6.9 Needs Help
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5th Wheeling
Joined: Sep 2006
Posts: 48
Likes: 0
6.9 Needs Help
This truck is a 74 F-250 that someone did a Diesel conversion using a 1984 6.9 Diesel w/ 40,000 miles. I looked at this truck when it was for sale but I didn't buy it and at that time it was running fine. Know it is for sale agian and the owner is saying that running rich and thats its not getting much throttle. Just woundering if anyone has any ideas what it could be or what to look for?
Thanks
Thanks
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5th Wheeling
Joined: Sep 2006
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<table border="0" cellpadding="0" cellspacing="4" width="100%"><tbody><tr><td style="padding-left: 25px;" width="100%">
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</td> </tr> </tbody></table> I took a look at the truck today and I took a look at the air filter and it isn't cloged. There is alot of smoke that comes out when you hit the gas pedal. The owner intsalled new glow plugs, starter and fuel filter. It seems like the motor is getting too much fuel. Any ideas?
</td> <td nowrap="nowrap" valign="top">
</td> </tr> </tbody></table> I took a look at the truck today and I took a look at the air filter and it isn't cloged. There is alot of smoke that comes out when you hit the gas pedal. The owner intsalled new glow plugs, starter and fuel filter. It seems like the motor is getting too much fuel. Any ideas?
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
First test the fuel for gasoline.........wouldn't be the first time. Not much throttle as no RPM rise or the accellerator on the IP is not working correctly.. How long has it been sitting...... is there a water/fuel separator installed somewhere.
How long has the engine run since installation ie miles....... there were concerns re galvanized gas tanks and diesel fuel. The galvanizing can be removed by the diesel fuel and sent to the injectors where problems occurr. This has been a long time since any discussion in this area though.
Was the IP ever turned up fuel wise. If this is an older OEM type IP the governor flex ring could be disintegrating and blocking the return of fuel from the IP. To check for the flex ring problem.... fuel collection from the return side of the IP is required or check the check valve for black particles in it
How long has the engine run since installation ie miles....... there were concerns re galvanized gas tanks and diesel fuel. The galvanizing can be removed by the diesel fuel and sent to the injectors where problems occurr. This has been a long time since any discussion in this area though.
Was the IP ever turned up fuel wise. If this is an older OEM type IP the governor flex ring could be disintegrating and blocking the return of fuel from the IP. To check for the flex ring problem.... fuel collection from the return side of the IP is required or check the check valve for black particles in it
Thread Starter
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5th Wheeling
Joined: Sep 2006
Posts: 48
Likes: 0
The motor is running rich. If you take your foot off the throttle the motor stals. The truck was bening driven frequently until the problem occured. I am not sure if the fuel has been turned up. The motor only has 40k miles origional.
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5th Wheeling
Joined: Sep 2006
Posts: 48
Likes: 0
I talked to the owner today and he said that he didn't adjust the pump. The truck ran fine then it started the loose throttle slowly. He said the fuel pressure is 7psi. There was gray exhaust smoke that came out of it. He said that he can get it to stay running/idle. Any further ideas, I'm trying to see how much it may cost to fix?
Thanks
Thanks
Last edited by 7.3Diesel; Dec 2, 2007 at 07:33 PM.
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Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
This is a very hard thing to diagnose.
Since it was a home built it could be something like a kinked return line causing to much fuel pressure in the IP.
As PLC said, the old style governor ring could be coming apart blocking the return line, to much fuel pressure in the IP.
Could be the IP is almost dead.
Could be a blown head gasket.
Could be an air leak into the fuel supply.
Injectors could be leaking fuel into the cylinders when they should be closed.
Remove the fuel filter, see how much fuel is in it.
Drain it into a pan, see if there is any water in the filter.
Take a little of the fuel, pour it on the ground, see if you can light it with a match.
Fill the filter with Diesel Kleen and start the engine.
Keep the RPM around 1500 for a minute or two.
See if it still tries to die at idle.
Have to start somewhere.
Water in the filter could be a bad thing.
If the fuel lights with a match, it has gasoline mixed in with it.
The small line to the tank is the return line, need to see if any fuel is returning to the tank while it is running.
Since it was a home built it could be something like a kinked return line causing to much fuel pressure in the IP.
As PLC said, the old style governor ring could be coming apart blocking the return line, to much fuel pressure in the IP.
Could be the IP is almost dead.
Could be a blown head gasket.
Could be an air leak into the fuel supply.
Injectors could be leaking fuel into the cylinders when they should be closed.
Remove the fuel filter, see how much fuel is in it.
Drain it into a pan, see if there is any water in the filter.
Take a little of the fuel, pour it on the ground, see if you can light it with a match.
Fill the filter with Diesel Kleen and start the engine.
Keep the RPM around 1500 for a minute or two.
See if it still tries to die at idle.
Have to start somewhere.
Water in the filter could be a bad thing.
If the fuel lights with a match, it has gasoline mixed in with it.
The small line to the tank is the return line, need to see if any fuel is returning to the tank while it is running.
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