Cat Products

[Tug]

Hello,

I have a 2007 Pete 335 with the pre-emission C7 in it. Since the day it was brand new, it has had a slight stumble or sputter in it, which has only gotten worse over time.

The CAT dealer had it about 5 times and said they couldnt duplicate the problem, yet as soon as I would pull out of their parking lot with it, it would do it.

The Peterbilt dealer had the truck just as many times and they claim they couldnt duplicate it either.

Currently, it has 115,000 and 4,383 hours on it. The truck gets a complete service every 5,000 miles using only CAT filters and Delo 400 oil.

In the last 6 months or so, the stumble has gotten more frequent and it stumbles on just about every take-off. Once the truck is up to speed, the stumble is gone however, it does seem to lack power on hills.

Upon scanning for codes (no codes found) the engine oil pressure is reading 78psi on the laptop. The oil pressure remains 78 whether at idle or WOT. The gauge on the dash however, reads normal (40-55 psi)

I do a lot of business with Cat here in Cincinnati. One of the techs there suggest I try replacing the Injection Actuation Pressure Switch and another tech suggests replacing the HPOP. Any ideas or suggestions from you all?

Thanks!

Tug

[lj0120]

It sounds like the oil pressure sensor has failed. If the CAT ET is reading 78psi all the time even with rpm change there is definitely something wrong with it. Look at this graph.