Hello everyone and thanks for sharing all of your wisdom. It is truly great to have access to such a wealth of knowledge. I have been searching here for months to try and find someone with my problem but can't seem to find an exact match so here I go with a post.

Have a 97 K3500 with 54k on the meter. Make/burn biodiesel in warmer months so I am burining it now. Now a little history:

Last year relocated and replaced PMD with pensacola diesel kit.

Got a bad batch of Bio (soapy) and truck ran like crap, was able to flush it out with some concentrated shots of PS 911. I sell oils and additives too and can afford to pour a bunch in the tank and it indeed cleaned the system to where it was running completely normal again.

Had been running dino all winter and made the mistake of putting a tankful of unfiltered saddle tank (rusty etc) fuel in the truck. Immediate check engine light after long crank.

Ran bad, done several stints of 911, liqui Moly diesel purge etc and it has seemed to get much better. Lot of fishbiting that was as low as 2700+. Now it doesn't start to fishbite until 3100 RPM and feels like it is about to break free at any time. Have codes PO370 and PO251 but one is only pending now. Here are some of the other things that have been checked:

Both batteries new
New lift pump and unless it is shutting down at high rpms it is working
Checks last ditch filter in housing
Checked filter on injection pump inlet line
New pickup and sending unit
Tank is clean as a whistle (courtesy of bio)
Waste gate functioning
PCV cleaned and helped leaks
NO READING ON AIR FLOW ON SCAN TOOL???
Truck seems peppy but falls on its face under load
Hard high rpm shifts
RPM's will drop slowly from 3000 back to idle without a problem

Since I have been running around with the MIL on for so long could the computer have normalized itself to this state?

Is the fishbiting cause or effect?

Cannot hear turbo at all, is it working in this kind of limp mode?

As I have put additives through this truck there is no doubt that the performance has gotten better but still have a long crank and these symptoms.


Just bought a rebuilt pump on CL today for 300. Want to make sure it is the problem before being stumped after install.

Also what are the best inexpensive scan tools that can reprogram after pump change out. I also sell tools and get wholesale pricing but don't know much about scan tools. Is there an aftermarket tool that talks nicely to these trucks. I was thinking the scantool.net blue tooth setup with scanxl pro and GM enhanced... Thoughts?

Well I tried to answer any questions that I see asked here that are meaningful to a trouble shooter if you all need any more answered please feel free to ask.

Thanks again and have a Great Day!

Joe

 

A snap on mt2500 works well on these trucks if you enter the model year as 2000 no matter what the real year is.

There are 2 PC based scan tools:
Carcode and Autoenginuity

Carcode is not at all user friendly though.

Sounds like the bio has clouded the optical sensor in the IP-if you are very careful some acetone can be use to clean it-a remove/replace is found here but must be followed exactly.it must be marked and returned to the very same place.
Roy Halvorsen