There was a post the other day about surging while going up hill on cruise control but I have a question. I was drivin today on the interstate and I always feel this surging while going uphill for a while around 70-80mph but today I watched my gauges. After going up hill at the same speed w/o cruise control it doesnt start surging until fuel pressure gets down to 5psi. It feels like its slurping for fuel. After that I dont think it would go any faster if I wanted it to. What is the deal? I can go WOT under 5psi. and not have any problems. Is it the fuel pressure? If so Im ordering the lift pump money or no money.

 

anybody?................

 

Sounds fuel pressure related to me. running two boxes can't be healthy for our weak little lp's mine just took a crap and the conversion kit and pump cost $350 i'm going to pick it up in just a little while. get a decent replacement before it goes out. I don't have a fuel press. guage and never noticed any surging and it just died out right. Even if its not the lp it will benefit you to have a replacement.

 

Did the lift pump fix your problem?

 

FASS or AIRDOG will fix you right up. Right now yor stock lp isn't supplying enough fuel. Soon you'll be on the side of the road.

 

I'm not sure I agree with you since it's been doing it for almost a year. If it's the LP then why does it only do it between certain rpms. Boost levels don't change and throtle position sensors don't show any changes.
Also I took the truck to Floor It Diesel and John hooked up the dbr and we went for a drive only thing we could find was the the ambient air temp went up faster than the intake air temp.

 

Walbro, does it bypass the stock lift pump? If it does, it itself isn't suppling enough fuel. If it doesn't, it's relying on the stock pump to help feed it, and if the stock one gets weak, won't supply enough by itself. Airdog or FASS.

 

If it's still showing a positive fuel pressure at the injector pump, there is still an abundance of fuel there. If there is a lack of fuel being supplied to the inj. pump, the fuel pressure will be zero, or will actually show negative pressure.

 

So if it's not fuel then what is it?

 

does the outside air temperature effect the surging? Does it only do it when it's below say 40 degrees or so?

 

Temp. doesn't affect it. I pluged my wastgate off and now it doesn't seem to do it. Maybe it's the electronic waste gate controler.