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Chevrolet c6500: I have a 1998 topkick chevy truck 6500 series…

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I have a 1998 topkick...
I have a 1998 topkick chevy truck 6500 series 6 speed with a 3126 diesel cat motor,the speedometer,odometer and tach stop working..it runs but sputters going uphills,then it just seems like the pedal does nothing..the prior owner put a new clutch in and before that it ran fine
Submitted: 10 years ago.Category: Medium and Heavy Trucks
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Answered in 41 minutes by:
3/19/2012
Technician: Cat Man, Cat Engine Expert replied 10 years ago
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
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Hi. Thanks for using JA! I will try and help you out.

Does the check engine light come on when the engine sputters?
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Customer reply replied 10 years ago
yes
Technician: Cat Man, Cat Engine Expert replied 10 years ago
I see. Thanks for the info.

Since the light ccomes on, I would like to pull the flash codres from the ECM. If you have never dddone this, here is how.

Turn key on, engine off.

Turn cruise control switch to off.

Hold the set/resume switch until the yellow check engine begins blinking. Then count the blinks. For example. Blink, blink, pause, blink, blink, blink, is a code 23. All codes are two digits. Let me know what codes you get and I can tell you what it means.
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Customer reply replied 10 years ago
ok,the cruise stop working as well,not sure where the speed sensor is on this,have heard the wiring may have been messed up when they put the clutch in
Technician: Cat Man, Cat Engine Expert replied 10 years ago
I see. Thanks for the information.

Iif the cruise has stopped working as well, it sounds like there is most likely a wiring problem between the engine ECM and the dash. Have you checked the harness?
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
Verified
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Customer reply replied 10 years ago
no,pulled the gauge cluster out,to check for problems,didnt see anything wrong with it..always thought it was in the wiring going to the trans,because all worked before they did that clutch,what can i look for there?no,pulled the gauge cluster out,to check for problems,didnt see anything wrong with it..always thought it was in the wiring going to the trans,because all worked before they did that clutch,what can i look for there?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
I would lookbatbthe engine ecm connector first. Make sure it is tight. It takes a 4 millimeter Allen wrench. I would also inspect the wiring on the top of the trans.
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Customer reply replied 10 years ago
replaced the 1 harness to the trans..where is the speed sensor on it?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
Thanks for the information.

The speed sensor should be on the tail shaft on the trans.
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Customer reply replied 10 years ago
is the a way to check that for power?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
There should not be power to the sensor. Its a mag pick up type os sensor. You could ohm it to see if it is open.
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Customer reply replied 10 years ago
how do i go about that?..thanks
Technician: Cat Man, Cat Engine Expert replied 10 years ago
I would unplug the speed sensor and use a multimeter to ohm the sensor on its two wires.
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Customer reply replied 10 years ago
with it running,or just the key on?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
Engine not running.
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Customer reply replied 10 years ago
it seems at the pigtail that goes into the speed sensor I am only get a ohms reading when the key is off...when i turn the key to the on position,I get nothing..thanks
Technician: Cat Man, Cat Engine Expert replied 10 years ago
That is odd. When the sensor is disconnected, I would think it would Ohm the same no matter if the key is on or off.
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Customer reply replied 10 years ago
yes as soon as i turn the key it goes to zero...could it be something in the ignition ,maybe on the column harness?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
That is what I would be thinking. I have not seen one do that before. I would think the sensor would ohm the same no matter if the key was on or off.
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Customer reply replied 10 years ago
I know its a needle in a haystack,but,any wires I could check?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
The only other things I would want to check are the power and ground connections on the engine and starter. I would make sure they have clean and tight connections.
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Customer reply replied 10 years ago
I replaced the ground strap from the frame to the starter and all the grounds look good,any other ideas what or how to check anything else? thanks
Technician: Cat Man, Cat Engine Expert replied 10 years ago
The only other thing I can think of is a problem in the cab harness it self. Of course the tough part is buying and replacing the harness. That is expensive and time consumming. I hate you are having sonmuch trouble with this issue.
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