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3126 Catapillar engine will start and idle fine When you try…

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3126 Catapillar engine will start...
3126 Catapillar engine will start and idle fine
When you try to move truck engine has Power for a few seconds then no power and will stall but will start right back up Does not matter if engine is cold or hot fuel system has been drained and fuel has been replaced speed sensors have been replaced
Submitted: 4 months ago.Category: Medium and Heavy Trucks
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3/10/2018
Technician: Cat Man, Cat Engine Expert replied 4 months ago
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 9,396
Experience: I am ASE Master Truck Certified.
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Thanks for asking your question. I will try and help you out.
Does the yellow check engine light come on when the engine is running?
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Customer reply replied 4 months ago
The read check engine light comes on when it starts to not run right the yellow engine protection light comes on also sometimes
Technician: Cat Man, Cat Engine Expert replied 4 months ago
Thanks for the information.
Since the lights come on. I’d like to try pulling the codes by using the cruise control switches. Here is how.Use the following procedure to retrieve the flash codes from the check engine light:
Turn the ignition key switch to the On position/ Engine OFF.
Turn the cruise control ON/OFF switch to the OFF position.
Move the SET/RESUME switch to either position. Hold that position until the yellow lamp begins to flash.
The yellow lamp will flash in order to indicate a two digit flash code and the SET/RESUME switch may be released. The sequence of flashes represents the system diagnostic message. Count the first sequence of flashes in order to determine the first digit of the flash code. After a two second pause, the second sequence of flashes will identify the second digit of the flash code.
Any additional flash codes will follow after a pause. These codes will be displayed in the same manner. Flash Code 55 indicates that No Detected Faults have occurred since the ignition key switch has been turned to the ON position.Let me know what two digit code you get and I can tell you what the problem is.
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Customer reply replied 4 months ago
The other day when I started talking about this I wasn’t your truck I just got my truck to get Flash codes I did it three times
the first time
the sequence was
37 15 39 34 34
The second time
71 15 38 34 34
Third time
12 71 15 39 34 34
Technician: Cat Man, Cat Engine Expert replied 4 months ago
Thanks for the information.
Code 39 is an injection actuation pressure system fault.
Code 15 is an erratic injection actuation pressure
Code 34 is an engine speed timing fault.
Code 71 is a low voltage to ecm fault.
Code 12 is a coolant level fault.
Sorry. There is no code 37.
I suspect code 39 and 15 are causing your problem. I see these a lot.
You most likely have a faulty control valve on the Heui pump. A weak Heui pump. A leak at an injector. Or a faulty iap sensor.Please reply back if you need more help or have more questions. I am happy to assist.
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Customer reply replied 4 months ago
Could you tell me the simplest way to check each one of those
Technician: Cat Man, Cat Engine Expert replied 4 months ago
To test the injection actuation pressure system you will need Cat ET software and a high pressure 5000 psi gauge. Do you have these available?
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Customer reply replied 4 months ago
I have the pressure gauge but no software available
Technician: Cat Man, Cat Engine Expert replied 4 months ago
I see. Thanks for the information.
The gauge is used to dead head test the Heui. It connects to the outlet oil of the Heui. While cranking. It should make 4000 steady while cranking. If it does not. You have either a bad iapcv or Heui pump.
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Technician: Cat Man, Cat Engine Expert replied 4 months ago
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.
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