No solution (long)
#31
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Thread Starter
Either something is wrong with the tracking in the pot, or it is being swung too far by the linkage.
In either case, the resister in the ground lead starts it out near the low end, and mechanically it shouldn't reach the high end.
The pot is 2.5Kohm, so 1V would be at 500 ohm, and 4V would be at 2Kohm.
With a 300 ohm resistor in the ground lead, 1V would be at 260 ohms on the pot, and 3.5V would be at 1660 on the pot.
Should be pretty close, maybe need to adjust trimmer downward a bit, but start there.
In either case, the resister in the ground lead starts it out near the low end, and mechanically it shouldn't reach the high end.
The pot is 2.5Kohm, so 1V would be at 500 ohm, and 4V would be at 2Kohm.
With a 300 ohm resistor in the ground lead, 1V would be at 260 ohms on the pot, and 3.5V would be at 1660 on the pot.
Should be pretty close, maybe need to adjust trimmer downward a bit, but start there.
#32
Registered User
When you turn up your pump and have to turn down the idle, that stretches the low end. Full throttle mod stretches the high end. sum of mods puts it out of range. The trimmer is to compensate for that.
Now, if you get it in range and it acts up, I'll be officially stumped.
#33
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Location: Dierks, AR SW
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I wish you guys would figure this out... my 92 has had this problem for several years. I am the one with a wire connected to the ground side of the OD solenoid - run through the floor - insulation peeled back a couple of inches - bent with a hook shape on the end and when it starts acting up I hook the wire on the shifter shaft (metal part of the shaft) and it stays in OD until I remove the wire off the shifter.
Please keep trying.
Has anyone tried a new OD switch on dash? I haven't but I keep thinking if the contacts inside are corroded or loose they may be causing the problem... but the light in the switch should be flickering...I assume???
Please keep trying.
Has anyone tried a new OD switch on dash? I haven't but I keep thinking if the contacts inside are corroded or loose they may be causing the problem... but the light in the switch should be flickering...I assume???
#34
Registered User
I wish you guys would figure this out... my 92 has had this problem for several years. I am the one with a wire connected to the ground side of the OD solenoid - run through the floor - insulation peeled back a couple of inches - bent with a hook shape on the end and when it starts acting up I hook the wire on the shifter shaft (metal part of the shaft) and it stays in OD until I remove the wire off the shifter.
Please keep trying.
Has anyone tried a new OD switch on dash? I haven't but I keep thinking if the contacts inside are corroded or loose they may be causing the problem... but the light in the switch should be flickering...I assume???
Please keep trying.
Has anyone tried a new OD switch on dash? I haven't but I keep thinking if the contacts inside are corroded or loose they may be causing the problem... but the light in the switch should be flickering...I assume???
Wire hooked over the shift lever? You, sir, are close to hopeless, as in terminal red neck.
#35
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What can I say... I am from Arkansas, and on top of that I am a Poultry farmer (40,000 birds) My day job is as an Electrician - self employed.
But i was thinking maybe even though it is a momentary switch it could be bad inside and bouncing on and off just as if you were pushing the switch on and then off and then on and then...
You sound like a very interesting guy. I would love to visit with you for a day or two and pick your brain. I enjoy your posts.
But i was thinking maybe even though it is a momentary switch it could be bad inside and bouncing on and off just as if you were pushing the switch on and then off and then on and then...
You sound like a very interesting guy. I would love to visit with you for a day or two and pick your brain. I enjoy your posts.
#36
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Thread Starter
The point is to get the TPS to give the right range of voltage for idle to full throttle. Start is 1V, range is 2.5V +- .25 V. That's what the PCM is expecting.
When you turn up your pump and have to turn down the idle, that stretches the low end. Full throttle mod stretches the high end. sum of mods puts it out of range. The trimmer is to compensate for that.
Now, if you get it in range and it acts up, I'll be officially stumped.
When you turn up your pump and have to turn down the idle, that stretches the low end. Full throttle mod stretches the high end. sum of mods puts it out of range. The trimmer is to compensate for that.
Now, if you get it in range and it acts up, I'll be officially stumped.
#37
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Would this be possible?
