stumble & mysterious low power with 370

[John L]

Hello-

I recently installed my Piers 370's, 3k governor & afc (med) springs kits & love the power increase but I'm still trying to work out all the little bugs. First I had a very touchy throttle which I fixed by loosing the governing spring retainer a couple of clicks.

The next issue is a stumbling problem at 1750-1900 rpms. The stumble is substantial & causes my truck to buck until the rpms are pass 2K. If I acclerate fast the problem isn't as present.

Could this be a delivery valve issue? I know normally 97 5 speed truck don't have any issues with delivery valve size but maybe a Calif egr equipped trucks have more differences beside the egr system?

Also yesterday my truck just didn't have the get up and go as it normally does. It just seemed low in power and the rpms didn't raise as nearly as fast as it did when I first installed the stuff. Today the truck is back to it normal self? I checked EGT (normal) & inspected and retighted the intercooler connection, afc housing intake, etc, etc. Could my overflow valve be going bad?

Any advice would be very appreciated.



John L

 

[Cummins Corvette]

California trucks have the 180 pump don't they? If so, then you need delivery valves too.

 

[Cooker]

The pump on the CA truck is not 100% a 180 pump. There are some 215 parts on it. The D-Valves in a CA truck are the 052 181's (the same in the 49 state 215 pumps).

 

[SlyBones]

My originally canadian truck, was a 180 pump, with 181 delivery valves. Didnt take to the 370's very well. Currently have 215's in there.

 

[John L]

Talked with Al over at Piers's shop and he said it sounded like a delivery valve problem so I orderd the High Flow ones from them (well see). Also ordered a new overflow valve just in case the mystery power lost comes back?

thanks again for the responses



John L