Running lean after engine swap

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Running lean after engine swap

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Honda Accord >> General >> Do-It-Yourself Section >> DIY Requests >> Running lean after engine swap

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Running lean after engine swap - 9/2/2008 3:01:31 PM

asilomar244

Posts: 3
Score: 0
Joined: 1/27/2006
Status: offline

Hello,

I just finished swapping in a used Attarco motor on my 2000 EX-L Accord 2.3 U-LEV. The Attarco motor passed comp and leak down, and tested out with 80psi of oil pressure (according to Attarco''s test tag). My friend is an experienced Mercedes tech and we did the swap at his shop. We took our time, had three people checking everything more than once.

The Attarco motor came with a black valve cover and had a slightly different intake. We swapped the intake, exhaust and valve cover off the OEM motor (CA smog) and everything matched. We also swapped the temp gauge sending unit, knock sensor, and oil pressure sensor. We installed a fresh timing belt, tensioner and water pump. The transmission was replaced by Honda under recall 3 months ago.

Everything went back together fine, we had no issues with the wiring harness, everything checked out. We started the motor and it idled a bit rough. It sounded as if it was running lean. We let it run for a couple of minutes and tried to slowly rev the motor. It climbed up to ~2.5k but continued to sound a bit rough. The motor sounded mechanically sound. There was no valve noise and we were relieved that the motor did appear to be good. When we released the throttle, the engine died when as it returned to idle. We tried this three times, the motor started right away, and died each time we revved and returned to idle. No error codes were logged. When we pulled the MAF sensor, an error code was set right away. We expected this to put the motor into limp, and run rich. We were hoping this might allow the motor to run smoother. There was no effect, which led us to believe that we have a serious vacuum leak that fuel trim cannot change.

It seems we have a vacuum issue. We spent some time troubleshooting the vacuum system and found nothing out of place. We will continue the vacuum troubleshoot this week but would appreciate any advice.

We left the Attarco motor''s distributor in place. Could this cause any issue? If the motor is JDM (which I believe it is), would the distributor need to be swapped?

Please let me know if you have any ideas on this. Thank you.