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3126 cat. is the two prong wire connection on the injection…

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3126 cat. is the two...
3126 cat. is the two prong wire connection on the injection actuation pressure censor have power in it with switch on.
Submitted: 10 years ago.Category: Medium and Heavy Trucks
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Answered in 2 minutes by:
4/16/2012
Technician: Cat Man, Cat Engine Expert replied 10 years ago
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
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Hi. Thanks for using JA! I will try and help you out.

I just want to make sure I understand your question.

Are you referring to the two prong connection on the HEUI pump?
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Customer reply replied 10 years ago
If the hevi pump starts and stops engine than yes.
Technician: Cat Man, Cat Engine Expert replied 10 years ago
Thanks for the information.

With the key turned to the on position, there will not be any power to the pump.

But, there should be power going to the pump when the engine is being cranked. The engine ECM will not send power to the HEUI pump until the ECM gets an engine speed signal from the engine speed timing sensors.

Please let me know if you need more help or have more questions.
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Customer reply replied 10 years ago
Would you recomend changing timing censor?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
If you are not getting any voltage tonthe HEUI pump while cranking, you may have an engine speed timing sensor problem. You could also have an engine ECM problem or a power to the ECM problem.

Does the yellow check engine light come on when you turn the key to the on position?
Cat Man
Cat Man, Cat Engine Expert
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Customer reply replied 10 years ago
checkengine comes on briefly and go out . anyway to test timing censor?
Technician: Cat Man, Cat Engine Expert replied 10 years ago
If the light comes on and then goes off, the ecm is working and getting power. So I would suspect the timing sensors next.

Yes they can be tested with an ohm meter. The top sensor should ohm between 75 and 230 ohms. The bottom sensor should ohm between 600 and 1800 ohms.

I would also check the harness for damage as well.
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Customer reply replied 10 years ago
Never changed timing censor on 3126 recomend where to get diagram so i will know where to start.
Technician: Cat Man, Cat Engine Expert replied 10 years ago
The sensors are a little tuff to get to. They are on the drivers side of the engine on the back of thebfront cover. They are under the heui pump behind then air compressor. Most guys remove the air compressor to get to them.
Cat Man
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