slimdawson

Alright, I just put a 4th gen tank and sending unit into my 91. The colors of the wires were the same for both so I just clipped the plug off of both, and soldered the 3rd gen plug to the 4th gen unit. But now, the gage in the car shows past full, which is wrong considering I only have 1 gallon of gas in there. Is it a wiring problem? Is there a way to check?

Thanks.

Ucantcme57

I had heard that this could be done.. The only reason I was interested in this swap was for the baffles.. ( the elusive baffled 1LE gas tank for 3d gens).. Some say but oh there plastic.. I cannot believe that there is a huge difference between weight maybe five pounds? does anyone know the difference. I relocated the pump to where the filter usually resides, and had a pickup tube welded onto the fuel sending unit instead of the intank pump. Which usually goes out whenever you go below 1/4 tank, without baffles the pump runs dry during hard acceleration braking and turning. Was the 4th gen a direct bolt in? Do you have any pics? The ohm's might be the problem, the sending unit for 3rd gen might be running on lower ohms or higher ohms, I cannot remember which.. sending unit putting out to many ohms = higher fuel level? My next guess would be to check all your grounds!!!! I had the problem of my Tahoe, (chevys are notorious for having fuel pump and or fuel sending unit problems, Trucks and camaro's are very similar) This sounds like a good swap.. Did your 4th gen tank have baffles? would the 3rd gen sending unit not work? how different are the sending units?

slimdawson

I am not really sure about the baffles. I didn't look to closely If I remember, I will look inside the 3rd gen tank and see. I do remember there being a plastic box-like piece that the pump filter sat in.

The 3rd gen sending unit will not bolt in. Too small diameter and the 4th gen uses a different retaining system(better).

Was not a bolt in as the neck was about 1.5" too long. I cut a section out and welded it back. Then it bolted in with no problems. Other than that, the external dimensions of the tanks are the same.

It must be an ohms problem as I reused all conections at the pump harness.

Any way to fix that?

slimdawson

The sending unit just started working tonight. I guess the float was stuck in the fully raised position and when the gas started sloshing around, it loosened.

IROC-T

So everything is working right,now?

slimdawson

Yeah it seems to be fine. It was screwy for a while. Just would float around for a while. Now it is steady. Hope it stays that way.