So I replaced the ECU with a 94 ECU and was told it's completely fine to do, and since then the fuel gauge been erratic. It could be a coincidence and the fuel sender unit got dirty. Now when full it show almost full but then after 50 miles or so goes to 2/3 tank, at 90 miles to half tank, then sits there for a 100 miles and rapidly goes to 1/8 tank. Now I'm at 270 miles and the needle is at E yet the low fuel light isnt illuminated. Before I swap out the fuel float or clean it, can anyone in the know tell me if they think it's the ECU ? Thanks

 

The ECU doesn't have anything to do with the fuel level gauge... your issue occurred coincidentally. You can test this by switching back to the previous ECU. BTW, why did you change ECU's ?

 

The capacitors went bad and I tried to solder them and messed it up and no longer works and didnt know of that eBay service that fixes them at times so I bought a ECU from HA Motorsports but was a 1994 and they said it'll work fine with no issues. Soon after the fuel gauge went crazy so I thought it was that. And around that time the rpm gauge sometimes sticks and I have to tap the dashboard and then it works so maybe it's the cluster? What do you think? Id like to get a best guess before I try to fix.

 

Do you have another gauge cluster that you could try ? If another cluster solves the tach issue and/or the fuel level issue... then the gauges were the problem. I have only ever seen a tach needle stick on a gauge cluster than had aftermarket gauge faces installed... and they had lifted slightly causing contact with the back of the tach needle. You will have to drop the fuel tank to access the fuel level sending unit. I would pull the fuel pump assembly and look inside the tank... if you see extensive amounts of rust, there is a good chance that your fuel level assembly/float is damaged. I would check continuity on the wire between the cluster and the fuel pump assembly plug before I pulled the tank.

 

Ok. I'll pull the sending unit and clean or replace. And tonight I chatted with Google AI and explained all the symptoms and it deduced ithe resistor strip in the fuel sender has gunk or a film residue from me using Heet a bunch of times while car sat awhile while in Florida. It said it isn't a faulty gauge due to the behavior I described. Currently it shows below empty yet no yellow light, while I'm at 288 miles though usually get 333 miles a tank and it said the yellow light come on soon because it's a separate mechanism. We will see. So I will clean the strip with contact cleaner and a rubber eraser. Thanks for your help...

 

I removed the fuel sender. I know why people have erratic readings as the car gets very old. The thin metal arm that slides along the resistor strip, is deliberately bent and it loses its form and loses contact at certain spots. And very hard to bend or fix, because there is a screw but when u turn it the arm moves too so it appears at assembly is the only time they can have the metal arm properly bent.