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Judy Ubben · 09-22-2021, 09:18 AM

We just bought a 2000 Newmar Dutch Star and are new to class A diesel pushers, we drove her from Ohio to Florida and noticed the amber dash light (light bulb with exclamation ) would come on and the engine would slow down losing 3-4 mph of speed. Then the light would go out and she would speed up again. We are trying to get her in the shop but until then does anyone have any idea what is going on with her.

Thank you
Judy

Skip426 · 09-22-2021, 09:40 AM

Welcome to iRV2 and the vintage Newmar family .

Because my coach is on a Freightliner chassis , I have a different dash warning system ( warning light package ) but , I'll ask a couple of questions , that may help Spartan chassis owner/members provide better answers.

During the time the light was flickering , was the cruise control in use , or did you notice the issue while using the foot throttle ? Both ?

What type of road conditions ? Long uphill ? Level road at steady speed ?

I'm pretty sure your coach has the Cummins 8.3L , ISC with a CAPS ( Cummins Accumulator Pressure System ) I'll have a look through the info I have on CAPS for any ideas on your condition .
In the mean time , making sure the cooling system if full to the MAX cold line and replacing the fuel filters are the first steps when looking into performance issues.
The fuel system returns unused fuel to the tank, so the fuel in the tank goes through the filters many times during a trip and any debris in the tank can plug the filters quickly , often before a full tank of fuel is used.

Judy Ubben · 09-23-2021, 07:48 AM

The slowing did start initially when we were using cruise control but eventually it continued when the foot throttle was used. The road conditions were dry and flat.

We will definitely replace the fuel filters and fill up the coolant to the max cold line.

Thank you and if you think of anything else that would be much appreciated!

Judy and Greg

Skip426 · 09-23-2021, 06:40 PM

Without a CEL ( Check Engine Light )solid on and a code set , filters are the first step .
I'll keep checking through the CAPS info I have and go through some of the posts related to the injection system .

Epp · 09-23-2021, 06:50 PM

I would go with the fuel filters also. Whenever you get a drop in power that seems like the first “go to” and seems to be, most often, the cause.

Ray,IN · 09-23-2021, 07:44 PM

If you actually have the ISC 8.3L engine, they are known to develop a leaking lift pump. Rather than attempt to cover the issue, please use the google search box at page top using leaking lift pump as the search terms.