I'm have a really confusing situation and I was hoping maybe someone could help. It started last week when my car started taking longer to start than normal, then after a few days it wouldn't start at all. I then found out if I kept turning the ignition on and off eventually eventually it would start.

I took it to my mechanic and they traced it to a connection to the ECM. He fixed the connection and said it started fine but the ECM was corroded and he thought it might be from water damage in the past. He said if he tapped the ECM with a rubber mallet sometimes it would cause the car to cut off and sometimes when it wouldn't start he could tap it and it would start. Well eventually he got it to start consistently, so he told me I should replace the ECU myself since it would save me a labor charge and it's easy to do. He said I could keep driving it until it acted up again because it may last weeks or years.

Well long story short I decided to order a refurbished unit from Autozone for $250 just for peace of mind. I removed the old one in the parking lot, bought the new one and gave the old one to them. I installed the new one and the car wouldn't start! The part number was an exact match but no matter what I did it just wouldn't start. It wouldn't even turn the fuel pump on! I went in and asked if I could hook up the old one and it started right away. Just to be sure I again put the new one in and again no start. The Autozone employee suggested I leave both terminals of the the battery disconnected for 5 minutes and try again. No luck with that either.

Fortunately, they gave me a refund even though according to their policy they aren't supposed to on electrical items once they are installed. So with the old one back in I headed home. I needed gas since I was below 1/4, so I stopped and got some gas and when I started it back up my fuel guage is no longer working!

I now have no idea what could be going on. Could the refurbished ECM have been bad? Would the problems with my old one affect the fuel gauge? Now it it starting every single time with no problems besides the fuel gauge. It cost $198 in labor just for them to get it running and I'm not sure what to do next.
The ECM part number is 37820-P06-A01

Any help would be greatly appreciated!

Thanks

 

What car?
What ECU? Get the numbers off the side of it and post it.

 

Sorry I am so upset I forgot to include the basic info! I edited my original post but here it is.

93 Honda Civic DX 1.5

Part # for ECU is 37820-P06-A01

Thanks

 

So you're still using the old ECU? Can you open it up and inspect it for corrosion yourself?

 

Yes when I put the new one in the car wouldn't start so I got a refund. I just opened the cover of and see no signs of corrosion on the inside except some dark spots where the wiring harness connector is soldered to the board. Besides that it looks like new.The outside case is where the corrosion is.

 

Possibly you had a loose connection prior.

 

Yeah the mechanic did say I had a loose connection but even after he fixed it and got the car running it would sometimes not start unless he tapped it with a rubber mallet. Could this also affect the fuel gauge or is this probably a coincidence? I already pulled the back seat out and checked for any bad wiring to the fuel sensor and everything looks fine.

 

The fuel gauge issue is probably caused by a bad sending unit. Remove the fuel cover under the rear seat, unplug the sending unit, and short the Yel/Wht wire in the plug to ground. When you turn the key to ON(II), does the fuel gauge needle rise toward full?

 

Well before I even had a chance to test the sending unit, a co-worker suggested that it might be a stuck float. He said try bouncing the car up and down in the rear to free it up and if that didn't work try filling the tank all the way up. Well the bouncing didn't work but I filled it up all the way and now the fuel gauge is working again. I guess it must have been stuck in the upper 1/4 of the tank.

 

If the problem continues, you now know how to solve it.

 

Yes and thank you