Fuel cackle, hesitation, surge, worse cold gets better as warms up.

[lmorris]

Driving from cold start, accelerates fine till it hits 2000 RPM, starts to cackle and buck RPM jumps around then it has a big surge, big enough to put me a little sideways. Steady cruise is ok. Once it warms up it's fine till you try a 5-6 WOT downshift at 65 MPH and has a very slight hesitation/ buck. It's not in regen either. My first thought is a slight gasoline mixture. No codes, KOEO, KOER, all pass. Cylinder balance fine, turn off compensation and all cylinders go loopy and it sounds like an IDI. Does not idle rough. Reset all fuel related adaptive tables, no change. Fuel sample from water seperator seemed ok. Drained upper filter, thought I got a whiff of gasoline. So customer gave ok to flush tank and lines , and replace filters. Drove after flushing it out and it was fine. let it sit for 3 hours and it's still doing it. Only happens at the 2000 RPM mark on hard to medium acceleration. If you 1/4 throttle it up to 50 MPH it is fine. Haven't gotten into fuel system contamination yet. It just seems odd that it happens at 2000-2200 RPM only and gets better as it warms up. Any input it greatly appreciated. Another odd thing is it only has 14260 KMS on it, has had the EGR valve and bypass replaced, but someone had the main degas bottle out, I know this because the rubber that holds the CAC at the bottom still is missing and the battery cables are pulled off the bottle. The connectors on the right side battery tray are all unclipped and stuffed down lower than they should be too. Something was done to this that is not documented.

[lmorris]

The plot thickens. Just found out this thing had a retail long block and turbo done it. Explains all the stuff I found wrong. I am going to check the HPFP gear to see if it's timed properly. 

 

What would happen if the guy forgot the CKP sensor ring?

[sneakypete]

 it would be a no start. had a guy here do that once.

[lmorris]

Found my problem.

[mchan68]

Okay, I'm a little late to join the party, but dare I ask WHY the vehicle had a RETAIL long block and turbo done when it only has 14260 kms. on the clock? What year is it? Is it out of warranty by time, or did the owner do something to it to cause a non-warrantable failure of the turbo and long block? And yes, if the tone ring was missed during the install it would be a no-start. I've read about MANY guys doing it, so on the only one I long-blocked, I was very attentive about not forgetting to install it.

 

And good find, by the way. I find it very odd that a mis-timed HPFP gear can possibly return PASS results on KOEO and KOER ​

[Matt Saunoras]

Worked on a truck not long ago with super low miles that already had a retail complete dropped in it.  It was a construction truck and the driver knocked the oil filter off on a rock and drove it until it locked up.

[Keith Browning]

Good Job Leon!

 I have always wondered what performance concerns would arise if this was done - now I know! We all know that a common rail fuel system does not necessarily need to have the pump timed for the engine to run but they do however need to be timed in order to run correctly. I am really glad that you posted this because I do not believe this is common but it did happen and could happen to anyone. The reason these pumps must be timed is because the pump cylinders create pulsations that can interfere with the fuel injection events thus causing performance concerns as described in this thread. Timing the pump sets these pulsations to occur between fuel injections to prevent or minimize the effect of fuel rail pressure pulsations also known a "hydraulic noise" which is nothing new if you are a seasoned Power Stroke technician.

Oddly, I don't think this is something many techs are aware of this perhaps this is because the workshop manuals make little or no mention of it at all. You will find it in the Coffee Table Books though. Early 7.3L DI engines that used a mechanical fuel pump is a good example that demonstrates hydraulic pulsations -if you have ever tested fuel pressure on one of those engines you saw some serious pulsations that sometimes made reading fuel pressure difficult. A gauge that had dampening features was helpful.  When Ford changed the fuel pump from mechanical to electric these pulsations were eliminated on the supply side.The HEUI injection systems used check valves in the fuel supply circuits to reduce fuel pulsations caused by the injectors that could affect system performance. Similarly, the high pressure oil system in the 6.0L engine used those "AWA" plugs that dampened the hydraulic noises in the high pressure oil rails. In later 2004 MY 6.oL engines the high pressure oil rails were modified to further improve dampening by increasing the volume of oil, channeling the oil through a wavy pattern and adding a second AWA plug. AWA means "Acoustic Wave Attenuation." which in simple terms means pulsation dampening.

[Bruce Amacker]

1.  +1 on good job! FMC told us in class it would NOT make a difference in how it ran but I always wondered.

