I just bought a 2000 Sterling quad dump, auto allison 6speed tranny, Cummins ISC engine. I just put the truck on the road today and with a load, its gets up to 45mph only and real slow. Not loaded it will get around 55mph, but not real fast. It has/had a engine warning lite. Im not crazy about this computer engines, but I guess its the new world and I must adjust and pay for the computer hookup and test. I currently have a appt with a shop, to have the computer checked out. Any ideas, or simple test I can do? I have checked all connections, etc This was a repoed truck and it had been setting for about a year. It has 250,000 miles Engine starts and runs good, no smoke, new filters:Banghead
There's not much that you can do other than to see what codes are showing. It could be in some kind of limp mode. If there are any electrical connection problems, the computer will let you know. I'd have the truck run on a dyno just to make sure that you are making the advertised hp. Not having enough hp with an auto will lead to all sorts of transmission/converter problems.
The Cummins ISC is a pretty small engine for a quad dump (only 8.3 liters). They usually run around 300hp and only around 1000 ft/lb torque. Sometimes the engines with auto transmissions run a little more hp but not much. Was the truck an original quad dump or converted to one? What was the GVW when you could only do 45mph? My guess is that is all that the little ISC could do.
I was asked to trouble shoot a Series 60 that had no power and no codes on the laptop . It had an accident and the intercooler had been replaced . I took it around the block and came back . The workshop boss said what do you think ? I said theres a pair of pajamas in the Turbo intake . He said have you got xray vision ? They took off the intake and sure enough a piece of rag was in the compressor wheel housing . He said i'll kill that mechanic , why would he do that ? I said i'd kill him if he did'nt do it while the cooler was out , the trick is , remove it before you put the hose back on . Has the intake been been off ? If not pull it off and check the impellar is not stuck from sitting , no one would have bothered to cover the exhaust to keep the rain out . On edit , if it is fitted with an ehaust brake , check that the butterfly/slide is not jammed shut .
Can that ISC motor be tuned? to make more power for the job you need?
troubleshooting update Had the truck checked out today and they found the camshaft speed sensors bad (I think thats what they said) This truck had two of them anyway. They did replace them and the code went off, they were checking something else (code) and will get back with me. The truck hasnt been test driven yet, I wanted to make sure all the old codes were checked. Answer to GVW question, I would guess 69-70,000 lb, it was sand, so Im not sure and this was the first load, so I couldnt eye ball it and guess comparing to the other trucks. I think the driver said it took forever to get to 45mph and it never did get about 4th gear as far as I know, this is a factory quad, it doesnt look like a conversion. This is my first automatic, so its going to be a learning experience, with what it will and wont do. Someone did tell me, the automatics were better pulling out of soft areas. The shop is checking on changing the computer to give more HP, I think they said it would cost $80 to get a upgrade code from Cummins, if they would let me change it. Not sure what I will get for $80, I should know tommorrow and will keep you posted This is a pretty nice truck, but I will be aware before buying another repoed truck, without checking it out better. It had a front spring broken, is the reason I didnt drive it on the road, for a test drive. Thats all for now, thanks for all the replies
sounds like its not getting full fuel. smaller Cummins of that vintage (ISB and ISC) are notorious for killing the lift pumps. The trucks will still run as long as it can retain the prime in the fuel system but will lack power. Running with a dead lift pump will eventually kill the Injection pump though and that's when it really starts costing $$$$
troubleshooting update I did pass this onto the shop and they said the fuel pressure was OK, but they think the wiring harness going to the module on top of the injection pump is bad. They think that when they test drove it, that the engine kinda died down and picked back up and someone has been messing with the harness. Kinda an expensive guess ($400) on their part, so I told them to hold off, unless they are sure. This is not a high tech shop, but they are a Cummins dealer. I guess I might try the truck with a load and see what it does. The closest Cummins, good dealer, is 2 hrs away, I might have to make the trip Thats all for now, still waiting to see if they can give it more HP
well if the harness has been messed with then its most certainly because of a lift pump replacement. Their engineering "FIX" for this problem was to install a big red light on the dash of the truck that would light up when the fuel pressure was below the required. That was when you knew it was time to replace the lift pump. MANY guys have opted to install the FASS system to replace the factory failure prone pump. Atleast it looks like you cought it in time before it started to kill your injection pump.
update Finally got the truck back, dont you just love those fly by night dealers. They said they thought the engine wiring harness had a short in it. At least the truck will pull a load now, it pulled 21 tons 60mph, it didnt jump to 60, but it got there with too much struggling. I ordered the harness to see if it corrects the flashing stop engine and engine warning light Thanks for all the replies
Willis B...I can't help but mention a good Cummins service department for you in North Carolina. It's in Kenly, exit 106 off I-95 out behind the Flying J travel center. It's a brand new building, with service 24 hrs. (I believe) Monday through Friday. I went there to have some work done and it was on second shift. The service mgr. was excellent, and so was the actual service. In your situation there was no alternative but to plug in and check for codes, and go from there. Unfortunately you get these "bluffers" once in a while that claim they're certified, bonafied & qualified in certain areas, and they are indeed...in certain areas.:cool2
Lowboy I've had a stop in there as well and everyone was freindly as can be.