Fluctuating fuel pressure issue
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
Fluctuating fuel pressure issue
I've noticed lately that my fuel pressure is really jumpy at cold start, and stays jumpy until about the time the oil temp passes the coolant temp. The pressures fluctuate from around 45 up to the usual 60-62 psi while this is going on. Then all at once the needle quits bouncing and the pressures level out and behave normally again.
While the fluctuations are going on, Auto Enginuity cylinder contributions look normal. Shutting off one cylinder at a time has very little effect on the fluctuating pressures and doesn't seem to provide any clues toward a problem with a particular injector. I really thought I would find an injector that was hanging open, but that doesn't appear to be the case.
These fluctuating pressures show up on the electrical gauge in the cab and a small diameter mechanical gauge I have mounted under the hood, so it's not a gauge problem.
Any ideas? TIA!
While the fluctuations are going on, Auto Enginuity cylinder contributions look normal. Shutting off one cylinder at a time has very little effect on the fluctuating pressures and doesn't seem to provide any clues toward a problem with a particular injector. I really thought I would find an injector that was hanging open, but that doesn't appear to be the case.
These fluctuating pressures show up on the electrical gauge in the cab and a small diameter mechanical gauge I have mounted under the hood, so it's not a gauge problem.
Any ideas? TIA!
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
The voltage is doing its normal thing... I think it dances around in the hi 12s-low 13s while the glow plugs are cycling, and then jumps to hi 13s to low 14s when the glows shut down. So I don't think there's any correlation to voltage.
I'll have to put my ear near the Hfcm next cold start and have a good listen.
The truck starts great in the cold and runs normally. I wouldn't have a clue this was going on without the gauges.
And this morning, just to add another piece to the puzzle, the pressure stopped fluctuating when the coolant temp was only in the 150s. So it doesn't seem to be temperature specific.
I'll have to put my ear near the Hfcm next cold start and have a good listen.
The truck starts great in the cold and runs normally. I wouldn't have a clue this was going on without the gauges.
And this morning, just to add another piece to the puzzle, the pressure stopped fluctuating when the coolant temp was only in the 150s. So it doesn't seem to be temperature specific.
Fleet Owner
Joined: Nov 2003
Posts: 27,900
Likes: 3,617
Sounds like either a sticking regulator or a pump issue Wade. I know of one case where it was the HFCM when fluctuations like yours were experienced. The HFCM "listen" sounds like a good idea though. Maybe pull the regulator spring and look for excessive wear?
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
I rarely run WOT. Must be getting old. Wouldn't even want to try it for fear of breaking something. ;-) HFCM only has 40-50k on it, but could still be the problem.
The HFCM deduction sounds like the most likely suspect, since the problem seems to fix itself like someone flipped a switch. I'll pop the cover off the regulator tomorrow to have a look see, then listen to the HFCM closely if the pressure gauge needle is still bouncing at start up.
Sure helps to have a sounding board. Thanks a million!
The HFCM deduction sounds like the most likely suspect, since the problem seems to fix itself like someone flipped a switch. I'll pop the cover off the regulator tomorrow to have a look see, then listen to the HFCM closely if the pressure gauge needle is still bouncing at start up.
Sure helps to have a sounding board. Thanks a million!
Cargo Master
Joined: May 2006
Posts: 2,116
Likes: 6
From: Florida
I rarely run WOT. Must be getting old. Wouldn't even want to try it for fear of breaking something. ;-) HFCM only has 40-50k on it, but could still be the problem.
The HFCM deduction sounds like the most likely suspect, since the problem seems to fix itself like someone flipped a switch. I'll pop the cover off the regulator tomorrow to have a look see, then listen to the HFCM closely if the pressure gauge needle is still bouncing at start up.
Sure helps to have a sounding board. Thanks a million!
The HFCM deduction sounds like the most likely suspect, since the problem seems to fix itself like someone flipped a switch. I'll pop the cover off the regulator tomorrow to have a look see, then listen to the HFCM closely if the pressure gauge needle is still bouncing at start up.
