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Another 1996 Suburban 6.5 Adventure

T

turbopower6

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Location
Fort Washington PA
Hi Folks,
The laughs keep coming.....Soooo-ooo after replacing the injectors with new Bosch from Bill Heath , new Durotherm (sic) glows while in there as well, new PT Wiring glow harness and battery cables, all new belts and hoses...including that bastard lower radiator hose that was...wait for it....I believe the original hose after 192,000 miles I figured I would be issue free for at least a while.

Pinch me...I AM delusional...as my wife informs me!

So here we are about 1,000 miles down stream with all systems working perfectly and the truck performance improved in a big way, smoother...more power...quieter (?) ....starting quicker and cranking way faster....she throws a PO236 code?

So I check it, make sure I have strong vacuum to the waste gate solenoid and the waste gate is moving freely. I then clear it drive a few more days...boom another P0236 code again pulling a grade.

This time I looked at the freeze frame and I am scratching my head:

Cal Load (%) 82.3
ECT (°F) 190
ENG RPM 1918
VEH SPEED (MPH) 24
IAT (°F) 145

What does this mean? If I understand the situation, I am guessing the turbo boost is not meeting the PCM expectation under load. Could the waste gate be slowly opening and bleeding boost under a demand for boost scenario? I am pretty confident my vacuum line is in good shape to the solenoid but I could check it more carefully and throw a vacuum gage on it to see where we are at. The vacuum pump was replaced before within about 10-15,000 miles with a new GM part.

I know we have guru's on this site who will be able to weigh in and help we get to the bottom of this.

Thank you...AArggh!

Chevy 6.5 Diesel Suburban is "ADVENTURE" spelled backwards!!
Now...time for cocktails and a debrief.....
Regards,
TGK
 
What boost pressures are you seeing under load going up hill?
Two of a few options are: 1) your turbo is either producing too much boost and you should be defueling or, 2) your boost sensor (top of the intake) is on the way out (not too common). Either will produce the P0236.
Could be the boost solenoid is failing....
 
ak diesel driver said:
still a stock tune?
Click to expand...
Yes. The truck is stock tuned. No upgrade just solid maintenance....clean and tight grounds(all of them!),treated fuel in every tank fill with the Bill Heath recommended "cocktail" and most of all driven in a sane fashion ...not flogged and tortured!

I have replaced virtually the entire fuel system from the tank to the fuel minder aka feed the beast enhancement including a Walbro FRB5 lift pump ahead of a Racor Parker fuel water separator/filter to improve overall fuel filtering and greater fuel flow. No issues here with the added Kennedy Diesel OPS / Primer upgrade. I feed her....wash her...what am I missing is this crazy affair?

Yet... She still insists on making me crazy... I wonder if this truck was a "redhead" in another life?
 
Last edited:
Paveltolz questions will help you figure it out. Keep in mind underboost/overboost can be caused by a clogged air filter, weak vacuum pump, vacuum leaks, bad vacuum actuator, bad turbo, bad MAP sensor, and/or the vac solenoid going bad. Most common is vac leaks followed by the vac solenoid. Still have a soot trap in the exhaust? That can clog up...

Can be fixed for a few grand with a turbo that doesn't have a waste gate, tune, and high stall converter. Sure it's a mechanical pump truck, but, would work just as well on the 1995, tuned DS4, it was intended for.

http://www.thetruckstop.us/forum/threads/let-the-insanity-begin-time-to-yank-it.43647/
 
turbopower6 said:
Yes. The truck is stock tuned. No upgrade just solid maintenance.... including a Walbro FRB5 lift pump . . .
Click to expand...

IIRC this is for the manual injection pump (DB2) and the FRC-10 is for the DS4 in the OBD-II trucks. Although it probably does not have any immediate need to change it out.
 
Hi All,
So after checking for vacuum leaks and finding none I decided to replace the waste gate solenoid with an AC Delco 214-1073 replacement. Oddly enough the bracket on the old original waste gate solenoid was broken where it mounted to the bracket on the DS valve cover. I don't think this would necessarily make a difference but one never really knows for sure.

It seems fine now, pulling stronger and has not thrown a code yet. We will continue to road test the beast to see if we are in the clear. The new injectors seem to make a big difference in how smoothly it runs I must say.

Thanks for the help and input folks!:happy:

TGK
 
JayTheCPA said:
IIRC this is for the manual injection pump (DB2) and the FRC-10 is for the DS4 in the OBD-II trucks. Although it probably does not have any immediate need to change it out.
Click to expand...
x2. I was coming in to say this. If you have the FRB5 you really need the FRC10. Do you run a fuel PSI gauge?
 
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