Fuel Flow Problem?

[kconnair]

My 84 Suburban has started to have some "issues". The truck surges after going around right hand corners (Boost jumps - feels like I just mashed down on the gas pedal for a second :eek:), the water in fuel light comes on when accelerating hard, and I start to have some power loss - like it is running out of fuel. The truck did this before when the fuel pump switch got accidently turned off - all symptoms went away before when the switch was turned back on. Pump is running - can hear it making noise before I crank it. Changed the filter - seemed to help for a brief while. The filter seemed to fill slowly when I pre-filled it with the fuel pump on (engine off, of course). Symptoms do not seem as bad with a full tank of fuel – gets worse with less than a half tank. I have been using Bio-diesel (not sure what %) off and on, without any previous problems. I have run as many as 5 tanks of fuel through (in a row) and didn’t need to change the filter (then).

Any thoughts? :confused:
Fuel Pump failing?

Background: 0.30 over thick head gasket 6.2 diesel "J" - gear drive, and main stabilizing cap kit with a 6.5 turbo set up (about 10 psi max boost), and a 6.5 style electric fuel pump - with a manual switch in line. The truck still has the stock bread-box style standyne filter assembly – I’m not planning on replacing it any time soon, although I have looked at the racor filters.


Thanks!

Kevin

[john8662]

Does sound like air in the fuel, suggest looking for leaks, especially considering the biodiesel comment.

Check out the thread at the beginning of the 6.2L forum about air in fuel.

The surging is normal when the thing gets a sum of air and continues to run!

For the WIF light, that light can come on for water in fuel, or excessive restriction in the fuel filter or somewhere in the system.

[Subzilla]

I too make and run my own biodiesel, use 75% in warm weather and cut it back to 25% in the cold, been doing this for 3 years now. And I run a cheap, small Fram pre-filter just to catch the initial crud. Never really had any filter issues until last month. Both my 6.2's, within a week of each other, had the surging and loss of power with the WIF light. I had to change filters in both about 3 times. That week, temps got down in the teens BUT I didn't have any biodiesel in there at the moment. The other common factor for both was I dumped in some Power Service additive because of the cold weather. My issues began shortly after this so I'm wondering if maybe this stuff reacted with some residual crud in the tank (doing its job), and then maybe slimmed up the filters??? I ran out those tanks of fuel then filled up again. No issues since then.

Again, I had to change my little pre-filters about 3 times before it cleared up. Also, to go along with John, check your old rubber lines. BD will mush these out pretty quickly.