I have a DD6v92TA Mechanical with Jake brakes and Automatic Tranny the Jakes quit working. I checked the 3 way switch by the driver and I have no voltage to it with ignition on. It has a fast idle solenoid. Does the 6v92 have a buffer switch if so where is it located? Can I remove the wire that is supposed to be hot at the switch by the driver and add a hot wire there to see if a solenoid is bad and etc?
The buffer switch is on the governor body ... looking at the front of the motor it's on the left hand side of the G-body. If you have a manual tranny there is a micro switch on the clutch arm that could be out of ajustment, I doubt the the buffer switch would come out of ajustment. I think you will need a elec schematic to how it's wired. Look for a fuse that could be blown.
As a side note, I had a problem with my Jakes a couple of months ago. They just quit all of a sudden. I had power at all the right places but the jake wouldn't activate. So after many hours of scratch my head wondering what the heck was going on, I grab the throttle level on the governer and revved the engine up and for some reason I pull back on the level this time instead of just letting it go ... and the Jake worked. Some how the throttle cable got a little shorter and the governor wasn't going to the no fuel position. I ajusted the throttle cable outer sleeve and all has been good since.
Ron
Quote]Can I remove the wire that is supposed to be hot at the switch by the driver and add a hot wire there to see if a solenoid is bad and etc?
Do not start trouble shooting in the middle of the problem. If there is no voltage at the switch then there is a problem somewhere before the switch.
There should be power to the buffer switch terminal with the engine at idle. In fact there should be voltage at both terminals.
If no voltage at either terminal check for bad fuse or connection. This would be the place to jumper voltage to to check everything thru the switch to the solenoids.
If voltage at one terminal and none at the other then check for throttle cable not fully released letting the throttle not return to full off, or
last resort, bad or mis-adjusted buffer switch.
Richard
Quote from: Eagle on June 08, 2007, 08:58:40 AM
I have a DD6v92TA Mechanical with Jake brakes and they quit working. I checked the 3 way switch by the driver and I have no voltage to it with ignition on. It has a fast idle solenoid. Does the 6v92 have a buffer switch if so where is it located? Can I remove the wire that is supposed to be hot at the switch by the driver and add a hot wire there to see if a solenoid is bad and etc?
This is what I have found today after tearing the Bedroom apart in order to get to the engine. I have a hot wire going to the Automatic transmission switch with 12 volts on it but no voltage on the wire coming back to the Buffer switch at the governor body. Does the automatic transmission have to be in a certain position for the voltage to come back to the buffer switch?
IF the wire to the tranny goes to a pressure switch on the converter lock-up port, you will not have power coming from the transmission unless the transmission is in converter lock-up mode. Might try a jumper wire acorss theswe to wires to see if you then get ower to the buffer switch. Jack
Jumped out the wires to the transmission switch and now have voltage to one side of the buffer switch. I sure do love this Bussing thing.
Quote from: Eagle on June 09, 2007, 04:24:59 PM
Jumped out the wires to the transmission switch and now have voltage to one side of the buffer switch. I sure do love this Bussing thing.
Now all you need to do is get voltage to the other side of the buffer switch. Since you indicated you had made some adjustments in your throttle cable, I would check that out first and make sure the governor is returning to the full off position.
If you still do not get voltage on the other sied of the buffer switch, then jumper the buffer switch and turn the Jake's on and off. You should be able to hear the solenoids inside the valve covers actuating. I think you are within a gnats hair of finding out what your problem is. And good job of troubleshooting.
Richard
My jakes had not worked since I have had my bus. It was one of those things that I finally got around to. I started at my jakes and worked backward. I had butt-end connectors every two inches and found that there were more under the valve cover. It seems that the combination of heat and oil was hard on the wire's insulation. I rewired the solenoid wiring to eliminate possible shorts or opens. With the valve covers off, I started the engine and tested each solenoid one by one. In case anyone is wondering, the oil does not squirt out of the valve train, it just kind of flow down back into the heads. I first manually pushed the tops to see that the valve would work; it was interesting to see what goes on under the valve cover. Using that method I found one that had a metal tab out of place that caused it not to work, easily fixed by bending it back, must have happened during installation. I decided to unscrew them to clean them up with carb cleaner. I tested each one with 12v to see that they worked. One thing I found out is that they like a full 12+ volts, anything less and they will not work. Now I was having fun, put them back on and started the engine again and applied 12v to each bank and verified all was well before putting the valve covers on. I then tested for continuity between each service panel till I found the bad (corroded) connection.
Now you're talking and working! Good Luck, TomC
Now you know why I installed a couple of cube relays in the engine compartment to operate the solenoids under the valve covers. 12 volts from a circuit breaker directly to the cubes and then to the solenoids. The jake switch and buffer switch are only used to feed power to the cube relays.
Good trouble shooting BTW. I had never tried leaving the valve covers off with the engine running.
Richard
I jumped out the buffer switch and everything works as it should. Either the buffer switch is out of adjustment or it is bad. Getting to the buffer switch is a real pain in the butt as it is under the edge of the governors top plate and behind the throttle linkage.
Thanks for everyones help in this endeavor.
JCB
Laryn, you Da Man! I wouldn't have thought that you could run a DD with the valve covers off. So on your v-drive, the "lower" head didn't poop out oil either?! Wow.
My Jakes are still acting up even after I replaced a solenoid last Fall. I think I'll follow yours and Richard's advice and redo the 12v feed with solenoids, one for each bank. And my buffer switch has been a pain, too, like JCBs.
What a great board!
Brian B.
I had a mechanic where I work tell me that the easiest way to tell if all solenoids are working is with the valve covers off. I had a hand full of rags just in case but I didn't use a one, even on the lower bank. I don't have a lot of experience with them so without seeing each one work I would have never known that there was one inoperable. I guess there might be different styles, but mine you can manually push on the tops to activate them. I made a long jumper wire to touch each screw connector and see each bank work. I have four solenoids, each working two cylinders, I don't know if there are other configurations. I admit that I was mesmerized by, and enjoyed, watching the valve train operate. I only wish I took photos.