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Cat Man
Cat Man, Cat Engine Expert
Category: Construction and Road Equipment
Satisfied Customers: 8412
Experience:  I am ASE Master Certified.
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What would cause a c15 accert engine to surge and vibrate

Customer Question

What would cause a c15 accert engine to surge and vibrate intermittently in high gear? Fuel pressure is. Replaced crankshaft position and harness.
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  Cat Man replied 1 year ago.

Thanks for asking your question. I will try and help you out.

There are several things I have seen cause a C15 to surge like this.

The first is a fluctuating fuel pressure. If it fluctuates below 70 psi and back. It can cause this.

Second is a faulty cam or crank sensor signal. This can be caused by a faulty sensor or harness.

And lastly is a faulty injector. To determine which injector it is you would need to use Cat ET to cut out each one until the surge stops. When it stops that's the injector that's faulty.

Please reply back if you need more help or have more questions. I am happy to assist.

Customer: replied 1 year ago.
I replaced the crankshaft sensor and the short harness,old one had a spot that was rubbed through,it didn't change anything the fuel pressure is steady at 70lbs even when the engine acts up and when it does it's white smoke. It only does it intermittently and seems to be worse when it requires more power
Expert:  Cat Man replied 1 year ago.

Thanks for the information.

If there is smoke then I would suspect a cylinder problem. It could be an injector or an Iva housing sticking holding open an intake valve.

I would have someone ride with Cat ET to cut out each injector when this is happening.

From experience I find a faulty Iva housing most often.

Please reply back if you need more help or have more questions. I am happy to assist.

Expert:  Cat Man replied 1 year 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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