I have an appointment first thing Friday morning for front end noise and loss of power. I am running FP gauges and I have noticed lower pressures under WOT. The pressure will drop to around 6.5 under load. I called the dealership and they said anything above 6 was OK but they are going to look at it.

As for the noise, it's kind of a squeal at low speed, like brake squeal but as soon as I touch the brake, it stops. I believe its coming from the right front. I took the wheel off and blew out all the brake dust, but the squeal came back. I have no idea what is causing it.

The dealership has been instructed to only troubleshoot the problem and report back to me before they begin repairs. I have a load to pull Saturday morning so I do not want it taken apart and parts be ordered. We will see. Wish me luck.

Tim

 

Sounds like a front wheel bearing.

 

Sounds like a combination of brake dust and glazed rotors. One thing you can try is while out driving, with no one else around, hit the brakes hard a couple of times, don't lock them up, and that will remove the glazing to the rotors. Try it and see what happens.

 

Back from the shop....

Low pressure, loss of power- not evident during test drive, no flow test done. No codes to indicate a problem.

Squeal - rotors need turned on back brakes - not under warranty

So my next step is to turn the rotors and see what happens. I guess I will just keep an eye on the fuel pressure. Bad part, the truck only has 28,000 miles on it. Good part - no major problems found. I guess I am just overly cautious.

Tim

 

Tim,

At 28,000 miles?? That doesn't seem right!!

Before turning the rear rotors, take some crocus or emery cloth and knock the glaze off of them. See if that doesn't stop the squealing.

Rusty

 

I don't have rear rotors, but I replacd my front pads at 90K and they were not worn out, but getting pretty thin, and the rotors are still OK. Getting rid of the glaze might fix your problem.

 

I will try the emory cloth to remove the glaze and see what happens. I could not visibly see and issues with the rotors. I have worked on cars for years and I know a little about what to look for. My personal opinion is that one of the pistons in the dual calipers is not releasing the same as the other and it is cocking the pad slightly causing it to touch constantly. As soon as you touch, just touch not apply the brakes, the squeal goes away.

Needless to say I was not pleased with the "we can see any reason to test the loss of power issue since there are no sign during the test drive." I have a fuel pressure gauge and it reads 6 PSI at WOT, but I guess thats not enough to get them to flow test it. I will probably spend the $150 on a new lift pump for my own piece of mind.

Tim

 

If your seeing 6psi at WOT doing the volume test is a waste of time. It will pass with no probs.

 

My FP gauge drops to about 7psi when fully gettin' it. I think you're over-reacting to a bunch of hype you've read on the internet.

 

My o2 runs about 7 also. 12 to 13 at idle and 11-12 at moderate speeds. 7 wide open up a steep grade. i checked the volumn per the cummins test and it passes just fine. i agee on what mechanos on the over reacting.

 

My original lift pump is still providing 16+ PSIG at idle, 14-15 PSIG at cruise and 11-12 PSIG at WOT - towing our 16K GVWR 5th wheel (see signature). The only fuel system mod is Ray Torresdal's oversized banjo bolts.

Rusty

 

I have over size banjos also, and I definetly feel a loss of power while pulling our camper. When the truck is not pulling the camper it is fine, no problems. As soon as its loaded with 7,000 lbs, the power falls off and their is a definite problem. I know the normal loss of power due to the load, but I have been pulling the camper for 2 years and I know the difference between now and before. Last year the fuel pressure spiked at about 22 PSI on this same pump. I posted then and was pretty much told the ball unseated itself. Before that time, never did the pressure drop below 10 PSI at anytime. So if I am seeing 6 PSI know it is definetly different. Maybe over reacting is true, but I cannot afford a $1400 injection pump now or at a later time. Just being cautious.


Tim