When riding done the road and I hit a bump, I seem to lose power for a fraction of a second. I can hear the engine winding up and it appears to go drop but does not shut off. No lights on the dash. No error codes. The Tach does not drop. I have checked the charging system, battery connections, Alternator connections, changed the fuel filter. It feels like someone flipped a switch and cut it back on fast. When bob tailing its hard to pick up, but the heavier the trailer the more noticeable. If I hit four bumps on a hill, it will happen four times and I will lose speed and have to down shift to make it to the top. I'm thinking turbo. Has this happed to anyone else. Thanks for any help you can give me.

 

It a 03 Volvo 770 w/ Cummings ISX auto shift

 

Honestly, I'd check those battery connections.

The volvos have a small wire for positive and negative running straight off the batteries.

 

Yup, I agree with Allan. The computer has a dedicated wire connected to the battery. It's a small one. If it's loose the computer will shut down and reset causing the engine to falter.

 

Cummings ??? has never been spelled with a "g"

 

i can't ever recall diagnosing a turbo's performance to be susceptible to hitting bumps : )

the engine warning lights never come on? even when the engine picks up again?

there should be a fused, 3-wire harness behind the ecm that connects the ecm directly to the battery

 

The dealership has check all of the connections, checked the fuel pressure, and updated the software. Still have the same problem. When you ride over a rough road and hit a bump, the truck is cutting out. It never shuts down, but cuts in and out. You can hear the engine pull and then nothing for a fraction of a second, and back on again. If you are on a smooth hwy nothing happens. Please help if you can. Thanks RaacerXX

 

can you reproduce this problem with a tech in the truck? i would ask them to run a snapshot during the road test, that should tell them what parameter is being lost

 

The lights on the dash never come on. It does not give a code when this happens. The dealership recreated the problem with the computer hooked up, and supposedly the needed to upgrade the software in the computer. I have been told by another driver that it was a loose connection at the battery that cause his truck to do the same thing and it didn't show a code. I told the service writer this and he said thats not the problem with my truck. I did drive the truck to see if the problem had been fixed. Now when you try to go through the menu on the computer it goes blank, and wont come back until you restart the truck. Just another shop trying to milk it for all they can. I'll be talking with the service manager on Tues.

 

I think I know what your problem is......when you hit a bump, either the motor is moving or a problem with your linkage to your injection pump. What ever it is it is happening when you hit a bump and is quickly moving your linkage either forward or rearward causing the abrupt change in its position. I had the same thing with my 9200 International and the service manager at my local International dealer gave me a lot of suggestions what it could be. Got to looking myself and found the linkage was loose near my injection pump. Tightened the linkage and not a problem with it since.