rickf

I have a 98 24V that seems to lack power at midrange on up. I get the normal turbo spool up sound when I start out, it is not real loud but I can hear it. At half throttle and about 1800 RPM I get a much louder whistle, it will increase with power added but not much and sometimes not at all. It just stays the same as I accelerate. When the sound does increase I also seem to have more power. I am thinking maybe a boost leak somewhere? The clamps are all tight and I don't see and leak trails around the hoses. I do not have any other 98's around to compare it to so I need to know if this is a normal sound and I will look elsewhere for my power loss. If you do think it is a boost leak is there any spot that pops up more often than others?

Rick

KATOOM

This does sound like a leak but if you had gauges, this would be much easier to figure out. So you're just going to have to look at all the boot fittings or if you still cant find anything then you may have to pressurize the intake to find a leak.

rickf

That is what I was thinking. What size are the pipes? I have seen plumbing fittings that would fit over the ends of them with schreader valves, Any ideas? I am also going to check to see if I may be pulling air into the fuel before the pump. I replaced the pump last year and after I bled it out the truck ran for about 15 seconds and shut off. Bled it again and same thing. I tightened the line at the pump intake and it stayed running. I can't help but think I may still be pulling air in there and that could be giving me a loss of power issue. Fuel pressure is good. The thing that worries me is when I got the truck there was 0 fuel pressure, that was when I replaced the pump. I have had no issues with the VP44 at all. I think what saved it was that the truck had a 75 gallon aux. tank in the bed feeding the main tank so the fuel level was essentially always above the VP therefor there was no suction and the built in lift pump in the VP was able to keep up. I know everyone is going to say that my VP is going out because they "ALL" go out. I don't really believe that because there are many thousands of these things on the road. I know you hear about a lot on here but think about it. On a forum how often do you ever hear about good things? Not very often. It is always the bad that surfaces on a forum. Granted, these pumps have issues but are they as bad as it seems?

Rick

KATOOM

So lets get this straight first..... Do you have any gauges? Because most of my questions are going to pertain to what those gauges are now reading and have been reading. If you cant answer that then anything we throw at this will be merely a guess. But, given the description of your problem, it does sound like a boost leak. You can get a 4" rubber pipe plug at the hardware store and build a pressure tester to look for leaks but just make sure not to use more than about 25 psi.
Now whether or not your VP was harmed from the 0 fuel pressure, I can’t say and I don’t think thats the issue here unless your loss of power is in the form of "dead pedal".

rickf

Gauges, not per say as you would think but I do have diagnostic gauges I can plug in to get boost and fuel pressure readings. Also my Snap-On scanner will give me what the truck is seeing as boost to verify that the truck computer and real world are the same. I have checked the fuel pressure but not the boost yet. I do need to put on a piece of clear fuel line to see if I am getting air in the line. I stood on it today and there was no loud scream for quite a bit then all of a sudden it started, I definitely think there is a leak somewhere in one of the hoses. There is one hose on the passenger side that is real tight to the A/C pressure switch. I can feel some gouging in the hose but I do not feel any air leak but it seems to need some pressure to scream.

Rick

SIXSLUG

Check the lower drivers side boot first. The fender sheetmetal at that one cut into my original boot. I bent it down and outward away from the new one.

KATOOM

Yes, sometimes leaks in the boots are hard to visually see unless you could place pressure on them while inspecting. And you might want to make sure of any potential boost leak too because boost and EGT's go hand in hand. Loose boost pressure and your EGT's will skyrocket, possibly hurting something. Do you notice any excessive black smoke out the exhaust pipe?

rickf

No smoke at all. I am beginning to think I have two problems at once, air in the fuel which is defueling the engine and the boost leak . Correct me if I am wrong but wouldn't the computer decrease fuel if it see's low boost through the MAP sensor? I know on the older manual pumps the smoke would roll with a popped boot because the fuel on them is a mechanical operation independent of the boost.

