I bought a 1991 Ford F-250 it starts and I can put it into gear but once let off the throttle it dies so I’m not entirely sure what’s wrong because I’m pretty new to diesels and mechanics in general any help would be greatly appreciate
Just bought a 91’ f250 having fuel issues
- Thread starter CalebH
- Start date
1992 idi 73
Registered User
Manual or auto? If its and auto you could be stuck in a higher gear or the throttle position sensor could be bad. Welcome to the forum too.
First thing to do is to check the high idle circuit.
With the key off... Look at the throttle linkage. Move it by hand. Not whether there is any space between the high idle solenoid rod, and the linkage, when you let it back. There should be space there.
Now go turn the key to run. No need to start.
Now do the same thing with the linkage. This time, the rod that comes out of the high idle solenoid should touch the linkage and follow it as you open it by hand. Then it should actually hold the linkage open just a bit. Until you turn the key off again.
With the key off... Look at the throttle linkage. Move it by hand. Not whether there is any space between the high idle solenoid rod, and the linkage, when you let it back. There should be space there.
Now go turn the key to run. No need to start.
Now do the same thing with the linkage. This time, the rod that comes out of the high idle solenoid should touch the linkage and follow it as you open it by hand. Then it should actually hold the linkage open just a bit. Until you turn the key off again.
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Proofread yer last!
Try running a couple tanks of fuel to see if clears up. My RV was like that when I first got it, due to probably extremely old fuel. A diesel fuel system cleaner like Hot Shots Diesel Extreme might help too.
Beware if you use that stuff, wear gloves! it'll give you chemical burns, if you aren't careful. I got it on my forearm from a paper towel that had it on it, and I used it to wipe off some oil/grease from my arm.
A video of the RV with weak idle when in gear, and stalling when letting off the throttle, before I fueled it up and drove it 300 miles back from where I bought it:
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gandalf
Senior Member
Lets see if we can clarify this a bit. You've said that it starts normally, but dies when you let up on the throttle. Does it die when you put it in gear and try to get it moving, when you let up on the throttle and it meets the resistance and weight of the vehicle? OR does it die if you have it in neutral and blip the throttle, rev the engine just a bit and let up on the throttle? If it's the later situation my money would be on the metering valve in the injection pump. When the engine dies after you let up on the throttle, without necessarily having it in gear, that would very likely be a sticking metering valve.
Report back which scenario seems to fit.
Report back which scenario seems to fit.
it doesn’t die when I put it into gear I can start driving just fine it’s just when I come to a stop is when it dies
gandalf
Senior Member
Okay, let me rephrase what I said above. You want to stop so you take your foot off the throttle to slow down, and it dies. Is that what's happening?
Explaining the high idle solenoid to a newbie...
Para. #2 is a little confusing (probably cuz I did not have my glasses on and misread it) but anyway!
op
my .02... Get her HOT AND SWEATY!
Load it down and find some long uphill grade, climb it at or on the governor,
in every gear (to a road safe speed) get the egt and coolant up for at least a half hr (as a 1 pull wonder won't do..)
P.S. It may take a few tanks to get it loosened up all the way.
You are in good hands here, as some of the best idi diagnostic hands around.
Para. #2 is a little confusing (probably cuz I did not have my glasses on and misread it) but anyway!
op
my .02... Get her HOT AND SWEATY!
Load it down and find some long uphill grade, climb it at or on the governor,
in every gear (to a road safe speed) get the egt and coolant up for at least a half hr (as a 1 pull wonder won't do..)
P.S. It may take a few tanks to get it loosened up all the way.
You are in good hands here, as some of the best idi diagnostic hands around.
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IDIBRONCO
IDIBRONCO
If the truck hasn't sat for a long time, and it has pretty fresh diesel in it, I don't think you have an issue with the injection pump. Are you driving down the road just fine and then, only when you come to a stop sign or red light, it dies? If that's what your truck is doing, I'd guess that it's the lift pump (mechanical fuel pump) on the side of your engine.
Cool you signed up C! Didnt see you last night to ask how your truck is doing. How long has it been sitting before you bought it?
Yes that is what is happening
It was sitting for about a week and a half
gandalf
Senior Member
As far as I'm concerned that's a classic sign of a sticking metering valve in the injection pump.
There is a possible fix, one which frequently works. Remove the fuel filter, empty it, refill it with ATF (automatic transmission fluid), put it back on the engine. Then start the engine and let it run for about 30 seconds. You can hear the engine sound change when it starts burning the ATF. After that 30 second run shut the engine off and walk away. Let it sit overnight. The next day start it up and drive it hard, "drive it like you stole it" as they say. Frequently this process will clean the metering valve so it doesn't stick. Basically you're soaking the internals of the IP with ATF, which acts as a detergent.
If that doesn't work then you've got a more serious problem. It might be time to start thinking about a new IP.
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