03 calif. 235 h.p. rail presure test ?

[HullD]

can anyone tell me or tell me where i can get detailed info on doing a rail presure test on 03 235 h. p. calif. emissions truck.

I have a snap on scanner to test with.

When testing with the scanner my rail presure tracks with what is comanded but presure seems to be low.

It maxs out at 21000 but stays there only 1 or 2 sec. before droping back.

I was wondering if the calf. trucks were runing less rail presure?

 

[rbattelle]

I think the SO trucks do run lower pressure. If it's tracking demand from the ECM, why do you think there's a problem?



What are the trucks symptoms that make you think there's a problem?



-Ryan

 

[HullD]

I talked to mark at tst to day who talked to some one he worked with in cummins engineering who said the rail presures should be the same as the 305 trucks

 

[Matt400]

I am driving my sons truck this week and he has a pressure gauge, also CA SO.

I will see how high I can record with the box off.

The highest pressure will be at WOT and near redline and with his big tires I will have to make sure Mr. Highway Patrol is no where in site.

 

[HullD]

I would be thankfull for any info you get for me.

What i am wondering the most is why presure only stays at 21000 max for 1 or 2 sec and then counts down even at 100% load on my scanner.

Mark at tst said about 23000 and hold at max load sould be wright.

Thanks for your input and I will look forward to your posts.

 

[Matt400]

I think what you are seeing is normal. If I remember the shop manual says 23200 is max and I was able to see 22600 with a few WOT stabs. The absolute max wouldn't be achieved unless RPM, speed, transmission position, throttle position, load etc. . are all in the right condition. This was recorded with the gauge right at the transducer.



On the other hand the scanner (same as yours) only caught 21000 and same as yours the pressure backed down shortly after. This could be from the rapid rise in RPM's with no load on the engine to hold it back. The scanner is displaying commanded pressure while the gauge is displaying actual.

So it may command 21000 which simply opens the FCS (fuel control solenoid) longer and then see from the transducer. . hey we are now 22000 and then command 19000 to bring things back in check.



Thats just my opinion in analyzing whats available, the fella that wrote the ecm program would be the one to ask for sure.

 

[HullD]

Matt 400 thanks alot for the info it sounds like yours tracks about the same as mine.

I would have to say mine must be normal then.

 

[Matt400]

I would have to say mine must be normal then.

I think it is. My sons runs pretty good for a 235/460 motor. The VA pressure box pushes it to 300/660 and makes it feel more like my 05 thats 325/610.

 

[Bob4x4]

I talked to mark at tst to day who talked to some one he worked with in cummins engineering who said the rail presures should be the same as the 305 trucks

No they are not :-laf But the injectors all supercede to the same reman #s



Bob