Detroit 8V-92 (Silver 92)

[Sam from WA]

We"ve got an older Kenworth W900 at work, and lately we"ve been having problems with the injector rack getting stuck open, causing a runaway. I"ve never had to do anything involving the fuel system on a Detroit, except bleeding the air out, so I"m kind of poking around in the dark here. The engine runs like its brand new and puts down pretty good power, starts easy, and everything, just like it should, and then you"ll be going down the freeway and it"ll run away.

help much appreciated
thank yall

 

[buickanddeere]

First of all get the Detroit Diesel service manual off the shelf.
There could be some tired or dirty injector(s) with stuck racks. Or a binding rack or throttle linkage. Did somebody recently change a fuel filter or start using bio-diesel?
Is there 20 years of dirt, grease and mud around the engine?
Is the governor working and properly adjusted?
How is the driver getting the engine out of run away mode?

 

[Sam from WA]

The engine is pretty well clean (bout as clean as a guy can get a detroit), we just had the engine overhauled (by a pro) 2 years ago, and haven't had a problem, until tuesday. Govenor is working right, near as I can tell. When it does run away, we pull out the emergency stop, lift the hood, and tap the racks back. It hasn't done it to me yet, but from what Troy says, it runs away when he's shifting into high gear and drops the throttle from high rpms to low when he shifts. Like I said, it hasn't done it to me yet.
I'm the mechanic, so if somebody says its got a problem, I take them serious and try to find it.

 

[guido]

Hello Sam.
If the engine is running away it does not sound like the rack is a problem. I would take and back off the buffer screw at least a full turn.
If you have an engine brake, that adjusment is critical for the brake to work and the engine not to run away. That engine has individually spring loaded injectors so if one is stuck in, it would not make the engine run away, the rest of the rack would go to the no fuel position.If one injector was stuck in it would sound like a single miss.If the rack is binding then it would act also like you described. There are pins inside the governor that wear as well. If you have a fuel modulator it can stick at times. It also has a throttle delay that can be sticking or not properly adjusted.
I have the manual for that engine and I know them well. If you want, drop me an e-mail I'll be glade to help.
Guido.

 

[trucker40]

Sounds like something is wore and getting in a bind.I dont know a lot about Detroit Silver 92s,but if they are like 318s they can get out of adjustment,pins cant be worn a lot or it will not work right,injectors can stick.Best thing to do is look it over while its not running and see if you can find whats hanging it up.Most likely you can adjust something and fix it.You want somebody that knows what they are doing to set the governor.I dont know how you can tell by looking at it,it takes a feeler gauge to set it.

 

[guido]

Hey Sam
Are you sure that you are pulling an emergency stop? That set up does not have one.
Eliminate the throttle pedal and the rest of the linckage. It there is a pto idle control cable, that can be sticking as well.
I would like to hear from you when you get it resolved. My e-mail is open.
Guido.

 

[Chris08]

most likely an injector hanging up. you will be able to feel this by pulling the rack and sliding each injector.