Any ideas on a no start P2291

Matt Saunoras · March 4, 2017

I need a little refresher course on 6.4 fuel systems. I'm starting to feel like I never diag'd one before.

To start I have a 08 F-550 with a ZF-6 towed in from the construction company down the street. They just dumped in a 6007 bought over the counter from us and it won't start. Now it's been a while for me but weren't 6.4 completes dyno tested and ran before shipping? If that is the case it seems odd to me that this one won't light off from the very beginning. It's not like this thing ran for a bit and died, it's simply never ran.

At first it acted like it was air locked but I've been through a dozen cranking sessions now with no avail. The first couple cranking bursts I wasn't getting any fuel flow from the high pressure bleed tool. This prompted me to remove the secondary filter, turn the key on and watch it fill with fuel, which it did. I checked low fuel pressure and it's right at 8 psi which is good because they just put in a new low pressure pump too. It seemed like every time I cranked it I would reach a different FRP and stay there. Say one time I cranked it would hit 1100 PSI then the next time a few minutes later it might only hit 400 psi. That was a few days ago and I gave up at that.

Today I started messing with it again and the first time I cranked it for a good 10-15 seconds I had good flow from the bleed tool which it did not have before. I really thought it was going to light off and it did for a split second and died. I did this no less than a half dozen times. It would crank for 10 seconds, hit right about 2900 psi, start for a split second and die. Every time. I captured a recording of it reaching 600 RPM so it was running. However it is definitely not reaching desired FRP. While cranking the fuel from the bleed tool is flowing pretty clear towards the end where it starts and dies.

Sync reads yes, RPM is 170 steady, FRP is .50v KOEO, I tried wiggling the wire and tapping the sensor through the valvecover opening but no change. I checked a bunch of other pids to see if anything looked biased but I didn't see anything unusual. The only DTC it sets is P2291. I have not made it to the balloon test or glow plug mist test yet. I'm trying not to get too intrusive until I think about this some more.

What I did find odd was it will do the same thing with the MAF unplugged or plugged in. I may be remembering this wrong but wouldn't a 6.4 not run with no MAF sensor? I seem to remember trying to start them in the past with the air box out and it wouldn't work.

Another thing I know about this truck is it has had 3 DPFs in the last 3 months. They got a DPF for it, then wanted that one SPW'd for DPF codes P2463/P246C so we gave them a new one. Now they just got a complete engine and another DPF. I may be thinking about this too much but I know I've had DPF codes like P2463 and P246C generated from a bad MAF sensor.

Jeff_E · March 4, 2017

I've had a couple 6.4's where the HP fuel system was so full of air it took quite a while to bleed out. I actually bleed the low pressure side first through the schrader with a hose from the old WDS fuel pressure test adapter which I have now re-purposed. Once it runs out of the low side without too many bubbles I then bleed the high pressure side with the adapter in the rear fitting of the fuel cooler until I get flow from that without too many bubbles. then I bleed from both simultaneously while jumping the starter to spin the HP pump. Then I command the LP pump to run and just let it flow from both bleed hoses for a while before I take my bleed adapters off the low and high pressure systems. Then I command the LP pump on again and let it circulate for a few minutes.

If you do all that and still can't maintain FRP, then I'd be suspicious of the HP pump or one of it's valves. If I got to that point though I'd be looking real close at fuel quality for signs of metal or DEF... I know this one is a 6.4 and doesn't use DEF, but if it is from a construction company that has a fleet of trucks and a bunch of employees that don't know what they're doing, anything could have happened.

Matt Saunoras · March 4, 2017

It's like as soon as it tries to run it shuts off. Its so predicable it makes suspicious that it's fuel pressure related.

lmorris · March 6, 2017

They will run without the MAF sensor. The erratic FRP is odd though. I would be checking for metal in the rails first.

KDS · March 7, 2017

Your supply side pressure sounds right, How about the volume? Is it running out of fuel just as it starts?

Matt Saunoras · March 7, 2017

Perhaps, I don't have my eye on the low pressure gauge while cranking because it's down by the frame.

I think I'll get a chance to dig into it more tomorrow

Matt Saunoras · March 7, 2017

Well I dug into it some more......and I burned up the starter :banghead:

It doesn't seem to be a fuel delivery issue or inlet restriction. So once I get a starter in the morning I'm going to be doing the balloon test and mist test. After that I should have enough info to throw a hpfp in it.

I did try cranking it with the FRP unplugged. That made for some odd noises but it didn't even come close to starting

March 9, 2017

I know most people won't like this but for problems like this, I sometimes run them on brake cleaner to diagnose it.

Turn the key on for a few minutes to let the glow plugs time out. Crank it, then spray brake cleaner into the throttle body. Once it starts, keep spraying cleaner in it. I have run them for about 5 minutes like this. Let the fuel system bleed out and watch the high pressure fuel actual and desired to see if there are any problems.

Matt Saunoras · March 9, 2017

This one is getting a HPFP. I was relayed the wrong information and this thing was actually running for 2 weeks prior to it not restarting.

KDS · March 9, 2017

I would check it carefully for metal. It may need injectors too!

lmorris · March 9, 2017

I would check it carefully for metal. It may need injectors too!

See a lot of diesels coming in filled with gas. A possibility with this one. They may have already drained the system and you will never know.

Matt Saunoras · March 10, 2017

I checked it for metal coming out of high pressure bleed tool, also there is none in the secondary filter. I'll pull an injector line tomorrow if I get to it. I worked on it for a half hour today before the other guy called off and I got pulled to do his schedule

Matt Saunoras · March 10, 2017

Well damn if I didn't find it today, luckily it confirms why I didn't find any metal in the fuel. The VCV was half unplugged from the gasket. The blue zip tie was installed but the connector wasnt locked prior to install. Never showed up during the resistance check of the 4-pin connector and it never set any codes other than P2291. I had 2.8 ohms of resistance until I wiggled the connector and it would go open. Perhaps this is why sometimes I would get good flow from the high pressure bleed tool and sometimes not. Also it almost starting makes sense too if the pump wasn't getting good volume.

First pic is how I found the connector which would still show up with good resistance. Second pic was light tug on the connector, ziptie still intact.

Honestly after all this work it's still getting a pump. The PCV and VCV on the new pump have some kind of extra locking tab on the connector. The old pump doesn't have that. I'll take pics on Monday. My new pump came damaged in the box so I couldn't even get started back together today.

mchan68 · March 11, 2017

GOOD FIND MATT!!! :cheers-jeers:

r-wats70 · March 21, 2017

Hello.. been awhile since ive been on here.....I have one doing the same thing....p2291, if i crank itl long enough , its starts for about 3 seconds......only ran once...., frp reading is about 3oo psi ,and my voltage was reading about .5..... but when it runs it reads 5000 psi, then fuel pressure drops off to 250 to 300.....if i use a fuel pressure gauge on the schrader valve on the low side , i have 10 psi of fuel pressure, however I can see air coming from it...now ...is it possible the low side pump could cause this..... it was in last week for a no start, so. i reset the tables and reprogrammed the pcm , and it ran fine until today , then towed back to shop.... fuel quality looks good..when it ran , it ran good , on all cylinders ..any help would be appreciated...any ideas ??