[celicaxx]

Still down on power (FIXED!!)

ISSUE RESOLVED / SEE POST 16
Vehicle in question:
2000 4wd 2500
23,000 miles
No mods till today > Carter GP4601HP

Bought the truck about two weeks ago. It idles and rolls out with no oddities except the fact that it feels like I'm dragging a massive boat anchor. It seems that after 20% or so throttle position, it doesn't seem to add more fuel or make more power. So I suspected APPS.

Did the white tag calibration and the reset, still the same, except it seems marginally less powerful. The numbers on the white tag calibration were: .573v before and .507v calibrated.

Haven't found any boost leaks, and the turbo does spool up. I'll put the boost gauge in today to check the actual boost level.

In the meantime, the stock lift pump was putting out 40oz of fuel in the 25 second relay test; recommended is 45oz. Pressure after the filter seemed a little low (around 8-10 psi), so I installed the Carter pump. No change. Filter looks clean and no pressure drop through it.

I may swap out the APPS with a friend's to see if what happens.

Does the ECM/PCM need a flash for low sulfur fuel? I'm not sure if that was ever done. No diagnostic codes except for the P1693 and no accompanying codes.

I'm grabbing for straws at this point.

 

[Ozoneburner90]

It's called the dead pedal and could be the map sensor..this was casing my dead pedal and cleaning it fixed the problem. Here is the link on how to clean it. MAP Sensor

 

[celicaxx]

MAP sensor was cleaned two days ago (no oil residue) with Electron cleaner. Thanks for the link; I haven't checked the IAT. Looks alot like a GM IAT I use for my Megasquirted turbo Supra.

 

[Ozoneburner90]

you might have a dead vp44 then, but that seems stupid if you only have 23,000 miles. Your trucks practically brand new..

 

[celicaxx]

how can you determine if the vp44 is dead or going out? all the symptoms i've read about so far aren't coinciding with my symptoms

 

[Ozoneburner90]

sometimes the dead pedal can indicate the death of the vp44 and codes may or may not show up if the vp44 is dead. The death code for it is p0216.

 

[rdix7991]

Dude! 23,000. That is amazing!

 

[texas503]

Welcome to the quest of finding out what is wrong with your truck... Good luck.

 

[celicaxx]

yeah, this looks like the same story with my supra.........bought it thinking "this will make a good daily driver". $10,000 in parts later it sees the asphalt only on trips to the track.
I see this turbo-diesel addiction will cost me much more.

 

[black01cumminstruck]

Vehicle in question:
2000 4wd 2500
23,000 miles
No mods till today > Carter GP4601HP

Bought the truck about two weeks ago. It idles and rolls out with no oddities except the fact that it feels like I'm dragging a massive boat anchor. It seems that after 20% or so throttle position, it doesn't seem to add more fuel or make more power. So I suspected APPS.

Did the white tag calibration and the reset, still the same, except it seems marginally less powerful. The numbers on the white tag calibration were: .573v before and .507v calibrated.

Haven't found any boost leaks, and the turbo does spool up. I'll put the boost gauge in today to check the actual boost level.

In the meantime, the stock lift pump was putting out 40oz of fuel in the 25 second relay test; recommended is 45oz. Pressure after the filter seemed a little low (around 8-10 psi), so I installed the Carter pump. No change. Filter looks clean and no pressure drop through it.

I may swap out the APPS with a friend's to see if what happens.

Does the ECM/PCM need a flash for low sulfur fuel? I'm not sure if that was ever done. No diagnostic codes except for the P1693 and no accompanying codes.

I'm grabbing for straws at this point.

Wow that truck must have been buried in an old man's garage or something. Have you tried adding some fresh diesel fuel to the tank and just go and drive it for a couple hundred miles? With that many miles, who knows how long that tank of diesel may have been in there. Just an idea. :confused013: Definitely check for trouble codes with a scanner though.

 

[celicaxx]

first day drove it to atlanta, ga (about 2.5 hrs away) to haul a car back..........the longest day of my life. I've ran two tanks out since then. funny enough, it got about 16-17mpg on the road trip with a 2k lb trailer on the way and another 3k back home; that seems reasonable/about the same as my old 12v '95.

I've checked the codes on the scanner; only time it threw codes was right after the white tag calibration and after i tried to run it without a MAP sensor.

One thing I've noticed, these trucks so far are easy to work on, but I imagine pulling the motor is hell. My cherrypicker would [email protected] itself

 

[black01cumminstruck]

first day drove it to atlanta, ga (about 2.5 hrs away) to haul a car back..........the longest day of my life. I've ran two tanks out since then. funny enough, it got about 16-17mpg on the road trip with a 2k lb trailer on the way and another 3k back home; that seems reasonable/about the same as my old 12v '95.

:confused013: Sounds like it is running like it should, in my opinion. Your fuel economy numbers are excellent. Try to describe your power problem in greater detail.. "it feels like I'm dragging a massive boat anchor. It seems that after 20% or so throttle position, it doesn't seem to add more fuel or make more power." So if you press the pedal to the firewall it does not accelerate like you think it should?

