The Hill Billy
New member
- Joined
- Feb 28, 2010
- Messages
- 204
Ive done a fair amount of searching and haven't come across anyone posting these particular set of issues at the same time. Ill attempt to keep the background story short...
Had the truck, sold it, the kid blew it up, kid had a shop fix it, I got the truck back.
Its a 24v 5.9 bored .20 over, studded, I think O-Ringed, with a hot rod VP and only about 5k miles on it since installed on the truck. Used stock injectors I'm almost certain. Airdog 2 165gph lift pump. Edge drag comp programmer.
Up until just recently, fuel pressure just before the VP sat at 13 lbs and never dropped below 10 lbs. The last few days I have gotten white smoke and a fuel knock at startup. The fuel knock only hits once, maybe twice and disappears. The smoke clears up after just a few seconds. Fuel pressure starts at 13 lbs, dips when load is applied and then begins to climb. At idle or when no load is present the fuel pressure stays constant, but once put under a load it dips (as you'd expect) and then begins to creep up. Sitting at a red light I turned the lift pump off (its on a toggle) for a couple seconds and turned it back on. Fuel pressure dropped with pump off but went right back to where it was (18 lbs) when I turned it back on.
I don't believe its the pump crapping out. My first guess is that it is an injector not sealing up and dripping fuel when shut off causing the fuel knock (occasionally) at startup and the excess smoke. Once the motor heats up a bit it all clears and cylinder pressures even out. If I start the truck without priming the line and turn the lift pump on after it starts, there is no fuel knock and very little smoke.
The rise in fuel pressure is what is baffling to me. I did notice the other day that when I left the truck running and stopped to fuel up, when I took the cap off i got a decently loud "ppsshhh". Is one of the lines having restricted flow? Its my DD and Id like to not have it down very long, so I figured Id ask the experts here and get an idea of where all to start looking for the fix.
Thanks for all the advice!
Had the truck, sold it, the kid blew it up, kid had a shop fix it, I got the truck back.
Its a 24v 5.9 bored .20 over, studded, I think O-Ringed, with a hot rod VP and only about 5k miles on it since installed on the truck. Used stock injectors I'm almost certain. Airdog 2 165gph lift pump. Edge drag comp programmer.
Up until just recently, fuel pressure just before the VP sat at 13 lbs and never dropped below 10 lbs. The last few days I have gotten white smoke and a fuel knock at startup. The fuel knock only hits once, maybe twice and disappears. The smoke clears up after just a few seconds. Fuel pressure starts at 13 lbs, dips when load is applied and then begins to climb. At idle or when no load is present the fuel pressure stays constant, but once put under a load it dips (as you'd expect) and then begins to creep up. Sitting at a red light I turned the lift pump off (its on a toggle) for a couple seconds and turned it back on. Fuel pressure dropped with pump off but went right back to where it was (18 lbs) when I turned it back on.
I don't believe its the pump crapping out. My first guess is that it is an injector not sealing up and dripping fuel when shut off causing the fuel knock (occasionally) at startup and the excess smoke. Once the motor heats up a bit it all clears and cylinder pressures even out. If I start the truck without priming the line and turn the lift pump on after it starts, there is no fuel knock and very little smoke.
The rise in fuel pressure is what is baffling to me. I did notice the other day that when I left the truck running and stopped to fuel up, when I took the cap off i got a decently loud "ppsshhh". Is one of the lines having restricted flow? Its my DD and Id like to not have it down very long, so I figured Id ask the experts here and get an idea of where all to start looking for the fix.
Thanks for all the advice!
