monkeyboy2

I got this email from a friend of mine who has put a F20C into a 66 mgb gt. He is a mechanical genius, but is struggling with a particular problem. Any help will be appreciated. Here is his email to me:

Just in case you know someone who can/will answer this very specific to S2K question...
Someone in the know about the AP1 ECM CEL warning strategy logic can probably quickly say "yes" or "no" (and most likely "no") without putting much thought into it. I just don't know any such person... so I am left with speculation and possible experimentation.

For background to whomever...I have installed a YM 2000 AP1 engine and trans into a '66 MGB GT. The engine is low mileage and bone stock. I have made every effort to try to provide the engine with exhaust and air inlet systems that will preserve its original volumetric efficiency and am thus hoping I can successfully manage the engine with the original ECM. My ambition is merely to have a well behaved and not fussy engine with nice driveability. I have no requirement to pass any emissions testing. Properly managed, the engine will run far cleaner than a new 1966 MGB ever did. In a perfect world, I would love to have a fully functional MIL lamp that is not perpetually "on" because of stored trouble codes.

I have gotten past most of the CEL hurdles associated with this swap, but I am flummoxed by the EVAP related warning codes. The car has an atmospherically vented fuel tank ala 1966. I wish for some approach that would allow the original ECU not to not look for or detect EVAP codes. Per the S2000 service manual, the only EVAP related codes are as follows:
P0451- FTP sensor Range/Performance problem
P0452- FTP sensor low voltage
P0453- FTP sensor high voltage
P1456- Vapor leak in the Tank system
P1457- Vapor leak in the Canister system

So here is what I am wondering...
With regard to avoiding the P0451, P0452, and P0453 codes, if I send a regulated 2.5V signal to the ECM PTANK sensor input terminal, would that make the ECU happy and would it avoid setting any of these three codes? Better suggestion?

...And with regard to the P1456 and P1457 codes, from reading through what little insight I could glean from the service manual, it looks like there might be some hope of not setting off the MIL with these codes IF I can prevent the ECU from enabling the "ready" mode for the EVAP monitor.

Here is what the Service Manual says about the Enable Criteria for the EVAP Monitor:
"At engine startup, ECT and IAT are higher than 32 degrees F, but lower than 95 degrees F" , and "At engine startup, the ECT and the IAT are within 12 degrees F of each other."

So... If I can create a momentarily engaged circuit that toggles the IAT signal to a value a little below the 32 degrees F value, will that prevent the monitor from being enabled and thus not allow the monitor to run its EVAP check that would otherwise detect P1456 and P1457? Better suggestion?

Thanks for any help, guys.

monkeyboy2

Looks like he already posted the question...it is just below this one. My apologies for the double post.