I've checked the codes on the scanner; only time it threw codes was right after the white tag calibration and after i tried to run it without a MAP sensor.

One thing I've noticed, these trucks so far are easy to work on, but I imagine pulling the motor is hell. My cherrypicker would [email protected] itself

Yes, they are very easy to work on, at least compared to my GMC with the Duramax engine.

 

[celicaxx]

Sounds like it is running like it should, in my opinion. Your fuel economy numbers are excellent. Try to describe your power problem in greater detail.. "it feels like I'm dragging a massive boat anchor. It seems that after 20% or so throttle position, it doesn't seem to add more fuel or make more power." So if you press the pedal to the firewall it does not accelerate like you think it should?

let's put it this way: my '03 tundra would out pull it by a far shot. I could go up a gradual incline and it slows down dramatically unloaded until kickdown, and even then it doesn't pull any better, just holds the same rpms until I come off the pedal to let it shift out. In a nutshell, the transmission is kicking down when it should, but the fuel side doesn't seem like it's responding after anything over 20% throttle. my old 12v d250 would outpull it big time, and it had the oversized turbine housing (ie: late spool)

another way to look at it that it's equivalent would be putting a small brick under the accelerator pedal, except for the kickdown. your going somewhere, but you better not be in a hurry unless it's all downhill

 

[black01cumminstruck]

let's put it this way: my '03 tundra would out pull it by a far shot. I could go up a gradual incline and it slows down dramatically unloaded until kickdown, and even then it doesn't pull any better, just holds the same rpms until I come off the pedal to let it shift out. In a nutshell, the transmission is kicking down when it should, but the fuel side doesn't seem like it's responding after anything over 20% throttle. my old 12v d250 would outpull it big time, and it had the oversized turbine housing (ie: late spool)

another way to look at it that it's equivalent would be putting a small brick under the accelerator pedal, except for the kickdown. your going somewhere, but you better not be in a hurry unless it's all downhill

That sucks, and yes, something is definitely wrong. It should do a lot better than what you describe. Checked your boost psi yet? There is a 3/4 inch pipe plug on the rear of the head on the driver side that you can remove and adapt it to 1/8" npt for a pressure gauge. Check your lower intercooler boots, it is very common for them to rub on the fender wells and tear. The tear can be hard to see with just a brief eyeball inspection. Again, just things to check. I know you said you checked for boost leaks, but it can be easy to overlook. Also, check transmission fluid level. ? That's just what I would do. Also, check your fuel pressure. I'm not sure if your fuel flow numbers are sufficient or not, sounds like they are though. Check out this website. Blue Chip Diesel Performance Specialists If you can't get it diagnosed on here, I am sure the guys there can help you out.

 

[celicaxx]

not much to update:

have noticed lately that occasionally (rarely at best), when I start off somewhere the truck will have a short burst of power. Almost like I had a 100 shot of nitrous for about three to five seconds. Seems like this usually happens when I get it warmed up, shut it down for at least a few minutes, then after I leave the second time the burst of power kicks in. Weird.

Also, I noticed one day that if I pull off the connector to the boost sensor, no change in power, just a CEL. Seems like I should get different response:confused013:
When I connect the sensor and clear the code, the CEL doesn't come back.

Got a new fuel pressure gauge (electric) and gauge pod. I'll try to install them and the boost gauge this weekend. My Supra has eaten all my time lately

 

[celicaxx]

I gave in and went to the Dodge dealer. They said boost sensor, so $400 later I'm back in business. Part was only $145, but diagnostics and labor owns me.

Runs soooo much better; let the mods begin!

 

[Ozoneburner90]

you could have bought the map sensor from here for $57 and saved yourself $343, but as long as it runs good then your fine..Cummins Sensors

 

[celicaxx]

you could have bought the map sensor from here for $57 and saved yourself $343, but as long as it runs good then your fine..Cummins Sensors

Yes, I could've blindly starting buying parts and hope it gets eventually gets fixed, or take it to someone who knows by experience what was wrong. I had people saying anything from APPS to VP44. I had a feeling about the boost sensor, but I also thought it was a fuel sump issue, bad ECM, wiring harness/connection, grounds, etc.

I'm the last person who wants to go to a dealer, but this time I felt it was necessary.

Thanks to all who responded:thumbsup:

 

[Ozoneburner90]

yea..you could have wasted extra money on another lift pump even if it wasn't necessary. Good to get the problem fixed the first time. Sweet supra buy the way; i always loved the sounds the supra makes.

 

[celicaxx]

yea..you could have wasted extra money on another lift pump even if it wasn't necessary. Good to get the problem fixed the first time. Sweet supra buy the way; i always loved the sounds the supra makes.

Too late on the lift pump, that was the first thing I bought. Thought it would be a good idea considering the stock pump's reputation.

Well, the truck is great. I've learned alot about troubleshooting these things although it seems to be a fairly simple system. Different, but simple.