Truck started stuttering again

[jtrakel]

Well i'm back again with more issues, I've been away from the internet recently as the truck has kept me very busy reinstalling the interior and finishing up the turbo/exhaust install. However my truck has been doing very good the last few days with no major issues (still leaking oil somewhere that I have not discovered yet, or possibly PS fluid). On the way home today my truck began to stutter like it was being starved of fuel and then it kick back on, if I get back into the pedal it happens again like it wants to die. No trouble codes and my fuel press read 15+psi under all conditions.

 

I've replaced literally every sensor I can think of at this point (MAP, Oil press, coolant temp, oil temp, cam position) If I read into my OBDLink on either ECM or PCM they both display P1693 in the freeze frame DTC. I cannot find any other code on the truck which I know is supposed to be impossible but there is nothing else. I'm getting to the end of the rope on this truck and the amount of money I've dumped into it makes me sick lol! I also checked the fuel cell vent line and replaced it with a new hose in case of a blockage.

 

Lastly i'm including a data log of the "stutter" happening from my quad which is having it's own issues staying connected to my phone which I'm in contact with Quadzilla about. The stutter happened twice towards the end of the data log but I don't see anything obvious. This issue was happening before I had any tuning software installed. 

 

Could there be air getting into the return line causing the truck to stutter? My brain says the return line should not affect the engine running. This issue happens randomly and I cannot recreate it on my own, its been operating as normal the last 3 days and I've put about 100-150 miles on it. Of note I also get the OD off and Trans temp lights flicker on and off at least once during a drive also.

 

lastly I've included a video of the truck stuttering before I tore it all apart and installed the tuner etc.

iQuad-2020-06-02-10.21.41.csv

Edited June 2, 2020 by jtrakel

[Dieselfuture]

At idle ecm is in control, if it's not ecm it could be vp or injectors of even a lose wire someplace in harness I suppose. I would think you have a code but if not it could be mechanical, I'm kinda thinking vp  hope there are other tests you can do to rule things out. Maybe hot wire vp, exclude ecm from scenario. 

[jtrakel]

11 minutes ago, Dieselfuture said:

At idle ecm is in control, if it's not ecm it could be vp or injectors of even a lose wire someplace in harness I suppose. I would think you have a code but if not it could be mechanical, I'm kinda thinking vp  hope there are other tests you can do to rule things out. Maybe hot wire vp, exclude ecm from scenario. 

 

 

I've been looking around for any type of testing I can do to move this along but no luck thus far. I was trying to rule out the VP as i'm getting great fuel pressure leading into the VP with zero codes but there is always a chance I suppose. I would like to determine the actual issue before throwing $1k for a pump and the issue still presents itself. 

[015point9]

What I would do for next test...in Later part of video to see if fuel is being pumped. (Not about lift pump) .loosen 1 injector at a time, see if fuel is like video, then torque down.   Or hot wire vp44...Cheaper than a grand for pump.  

Beware though,  I dont know much about these, just what I would do

  

 

 

[wil440]

If that was mine I'd be looking for air getting in on pump suction side first, can you put a peice of clear hose into the line at the vp to check for air ?  Air getting in will not necessarily mean a reduction in fuel pressure certainly if it's not much and the fuel pump is good/ fast enough to pressurize it, it just becomes a 15psi air bubble or whatever fp is but when that bubble gets to injectors then engine is off until fuel is present again

My truck had a stumble last year, that was fuel starvation, truck had a direct replacement Fass..... needless to say it does not have an electric f pump now

[jtrakel]

Thank you for the replies I will look into suggested approaches. Drove it to and from work again today (roughly 25miles each way) with no issues. I really wish it was consistent enough for me to troubleshoot as I feel she’s going to leave me stranded on the side of the road one day.

[wil440]

1 hour ago, jtrakel said:

Thank you for the replies I will look into suggested approaches. Drove it to and from work again today (roughly 25miles each way) with no issues. I really wish it was consistent enough for me to troubleshoot as I feel she’s going to leave me stranded on the side of the road one day.

Is the stumble in any way related to fuel level by any chance, not necessarily empty tank but split/crack/hole in suction tube in the tank  ??

[jtrakel]

I don't believe so, I recently within the last 2 months installed the FASS lift pump and the associated 1/2 I.D. line from the fuel cell to the VP44. I removed the stock fuel filter for the time being. I'm going to try and get a hold of some clear hose like you suggested and see if there is some bubbles going into the VP along with 015point9's suggestion about cracking the injector lines post VP.

