Slip from lock up

[DmaxMaverick]

I suggest trying a #5 resistor (including a PCM reset). If no joy, then you are probably looking at a failed IP.

[Truckie117]

Will do that to day I have a 5 & 4 resistor from previous pmd'
Ok replaced resistor.
Now to relearn is that foot to the floor turn on ignition hold down for 45 seconds and still holding peddel down shut off ignition?

[Truckie117]

OK I have tried the #5 resistor and still have the problem.
No Codes I ran on Hwy with computer connected and there were no codes.

[JohnC]

Did you do a TDC Offset learn after installing the resistor? If not, th ePCM doesn't know it has been changed.

Have you tried locking OD out by putting the gear selector in "3"?

Monitor the solenoid closure time while it is acting up and let us know what it reads and if it is steady.

[Truckie117]

Hi Guys
Well I think I did is that where you put the pedal to the floor turn on the key and while holding 45seconds the pedal to the floor turn off the key. Take your foot off the pedal and start the truck?
If that is it then I did it.
Here is a link to my web site : http://mysite.verizon.net/vze7ye05/
I have the xls file there if you have excel or a program that opens xls files you can look at it Thanks
Merry Christmas to all
We Have a lot of snow on Long Island to night

[JohnC]

Have you tried locking OD out by putting the gear selector in "3"?

I looked at the spread sheet. As far as I can tell, everything looks normal. Exactly what does the file cover? If it covers the "behavior", what timeframe?

[Truckie117]

Hi
The spread sheet covers about a half hour of driving from streets to hwy It is from carcode program l asked for all systems check. If all things seem normal then maybe the IP is going the symtoms are worse when the truck is cold but they get a little better as the truck get up to operating temp. The Ip has about 100K on it can I ask for more?
Thanks for looking
Merry Christmas
Truckie117

[JohnC]

If the file covers 1/2 hour then it is not much help. That much data should cover about 20 seconds...

One last time: Did you try driving with the shifter in "3" instead of OD? Does it do the same thing?

Do you have EGR? Faulty EGR can cause surging around 45-50 mph.

[GMC Hauler]

Can you drive and look at what your computer is calling engine temperature? I had a problem where the temperature sensor appeared bad (the one on the crossover)

I replaced my engine coolant temperature sensor, but that did not fix the problem. Turns out it was the wiring at the sensor. It was also included in the box that the new sensor came with.

DO what John says. Put the trans in 3 and drive, see if it does the same thing.

[Truckie117]

Hi
Yes John I did drive in just 3rd and still had the same problem. Now that it is below 30 here I seem to have more surging till the truck really warms up. I did change both coolant sensors. One in lower block and the cross over. Just had my wife's car inspected and mechanic at the shop said it sounds like a bad Throttle positioning sensor. Is there a replaceable one on the pump. I was wondering if the injection pump advance solenoid could have anything to do with this and where is it located?
The truck starts up like a champ glow light goes out turn the key and bang she is running.
Once warmed up she idles smooth as silk. runs great warmed up untill 45mph.
I have gm online service manual but that is a lot of information to wade through.
Hard to work on broken truck and take care sick wife.
Thanks Guys

[JohnC]

Does it have EGR?

Do the symptoms in "3" occur at the same engine speed or the same road speed?

Problems with the throttle and with the advance solenoid will set codes. Also, you can watch the actual vs. desired injection timing and the throttle position with your scan software. The throttle position sensor is on the end of the shaft attached to the accelerator pedal.

Have you confirmed the fuel pressure to the injection pump? Have you changed the filter and tried straight Diesel fuel? Any chance the veggie oil has deteriorated the fuel lines? The symptoms sound more like a fuel problem than an electronics problem.

Can you get a 10-20 second snapshot including every data frame from a time when it is surging?

[Truckie117]

John
Does not have EGR which is located on the top of the intake I do not have the plastic cover on the engine I do not run veg and have not for a while. The lines are new and I do a regular fuel filter change. I have a fuel pressure gauge in cab and that is how I knew the lift pump was gone that is now changed. To me it doesent seem like a fuel problem because I can go as fast as i want it is just when I let off the accelerator that the engine seems to not be able to find a happy medium it just seems to drop off. To controll it I just take my foot off accelerator and coast till I reach 55 and then try to touch the pedal to keep a steady speed. I should video this. Also only laptop with xp took a dump and now I cant find xp disk to fix they are at my job so it will be a while.
Thanks
Truckie

[Truckie117]

Hi
Does anyone know how to check if the pmd id good? I have a new pmd DTECh and my mechanic says that the pmd needs to be changed because he is getting reading on scanner that there is something wrong. I had to bring the truck in because I do not have the time while caring for my wife. Does the resistors ever go bad? I replaced the #9 with a 5 because someone said the #9 might give the problems I am having.
At the end of my rope thanks