|
> How do you know the fuel pump relay is
> good? Has it been replaced or resoldered?
I totally agree. The fuel pump relay is often associated with intermittent stalling problems due to heat stressed solder connections. These are most prevelant just as a cold engine is starting to warm up. As soon as I hear "restarts after a few minutes" I just have to think it's a primary electrical connection like the FPR. I wouldn't go any further until that thought had been exhausted. On 700's, it's not just this relay you have to worry about, it's also the socket in the relay tray. When the relay gets hot the plastic will scorch and deform. You need to remove the tray and inspect the underside wiring for this. Another good idea would be for him to clean up all ground points for the fuel and ignition system, including behind the LH ECU. Throwing expensive parts at this problem is totally ridiculous.
> When the engine dies and
> fails to start do you hear the fuel pump run for a second or two when
> the ignition is switched to the run position? If you do not, the
> relay probably is bad.
I think that's only true for the early K-Jet systems. For the "newer" K-Jet and LH systems the fuel pump only runs during starter cranking and when the engine is deemed to be running by the ECU (as determined by the Hall sensor or rpm sensor). This was changed primarily as a safety measure to minimize fuel spills in accidents. For diagnosis, you get the engine in a no-start state then use jumpers to bypass the relay and see if the fuel pump runs and now starts the engine.
|
