Hello, the company I work for bought a 2005 or 06 944e Lull this past summer. It worked great all summer. A few days in late fall it got down to around 35 degrees it started acting up a bit. Driving it seemed to have a loss of power and surge. After driving it awhile the problem would go away. Now that it is full out Winter it seems to get worse the colder it is outside. For example today it was -4 degrees outside. I had it plugged in all night and it started just fine. I let it idle for 30 minutes. Went to drive it and it would not move one bit. I hit the accelerator pedal and it acts like I am doing nothing. Te engine would not even rev. So another 15 minutes later I decide to shift it into reverse and then forward over and over. I would get it to slowly move a couple inches then a couple feet then finally I got to a point where it would drive but barely. Driving it in reverse also helped way more than trying to go forward. Still I would have the pedal to the floor and it would act as if I was doing nothing, About every 15 seconds it would surge the rpm's slightly but that's it. It took me 15 minutes to go 100 feet into our heated shop. I got it into the shop and no kidding 20 minutes later I fired it up and it revs and accelerates just fine. However if I try to work with it outside it will go back to surging when it is cold. It is like there is no pressure in the fuel or a throttle position sensor is out but when it is warm out it works great. What am I missing? We use winter diesel fuel and I have changed all the filters. It is the Cummins engine in it. Thanks
More than likely you have a service brake thats frozen. Also, check your hydraulic tank and see if its foaming in any way shape or form. if there is, the system has been breached and there is moisture in their, you could have a frozen drive valve. Send me a PM and I can get you in touch with my tech dude via email or something and maybe he can help you some more.
You're going to be spending $$$$$$ if you keep doing that. You should follow TriStar Aerial's advice, check the basics, and go from there
Oachs83, any resolution of the derate/surging issue with your Lull 944e42? I have same Lull, 2004 model. Seems to be doing the same thing as yours. Cummins Northeast ran diagnostics and no codes. Thanks.
A parking brake would not cause a no throttle issue. Its spring applied pressure released. The parking brake switch activates the park brake soleniod that has nothing to do with engine rpm. The function pump supplies enough flow at idle to release the parking brakes. If you can work boom functions/tilt/frame tilt then parking brake isnt the issue. Same pump supplies all the above. What is your serial number and what pump do you have ? The ecm will have a threshold that will need to see a temp rise from the temp sensor before you get full throttle. Plugging in the block heater does not ensure that the pre determined temp is hit. Its simply to keep engine and coolant above freezing. Glow plugs or intake heater grid cycle times are adjusted by ecm to aid in starting.