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Just installed 3126 cat in freitliner fl70 used will not fire…

Just installed 3126 cat in...
Just installed 3126 cat in freitliner fl70 used will not fire looks to be hooked correct not sure were to start
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Answered in 2 minutes by:
4/19/2014
Mechanic: Cat Man, Cat Engine Expert replied 8 years ago
Cat Man
Cat Man, Cat Engine Expert
Category: Construction and Road Equipment
Satisfied Customers: 10,344
Experience: I am ASE Master Certified.
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Hi. Thanks for asking your question! I will try and help you out.

When you turn the key to the on position, does the yellow check engine light come on?

Also,'does it have a hand primer pump? If so , does it get stiff when operated?
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Customer reply replied 8 years ago

Mr cat man the check eng. light comes on and the primary pumps up hard
Mechanic: Cat Man, Cat Engine Expert replied 8 years ago
Thanks for the information.

That tells me you have plenty of fuel pressure and the ECM is functioning with correct power.

Since you have replaced the engine speed timing sensors, I would next suspect an injection actuation pressure problem. I see this a lot on these engines. The 3126 needs at least 870 psi to activate the injectors. If it is low. The engine will not start.

There are four things if have seen cause low pressure.

The most common is a faulty injection actuation control valve. IAPCV. It's located on the high pressure pump. It's where the two wires connect.

Next is a failed high pressure pump.

Third is a faulty IAP sensor.

Lastly is a leaking injector.

Please reply back if you need more help or have more questions. I am happy to assist.
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Customer reply replied 8 years ago

Can I check pump pressure and were is iap sensor
Mechanic: Cat Man, Cat Engine Expert replied 8 years ago
Yes Dave you can.

You will need a high psi gauge and install it into one if the Allen head plugs on the head.

The injection actuation pressure sensor is the three wires sensor on top of the head near the front of the engine.

Let me know if you need more help.
Cat Man
Cat Man, Cat Engine Expert
Category: Construction and Road Equipment
Satisfied Customers: 10,344
Experience: I am ASE Master Certified.
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