I converted my 99 GSR's ECU to chipped P28 ECU and the tach is of about 200-500 RPMs at 7000 RPMs and above. I would shift at the 8200 rpms on my stock ECU and i knew extactly where it would hit the revlimiter, but when I switched to a OBDI ecu with a 9100 RPM revlimit it moved the point where I knew 8200 rpms was to somewhere near 8400 rpms. When I did shift at 8200 RPMs on the tach, my VAFC would register the highest RPMs 8000 rpms. But if I reved up to 8400 RPMs I would get a peak RPM at 8200-8300 RPMs. I know the tach is off at higher RPMs, but why would it change when using an OBDI from OBDII ECU ?

 

^^^

 

I have seen instructions for OBD-II to OBD-I harnesses that mention putting a 1k ohm resistor in parallel between the ICM and the 12V connectors.

Perhaps this is the issue?

Email me and I can forward you the instructions.

 

no. thats for when the tach doesnt work.
usually do to an install of something that bypasses the ICM.

Trust: its all in your head.

 

norice,

The information you gave is false. There is no need to put any sort of resistor anywhere in the harness. There can be an issue when doing a '99-'01 OBD2 to OBD1 ECU conversion harness if the person doesn't know what to do.

sgt is right about the tach issue. It is all in your head and due to the inaccurate analog tach.

-kenji

 

I made a suggestion - I did not make any definitive statements. Clearly I was in error.

In any case, the stock tach is incredibly innaccurate.

 

That's for when you're using a Hondata and a J&S Safeguard, trust me as I know that one fairly well.
Ausitn