[Gmecm] TBI Fuel problem

[Craig Smith]

Darryl 

The fuel is being heated up by the return from the TBI circulating back to the tank.  When the temp at the inlet of the pump gets to about 110 is when the pump cavitates.   I think the problem is compounded because the pump is external, it is pulling the fuel out of the tank (lower pressure the fuel flashes easier) Im going to pull the tank back out and see if I can figure a way to add an internal pump. 

I figured out where were picking up the heat, It's between the intake and exhaust manifolds. The Exhaust manifold for cylinders 2&3 run 1/2" below the bottom of the center of the intake (directly below the TBI) the exhaust manifold is runing 700 or so degrees F.  The base of the TBI was over 200, I added some insulation and was able to lower the temp considerably.   I have access to some real good insulation blanket we use at work on high temp piping, that should get the heat transfer under control.  Do you have anyone have any other suggestions?  

Thanks
Craig

P.S.  Carrying fire extinguisher on test drive.




----- Original Message ----- 
From: dgilbert78 at juno.com 
To: kc5aeq at earthlink.net
Sent: 8/14/2006 2:51:17 PM 
Subject: Re: [Gmecm] TBI Fuel problem


Hmmm! That appears dangerous to me, don't know. Typically most TBI pumps are located right in the tank. Fuel lines are than routed inside the frame rails and exit in the vicinity of the engine. Where is this fuel tank, is it not located at the rear of the car?? sounds like it is located in the vicinity of the exhaust manifold??? is that correct?? Then the pump is cavitating (sucking fumes)
Darryl..