Too much fuel

[smokin69]

My friend at school has a 89 F250 with a 7.3 and zf5 and we where messing with it and decided to turn his pump down, as it was maxed out and had some non-stock parts, dumping lots of fuel in from when you put your foot to the floor to redline, and never cleared up. Before he would run around 1250-1300 on the egt's going up a 6-7 mile hill. After we turned his fuel down he pulled it again and hit 1800 from about a half mile up and by 3 miles into it the pyro was burried. I know this isn't good for it but he doesn't care about the truck as he pulled it out of a farmers field for 300 bucks and just does whats neccasary to keep it running. Anyway, I was wondering if you put too much fuel into an engine if it can end up actually cooling down the egt's because there is so much unburnt fuel and it's running so rich that it can't burn hot enough?

 

[Agnem]

Not a chance with a stock pump. Not sure why your EGT's went up, but he's going to fry it big time eventually. $300 bucks is $300 bucks. Your friend is just stupid. It's that kind of attitude that seperates the men from the boys. Has he considered the fact that when the piston lets go and the connecting rod comes through the block or the pan, that there will be a huge cloud of smoke, oil all over the road, and that he may have to pay someone to tow it or the cops might be crawling all over him? Could end up costing him some coin to get out of that mess. Obviously the PO put the pyro in. Surely your friend wouldn't have spent the money.

 

[icanfixall]

 

[hesutton]

Not a chance with a stock pump.

...........Your friend is just stupid.

X2. Are you sure you guys turned it down? I wouldn't ride with that guy again. He sounds like a fool.

Heath

 

[Compu Doc]

When I was living in CA right outside my apartment building there was a tow truck that had a PS in it. The motor let go and all you seen was a big mass of oil that got dumped from the pan. It was a huge puddle and another tw truck came out to tow the broken down one. When they left they did nothing to remove the oil or even try to cover it with speedi dry. I called the police and they sent out a fire truck to clean it up. When they arrived I told them exactly what towing company it was along with their phone number and they said they will be issuing a bill and a citation to the company so I am sure they paid for it big time.

If that happens to your friends engine he will pay big time also as the emergency services will charge him with the cleanup and if the oil just happens to rund own a storm drain then the EPA will be paying a visit to him also and it will not be to present him with a check. Quite frankly I feel he would deserve what he has coming to him if that were to happen.

 

[smokin69]

well he put the pyro in and put new injectors in and modified the ip with a -3 spring and some other tweaks to make it fuel the most possible, like a home made moose pump.

 

[Diesel JD]

Well this is experimentation, not willful and wanton destruction.... unlike our government, so I think some of us have been too ******* your friend. I think he a) went the wrong way and turned the fuel up instead of down(happens to the best of us I'm afraid) or the pyro is wrong. Ain't no possible way you'd turn the fuel down and get 500* MORE on the pyro unless you changed something else, like the fuel delivery curve or timing curve. If I'm missing something maybe someone can enlighten me.

 

[DeepRoots]

having owned a moose pump for some time....

I havn't noticed the moose pump overfueling my engine, ever.
Increasing fuel that is USABLE is a balancing act of more fuel, timing, more air.

any ******* can light up a 5 gallon can of diesel in the backyard, why do it in an f250?

 

[smokin69]

well his truck puffs black at idle, it was REALLY overfueled before. Yes Im sure we turned it down because it was bottomed out to the stop. I don't know how its possible but thats what happened. I was just wondering if anyone could explain it. The truck is stock besides the pump, injectors, and recent head gasket job because he blew one out between some cylinders. Exhaust goes from the stock y pipe to a 5 inch stack mounted in the bed. If you floor it just idling along in 1st it will overfuel it to the point of killing it if you don't let out. He also did a gov spring mod and it turns around 4200-4300 rpm when pulling the hill in 4th. I don't agree with a lot of stuff he does with the truck but its his and I can't stop him.

 

[CDX825]

Sound like the timing might be a bit to advanced to me.

 

[Diesel JD]

having owned a moose pump for some time....

I havn't noticed the moose pump overfueling my engine, ever.
Increasing fuel that is USABLE is a balancing act of more fuel, timing, more air.

any ******* can light up a 5 gallon can of diesel in the backyard, why do it in an f250?

Which is why anyone who cranks up a pump beyond stock has to adjust the timing and fuel delivery curves.

 

[DeepRoots]

ok ok ok, well I lied.... Diesel JD overfueled my truck when he accidently shifted from 1st to 2nd to 5th....
no permanent damge tho, two dead birds, and it looks like my truck sh*t out a honda, but hey, whatever.

 

[Agnem]

If you floor it just idling along in 1st it will overfuel it to the point of killing it if you don't let out...

What happens is the full throttle position moves the external cam that actuates the low speed advance mechanism and the timing is getting retarded to the point where it won't run and obviously doesn't have enough air to support complete combustion, and the excessive fuel is cooling the precup until it puts the fire out. Without the RPM's to support that timing position, this would be expected behavior. These trucks should never smoke black at idle. That would be a sign that the timing is way out of whack. Your friend is obviously in need of a new pump, injectors and a dynamic timing. For $800 that truck could run like new, but it appears he's content to run it into the ground instead.

 

[hesutton]

If you've ever seen a pulling truck on the line, they white smoke like crazy. Too much fuel for complete combustion and raw fuel makes it to the exhaust. They use a hand throttle to "feather" the fuel up, one EGT's start to climb, and more complete combustion starts, the smoke turns black and they start to pull. But, I've seen them get a little "antsy" and drop the throttle too soon and litterally put out the fire like Mel said above.

This guy is running that much fuel to a NA? Crazy.

Heath

 

[Mat J]

MY neighbors got a durtymax with stacks that hes got tons of mods and can blow fire right out the stacks 6ft high its awesome but only good for show.

for those non belivers

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