I have noticed over the last week on several occasions at various times, usually when I am at 1600 rpms in 3rd or 4th that if I press the foot feed I get no accelleration. it just stays at the speed I was currenlty at. If I take it out of gear and hit the gas it will rev up then I put it in a lower gear and then it accellerates and sometimes with hesitation.

Well this am on the way to work it was happening more frequently and in 2nd gear. I would have no response and then it would surge to the speed to match the pedal. This seems more prevelant in lower rpms. between 1500 and 1700. I have replaced the vp 44 about 100k ago and then the fuel pump about 40k ago. I am going to replace the fuel filter after work and see if by some remote chance this may be the problem although I highly suspect ist is something worse. Any thoughts?

 

Time for another VP.

Check for codes, chance are you've got a P0216 in there. (VP-44 timing failure)

You have what is called a "dead pedal".
Classic.

Do a search, that will confirm your worst fears. You really need to get yourself a fuel pressure gauge, a lot of these failures are caused by Lift Pump (the cheap one) failure and can be avioded.

 

Another tidbit.

I have read more than a few times, people are having fuel related issues, their first thougth is to swap out that filter they had been neglecting (not that you have), truck never starts again. Not sure why, but it happens.

 

Thanks for the response, was hoping for better news. It P---s's me to no end if I have to buy another vp 44 for this truck as I just replaced my wifes rotary also in her 93.

Your last post is exactly what happened when my electronic fuel pump went out. I thought the filter might have plugged up even though I knew in the back of my mind it was unlikely since it only had 5k on it. I swapped it with a new one and turned the key to fill the reservoir with diesel and-nothing. (the buzz was gone from the electronic motor turning on.)

Before that I had always thought if the fuel pump was bad it was either working or not working nothing inbetween or intermittent as it was with my truck.

Do you know of any better after market electronic pumps or injector pump set ups other than the cummins fuel pump or Bosch vp-44?

 

Well, there are other options out there for the "lift" pump. The FASS pump (not kit, just the pump) seems to be popular, I have also read some positive opinions on the "Glacier Diesel" (aka Walbro) kit. If it were me, I would go get myself a Campaign 504 pump from a Cummins dealer (search that name here), they are about $64.00, a direct replacement for the stock Carter pump you have now. One step further would be to get a LP relocation kit, it moves the stock pump down in front of the tank, away from the vibration and heat of the engine bay. ($115.00?)

Not much can be done about the VP-44, you are pretty much stuck with that. There is a conversion back to the "P" style mechanical pumps that involves a cam swap, I would imagine it is more than you want to get into.($$)

If you plan on keeping the truck I would suggest investing in some gauges (approx. $325.00).

How many miles on the truck?

 

looking at your sig. you dont have a fuel pressure gauge. that for our gen. trucks is a must.. i saved myself 3 weeks after i installed mine. just a thought.

there are many ways to go as for lift/transfer pumps. i personally run a holly blue label. but there are many many many choices. as for the vp44. they are all still the same pump with diffrent parts put on them .. wether its a vp-44, hrvp-44. blue chip. stock etc. there is talk occationally of people going to the old 12v 2nd gen style i/p . almost bulletproof from i have seen and read! but you will loose the ease of changing power levels with electronic chips!

 

I have 209K on Besse and hope to keep her for another 200K. These trucks are just getting too expensive to buy new.

I swapped out the fuel filter even though I had low miles on it and the truck started and runs as before. Last time the lift pump quit after I changed out the filter.

What should my pressures be from the lift pump? I have been told in the past that there is no code for the lift pump going out and unless the "check engine" light is on I will not be able to get any codes indicating a bad VP44.-is this correct?

Could this intermittent hesitation on accellerating in 4th and 5th "dead pedal" in the 1500 to 1700 rpm range possibly have to do with my Superchips D box? Not sure how to tell if it is working.

It would seem to me that if the VP44 or lift pump is going out it would be more prevalent at higher rpms...?