Rick

KATOOM

Yes and no. If the MAP sensor fueled only based on the pressure then it would be a fail safe system, which its not. Take off a boost boot and see how fast your EGT's peg. Thats because there is still fueling going on and boost and EGT's are byproducts of fuel. The IAT sensor also controls fueling based on intake temperature so the MAP isnt alone in that duty. One of boosts many rolls is keeping the EGT's in check by pushing out all the heat while shoving air in the cylinder. If there's no boost then the engine is acting as a natural aspirated engine and therefor your HP will be significantly less. I'm not saying this is your problem but merely pointing something out. And if you truly have so much air in the fuel that you're starving the VP then you may also be hurting the VP since air is not a lubricant in this situation. You can add a clear section of hose just before the VP to identify air bubbles but what we really need to know is what your fuel pressures during at idle, cruising, and WOT. And what your EGT's are during those fuel pressures.

rickf

I tried the clear tubing but I found out real quick that you need 1/4" clear tubing to go on the 5/16 fuel line tight enough to be able to clamp it without leaks. I can tell you the pump puts out a LOT of volume!!! Found that out when I bumped the starter and went out to look at the line, Fuel everywhere! And you can't stop it till it times out. I am going to pick up some 1/4 inch line to check for air. Fuel pressures are 18 at idle, around 14-16 at cruise and 12 at WOT. It is a NAPA replacement pump that I bought before reading about all of the pump issues. I do not have a pyro but I am planning to get a Glowshift gauge that has the EGT, Fuel pressure and boost all in one. From what I have read on hear nobody has said anything bad about them. I really do not know if I am losing all that much power because the truck has made this sound since I bought it a year ago. I came to this truck from a 96 Powerstroke which I still have. The trucks are about equal in power. I would think the higher horsepower rating along with the lower gears of the Dodge should make a substantial difference in seat of the pants feel.

Rick

rickf

OK, I was poking and prodding at the boots and now it is not screaming. I can be pretty sure I have found the leak but then again I have not really found it. There is no sheet metal near my drivers side hose but that hose is fairly soft compared to the others. The pressure sender for the A/C is rubbing on the passenger side upper hose and there is an abrasion there. I can not feel any air just by revving it but when driving it does not squeal until I have been on it hard for a few seconds. I can not duplicate that sitting in the driveway. I am going to have to find the rubber plumbing boots and pressure test the lines. Any suggestions on a source for new boots?

Rick

KATOOM

Be careful with the fuel line. You dont want to create a restrictive spot just so you can see bubbles. If your fuel pressure is what you say then I'm sure your bubble problem is nothing. What you're not getting is any "volume" of fuel with those tiny lines. 1/4" fuel line is hardly big enough for a VW bug let alone your Cummins. Thats why guys are changing to high volume fuel pumps with 1/2" fuel lines. But thats another topic.

Back to the potential boost leak. You can make a way to pressurize the engine with a 4" rubber pipe plug at the hardware store to plug the turbo intake and a brass barb fitting to replace the wastegate boost elbow. Then take an air compressor and pump about 20 psi of air in through the barb fitting and look for leaks. You will never be able to make boost sitting in the driveway. Boost is a byproduct of fuel and RPM's so revving in neutral wont do anything but maybe build about 1-2 psi at most. Thats why when you increase throttle rapidly, you the turbo lags behind. That lag is because it takes a moment to build boost. And two engines with similar HP ratings dont have to feel similar at all. HP and torque ratings will be at different points of the RPM scale, not to mention that gear and engine design will all affect the seat in your pants feel.

rickf

I was not able to get out and get the stuff I need to check for leaks but I have another possibly stupid question. When the wastegate opens is there any change in sound? I know the ricers with there turbos will really scream when the wastegate opens usually at the shift. Since I have been feeling and poking at the hoses it seems like the noise has become intermittent. I still think it is a hose but I am checking all possibilities. Any suggestions on replacement hoses if I find that is the problem?

Rick

cohocoal

I had similar problems, and found my waste gate actuator was failing. I could not get past 17-18 lbs. of boost. I clamped the hose to the actuator with vise grips and the boost went up to 21-22 and performance improved. I then changed the actuator and that solved the problem. Not sure if this will help, but it cured my issue. Hope it's as simple as that.

KATOOM

Maybe the question I should be asking is what is the sound you think you're hearing that is giving you reason for concern? There is a clear difference between turbo whistle, a boost leak, and an open wastegate valve.