Cadillac Repair: gas tank pop killing fuel pump, selinoid, fuel gauge

Question
Hi Bill

You were very helpfull with my last question and my Mech. is very impressed with the whole Idea of this site.  He was wondering if you knew why the 00 caddy gas tank started to pop when the selinoid shut down and why this would kill a fuel pump.  I have been in contact with the Caddy people and they are working on my case.  My gas tank still pops and I am afraid I'm just going to burn up another fuel pump.  Also my fuel gauge is not acurate does the computer auto calibrate or does the fuel pump need to be calibrated.  

Thanks again,
Steve

Answer
Hi Steven, The reason for the shutdown is because the tank needs to vent otherwise it creats a vacuum in there and the gas can't be pushed out by the pump. I'm not sure why this would have happened after your repair and maybe the tech assist at the Caddy Dealer can shed some light on the problem. I would go back over what was done and test the tank vent for propper operation.
Cadillac has had problems over the years with their tank sending units and gas gages not working properly. If you use an ethenol blend then that caused the problem in the begining(1986) and as resently as '98-'99 there was a bulletin to replace just the float assembly on the sender and do a reprogram of the computor. But the fuel pump and module do not have to be replaced or calibrated. The computor might need to be calibrated and the sender float assembly/card replaced. I would be interested to know what fixes your problem. Hope my explanation helped explain things. Bill