 

Still hoping for some response to my previous questions...................and one more question.....what is an isolator that has been referred to in previous posts about fuel delivery issues?

I can't seem to find a guage to check my LP pressures from the test port on the VP44-AutoZone only has a "rental" guage for gasoline motors. Any ideas on this?

Also what about a possible fuel relay issue causing these problems? A mechanic friend relayed an experience from the past that he replaced an LP and an injector pump only to find out it was the relay....how does one test for this?

 

Is the LP an electric pump or driven off the cam shaft?

 

the LP is an electric pump mounted on the engine just behind the fuel filter. When you turn on your ignition you should hear it cycle. If you bump the starter and don't start the engine the LP should run for about 30 seconds.
I am running the Bully dog kit with the Holley blue and it works great.

 

13.5-15.5 on a healthy pump. Correct, there is NO code for a failing lift pump (hence the need for a F/P gauge in the cab) Check engine light DOES NOT have to be on for you to have a failing VP-44.


Take it off for a week, if the problems subside, there was a problem with it, this is highly doubtful given your symptoms.
Not necessarily so. The lift pump itself wouldn't care what rpm you running, it is electrical.

If you are going to go through all this, you might as well do an "APPS RESET" too. I think it is listed in the tech facts section up to there, basically required you to unhook the batteries for a while to reset things.


An "isolator" is a diaphragm device that measures fuel pressure and sends the signal to your gauge. They are notorious for failing, giving false readings and having folks think they have a fuel delivery issue. If you don't have a gauge, you don't have an isolator. If you DO get a gauge, please skip the isolator set up, just run fuel straight to the gauge, using a needle valve in-line.

 

Thanks P.J. and all- I am looking at the Vulcan big line kit to relocate my next pump to the frame. I can't believe the $125.00 price for some fittings and rubber fuel hose! I may put it together myself for that price!

I can't seem to find a test guage to screw in to the pressure test port on the incoming fuel line to the VP44. What type of test guage and where to buy is now my issue. Also maybe a dumb question but-how to test pressure at WOT?

As far as installing a fuel pressure guage and EGT guage I am hoping to do this in the near future with pillar mounts as soon as I can set aside some OT money. Any thoughts on the best pillar mount guage set up without breaking the bank?

Also one more question--why use a needle vlve on the pressure guage set up? Is it to bleed air for more accurate test?

 

Good questions.

1) Yes, you can put your own "Big line" lit together, the convenience of having it all there in one tidy package is worth something too though. Eric sells a nice kit, is it worth $125.00?, probably not, but he is in business to make money.

2) You can make one of those up too, it is much easier with what is called a "tapped banjo" (a bolt that replaces one of the brass looking banjo bolts on your fuel system) This fitting gives you a 1/8"NPT connection for a line to connect to a gauge. You can use the Schrader fitting on the VP-44 itself, just a matter of finding the appropriate fitting to go there.
Testing at WOT, this has been done with some duct tape and a gauge on the windshield. I would just concern myself with the idle #'s for now. The installed gauge will be there for you to peek at to see your highway cruising and WOT readings.

3)www.dieselmanor.com You can get fairly set up for under $300.00 (3 gauges, related wiring and pillar mount) Keep an eye on the classifieds here too, sometimes people take gauges out of their truck before they trade in, or upgrade or whatever.

4)Needle valve: This is INSTEAD of an isolator. It is similar to what you would see someone hook up the water line to the back of a refrigerator with. There are pictures all over this site detailing how to hook up a FP gauge "mechanical" without an isolator. (search, Moparman1973 has some nice pictures of ALL the fittings and tubing needed).

5) My bill is in the mail.

 

By the way, you are in the heart of Diesel Truck county down there, you shouldn't have a hard time finding someone to give you hand with this stuff when you gather some of the parts up.

Can't hurt to ask, Texas is a hotbed of guys with nothing better to do than tool on these trucks.

 

Hmmmmmmm......I think some of us resemble that remark.

True, Bastrop is in Texas, but it's still a 3 to 4 hour drive from here.