 

2. If the CKP ring on a 6.7 is missing I'm pretty sure it will start and run with no tach reading in IDS and a hard CKP fault, it has been discussed here before.  In my notes I have Greg H here forgetting the CKP ring and posting about it, and another tech whose name I didn't record doing the same thing, both ran but with a hard CKP code. Greg said it wouldn't run the KOER test or the HP fuel test.

 

 

 

 

[Keith Browning]

FMC told us in class it would NOT make a difference in how it ran but I always wondered.

That begs the question: "why time it at all then?" 

If the CKP ring on a 6.7 is missing I'm pretty sure it will start and run with no tach reading in IDS and a hard CKP fault

I would bet on it. A CMP signal would do just fine if the CKP was missing. However I have never tried it  The CMP only reads from three raised areas on the camshaft gear representing 6 points. Good enough to define crankshaft speed and cylinder ID. Probably not good for accurate fuel control, misfire monitoring and so on.

[Bruce Amacker]

 

FMC told us in class it would NOT make a difference in how it ran but I always wondered.

That begs the question: "why time it at all then?"

 

NVH, not how it ran.

[Steve Mutter]

Nice find man!        

[lmorris]

Mike. The guy that rented the truck dusted the engine. It's a 2015 Driving Force truck.

[2006]

If the pump timing wasn't set, then I wonder if the injector IQ codes are all mixed up also...

[Brad Clayton]

That's a very good point.

[jimmy57]

I guess the reason 3/4 ton diesel pickups rent for so much is now explained.

[lmorris]

If the pump timing wasn't set, then I wonder if the injector IQ codes are all mixed up also...

Holy frick, never even occurred to me to check that. Thanks, will definitely check that before we return it to the customer. I hope the tech at least had the sense to put the injectors back in the same hole they came out of. 

 

Quick check, thankfully the shields were only half on. IQA is good.

 

Thanks for the heads up 2006. 

 

 

Nooooooooooooooooooooooo...........

 

They omitted the holes on the gear. Can't use a puller to get the gear off. WSM says to removed HPFP bolts, push the gear back against the housing and tap on the pump shaft to loosen the gear. Thankfully I haven't given a quote on setting the gear right yet. 

[Brad Clayton]

This is one of the biggest things that pisses me off about this engine..........the longer it's in production the harder they make it to work on and service. This is completely opposite of the 7.3 and 6.0, they got easier and easier as time went on and production runs changed.

[Matt Saunoras]

Yeah tell me about it. I just did that fuel system on that 15. Already had the puller and perfect sized bolts to pull the gear. Got in there and no holes in the gear. WTF? Left me wondering for a second if I was losing my mind.

 

Thankfully the gear is not as tight as a 6.4. You may be able to give it a few raps without removing the pump.

[lmorris]

Update: Took the truck home last night, 20-30 minuted drive city/highway. The stumble/surge at 2100 rpm is gone, but on warm up it had a toned down version of it at around 1500 rpm which went away as it got hot. Definitely load related because I can manually shift down to hold the rpm with no load and it is fine. All the way home this thing has a fuel cackle under load. Took it out in the evening and the stumble was gone but still very noisy under load at any rpm below 2000. This morning coming back to work it had a very mild hesitation at the 2100 rpm mark and cackling. As it warmed up the hesitation went away but still noisy under load. Got to work 30 minutes later, parked it, shut it off and restarted it, Now it sounds normal. When it is noisy the boost is also slow to build. Putting this one to hotline.

 

Something else that just dawned on me. It is below freezing here now. This truck didn't idle up when I cold started it this morning. It started good but idled at around 600 RPM. They usually run around 900 RPM on cold starts, and will ramp up to 1100 at times. Not this one. 

[Matt Saunoras]

I noticed these trucks not ramping up the idle cold anymore too. Perhaps this was a 14e03 change.

 

Also did you reset the HPFP tables?

[lmorris]

Reset them 2 or 3 times already.

[lmorris]

Hotlines response is that the reason for timing the pump is for noise and vibration control and will not cause running issues. So I am back to square one diagnosing a rough idle and the fuel cackle is back. Relative compression and fuel system analysis are next up. Part of me hopes there is metal in the fuel system, I need some closure on this thing. There still may be the possibility that this thing ran on gasoline at some point in it's life.

[Keith Browning]

Hotlines response is that the reason for timing the pump is for noise and vibration control and will not cause running issues.

 

That is consistent with what Bruce stated. So much for my long-winded theory.

[lmorris]

Found some metal flakes in the rails....thankfully all my previous time on this is covered by the customer.

[Fordracer]

I have a 6.7 right now with a vref short and I unhooked the crank sensor to see if it went away and the truck started right up with it unhooked. Also it set no codes for the ckp.