Fuel gauge fluctuations after changing ecm

[Bulkyluther]

Changed ecm for 97 jeep wrangler and fuel gauge goes from empty to full and back

 

[Chris]

So are you saying that the fuel gauge is constantly fluctuating between full and empty while the vehicle is running?

It doesn't just do it on startup, it does it repeatedly?

 

[Bulkyluther]

Yes while driving full to empty no in between

 

[Bulkyluther]

Even while driving no in between

 

[StG58]

Check the connections on the PCM. I'm betting that the connection for the gas tank sending unit is defective. This would be especially true if the problem started with the PCM change.

 

[Chris]

Check the connections on the PCM. I'm betting that the connection for the gas tank sending unit is defective. This would be especially true if the problem started with the PCM change.

I would have to agree. If this problem didn't start until after you swapped PCMs, it very well could be the sending unit is defective.

Where did you get the PCM from? I assume it was from an auto wrecking yard?

 

[timjor]

So, anyone know the solution here (to this thread)? I just bough a new ECM, and when it is connected, the fuel gauge goes from empty, to full, and back to empty, then stays on empty (even with a fuel tank). If I put the old ECM back in, the gauge works fine. Any ideas?