trucks at martys... again

[97stoker350]

so i had all the work done in my sig at martys diesel last year. about a week before i picked it up it developed a miss at high speed and high rpm under a heavy load. figured it was a cps. so i got the truck put a new one in and it still did it. finally got a different oil pump recently to try out. still didnt fix the issue. so i took it back to martys for him to look at. so far he has tried reburning the chip and swapping idm's. neither has fixed the issue. the truck has to be hot, and under a heavy load in a high gear at high rpms for the miss to occur. him nor i have no idea what could be causing this. any help would be awesome. thanks

 

[mandkole]

how high of rpm? ( I would assume high boost pressure as well.) The truck runs great until that point? Have you datalogged in these conditions?

 

[97stoker350]

Yes runs great until then. Marty datalogged it and said nothing happened and yes high boost

 

[mattman347]

Do you have a boost fooler on the truck?

 

[97stoker350]

No.

 

[mattman347]

Install one. My truck cut out at high RPM and acted like a shudder. Put on a boost fooler and problem was fixed. Just something to try...

 

[97stoker350]

Ok I txted Marty about it thanks!

 

[powerstrokenstang]

I vote boost fooler too. How much boost is it making?

 

[97stoker350]

Over 30 everytime it does it

 

[mandkole]

valve sealing or control issues perhaps? Springs?

 

[97stoker350]

^ elaborate please not sure what youre talking about.

 

[Swaan]

You need a fooler on the line going to the map sensor. Put a regulator on there so the map sensor only sees 25 psi of boost max. My 97 would fall on its face at high boost high rpm. This fixed it.

 

[mandkole]

its not falling on its face, its breaking up (as I understand it from the original description). Its one or two cylinders getting pissed off... My thought was a valve being held open, bent, etc. but, if that was it, it should do it earlier.

 

[97stoker350]

Yes it cuts out for a split second. If I let off it stops get back in it and it does it again

 

[Swaan]

Yup that's what mine did. Just try what I said. It's just like you shut the key off for a split second.
Two words. Boost fooler!

 

[97stoker350]

That's what it was Marty put one on and it stopped! Thanks for the help guys!

 

[Swaan]

Bam!! Told ya! :rockon:

 

[always-strokin]

OP who's tunes are you running and how old are they? Most good tuners will be able to tune an OBS (and maybe even an SD) to not need a fooler

 

[97stoker350]

Swamps

 

[Marty]

This is the first obs I have had to put a fooler on. Fwiw I also changed chips at the same time so the fooler may not be the fix. The original chip was having issues that only 1 or 2 positions on the chip even made a difference.

Todd you can come pickup the truck after the holiday, wednesday works.