 

I was trying to wrap my head around the possibility of the return system possibly being an issue like the overflow valve or the t-fitting that connects the return lines from the injectors and the VP before going back to the tank. When I had my VP off last time I noticed the o-rings going to the t-fitting where not in the best shape but again, would this play a role in my current issue?

Edited June 3, 2020 by jtrakel

[wil440]

10 minutes ago, jtrakel said:

I don't believe so, I recently within the last 2 months installed the FASS lift pump and the associated 1/2 I.D. line from the fuel cell to the VP44. I removed the stock fuel filter for the time being. I'm going to try and get a hold of some clear hose like you suggested and see if there is some bubbles going into the VP along with 015point9's suggestion about cracking the injector lines post VP.

 

I was trying to wrap my head around the possibility of the return system possibly being an issue like the overflow valve or the t-fitting that connects the return lines from the injectors and the VP before going back to the pump. When I had my VP off last time I noticed the o-rings going to the t-fitting where not in the best shape but again, would this play a role in my current issue?

overflow valve sticking would do it but you should see a drop in fp I'd have thought.

Do you know anyone with a new snap on scanner as it is possible your scanner can't read whatever is throwing the 1693, just a thought as I got a S-O Modis Ultra and that reads everything including abs

[jtrakel]

5 minutes ago, wil440 said:

overflow valve sticking would do it but you should see a drop in fp I'd have thought.

Do you know anyone with a new snap on scanner as it is possible your scanner can't read whatever is throwing the 1693, just a thought as I got a S-O Modis Ultra and that reads everything including abs

See a sticky overflow in the FP was my thought process as well, just trying to rule out all possibilities.

I’ve been looking at some of the Autel scanning units, the S-O is a little to rich for my experience level but looks like a solid unit to never have to buy another scanner!

[dripley]

27 minutes ago, jtrakel said:

or the t-fitting that connects the return lines from the injectors and the VP before going back to the pump.

The return should go to the fuel tank and not the pump. Hopefully just a typo, not sure how you could do this.

Edited June 3, 2020 by dripley

[jtrakel]

3 minutes ago, dripley said:

The return should go to the fuel tank and not the pump. Hopefully just a typo, not sure how you could do this.

Yes that was a typo thanks for the catch Dripley! 

 

Edited June 3, 2020 by jtrakel

[dripley]

Just now, jtrakel said:

Yes that was a typo thanks for the catch Dripley! 

 

No sweat, I make my fair share of them.

[wil440]

25 minutes ago, jtrakel said:

See a sticky overflow in the FP was my thought process as well, just trying to rule out all possibilities.

Have you checked the one at the back of cyl head 

[Mopar1973Man]

I'm going to say more electronic way it comes and goes randomly. The only thing I would figure is fuel related is huge air bubbles.

[jtrakel]

On 6/14/2020 at 11:14 AM, Mopar1973Man said:

I'm going to say more electronic way it comes and goes randomly. The only thing I would figure is fuel related is huge air bubbles.

 

I'm leaning that way also, I think during my VP replacement the PCM and ECM will be removed and sent off for testing, I need to call and ask what they can do though since I'm not getting any codes or check engine lights associated with any of my current issues. I planned to utilize @Auto Computer Specialist

[IBMobile]

Could it be that the "Injection Pump Fuel Shutoff" signal from the ECM to the PV44 is getting turned on for a longer time frames.   @wil440 could you scan your trucks pump fuel shutoff with the Modis and see if it is normal to fluctuates like this.

[jtrakel]

I have a feeling I’ll need a better scanning tool than my OBDLink to do anything, so far this scanner has basically yielded nothing for me as I’m not able to read the associated P1693 that keeps showing up on the scanner and nothing else associated 

 

I’ll be putting in a new VP and some 7x0.0095 with head studs in the upcoming weeks. I may send the ECM and PCM off for testing as well however I’m not sure what all to give then for information about my issues as it’s never consistent 

[Mopar1973Man]

Remember P1693 code is just a signal that the opposite computer is having issues. Being most likely the PCM is calling the P1693 and ECM is not responding then I would say you might be looking at ECM problem. This could be reversed to if the ECM is reporting the P1693 code then PCM could be having the problems. 

 

12 hours ago, jtrakel said:

I may send the ECM and PCM off for testing as well

 

Best answer... Send them both out and have them tested. 

[wil440]

15 hours ago, IBMobile said:

Could it be that the "Injection Pump Fuel Shutoff" signal from the ECM to the PV44 is getting turned on for a longer time frames.   @wil440 could you scan your trucks pump fuel shutoff with the Modis and see if it is normal to fluctuates like this.

Yes i'll have a look when I get home