Arrrrrrrrgh! Intermittent dead 90q ignition (long)

Huw Powell human747 at
Sun Aug 11 00:49:59 EDT 2002

> << The only ignition/fuel pump
> interface is a tach wire running to the fuel pump relay, which provides
> the safety feature of shutting off the fuel pump if the rpm's go to zero
> or the red line. >>

> but now that I think about it tach was going dead for about four
> months before the real ignition problems set in.......there was no safety
> shutoff... car kept going with dead tach , and then a few miles down the road
> it would jump back to life.
> I wonder if my problem lies there.....

the tacj is on another "leg" of that circuit - disconnecting it, for
instance, does not affect runnability.  So even with a bad tach the FPR
shutoffs should work - based on reality, not the bad tach's reading,

> now the car is dead again after running good for 2 weeks........and I know
> the ignition is dead because I powered up the pump bypassing the relay and
> still no start

Time to do much digging in with a multimeter and Bentley schematic... is
the ignition switch good?  Is power getting to the coil?  etc...etc...

Huw Powell

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