Engine swap problem

2279 Views 7 Replies 4 Participants Last post by Chillerguy, Dec 18, 2021

Samhalabi

Discussion Starter · Jun 24, 2021

Hello, I bought a Honda off a friend as a project it had a cracked block, I swapped the block from a local junkyard and now I am having trouble starting it.

To further explain after swapping it the engine started I let idle for a bit and then turned it off ( it was over heating, changed the thermostate) , 5mins later I went to start it again I would get weird rpm spikes then the engine dies while at 2000 rpm.

Noticed the key sign showing up when the engine dies, but the key is the one that came with. the car and i did not swap the ECM and it does lock and unlock the vehicle if it was an immobilizer issue the car wouldnt start at all..?

Any input would be appreciated I tried almost everything I dont want to just sell it to a junk yard I encourage any help. thank you in advance.

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FD7683

· #2 · Jun 25, 2021

If the green key is flashing and the car shuts right off, somethings up with the immobilizer. It might need another key reprogram.

For the idling issues - the throttle body is electronic and when it's messed with, the computer gets confused and starts idling weird until it gets a TPS reset with a special scan tool. This could be your issue so I would check for fluctuating idle when first starting the car.

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Samhalabi

Discussion Starter · #3 · Jun 25, 2021

FD7683 said:
“If the green key is flashing and the car shuts right off, somethings up with the immobilizer. It might need another key reprogram.”

For the idling issues - the throttle body is electronic and when it's messed with, the computer gets confused and starts idling weird until it gets a TPS reset with a special scan tool. This could be your issue so I would check for fluctuating idle when first starting the car.

It is not right away that is what is confusing me the car runs with very rough idling for 30 seconds or so then remembers to shut off

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FD7683

· #4 · Jun 25, 2021

If everything is connected correctly, I would inspect the PCV Valve and the EGR valve. The PCV Valve gets old and the ball will not rattle which will need replacement - an OEM one will run around $20 on eBay. The EGR Valve gets dirty over time and could get a nice cleaning with (I think) brake cleaner.

This is my top knowledge when I was facing idling issues a year ago. I did these 2 jobs and I now have a steady idle.

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FuntanaS

· #5 · Jun 25, 2021

My money is on something not being hooked up or not connected quite right. My dad and I swapped engines on our 2008 civic and there is a lot of stuff that needs to be reconnected.

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Samhalabi

Discussion Starter · #6 · Jun 25, 2021

FuntanaS said:
My money is on something not being hooked up or not connected quite right. My dad and I swapped engines on our 2008 civic and there is a lot of stuff that needs to be reconnected.

I wish!! I went through everything twice with 3 separate set of eyes everything is hooked up

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Chillerguy

· #7 · Dec 12, 2021

Did you ever get this resolved...? runiing into something similar
with an engine replacement( cracked block) not reving but just shuts off after 15 min
cranks a little to much and then starts and runs
im wondering if it needs a relearn
any help would be appreciated

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Chillerguy

· #8 · Dec 18, 2021

Chillerguy said:
Did you ever get this resolved...? runiing into something similar
with an engine replacement( cracked block) not reving but just shuts off after 15 min
cranks a little to much and then starts and runs
im wondering if it needs a relearn
any help would be appreciated

I wanted to update this , incase anyone ran into this..

I did an idle relearn from cold and it fixed the issue

look up r18 idle relearn on here...its detailed

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