Sure helps to have a sounding board. Thanks a million!
Don't be scared. I run WOT at least once per trip. Since my truck does sit more than it runs . I would rather it break on a short trip than when towing out of town. Although I have no tuner. BTW do you have an air bleed for the sender? I was thinking maybe it is air in the lines that has to find it's way out which is when it stabilizes. Try locating the sender lower than the test port on the fuel pressure regulator test port.
Trending Topics
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
Anybody ever had trouble with the schreader valve leaking on the IPT fuel pressure hose? There are definite bubbles coming out of it when I take the cap off.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Hotshot
Joined: Apr 2010
Posts: 19,060
Likes: 238
From: Saratoga Springs,UT
Is the Bubbles in the Upper Fuel Filter housing upon ccranking
Id try a Bubble test
SOunds like you are leaking combustion gasses into the Fuel Rail until warm then it seals
That valve must just be releasing the Pressure
Maybe a Bad injector or Orings
Id try a Bubble test
SOunds like you are leaking combustion gasses into the Fuel Rail until warm then it seals
That valve must just be releasing the Pressure
Maybe a Bad injector or Orings
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
Dang... That sounds like a legit possibility.
Balloon test isn't the easiest thing in the world to do. I've been thru it once though on my old 03 and it worked great.
Maybe I better leave the leaky IPT fuel pressure hose alone until I have time for the balloon test. It'll keep me running instead of air locking a rail!
Balloon test isn't the easiest thing in the world to do. I've been thru it once though on my old 03 and it worked great.
Maybe I better leave the leaky IPT fuel pressure hose alone until I have time for the balloon test. It'll keep me running instead of air locking a rail!
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
Oh Crap... You said bubble test, not balloon test. I'm jumping ahead a bit with my talk about the balloon test.
Bubble test is popping the fuel bowl lid and turning g the key looking for bubbles, right?
Bubble test is popping the fuel bowl lid and turning g the key looking for bubbles, right?
Hotshot
Joined: Apr 2010
Posts: 19,060
Likes: 238
From: Saratoga Springs,UT
Yes Sir
IIRC you just Pull the Fuel pump and FICM Fuses and Crank while looking into the Fuel bowel
COMPRESSION/INJECTOR BUBBLE TEST
Compression Bubble Test - DTS Articles - Articles - Articles - DTS
Then there was a Ron Video to Single out what Side I don't have that Link Maybe Bill does
Hotshot
Joined: Apr 2010
Posts: 19,060
Likes: 238
From: Saratoga Springs,UT
Ya there should be No Air Bubbles in there at ALL!!!
Definatly compression Gasses Unless its Sucking Air in somewhere
Usually we see High Fuel PSI when this Happens But that schreader valve must be Bleeding it OFF
and I just remembered that you can use that Yellow/Blue wire by the Heater Box passenger side it pulls apart and you can touch to Battery + side and that will engauge the starter and long as key is off position it wont start or run fuel pump
That wire is the Fastest way to do it sorrey I forgot about it then all you have to do is Pull cover off upper fuel filter
Definatly compression Gasses Unless its Sucking Air in somewhere
Usually we see High Fuel PSI when this Happens But that schreader valve must be Bleeding it OFF
and I just remembered that you can use that Yellow/Blue wire by the Heater Box passenger side it pulls apart and you can touch to Battery + side and that will engauge the starter and long as key is off position it wont start or run fuel pump
That wire is the Fastest way to do it sorrey I forgot about it then all you have to do is Pull cover off upper fuel filter
Thread Starter
|
Elder User
Joined: Dec 2007
Posts: 971
Likes: 1
From: IA MN SD
Apparently ITP Diesel is no more, or has turned into Strictly Diesel. Do they still sell the fuel pressure adapter hose with the schreader valve on it? If they do, I'm not having any luck finding it on their website.