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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #1 ·
Hello All, I'm new here (again) and would appreciate thoughts or ideas about my issue at hand.
I have a 1997 F-250 Centurion Crew Cab fairly well maintained with 112,000 miles. I have what appears to be a fuel delivery issue, the truck starts and runs fine for about 10 minutes then begins to miss slightly at first then that progresses to severe and then it starts to backfire before finally sputtering out. The same process can be repeated in a couple of hours. I can restart after only 5-10 minutes but the above process cycle takes about 1 minute. The truck was sitting for about a month without starting and I was a bit concerned about the fuel. Fuel looks good but the fuel bowl had some junk (particulate matter) in the bottom, no sign of slime or algae. This happens with both tanks and I replaced the rear tank about two years ago, the rear tank is completely full and the front is at 1/4. I replaced the fuel filter, cleaned the regulator screen but no real change.

Truck is completely stock other than a larger downpipe, has never had any tuner installed or performance upgrades.

Thank you for any thoughts or suggestions.
KarlM
 

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What's the fuel pressure when it's cranking and idling? Has the Fuel Pressure Regulator (FPR) screen (between the FPR block and fuel filter bowl) ever been inspected and cleaned? Cheers!
 

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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #3 ·
What's the fuel pressure when it's cranking and idling? Has the Fuel Pressure Regulator (FPR) screen (between the FPR block and fuel filter bowl) ever been inspected and cleaned? Cheers!
Thank you Patrick, I will check the pressure at the regulator tomorrow and the screen appeared clear via an inspection mirror. I will pop off the regulator and give the screen a good look over tomorrow as well. Just what to add that after the last run with new filter and cleaned bowl I removed the top of the filter bowl and it was full of fuel and clear. Can this have anything to do with engine temp? No Check engine light, no DTC's stored?
Thank you!
 

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When it sputters our is there fuel in the filter housing?

Also take the oil filler cap off and smell the fumes and see if it smells like burnt wiring.

Sent from my SM-A426U using Tapatalk
 

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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #5 ·
When it sputters our is there fuel in the filter housing?

Also take the oil filler cap off and smell the fumes and see if it smells like burnt wiring.

Sent from my SM-A426U using Tapatalk
Yes the filter housing is full. I will check the fumes from the filler cap / valve cover. I did not do that although the oil on the dipstick looked and smelled fine and was full slightly above the full mark, I was a bit heavy handed on the last oil change I guess. Oil in the oil pump housing / reservoir was about an inch below the check plug on top.

Thank you!
 

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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #6 ·
Yes the filter housing is full. I will check the fumes from the filler cap / valve cover. I did not do that although the oil on the dipstick looked and smelled fine and was full slightly above the full mark, I was a bit heavy handed on the last oil change I guess. Oil in the oil pump housing / reservoir was about an inch below the check plug on top.

Thank you!
So no smell of burnt electricals from oil fill cap. Fuel filter housing is full and Regulator screen was removed and cleaned (maybe 15% blocked), did not look too bad. I looked over all the injector wiring for any cuts, abrasions at contact points and all is clear. There is evidence that some mice were in the valley, the only damage I could see was to the single wire that plugs to the regulator sensor, some minor damage to the sheathing. For the first time it was hard to start cold, it took multiple 15-20 second cranking attempts to even get it to fire then it sounded smooth for about a minute then it started missing then stumbling until it could not run at all. While running (idle) I checked the regulator pressure at the Schrader valve, bounced between 45 - 55 PSI. What I did notice was that the oil pressure gauge while cranking took over 20 seconds to register pressure (pop up) on the instrumentation. In fact it did not register until well into my second cranking attempt?
 

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The oil pressure gauge is really an idiot gauge. It is supposed to read mid-scale when the pressure switch (not really a sending unit) threshold is reached (about 6 psi). It is not really reliable as to pressure. I would really check that wiring, especially the Injection Pressure Regulator (IPR) valve portion. Cheers!
 

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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #8 ·
So I finally picked up a BT OBD scanner (OBD LINKMX+) and downloaded ForScan for IOS. After doing some research I suspected that I may have IPR, or injector pressure issue. I am still working on getting familiar with the software and reader but I can already see that the IPR duty cycle ranges between 12 - 19% from idle up to ~ 2000 RPMs and the injector system pressure ICP ranges between ~570 at idle to ~850 at 2000 RPMs, which from what I have read seems pretty normal. These numbers are maintained until the engine begins to stumble then eventually quits. I can restart numerous times but it wont run long then eventually it wont start at all. It's been sitting for a week and it ran smooth for about two minutes today before beginning the stumble. Any other thoughts about where or what to look at with the ForScan tool? No DCT's stored in the Powertrain or general Control module?

Thank you
 

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1997 F-250 Heavy Duty Centurion Crew Cab Short Bed 112K
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Discussion Starter · #9 ·
I started the truck today (cooler dryer day) and just let it idle, it idled fine and smooth for about 15 minutes and warmed up to just about operating temp. It started to stumble just a bit and then began to lope a bit but still idled along for another 10 minutes, all the while the ICP was between ~570 to ~625. The IPR duty cycle stayed steady in the 12 to 14% range. I then increased the RPMs a few times up to about 2000 and that clearly made things worse. It struggled to get rpms up and sounded like I would lose 1 cylinder then over a minute then another and eventually it couldn't run. Then opened the fuel bowl, it was full, I drained it removed the stand tube (there was fuel in the tube port), cleaned the interior of the bowl even though it really was still clean from last time and reassembled and restarted the engine for 10 seconds. Checked the bowl and it was full again. No codes stored. Performed a buzz test and it passed per the scan tool, there was a slight variation in sound between injectors but all could easily be heard. Restarted and performed a cylinder contribution test and it threw code p0196 for engine oil temp, I assume it was not up to temp (170f) as the scan gauge reads oil temp.

Any other thoughts? I'm stumped by how starts fine and just progressively gets worse as its run until it just wont run anymore. Let it sit for and repeat. I should add that the trucks use has been very intermittent over the past year or two with lots of downtime.

Thank you,
 

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Most of the time I prefer the genuine Motorcraft gaskets and UVCHs, but they can be fairly expensive. You can get those from places like Diesel O-rings.com or Riff Raff. They should have the external pigtails as well. If you need to go with a less expensive alternative, you can get the gaskets with the integrated UVCHs from NAPA or other local auto parts places. Cheers!
 
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