vapor lock

[Phil Payne]

> I'm confused. I thought on my car (1986 5000 CSTQ) the fuel pump did not 
> get energized until the sensor detected crankshaft rotation? Does inserting 
> the code dumping fuse cause the ECU to bypass that?
> If so, driving with the fuse in is a potential safety hazard. If the fuel 
> line breaks (in an accident) and the engine stops (no fuel), the pump turns 
> off. 

The fuse has TWO purposes. Inserted AFTER the ignition is turned on, it dumps codes.  Inserted BEFORE the ignition is turned on, it's a request for output diagnostics - the first of which is running the fuel pump.

It's only a command to the ECU - not a direct bypass of any sort.  The ECU stays in control.  If the engine is revved beyond a certain limit (I think 3000 rpm - might be 2000 rpm) the ECU will then ignore the fuse until the next time the igntion is cycled.

I _suspect_ (but haven't bothered proving) that it also inhibits code storing. 



_______________________________________________________________________
FSmail - Get your free web-based email from Freeserve: www.fsmail.net