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HELP: Fuel Delivery Problem

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I am having this problem on my Girlfriends 2000 Ford Mustang V-6 Automatic.

Anyway, at startup everything is fine. AutoTap reads 52 PSI fuel rail pressure. After it is warmed up that pressure will drop to 40 PSI and after another minute to 30 PSI. At any stage I can turn off the engine and immediately recrank in which case pressure is back in the 50's.

While driving, within seconds of starting the engine, I can punch it (WOT) and all is well. By the time I get into 3rd gear the engine will begin to shutter or stall and with the throttle wide open (4.8 volts on AutoTap so TPS is good) the engine RPM and vehicle speed will decrease. Timing during acceleration is usally 32 degrees. However when it stalls timing is pulled to 12-18 degress. Torque converter maybe? Just got a rebuild on Friday.
I looked around at the lines and could find no leaks. I looked as much as I could and saw no external leaks at the injectors. I did change the filter and average pressure increased about 4 PSI, so that wasn't it.

1. Is it possible an injector is stuck open and causing the SLOW loss of fuel pressure? My thinking is if an injector was open, pressure would be poor all the time. But I dunno.

2. Could the fuel pump be failing?

3. Is it POSSIBLE that I am not getting the correct power to the fuel pump? Remember, as soon as I crank OR recrank the engine from a stall, fuel pressure is back up for a few minutes.

4. Could it be the fuel pressure regulator?

5. She just got the tranny rebuilt and picked it up Friday. Could the new Torque Converter be the problem? My problem only exists above 2000 RPM in any gear when warm and timing is pulled.

I know this is a Ford and I am not an Engine Guy. I assume EFI is BASICALLY the same and ya'll can help me out.

Thanks,
V
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Sounds like a fuel pump to me, although those generally work or they don't work. When was the last time the fuel filter was changed?

I don't think it would be an injector being stuck open, because it would run really rich or wouldn't run well at all. Can you see the individual injector positions with the Autotap? We were playing with the Tech2 on a GM the other day and you can shut them off individually with the tool...

You could check the voltage at the fuel pump, but usually its on or off, not somewhere in between.

DUnno though, like you said, its a Ford. :D We had an f350 firetruck out here, pretty much brand new. Couldn't get the windshield wipers to come on, tried all kinds of things. Finally gave up and took it to a dealer, they found that the GEM (whatever that is) module wasn't plugged in all the way at the factory :crazy:
 

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Discussion Starter · #3 ·
Thanks dude,
I made some changes to my question. I forgot to add that this only happens above 2000 RPM and she just got her car back from a tranny rebuild on Friday. At the same time when the engine is WOT and stalling aboe 2000 RPM I noticed that timing was pulled from 32 degrees to a low of 12 degrees. Could it be the torque converter???
 

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I don't have a clue.

My sister's '94 tbird did some crazy stuff when the battery was bad. It wouldn't shift right, it would run really rough, all kinds of stuff. Put a new battery in and everything would be peachy. How old is her battery?
 

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Discussion Starter · #5 ·
I fixed the problem. I will answer this may come up in a search.

The problem was the fuel pump. At idle the pump could privide the 50 PSI necessary in the fuel rail. However at WOT I was getting ~15 PSI and the local speed shop advised me I could have no less than 30 PSI.

I changed the pump and all is well.

The Shell gas probably blew the pump.
 
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