Another fueling problem.

4x4dually

4x4dually

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Here's the skinny now.

After starting the truck up, it idles bad, like it has high flow tubes or something but it doesn't. I can hit the pedal a time or two then it will clear, sometimes. It stubles a little when I take off then clears up. Runs fine down the road. After a while it will quite, then come back. Gets worse every day. The fuel pressure from the LP reads 15 psi then when it cuts out goes to 18 or 19 then back. Doesn't make sense. Pressure is read at the IP so the fuel filter is out and the LP works because I have great pressure. Can an IP failure case the input pressure to vary? I know I have an APPS issue but still haven't switched it out yet. It issue is only at 18 to 20 % throttle. At idle, the APPS is out of the picture other than the little switch telling it to idle.

Any ideas on what it is....other than buying a new freakin', piece of crap, designed by the devil, VP44?
 
Sounds a like a new piece of crap designed by the devil VP44...wait...doesn't that high tech WTF code reader you got not tell you if your phaluter valve is out of tolerance with the doohickey??
 
Nope. Everything is normal. The only thing that varies is the LP pressure and the RPM.
 
You've got as interesting of a problem as I do. I've never heard of that but there's a lot of stuff I ain't heard of.
 
What about the overflow ( return ) check valve on the VP ? That could effect fuel supply pressure?
 
that sucks that you got another fuel issue. hope you get it figured out, but if not there is a nice resistol mega cab sitting right down the road from you that might cure your problems.
 
I think you need a VP Jory, the fluctuating FP is telling me something ain't right internally. I'm thinking internal fuel transfer pump is having issues.
 
So if it were to be replaced, get a built SO pump if I'm going to tap the wire? Or do I get a built SO pump and not tap the new wire? I want over 400 ponies. My clutch is built for 450. Would it be a wise choice to buy a pump from II and buy new injectors like dragon flys or something? Any chance these jammers could cause the pump to dump or is it just the fact I have the wire tapped? I really hardly EVER put it on 5-5 and stomp it. Maybe once a month. Really sucks. Where's the check valve?
 
First thing when I get home today I will be checking all the lines. It really hasn't been but off and on until I drove to town yesterday. Atwoods parking lot gave me a fit. I looked for fuel but need to put a wrench on them. Thanks for the idea. I'll check it out.
 
The check valve is right next to the feed line on the side of your injector pump. It's a banjo bolt with a ball and spring in it to regulate internal pump pressure. It's a long shot though. You have to pull the bolt out and check the ball and spring. PM if you have any questions. I believe you need a pump to be honest, but you ask not to be told that. Your pump whoes go way back to the problems you've been having.
 
I WANT a new pump, I just DO NOT WANT to tell the wife I need a new pump. :D
 
4x4dually said:
So if it were to be replaced, get a built SO pump if I'm going to tap the wire? Or do I get a built SO pump and not tap the new wire? I want over 400 ponies. My clutch is built for 450. Would it be a wise choice to buy a pump from II and buy new injectors like dragon flys or something? Any chance these jammers could cause the pump to dump or is it just the fact I have the wire tapped? I really hardly EVER put it on 5-5 and stomp it. Maybe once a month. Really sucks. Where's the check valve?
Click to expand...

For you? I would say just get the best priced SO pump you can and tap the wire the second day you have it. Get a set of DDP injectors for it at the same time.

4x4dually said:
I WANT a new pump, I just DO NOT WANT to tell the wife I need a new pump. :D
Click to expand...

Disconnect power wire from the lift pump and keep driving, you won't have a choice before to many miles. OR you could always point out the likelyhood of your "old, tired and worn out" pump's likelihood of failure...with the young one in the truck!! :evil
 
UM.....just a thought........Not loosing power to the pump or truck??? Gauge electric? Or mechanical? When the pressure/truck stutters....does the lift pump still have power? Might be the ECM doing something funny. Might rig a test light to the power wire of the lift pump and monitor the power when the truck hiccups. The ECM might be killing the VP and LP at the same time....causing the act up......my 2....and have seen stranger.....

Its just strange that your FP fluctuates slightly when the issue happens......
 
Oh God, here we go with the "grounds" again. :hehe:

I just put a new (used) ECM in it from Bob Wagner. My ECM took a dump and went all kinds of crazy. He sold me one for a great price out of another truck. It ran great since the first time I fired it up about two months ago. Only problem is, my ABS and Brake light won't go off because I get a "VIN mismatch" error. The PCM has the correct VIN, but I didn't know the ECM had to have the VIN too. Is that true? The LP must have power because when it studders the PSI actually goes up to 18 or 19 where it doesn't usually go. The gauge I'm looking at is the one connected to the Attitude monitor. The sensor is, well you know where it is. I guess it could be cutting it real short and then when it turns back on it surges. I'll put my DMM on the wire when I get a chance and test out the lift pump first since it is easier.

Thanks for the tips.
 
The ECM controls the IP and LP, correct? Why don't you get off your lazy rear end and get the ECM reflashed to your VIN and see if that helps?
 
You know, thanks for bringing that up. That might just be a cure. I'll call their stupid asses right now and see if I can get into the dealership in the next month! :D
 
Holy Lord, they can do it first thing in the morning...I don't beleive it!!!
 
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