6.5 lunging and surging

[scot5146]

Hey y'all- my diesel 99 k2500 suburban was lunging while traveling down the freeway, fuel was low but not empty. Got to a gas station, put a few bucks in it, tried to start it but just cranked over. NO START...

I am at a loss, been sick with cold so I haven't worked on it yet but I am trying to figure out where I should start, I think it's a fuel problem.

Thanks.

MIKE

[scot5146]

Hey folks

So I have noticed that the gas cap has a lot of suction behind it... Is that normal for a 6.5 diesel?

I am heading to the shop now for some diagnostic work on my rig... I will keep you all updated.

Thanks

Mike Scott

Firefighter
VANCOUVER, WA

[rapidoxidationman]

IIRC a fuel tank cap is meant to hold pressure but vent vacuum. Try a new cap and see if that fixes the problem. Vacuum building up could make your lift pump and injector pump work harder than they need to, as well as suck in air from any leak in the system especially before the lift pump.

[sctrailrider]

You could try leaving the cap loose or off and see if that helps... if you get a new cap be SURE it's for a diesel and not gas, they are different.

[scot5146]

:DTruck runs great once I got all the air out of the system!

Well it turns out the fuel system was air locked, my wife was driving it and is not very familiar with the fuel gauge on the truck, hence it sucked air from being to low.

The Gauge is really inaccurate so I am trying to figure out how to remedy the problem...

Is there a better fuel sending unit on the market for 89-98 Chevy 4x4s 6.5 diesels?

Thanks;)

Mike

Firefighter
Vancouver/WA

[a5150nut]

Glad you figured it all out. When 6.5s run right they sure are nice. Had my PMD go south recently. The new one made it so much nicer. Stopped the smoking at startup and the rough idle. Not sure why it effected that, but it did.

Enjoy the ride.