Well I'm trying to figure this truck out yet. Took it in today and had it scanned. No codes, buzz test was ok, but cannot do a cyl. cont test. Is there something else that needs to be done to do one? I made a HPOP gauge, tested the pres, 550 psi at idle, 1500 psi WOT no load, spikes to 2650 psi WOT under load. Bought new UVWH to put in later today, we'll see if that helps at all.

 

If the scanner is capable of a CCT you need to have the engine fully warmed. It needs to see the EOT at 140F IIRC.

 

What he said

 

Whats the problem ?...

 

Misfire from about 1800 rpm to 3000 rpm under load or not. The scanner said the oil temp was not high enough, the truck had been running for about three hours. Ordered a new temp sensor them we'll try again. Replaced o-rings on injectors, but did not help.

 

ahhh, I've encountered this problem on a cummins, I've actually had to do a cylinder cut out test which cuts out one cylinder at a time manually. you'll run one cylinder down and cut out another having 2 cylinders down untill you find the faulty cylinder you want to cut out.

Unfortanitly we do not have the option with our truck, we have a contibution test yes and are fine but can be difficult for intermittant problem injectors. The cummins has a contribution test but at times will not find the problem.

I'm not on the computer that much but when you do get your scanner to work and if the contribution test does not work for you another way you can possible do this which will be a big PAIN IN THE A$$ is to unbolt your valve covers, dissconnect each injector one at a time and drive the truck under load, when you get to the rpm you encounter your problem you will be down 2 injectors, when you finally come across an unplugged injector and it still only feels like you have one cylinder down, you found your faulty injector. Just remeber every time you take for a test drive you may want to throw a couple bolts in the valve cover cause you will lose alot of oil.

 

Thanks, I was about to do the unplug the injector trick anyways. I did not think about doing it under a load though, I'll give that a try. Just need the time to do it!! I am going to try replacing the UVWH too. Piece by piece this thing will be new.

 

I dont mean to doubt you dave, but doesnt the snap-on type scanner cut out each cylinder by itself? we just had my brother's truck scanned and it found a faulty injector (cyl 7 contribution). the reason i ask is because test sounded like it shut off each injector. i could be wrong, but isnt that the same test? sorry if i

 

the cylinder contribution test wont run until engine oil reaches 170 degrees...not 140...lol.

if the scanner does all the other tests then it should have a choice for that one as well. if not then your best bet may be doing it manually as described above

 

IT does have the choice for it, it will not let you do it though. I wonder if the oil temp sensor s not working correctly, or its just not hot enough.

 

read the "eot" pid. that will tell you what is going on