91 Accord, Auto, 90K miles, No CEL.

I recently replaced the ECU due to some moisture problems (it got fried). The car is running perfect now however I am having some issues with the following gauges:

- Tach is bouncing around all crazy like.

- Speedometer cuts in and out.

- Fuel gauge is not accurate, when i fill it, it only shows 3/4 tank.

- Temp gauge appears to be working just fine.

None of these issues were there prior to changing the ECU. I know I put the correct ECU in it. What could cause all these issues at the same time? Possible ground issue somewhere? Where would the instrument cluster be grounded to?

 

There are several grounds on accords in the cabin. I would probably buy a 90 accord shop manual in pdf form from Ebay. It will show you the exact location of the grounds.

I would also check the #1? fuse in the fuse box inside the car. That powers the yellow wire to the instrument cluster. Check to see that it isn't loose? #1 is based on my 95 manual, so your 90 accord may have the fuse in a different location. The labels should be on the cover for the fuse box and listed in the owners manual.

The 90-93 manual that you can get from the online manuals thread in the DIY section is tough to navigate, covers non-US accords, and has sections missing.