Engine/Transmission (1994 - 1998) Question About Diesel Fuel

[Dave Remillard]

Since making power upgrades I've had a slight stumble problem. One thing that is more noticable is when the weather is much warmer, (80's +)the stumble is more evident. Just curious why. It must have something to do with better ignition of the fuel, since in the winter we need to pre-heat. Just wondering if someone can explain it. Thanks

 

[illflem]

Could it be that when it's warmer you're more likely to have your windows down and just hear it better?

 

[jerryrigg]

Remember Cold air is more dense than Warm air. This is why intercoolers make diesels more efficient. Warmer air means less air to the engine thus less power, as the temp increases a clean air filter is even more important. I'm not saying it's your filter but it is a good idea to check when temps rise. I'd look elsewhere for a problem.



As far as the fuel heater in winter this is not really to aid in combustion so much as it is to prevent the fuel from turning to gel in the filter after all if it is 80+deg, your fuel is warmer than if it is 32deg going through the heater.



-Matt

 

[Dave Remillard]

Bill and Matt----Thanks for the replies. As far as windows down and hearing a change I see what you mean Bill. The stumble is something I feel and not hear so much. I have had this stumble pretty much from the time the 3K kit went in and the #6 plate which has been replaced with a #4. I have a combination of something the engine doesn't like at low RPM's.



I only put the Amsoil filter in a about 6 months ago, but will check that. It does get pretty dusty around here when the warm weather arrives.



I need to talk to Bill Kondolay about his smart controller. I'd be interesteed to hear from anyone familiar with it. Again, thanks for the replies.

Dave

 

[JohnE]

Stumble?

I can almost guarantee that is it the infamous GSK stumble.



We noticed it immediately in JJW-ND's 96 manual. It took me a couple weeks to recognise it in my 97 automatic.

On JJW's Cummins, it was most noticeable when dropping the throttle and it would give a light surge around 1,000 RPM before dropping to idle.

On my Cummins, it will surge if I hold light throttle pressure and the RPM drops to around 1,100 It is even worse in warm weather and my overadvanced (20° BTDC) timing.



Not sure if a cure exists or is neccessary. I know others report no stumble. ???



If it annoys you call, Piers or All for some help.



diesel on

-John

 

[Dave Remillard]

John----Your description says it all. I think I have one of those that in order to cure it will require removal of the GSK. In talking with Piers and Mark at TST, they suggested 181 D. V. 's and the #4 plate for its fueling cure at the low end. It's still there even after the changes. I'm happy with the changes regardless of the stumble. I'm wondering about a smart controller from DTT. I need more information, but if I could control the shift points on deceleration or light throttle conditions, I think it would help alot. Thanks for the suggestions.