[QUOTE=j_martin;3189399]The point is to get the TPS to give the right range of voltage for idle to full throttle. Start is 1V, range is 2.5V +- .25 V. That's what the PCM is expecting.
j_martin, what would happen, for testing purposes, to supply a 1.5 or 2.0 volt steady voltage to the varying voltage pin? Or does the voltage have to vary.
If that would work wouldn't it rule out everything but the TPS and it's circuit.
j_martin, what would happen, for testing purposes, to supply a 1.5 or 2.0 volt steady voltage to the varying voltage pin? Or does the voltage have to vary.
If that would work wouldn't it rule out everything but the TPS and it's circuit.
#38
Registered User
Found this on another forum I frequent. Being electronically challenged I'm not sure if this would even help or if thats what you all have been talking about already anyway?
http://www.cumminsforum.com/forum/89...e-out-fix.html
http://www.cumminsforum.com/forum/89...e-out-fix.html
#39
Registered User
[QUOTE=ricky0677;3189617]
Funny you should ask.
https://www.dieseltruckresource.com/...&highlight=tps
It works, OD shifts at a set speed. Cruise works.
The point is to get the TPS to give the right range of voltage for idle to full throttle. Start is 1V, range is 2.5V +- .25 V. That's what the PCM is expecting.
j_martin, what would happen, for testing purposes, to supply a 1.5 or 2.0 volt steady voltage to the varying voltage pin? Or does the voltage have to vary.
If that would work wouldn't it rule out everything but the TPS and it's circuit.
j_martin, what would happen, for testing purposes, to supply a 1.5 or 2.0 volt steady voltage to the varying voltage pin? Or does the voltage have to vary.
If that would work wouldn't it rule out everything but the TPS and it's circuit.
https://www.dieseltruckresource.com/...&highlight=tps
It works, OD shifts at a set speed. Cruise works.
#40
Registered User
Found this on another forum I frequent. Being electronically challenged I'm not sure if this would even help or if thats what you all have been talking about already anyway?
http://www.cumminsforum.com/forum/89...e-out-fix.html
http://www.cumminsforum.com/forum/89...e-out-fix.html
#41
Registered User
[QUOTE=j_martin;3189661]
So basically what you built is a fixed point POT? That eleminates the TPS but now it shifts at a set speed no matter what the load, correct? If so, then that little gizmo would at least let us rule out a faulty TPS which would narrow down the possibilities. I'd be interested in one of you're making them...
Funny you should ask.
https://www.dieseltruckresource.com/...&highlight=tps
It works, OD shifts at a set speed. Cruise works.
https://www.dieseltruckresource.com/...&highlight=tps
It works, OD shifts at a set speed. Cruise works.
#42
Registered User
[QUOTE=KRB;3189672]
So basically what you built is a fixed point POT? That eleminates the TPS but now it shifts at a set speed no matter what the load, correct? If so, then that little gizmo would at least let us rule out a faulty TPS which would narrow down the possibilities. I'd be interested in one of you're making them...
Actually, I'm making one today, I'll make 2. PM me.
Used it for awhile, but I either run empty or pull a double that weighs 11,000 lbs, so I need the dynamic OD control. Made the touchy TPS run an extra year with DeOxit contact cleaner. Just replaced it with the TPS off my other truck. (Blue, thelocal wood hauler and parts mine rust bucket) Now I need the resistor pack for Blue. Do you suppose I can find it?
So basically what you built is a fixed point POT? That eleminates the TPS but now it shifts at a set speed no matter what the load, correct? If so, then that little gizmo would at least let us rule out a faulty TPS which would narrow down the possibilities. I'd be interested in one of you're making them...
Used it for awhile, but I either run empty or pull a double that weighs 11,000 lbs, so I need the dynamic OD control. Made the touchy TPS run an extra year with DeOxit contact cleaner. Just replaced it with the TPS off my other truck. (Blue, thelocal wood hauler and parts mine rust bucket) Now I need the resistor pack for Blue. Do you suppose I can find it?
#43
Registered User
Thread Starter
Replaced the 3 capacitors on the original ecm board and cleaned up some solder joints and it was working beautifully for 2 days, then the OD solenoid quits. Wide open, guess it couldn't take the shock of having to work right again. Can't I ever get a break?
#45
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