Keith Browning Posted April 3, 2010 Share Posted April 3, 2010 A 2008 F550 - customer complains about intermittent check engine light accompanied by low power and smoke out the tailpipe. If he shuts the truck off and re-starts it is fine but eventually it repeats. All pre-checks and inspections are good. I got as far as retrieving DTC P0087 from memory, KOEO and KOER both pass. Then I checked the fuel supply pressure and saw something I never have before. The fuel pressure at the test port is wildly erratic ranging from 20" vacuum to 35+ PSI at idle. See the video. At the moment I had to stop - customer took the truck (yes, that is right) and FMC Dealer has bee down for two damn days not to mention the Hot_Line is closed for the holiday until the 5th. Apparently the pump has a problem... I thought I would share this and take some thoughts on this. Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 3, 2010 Share Posted April 3, 2010 That shows up as a private video, Keith: This is a private video. If you have been sent this video, please make sure you accept the sender's friend request. Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 3, 2010 Share Posted April 3, 2010 Have you made any headway with repairs? Did you measure the fuel pressure on the pump outlet at the HFCM also? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 3, 2010 Author Share Posted April 3, 2010 At the moment the truck is gone - this customer is a real fucking pain in the ass about leaving the truck and he knows the owner of my dealership so... we all know how that goes. So I have not gotten any further with this. I really wanted to speak with the hot line as to what tests to perform from here as this as far as I am concerned is a big red flag in and of itself. BTW: this was my first You Tube video so bear with me... I made some changes and the video should be public now. I will actually be deleting it soon and replacing it with a slightly longer take that has a DTS watermark on it. Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 3, 2010 Share Posted April 3, 2010 I've never been able to get Youtube videos to work either, don't feel bad LOL You can host 'em on Photobucket, too, but unless you have the 'Pro' version, there is a bandwidth limit, but it's fairly high. I think it's only ~15 to upgrade to pro? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 3, 2010 Author Share Posted April 3, 2010 You just need to fiddle with the settings. I just threw this video up to try it out... I'll probably keep using it. I could put videos on my server but they wont be streaming now will you be able to post them in a forum post. If I use a video in a presentation or an article I convert it to a Shockwave file .swf and embed it. Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 3, 2010 Share Posted April 3, 2010 Now that it works, HOLY SHIT! That's gonna bust your gauge, that's crazy! Wonder if the HPFP is contributing to this somehow... Pump leaking internally, check valve or something, I dunno. It sounded like it made sense in my head. IIRC, I think the teach told us that the lift pump on the 6.4 only hangs out like ~15psi. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 3, 2010 Author Share Posted April 3, 2010 Thats what I am saying. There has to be a problem with the HPFP for this thing to be showing that big of a swing from pressure to vacuum. What seems like a no brainer should require at least a couple of brains agreeing on the cause before I go unbolting stuff. I also have uploaded a better video and changed the post. Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 4, 2010 Share Posted April 4, 2010 What is the low side fuel pressure KOEO? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 4, 2010 Author Share Posted April 4, 2010 6 PSI Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted April 4, 2010 Share Posted April 4, 2010 Creeping out on my favourite shakey limb... you appear to have a problem with flow, not pressure... Hook your handy-dandy purge line to the low pressure port and see what you get KOEO... This should be quick and easy... Your pressure shouldn't dip into vacuum (duh!!!)... but it might be quite revealing to see what it does... This should also tell us if you need to check pressure at the HFCM or even if you need to check inlet restriction... Or if we can simply blame the flex portion of the low pressure fuel line. I think your P0087 is merely a symptom... (another DUH, right?). Quote Link to comment Share on other sites More sharing options...
Aaron Posted April 4, 2010 Share Posted April 4, 2010 I wonder what the fuel looks like coming out of the cooler at the back, with the block-off tool/bypass hose in place? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 4, 2010 Author Share Posted April 4, 2010 Creeping out on my favorite shakey limb... you appear to have a problem with flow, not pressure... Hook your handy-dandy purge line to the low pressure port and see what you get KOEO... This should be quick and easy... Your pressure shouldn't dip into vacuum (duh!!!)... but it might be quite revealing to see what it does... This should also tell us if you need to check pressure at the HFCM or even if you need to check inlet restriction... Or if we can simply blame the flex portion of the low pressure fuel line. I think your P0087 is merely a symptom... (another DUH, right?). The gauge also should not shoot above 30 PSI either. I would agree with you if this were a steady vacuum reading. I have had one of those already where the fuel filters were plugged. Testing started with 2 PSI and steadily and smoothly pulled a vacuum that never returned to the pressure side until the truck shut off and the key returned to run. There were no pulsations whatsoever. Oh we have a flow problem alright but I don't think it is on the supply side. However, since I have never seen this and I have not completed testing I am keeping an open mind Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted April 5, 2010 Share Posted April 5, 2010 Something I have seen on some rare occasions is a flex line that has fingernailed... I don't know if you are familiar??? Early 90s Chev pickups had front brake hose problems (you could apply a brake and it would take a long time to release due to a reverse flow restriction) and I've seen all marques fall victim to a fingernailed fuel hose from the frame to the engine mounted mechanical pump creating an inlet restriction. We are back to dealing with some comparatively low fuel pressures - pressures we haven't seen for many, many years (less than 8 or 10 PSI) but we are still depending on maintaining our flow rates.. 50 PSI of head pressure might make a hose do whatever you want it to... 5 PSI could be a whole 'nother story. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 7, 2010 Author Share Posted April 7, 2010 It's the HPFP and injectors. I got some nice shiny debris from the injector lines. Apparently Ford is now looking REALLY HARD at pump failures when they get clued in on them. They immediately sent an FSE out and the job is at a standstill until the results from the fuel samples come back. Continued diagnostics also revealed high fuel trims on 2 cylinders with one at 12%. Relative compression showed -6% on a perfectly good cylinder... and showed no loss on a cylinder 50 PSI down. We have been here before. Gheeeee. I wonder were this is headed? And the fuel pressure anomaly I reported is not normal. My personal manual gage is sensitive and picked it up. The PVT in IDS did pick it up but it was not as wild - the IDS display showed pressure fluctuating from 3 to 7 PSI rhythmically. The gauge bar gauge was rock steady. I used all these to determine if this was a gauge problem, it isn't. I took my MAD tools gauge to another truck and it was steady as usual. I proved out the supply supply system with a steady 6 PSI at the HFCM and less than 1" Hg restriction on the inlet. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted April 7, 2010 Share Posted April 7, 2010 When I was in 6.7 class last week our FSE said that the water in fuel light strategey is causing alot of 6.4 pump failures. He said that if the light comes on and you drain the water the light won't come back on again untill it sees five key cycles with a vss input. If you get a bad batch of fuel with alot of water in it the water trap will fill back up after you drain it and the light won't come on untill it's to late. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted April 8, 2010 Share Posted April 8, 2010 The water in fuel light strategy is causing pump failures? I would say that tiny frickin shot glass of a water seperator is the cause. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted April 8, 2010 Author Share Posted April 8, 2010 Or how about this cheese fouling the sensor and filling up the water chamber in the HFCM? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted April 8, 2010 Share Posted April 8, 2010 Looks more like toe jam. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.