jrs_dodge_diesel

I noticed today that when I floor it the tach only swings up to 2500 RPMs. My fuel pressure is good and the truck is stock. I thought I would be able to get 3000 out of her but every time I floor it only 2500 max. Filters are good too. I'm confused.

Olratlr

Stock Truck will start to defuel about 2700 RPM's.

Ian

it only defuels to 2700rpm, but the actual rpms should go just a bit past 3k...
thats odd...the actual needle doesn't move past 2500rpm? any codes?

jrs_dodge_diesel

No codes and the needle don't go above 2500. I wonder if I might have a slight boost leak at that power level as I do see a gray haze behind me when I floor it.

HOHN

Boost leak won't cause this RPM limit, as you're making little to none for boost in neutral.


I'd suspect the timing solenoid in the VP44. If your pump has high miles, it won't advance fully, and you won't get RPM over a certain point because there's not enough timing advance to make it happen.

Sorry to say, but I think you need a new pump

jrs_dodge_diesel

I really hope that is not the case as the truck runs great otherwise. Also the truck just rolled 90,000 miles and is still on the original VP.

BSmalley

My 01.5 acted very similarly last year, only it was maxing out at about 1200 rpm. I ended up having to replace the ecm and the VP44. It started out as a weak LP. I replaced that, but it had apparently gone on long enough to do some damage to the VP44. The day after I changed the LP, I left for a 2500 mile round trip and the truck acted up all the way. When I returned 4 days later, it had set several codes (don't remember all of them now, but it was the VP44 code as well as a bunch of others) Took it to a dealer I trust and they said the ecm was bad. Replaced that then found that the VP44 was also gone. I had about 97k on the truck then. I got lucky and the dealer ate the cost of the ecm and I paid 1/2 the labor to install and the VP44 was covered under warranty. I hope you don't have to go thru all that. Good Luck.

jrs_dodge_diesel

I am wondering if the APPS may also be a factor. I may be physically putting the pedal all the way down but if the APPS isn't putting out the proper voltage for WOT then that would limit it too, i think.

HOHN

Good thinking. Always eliminate that factor first.

Try a reset, but I think you'll have to put a meter on it to really check it out.

jh

jrs_dodge_diesel

Ok, I put the hammer down from a standstill and she ran all the way up to 3200 before shifting to second. I had to let off shortly after that. the other day when I floored it I wasn't able to look at the tach until 3rd gear and saw the 2500 RPMs. Does that sound normal?

Silverjay

Don't know if it is normal, but mine does the same.

possum67

well my 01 will hit 3200 in first 4 gears but only bout 2500 to 2700 in 5th around 85mph it dies off i think some of thess trucks had limiters on them so maybe a programed error

tenbrooks

Well, there must be something wrong with my truck, it will wrap up to 3600 rpm in neutral.
I got off the go pedal at 3600 as sounded like it would keep going if I didn't
I'm not complaining or anything

jrs_dodge_diesel

If you smash the pedal to the floor the engine will rev past the limit before the governor kicks in. Now if you ease it to 3200 it will stay there all day no matter if you push the pedal harder.