yup the bio diesel can foul up the optic sensor which will cause it to not work or screw up the readings. that is a commpn problem for guys running bio on thier 6.5. ive never heard of the throttle not working especially on drive by wire 6.5s.

set timing back. anf it smoothed out idle. and the "service throttle" dummy light is on... no pedal control still. dies when u put it in gear.

looking into part cost of sensors he thinks he would be better off just buying a new pump vs. guessing and throwing money at random sensors.

how many miles

210k or so..

ran perfect with no problems other than the servo motor code here and there, and then boom. this. *shrug*

i guess the pump is towards the end of its life. but im still think its a sensor of some sort not mechanical

I dunno if it's origional pump or not. it runs strong. but he see's almost $500 for an optical sensor and servo motor and a whole new pump for around 600 and i think we might just end up swapping pumps. he needs it up and running pretty fast here.

so... were down to a long hard start, idles but dies in gear

DTC 18 - Pump Cam Reference Pulse Error
DTC 35 - Injection Pulse Width Error (Time Short)

and when you press the throttle to the floor(new APPS) it will climb SLOWLY from idle to about 2000rpms at the same time the speedo shows about 8mph (in park)

leaning at the optical sensor still or the noise filter harness, and looking for someone with a scanner to hook to it, not a lot of free cash to just keep replacing parts.

Yeah i'm gonna beat the dead horse. but this has to eventually help someone right?

got the truck on a scanner so we could see what's going on..

long cranking, doesn't want to start AT ALL hit it with a little either to kick it over to read sensor data.



still code 18 and 35.

starts ROUGH and surges once or twice then idles fine..

From what I see it missed 8 cam reference pulses when it first fires up then my guess is it goes right to limp mode, fixed idle rpm, fixed fuel rate, fixed timing etc.. nothing changes no matter what you do, clear the codes and they instantly come back.

I see the PCM requesting 14deg of timing and reading the actual timing at 0
fuel rate bounces between 30mm3 and 35mm3 to hold idle. and injection pulse width is just a hair under 1.96ms

Still thinking it's the optical sensor :tttt:but were just gonna throw a new pump on it for the cost. let yall know how it goes.

yeah the computer doesnt know whats happening so it reads 0. that has to be optical sensor. but hey why not get a brand new pump for a similar price.

I think the route is going to be new pump and new PCM, there's a intermitent code 54 which is fuel circuit failure or something like that.

according to a reputable shop that deals with the 6.5 mainly they said the pump shorted out and took out the pcm, or vice versa... :booo: I don't see a short in any sensor but oh well, gonna stick the new stuff on and look for someone with a scanner to time it, or pay up for the full GMTDScan software to do it ourselves.