F/P to GND Jumper (Newbee question)

[hutch]

I recently purchased a 92 V6, and while familarizing myself with the engine. I found that a jumper as been put in the diagnosis connector box from f/p to GND, along with some of the most amatuer wiring work on the face of the earth.

After removing this jumper there was no spark. So my question is this what is this jumper be bypassing? and by leaving it in would there be any performance/fuel economy issues?

Thanks is advance for helping out a newbee.

[Custommx3]

not sure on FP/GND
but
TEN to GND is diagnostic mode

[shameem]

F/P -> GND - in a normal mx3 it forces the fuel pump to be on all the time when ignition is on so you can diagnose fuel issues..... (normally it comes on only when ecu "sees" airflow into the engine or heavy load)

[hutch]

Thanks Shameem,

Now after investigating it, the damn thing will not start at all,
Its cranking but no spark which was probably the problem in the first place, the distributor is fine, any ideas?

I only paid about 1000 cad for the car so am wondering if its worth even trying to get it going.

[shameem]

Check for codes (jump TEN->GND & count the check engine light flashes)....
Check Crank position sensor, coolant temperature sensor, vaf sensor etc......
Look into "HEI mod"...

[hutch]

Well, i gave in and got the damn thing towed to a proper machenic. And the verdict is that the jumper does indeed force the fuel pump run when the inigtion is on (perfect diganosis Shameem). By messing with it i managed to totally flood the whole engine thus it was not starting at all. Basically its going again but why the jumper is there is another issue is for another day.

I've learnt the hard way that buying a cheap car isn't always that cheap and to check the wiring before buying a vehcile.

Cheers Hutch