mx5cartalk.com

So I thought I was finished after my last post on fuel pumps. Starting a new thread as I have another development. Car appears to be running well but before I put everything back I thought I'd do some more checks with my new volt/amp meter. When I bridge the gnd/fp at the diagnostic switch and turn on the ignition the pump works fine. Only trouble is it doesnt stop after 5 or so seconds and was still running a minute later (I had removed the pump earlier when solving other problems). When I put a voltmeter on at the tank connections (with the dianostic switch bridged) I get 12 V. If I take away the bridging wire and turn the car engine over it jumps to 12V then settles at 8V while still turning the motor over. When I turn key the key back to the "on" position the voltmeter goes straight to zero. This does'nt seem normal when I read Patchy's thread.
Is there any problems with driving like this (maybe its been like it for ages as I've never had reason to check). If its not normal I suppose it will eventually wear the pump out.
Any clues or am I jumping at shadows.

It's probably 8V for cruising & idling, & 12V when giving it some decent revs. Same thing happens on the TX3s etc, when they upgrade the pump to a Walbro they bypass the voltage regulator thingy & run them at a constant 12V as the Walbro doesn't like 8V.

I don't blame you for being paranoid trader. Everytime mine hesitates to start I start to worry about pumps, ECUs and ignitors

With the FP/Gnd connection jumped the fuel pump will stay on as long as the key is in the on position, or the engine is running. This does bypass the safety feature in the AFM that cuts power to the pump in an accident.

J