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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Sharkbait on October 22, 2015, 10:19:05 AM

Title: 8V71 stuck injector?
Post by: Sharkbait on October 22, 2015, 10:19:05 AM
Hi guys, I finally made it back to my bus and started working on it. The motor hasn't been started in about 6 years (I know, I am now paying for my sloth).  Someone on this board in another post suggested pulling the valve covers and pulling the pin on the throttle mechanism and see if the fuel rack moves freely. Sounds like a good idea so that's what I did. The one closest to me moved fine. The one that's harder to get to is stuck. Any ideas to free it up before I start taking things apart.

Also, any tricks to getting the forward valve cover out? There doesn't seem to be enough room to squeeze it out with the right side being congested with oil lines for the generator and wiring and the left side not being tall enough. I thought maybe if I remove the breather on top of the valve cover I might be able to squeeze it out from the left. How do you guys do it?

I would like to try and rotate the motor by hand before starting. Da book says to use a bar back by the flywheel. Is there an inspection port or some other way I could access the flywheel side of the motor to move it by hand? As always thanks for your help and advice. Phil
Title: Re: 8V71 stuck injector?
Post by: chessie4905 on October 22, 2015, 03:01:57 PM
 Can you still get to the access cover on inside rear? Or did it get covered up. Do not try to start it with stuck injectors!!!
Title: Re: 8V71 stuck injector?
Post by: Bill Gerrie on October 22, 2015, 04:36:26 PM
Bar the engine over with a 1 1/2" socket on the front cam pulley. You should be able to get the cover out if you remove the breather.
Title: Re: 8V71 stuck injector?
Post by: bevans6 on October 22, 2015, 05:38:01 PM
I had several stuck injectors, on the advice of Don Fairchild I pumped solvent through them for a while (a half hour) and they freed right up.  Barring the engine over so they get exercised is the first thing I would try.

Brian
Title: Re: 8V71 stuck injector?
Post by: luvrbus on October 22, 2015, 07:21:48 PM
If he has the new style spring load control tube with 1 adjustment screw per injector it won't hurt to start the engine,if he has the 2 adjustment screws for each injector it is a bad idea to start it 
Title: Re: 8V71 stuck injector?
Post by: Sharkbait on October 27, 2015, 09:06:17 AM
They're unstuck. I removed the breather so I could pull the valve cover. I couldn't figure out which injector's were stuck so I removed the fuel lines from all of them and put PB Blaster in all the injector's. Took about 2.5 hrs but they all freed up. I now have to blow out all the excess solvent and re-connect the fuel lines. Then before starting it I think I will re-insall the breather but leave the valve cover off for now so if there's any leaks in the injector's lines I can tighten them up. Thank for the help, Phil
Title: Re: 8V71 stuck injector?
Post by: lostagain on October 27, 2015, 01:17:47 PM
While the valve covers are off, and before you start it, make sure that all the injectors go to the no fuel position when you move the stop lever on top of the governor. It is important to be able to stop the engine...

JC
Title: Re: 8V71 stuck injector?
Post by: Sharkbait on October 28, 2015, 10:07:59 AM
Thanks, I'll check that before I start the engine.
Title: Re: 8V71 stuck injector? Solved, well sort of.
Post by: Sharkbait on December 01, 2015, 01:14:41 PM
Got past the injector's problem. I watched a U Tube video on how to run the rack after I pulled the injector's out. Must have done okey since the motor started and ran pretty good. I've got another problem though. As the air pressure builds up it starts actuating the shut-off soloniod, the one on top of the governor. My question is, what is supposed to actuate that solonoid? Could something be stuck causing that solonoid to actuate? I see my problem being I just don't know enough to know what I'm looking at. Any ideas? Thanks, Phil
Title: Re: 8V71 stuck injector?
Post by: eagle19952 on December 01, 2015, 02:47:09 PM
that plunger is controlled by a Skinner valve up on the bulk head...

take a jumper wire and energize the valve and then air will not "get to" the  plunger...

were all of your wiring intact shutting off the key switch would open that skinner to let air do it's job.

clear as mud ? :)

ps is this a coach that has a lot of hacked wiring...
Title: Re: 8V71 stuck injector?
Post by: luvrbus on December 02, 2015, 12:38:52 AM
Check the position of the front and rear start
Title: Re: 8V71 stuck injector?
Post by: bevans6 on December 02, 2015, 03:48:06 AM
Might be a bad ground connection at the skinner valve.  It should be "normally open", so no voltage and ground to it, it's open and passes air to the air cylinder.  When the front and rear switches are on it gets voltage and closes, blocking air from the air cylinder.  I had a bad ground wire once.

Brian
Title: Re: 8V71 stuck injector? Solved, well sort of.
Post by: Oonrahnjay on December 02, 2015, 05:10:55 AM
Quote from: Sharkbait on December 01, 2015, 01:14:41 PMGot past the injector's problem. I watched a U Tube video on how to run the rack after I pulled the injector's out. Must have done okey since the motor started and ran pretty good. I've got another problem though. As the air pressure builds up it starts actuating the shut-off soloniod, the one on top of the governor. My question is, what is supposed to actuate that solonoid? Could something be stuck causing that solonoid to actuate? I see my problem being I just don't know enough to know what I'm looking at. Any ideas? Thanks, Phil   

     Phil, you have some good advice above, but think of it this way.  The air valve (Skinner) is there so that when it's activated, air shuts down the engine.  It won't work -- either for good or bad -- when you first start the engine and air pressure hasn't built up in the system.  So, if it doesn't apply when you first start up (normal and good, but it doesn't tell you anything) but air comes on and it actuates the shut-down, then it means the air valve is probably working as it should but there's some other part of the control system that's telling the air valve to do something you don't want it to do.
     It *could* be a problem in the air valve but it's much more likely that it's in the other parts of the system that the comments above tell you about.
Title: Re: 8V71 stuck injector?
Post by: bevans6 on December 02, 2015, 06:24:15 AM
Actually the skinner valve shuts down the engine if there is air and it's deactivated.  It has to be switched on for it to not send air to the air cylinder and let the engine run.  If the skinner valve fails it would normally fail open and so kill the engine as soon as air pressure comes up past 60 psi.

Brian
Title: Re: 8V71 stuck injector?
Post by: luvrbus on December 02, 2015, 06:37:56 AM
A lot of buses are wired if the front key is not on they shut down when starting from the rear @ about 60 psi,I never saw a Eagle that wouldn't do it fwiw mine does
Title: Re: 8V71 stuck injector?
Post by: eagle19952 on December 02, 2015, 10:45:11 AM
If this is the coach I think it is ...it is a rescue salvage type with cobbed wiring. (Maybe not.) ..switches missing removed etc..

that's why I suggested the hot jumper to close off the air to the governor slave.
Title: Re: 8V71 stuck injector?
Post by: Sharkbait on December 02, 2015, 03:35:49 PM
It lives! Pulled the cannon plug off the Skinner valve, checked for voltage, looked good. Cleaned the contact points, a little WD40 and tapped the valve for good measure and it worked fine.

In case nobody has told you recently YOU GUYS ROCK! Bus seems to be running fine. Fixing problems are a lot easier when I know what I should be looking for. Thanks for all your help, Phil
Title: Re: 8V71 stuck injector?
Post by: bevans6 on December 02, 2015, 11:53:25 PM
Good job well done!