12+ PSI Boost Motor Craps Itself

[DA BIG ONE]

I am using the mech boost controller on my turbo, I cranked the boost to about 12+ it runs like a bat out of hell at first, then craps itself like it went into limp mode, also suffers loss of boost, and gets real hot.

My pyro meter "probe pre-turbo" never went past 900 deg. when this happened.

I let the motor idle to cool down, the intake and IC were super hot too.

Question: I have the HD programming, is perhaps the MAP sensor causing the ecm to go into limp mode, or, that maybe my 3" B&D exhaust has too much backpressure at upper boost levels causing superheating of aircharge.

Below the 12+ psi never a problem!

Any thoughts?

[markrinker]

My truck runs best with a nominal setting of 12psi, spikes beyond that. You have similar mods in place, I'd look to exhaust restriction, or maybe your boost gauge isn't right and you are really making TOO much boost.

[john8662]

Sounds like you need a electronic boost control, or fooler. If you have a turbo master installed on an electronic 6.5 the computer will sense a too high boost pressure and fuel down. Thats why it was a dog. On stock computer settings you won't want to run anything more than 9psi, unless you get an electronic boost controller, or you'll fuel down or set a code.

[Dvldog 8793]

Howdy
Ditto what john said. My 1999 wont run with a turbo master without PROBLEMS. I have a JK boost control and it works GREAT, installs simple and I made a cover for it so it even looks cool! :D
the 1999 trucks have the OPTIMUM computer settings right from the factory, not much you can do to improve on it.
I run about 12 psi max with spikes of 14.
Hope this helps.
L8r
Conley Janssen

[Perry]

I keep hearing about the 99 factory programming to be the best, but how different was it from 98 for example? I thought the HP and torque ratings were the same for the two years?

My 99 was ok when completely stock, and was a bit better with a free flowing exhaust. But it didn't wake up until I had the Heath 2.0 reflash. Or could I have had the same improvements by just putting in a boost fooler with the stock 99 programming?

[Dvldog 8793]

Howdy
From what I've heard the 1999 NON-egr/NON smog HO motors had the good programing. I'm not sure of anything else. I have been told by vendors trying to sell a reflash that I would be waisting my money! :D
L8r
Conley Janssen

[DA BIG ONE]

Originally posted by Dvldog 8793:
Howdy
Ditto what john said. My 1999 wont run with a turbo master without PROBLEMS. I have a JK boost control and it works GREAT, installs simple and I made a cover for it so it even looks cool! :D
the 1999 trucks have the OPTIMUM computer settings right from the factory, not much you can do to improve on it.
I run about 12 psi max with spikes of 14.
Hope this helps.
L8r
Conley Janssen

[rjschoolcraft]

I run JK's chip and boost control on my truck. I sustain 18 psi boost when towing heavy. About 16 psi sustained (short period) on hard solo acceleration.

[DA BIG ONE]

Originally posted by Dvldog 8793:
Howdy
Ditto what john said. My 1999 wont run with a turbo master without PROBLEMS. I have a JK boost control and it works GREAT, installs simple and I made a cover for it so it even looks cool! :D
the 1999 trucks have the OPTIMUM computer settings right from the factory, not much you can do to improve on it.
I run about 12 psi max with spikes of 14.
Hope this helps.
L8r
Conley Janssen I'll get the JK boost controller now, I am just hoping that the entire boost circuit in the ecm has not crapped out on me.

I went with the mechanical controller after a mech told me the ecm boost circuit is most likely bad, but that was a guess on his part. I checked the vacuum pump, is ok, then changed out the solenoid when having problems, it worked ok for about 1 week then went south again.