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Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Pontiac Technician
Category: Pontiac
Satisfied Customers: 47673
Experience:  16 years of experience
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Bought car not running previous owner said they swapped

Customer Question

Hello bought car not running previous owner said they swapped parts including the computer. I swapped the engine with a known good engine from a 06 Chevy hhr 2.4. Same result. I changed the ignition switch same result. Trouble codes i get are p2078 intake manifold tuning and p0315 crank shaft sensor variation not learned. When trying to start it back fires out the intake manifold. Do i need a currency hhr computer?
Submitted: 1 year ago.
Category: Pontiac
Expert:  Chris (aka- Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose). Experts aren't employees / agents of Just Answer. We are independent service providers using the Site to sell their Expert knowledge to Customers. I strive to provide EXCELLENT 5 STAR service, let me know what's needed from me so your pleased.

2078 will not cause a no start issue, but the 0315 can. The crank position has to be learned via a scan tool. The PCM uses this signal to know when to pulse the ignition system. Since your back firing that means the plugs are firing at the wrong time or valves are stuck open from possible timing issues.

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Customer: replied 1 year ago.
Thanks i will be happy to rate 5 stars when i have a clear path to take. Can any sophisticated scan tool learn the crank pulse or do i need to bring the car to GM? Would you recommend that i install the computer from the car the motor came out of? Since its a Chevrolet HHR engine?
Expert:  Chris (aka- Moose) replied 1 year ago.

Yes many upper level scan tools can do a crank relearn.

Since you have disconnected the computer and or battery and or swapped the engine, the computer has lost the memory of the crank position. Swapping the computer now will not resolve this.

Expert:  Chris (aka- Moose) replied 1 year ago.

Hello again Chris here,

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Thanks Chris