93 F450 Diesel running bad

[sc72]

Hello Friends, the question i have today is about this 92 F450 rollback truck i bought 6 months back, the truck has been running fine till a week ago when i put 14gal in the 16 gal tank, drove it two blocks then it started to mis and pitch a fit, chaged fuel filters and no differance, tonight i'm going to cut the fuel filter apart and look for junk, hard to start, it will rev but really slow and only to 2000rpm. OK so any thoughts, comments or concerns. I do need this truck to run so any help would be greatful.

[Larry Hampton]

Sounds like it might be the lift pump.

Have a friend with a '94 F-350 Diesel. It sat for 4 years, he got it home, same sort of deal. We changed filters, worked for a bit, then the same thing.

He took it to a shop, I'll try and find out what he replaced tonight at church and get back with you.

[Zanzer]

I have a 95 with a similar issue. I would be going through the gears and it would sometimes fall on it's face from one gear to another. I thought it was a fuel issue because I could press the clutch and rev it a few times and it would clear up. I changed all the filters and ran Diesel Kleen through it religiously but it still did it. Then one day it wouldn't take any fuel at all. It idled fine but when you hit the accelerator it was like it wasn't connected to anything. I think I've got mine somewhat pinpointed down to the drive by wire throttle set-up. After messing with the throttle driver a little it finally cleared up enough to get it to move again but it still acts up from time to time. I can't comment as to whether replacing the switch cleared it up because I haven't been able to locate a replacement yet. It's just something for you to consider while troubleshooting the issue.


EDIT: I'm curious to find out about the lift pump too. Thanks for the heads up Larry

[sc72]

Sounds like it might be the lift pump.

Have a friend with a '94 F-350 Diesel. It sat for 4 years, he got it home, same sort of deal. We changed filters, worked for a bit, then the same thing.

He took it to a shop, I'll try and find out what he replaced tonight at church and get back with you.

Larry, went you get to Chuch tonight, pray for the truck, i'm not nomally a hot head but this things got me scratching my head. the truck was a working unit when i bought it, so there was no down time. hey i'm getting 10 mpg whats the average with these. Thanks

[FB71]

ok, first question; 7.3 DI or DIT? (no turbo, or turbo?)

second; do you have access to a scan tool? Not a code reader, but a real scan tool.

it could be a fuel issue (as stated), a high pressure issue, or an electronic issue.

I repaired and taught PowerStroke 7.3L DIT repair for many years at Ford. I'll be glad to try and help.

[FB71]

hey i'm getting 10 mpg whats the average with these. Thanks

Around here, in Balto/DC traffic, the F450 JerrDan rollbacks usually average 8-10. 12-14 out in the burbs and rural areas.

[sc72]

I have a 95 with a similar issue. I would be going through the gears and it would sometimes fall on it's face from one gear to another. I thought it was a fuel issue because I could press the clutch and rev it a few times and it would clear up. I changed all the filters and ran Diesel Kleen through it religiously but it still did it. Then one day it wouldn't take any fuel at all. It idled fine but when you hit the accelerator it was like it wasn't connected to anything. I think I've got mine somewhat pinpointed down to the drive by wire throttle set-up. After messing with the throttle driver a little it finally cleared up enough to get it to move again but it still acts up from time to time. I can't comment as to whether replacing the switch cleared it up because I haven't been able to locate a replacement yet. It's just something for you to consider while troubleshooting the issue.


EDIT: I'm curious to find out about the lift pump too. Thanks for the heads up Larry

Zanzer,i'll start with the lift pump tonight, were would be the best place to split the fuel delivery after the pump and what should the gallons per minute be for a good working pump. I will look into your other suggestions also.

[sc72]

Around here, in Balto/DC traffic, the F450 JerrDan rollbacks usually average 8-10. 12-14 out in the burbs and rural areas.

OK. thanks then i'm not far off if any.

[sc72]

ok, first question; 7.3 DI or DIT? (no turbo, or turbo?)

second; do you have access to a scan tool? Not a code reader, but a real scan tool.

it could be a fuel issue (as stated), a high pressure issue, or an electronic issue.

I repaired and taught PowerStroke 7.3L DIT repair for many years at Ford. I'll be glad to try and help.

It's a DI engine, please excuse me i have to leave for a little bit, i'll get back to you in a little bit. Thanks

[shadetree]

Well this is going to sound stupid but ill explain ... when is the last time you changed the oil ?? If its the 7.3 the inj work off oil pressure . Fb71 correct me if I'm wrong but a 93 should be the 7.3 . I'm not saying that's your fix just something to try. I have had the same problem before on high mileage engines mostly .

[Larry Hampton]

It was the lift pump. He took it to a diesel shop, $400 for the lift pump, labor and 2 gallons of diesel is what his wife told me, he's in a meeting.

His is a DIT too.

[sc72]

Well this is going to sound stupid but ill explain ... when is the last time you changed the oil ?? If its the 7.3 the inj work off oil pressure . Fb71 correct me if I'm wrong but a 93 should be the 7.3 . I'm not saying that's your fix just something to try. I have had the same problem before on high mileage engines mostly .

OK. note taken, will check records. might just change the oil anyway.

[sc72]

ok, first question; 7.3 DI or DIT? (no turbo, or turbo?)

second; do you have access to a scan tool? Not a code reader, but a real scan tool.

it could be a fuel issue (as stated), a high pressure issue, or an electronic issue.

I repaired and taught PowerStroke 7.3L DIT repair for many years at Ford. I'll be glad to try and help.

Thank you sir, i'm headed out to the truck now, crap all i have access to is a code reader and this truck is a OBD1 and it is a DI Engine. I'll be back later.

[Zanzer]

ok, first question; 7.3 DI or DIT? (no turbo, or turbo?)

second; do you have access to a scan tool? Not a code reader, but a real scan tool.

it could be a fuel issue (as stated), a high pressure issue, or an electronic issue.

I repaired and taught PowerStroke 7.3L DIT repair for many years at Ford. I'll be glad to try and help.

Ok, Jim's on board so I'm totally subscribing to this thread now

Mine is a 7.3 Turbo. I don't have a true scan tool, just a reader I was thinking maybe my SCT Xcalibrator interfaced with my laptop but I'm not sure if it has diesel capability.


Per Shadetree's question - I service the truck religiously with Motorcraft filters and Rotella oil.


I'll be the first to admit that diesels aren't my thing. I've worked on the simple stuff like services, glow plugs, injector pumps, etc but my knowledge is still way behind what I know about gasoline engines IMO.

[FB71]

I just realized I misread the OP. I thought it said the truck was a 94. I see its a 92. OK, so to revise my first question; 92 could have been either a 7.3L IDI or DI. IDI uses a conventional injection pump, the DI uses the CAT HEUI injection system. Diagnostics for each are significantly different. Can you tell which you have?