engine won't stop running
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Joined: Dec 2002
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engine won't stop running
Hello all, I have recently rebuilt my 351M. I set my initial timing with vac to dist. plugged at 10. engine still diesels. I tried advancing a few degrees and retarding a few only got worse.
My build includes: 268H comp cam, TRW flat tops and holley 500cfm 2bbl. any ideas whats happening here?
My build includes: 268H comp cam, TRW flat tops and holley 500cfm 2bbl. any ideas whats happening here?
Posting Guru
Joined: Aug 2002
Posts: 1,214
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From: Minneapolis, MN
engine won't stop running
Dieselling is usually caused by too high idle speed. The air/fuel mixture is being lit by a hot spot. Timing won't make much difference as the spark is off when you turn the key off unless the wrong timing is causing excessive heat in the cylinder.
Just my 2¢
Greg
Just my 2¢
Greg
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Joined: Aug 2000
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From: PacNW
engine won't stop running
FWIW I've had gas sit in a vehicle's tank for over a year outside and had the vehicle start right up and run fine until the tank was dry with no problems. Bad gas won't cause dieseling anyway...macguyver is right on the money with the idle being too high or the timing being too advanced and causing the comb. chamber to be so hot that it causes the fuel to spontaneously ignite.
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engine won't stop running
I noticed a vaccum leak around the base of the carb today.
Could this cause it? I have played with the timing and doesn't seem to matter its set at 8* now. my idle is set at 700-800. won't set right i assume because of the vaccum leak. I will fix the leak tomorrow. thanxs for input.
Could this cause it? I have played with the timing and doesn't seem to matter its set at 8* now. my idle is set at 700-800. won't set right i assume because of the vaccum leak. I will fix the leak tomorrow. thanxs for input.
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Joined: Aug 2002
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From: Minneapolis, MN
engine won't stop running
Originally posted by Hidome
I noticed a vaccum leak around the base of the carb today.
Could this cause it? I have played with the timing and doesn't seem to matter its set at 8* now. my idle is set at 700-800. won't set right i assume because of the vaccum leak. I will fix the leak tomorrow. thanxs for input.
I noticed a vaccum leak around the base of the carb today.
Could this cause it? I have played with the timing and doesn't seem to matter its set at 8* now. my idle is set at 700-800. won't set right i assume because of the vaccum leak. I will fix the leak tomorrow. thanxs for input.
Is the idle speed set with the tranny in drive? I'd try for 550 to 600 rpm max. in gear. Do you have an idle stop solenoid? That's the metal can on the drivers side of the carb that holds the idle speed when the key is on and drops off when the key is off to completely close the throttle. Sometimes that's the best way to stop a dieselling problem.
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engine won't stop running
Hey thanks all, Problem is fixed and she purrs like a kitten. It was a vaccum leak at base of carb and possibly others. I did away with all the vaccum lines except for essentials. thanks again
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Joined: Apr 2002
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From: Lawrenceville USA
engine won't stop running
My newly rebuilt engine is dieseling a little as well. Sounds like I should check for vacuum leaks before I try to set up an anti-diesel solenoid. Anybody ever put one of those on a holley? I assume that they are available.
Fleet Mechanic
Joined: Jan 2003
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From: Central Ohio
engine won't stop running
I have had dieseling problems myself, the only thing I have recently changed is I swapped on a 670 cfm holley truck avenger. Vacuum appears to be holding well but seems kinda high... idles around 16-20 ("of merc or whatever the heck it is). I have however had a problem with the idle, I cant seem to get it to idle any lower. When I start the truck for the first time and if it idles for more than a couple minutes it will start to slow down and blow smoke and make loud pops. And although it has good off idle power it sometimes stalls off idle from a stop and sometimes when you hit the gas and the tranny hasnt kicked down yet. Other times it hauls a$$. And to top it off my WOT is all out of whack. I dont know even were to start tuning it lol. But I still drive it daily, just dont floor it. I know I should have it professionaly tuned but I am unemployed currently so I do everything myself. Those truck avengers supposed to run out of box, but to get em to run perfectly has eluded my thus far.
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Joined: Apr 2002
Posts: 146
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From: Lawrenceville USA
engine won't stop running
If you can't get it to idle lower, sometimes there is a idle screw in the choke assy that is holding it off the regular idle screw stop. I guess that the plates could be bent if it's been manhandled.
I can't help with the other problems, but I do know what inches of mercury means. It was a term set up in the 50's to describe how bad grill assemblies looked as compared to the '58 Mercury. You would just assign a number to say how bad it "stinks" compared to the aforementioned grille.
The UN is trying to get the standard changed to the Avalanche...
I can't help with the other problems, but I do know what inches of mercury means. It was a term set up in the 50's to describe how bad grill assemblies looked as compared to the '58 Mercury. You would just assign a number to say how bad it "stinks" compared to the aforementioned grille.
The UN is trying to get the standard changed to the Avalanche...
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From: Minneapolis, MN
engine won't stop running
Originally posted by D9351
I can't help with the other problems, but I do know what inches of mercury means. It was a term set up in the 50's to describe how bad grill assemblies looked as compared to the '58 Mercury. You would just assign a number to say how bad it "stinks" compared to the aforementioned grille.
The UN is trying to get the standard changed to the Avalanche...
I can't help with the other problems, but I do know what inches of mercury means. It was a term set up in the 50's to describe how bad grill assemblies looked as compared to the '58 Mercury. You would just assign a number to say how bad it "stinks" compared to the aforementioned grille.
The UN is trying to get the standard changed to the Avalanche...
I wonder what the conversion factor will be?
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