. It has strong spark. I haven't looked at the ignition timing because it was running fine and went kaput. Would the EST compensate enough to run for a minute or so if the timing chain is sloppy or jumped? If it skipped a tooth, the cam would be behind the crank and the injector shot would be late right? The EST would be trying to retard a bunch. The piston would be headed down already. Or am I backwards? In any case, it isn't on the fuel side. Thanks for all of the suggestions. Y'all helped me get my car rolling and I appreciate it. Maybe we can figure this out as well. I guess I could pull the valve cover and check the valve timing. Any other suggestions as to where to look?
It's fairly rare for any vehicle to jump a tooth on the timing chain and when they do they don't run at all. Sometimes when plugs get soaked too much it is hard to revive them. Does this car run at all now? It's hard to believe there are no codes. Maybe it's the ECM. How new is the dist cap and rotor?
Cap and rotor are almost new. The car barely runs. It will start with the throttle cracked and run for about 30 seconds. With more or less throttle it stalls. There are no codes!! I wondered the same thing. Today I ran through all the "make sure none of these circuits are bad before you replace the ECM/PCM" and they were ok. I'm kinda gunshy since I just had to put a new ECM in my car and don't want to jump to any conclusions. I checked to odometer and the car has 190,000 on it. My bud has owned it for 6 years and he hasn't done anything but tuneups and maintenance. (and few of those I suspect)
Maybe keep the pressure gauge hooked up and see what it's at when running poorly.
The gauge is still on it. I haven't been able to sneak a peak at it w/ the car running. (if you call it that) I'll make sure and do that. The injectors are new, but I will check them anyway. The only way I know to do it is with a stethoscope, listen for click clack. I guess I can check voltage to the injectors to make sure they aren't getting energized when they shouldn't be. Do y'all think I should pull out the plugs and clean them as well? They have been soaked pretty good. Ya know, besides my Fleetwood, I have an all-original 1952 Willys truck. It sure is easier to troubleshoot! Thanks for all of the input.
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