Slow reving/low power 6.5

[diesel dave]

Hi guys,
have a 998 with a get 6.5. Starts and idles ok,but is so sluggish,it is not usable in high range. Air cleaner is ok. I'm getting 7-8 psi out of the fuel filter. So I'm leaning towards injection pump or timing issues? Any thoughts?
and yes,I bought it this way,so I have 0 history.
thanks,
dave

 

[dmetalmiki]

That sounds as the fuel pump needs some adjustments. Or worst case, changing. Can you check the timing? When running try spraying diesel into the intake..if it revs up..could be the pump delivery.

 

[dilvoy]

You might have a stuck glass check valve in the return fuel nipple that is located at the top front of the Injector Pump. When it gets stuck it can cause the problem that you are having. It may be getting stuck with dry rotted bits of the rubber return fuel hoses or maybe just stuck. You can remove the nipple and try to blow through it. It is a clear glass plunger so just looking through it and seeing light is not good enough. If you can't blow through, break it out and make sure to get all the glass bits out. The little spring can stay in there or you can get it out too. Easy enough to try and it will run just fine without the plunger or you can get a new nipple assy and install it. Shouldn't be too expensive. A badly performing fuel lift pump might cause the same issue and I guess you might just change that to start with all good rubber bits on your vehicle too. If these two items are OK and you have good fuel flow, then you probably need an IP. There is a little timing mark on the timing cover and one on the IP. They should be aligned or misaligned by the thickness of the marks and no more.

 

[diesel dave]

Thanks guys. I'll try and let you know how I make out.

 

[Texas187]

Thanks guys. I'll try and let you know how I make out.

To be honest...I'd probably keep that one to yourself...

 

[diesel dave]

Dilvoy,
tried your suggestions,same issue. I guess it's time to remove the IP and take it for a rebuild.
thanks for your help!

 

[diesel dave]

After removing the pump,I found the problem. Seems water had accumulated in the engine valley at some point and had rusted the shaft that advances the timing. Cleaned out the drain hole and had the injection pump rebuilt. Runs perfect now.

 

[gerrykan]

Thanks for the follow-up.
It may help someone else in the future.

 

[mountainmanmdk]

I had a similiar issue found out the inlet rubber hose to fuel pump was collasping in on itself.