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, 20204 yr by jtrakel

Testing if relays cause Off/ON spikes in injector pump fuel shutoff circuit 

 

Test condition:

• Engine cold
• Ignition switch on 
• engine RPM 0
• battery voltage 12.4V  
• Injection pump fuel temperature 84°F

Test guideline:

• FPR (fuel pump relay) out and pins 30 and 87 jumped, ASR (automatic shut down relay) in place.
• FPR in place, ASR pins 30 and 87 jumped.
• FPR out, ASR in.
• FPR in, ASR out. 

Result observed:

• Injection pump voltage constant 12.2V during testing
• ECM voltage constant 12V during testing
• Injection pump shutoff circuit, OFF with random ON spikes
• fault codes 1689 and 1693 induced  
• faults cleared and engine started with no problems.

Conclusion:            

• Both the FPR and ASR have no control over the fuel shutoff circuit between the ECM and injection pump.  

• The ECM is responsible for this OFF/ON condition.  The ECM power is supplied by unswitched fuse #3 in the PDC.