94 6.5td hard to start studders at 3500rpm
 

Ok, new guy here. Ive been reading this forum non stop for 2 days. Hopefully someone out there can help!

I just bought a 94 k3500 with the 6.5l turbo. My friend owned it for a while and its been a bastard child for him. The problems he has had in the past was difficulty starting and when going down the road it was sluggish and would randomly kick in and out of overdrive. He replaced the pmd with the cooler the front grill, the fuel injector pump (blindly timing it to whatever made it run the best) and had no improvement. He then replaced the computer with a chipped one. At that point it would start up instantly and flat out lay 25' of rubber... Which aint bad! The 3rd time he went to drive it it acted up again. So he sold it to me for a decent price.

Symptoms are.... Takes about 10sec to start with slight throttle, then chugs a couple times and then idles fine. @ 3500rpm with a load it starts chugging (almost like a rev limiter kicking in) but in park itll rev to 3800 steady but no higher. I checked the tbar and fuel flowed fine at idle. I did find a injector return line leaking on the front injector on passengers side, cut the hose down and resecured, no changes (new line on order). A friend told me to check the egr but the vin code is f and i did not find one on top, could not find any other info as to where it could be. As this is an obd1 i dont fully trust the fault codes however the codes are as follows
17 ignition system problem loss of high res pulse signal
2 18 codes Ignition control camshaft sensor circuit problem
29 glow plug relay problem
35 response time too short
2 42 codes fuel temperature sensor signal is too low
2 64 codes pedal position 3 input signal voltage is too low
73 transmission force current motor problem

The service pedal light was on for a bit... I did disconnect the computer for a few minutes and that light went out. Still no change in driving. The truck is sluggish, you can tell the motor has power but feels like its holding back. Any advice would be tremendous!!. Thank you!

DTC 17 - High Resolution Circuit Fault
DTC 18 - Pump Cam Reference Pulse Error
DTC 29 - Glow Plug Relay Fault
DTC 35 - Injection Pulse Width Error (Time Short)
DTC 42 - Fuel Temperature Circuit Low (High Temp)
DTC 64 - Accelerator Pedal Position 3 Circuit Low
DTC 73 - Pressure Control Solenoid Circuit (Current Error)

First clean and repair the 3 ground wires on the passenger side rear of intake.
Next clear codes and have a TDCO relearn done-timing relearn for the ECM,since the IP is electronic the timing needs to be set with a scan tool or at least verified with 1 to be in spec.

Possible air in fuel problem as well.

Repair any codes that return.

still studdering
 

I dropped the tank and pulled the intake and checked all fuel lines, no cracks. Put clear line from ip to return line, no bubbles. Eliminated that black box harness thing that runs from the top of the ip to the wire harness. Put the 94 computer back in it with the original chip and tried it with the power chip... No codes either way however my service engine light is still on... What would cause that?
Most of my power is restored however it still studders at 3500rpm with both chips as if a rev limiter is kicking in. I have not been able to find a mechanic around here what works on old diesels to set the tdco. Could the tdco be causing this issue?

If the service engine light is on there should be codes of some description.