On 3/11/15 2:44 PM, Neil N wrote:
> On 3/11/15, John Goubeaux <john@ucsb.edu> wrote:
>
> So engine didn't start while FP relay was jumped right?

Correct,  I did NOT have the ignition ON when jumping  #87 to # 30 So FP
ran BUT without ignition.
> Ground being present at FP relay while cranking engine indicates
> that the ECU is supplying ground, as it should.
> Assuming ignition was off, that is correct; you should not see + power at FP 86

OK, that makes sense Now.
> So, what does the fact that I do NOT get battery current from # 86 mean
> ? And is this from the Ignition switch? (  or should I have left the
> relay plugged in while testing ?)  There is No indication in the steps
> other than to "diagnose the circuit". I'm unclear IF that circuit is
> energized from the FI Relay OR the ignition switch. So this is where I
> am stuck.
>
> FP 86 (+) is supplied from ign. switch 15. So, you should see voltage
> there, key turned to ign. on, even if engine not running. ECU supplies
> ground to FP relay which energizes relay.
> I'm unclear as to whether or not + at ECU relay 86 is supplied to ECU
> 23 and exactly what that is for. Mark Drillock has posted on the newer
> 5 pin ECU relay.

Oddly I'm told that my model ( a late 89) *should have a different ECU
Relay than the FP relay However, they are both the same ?  eg they are both
part # 141-951-253B  What explains that ?
>
>> I've got a new ignition switch and relays on the way so can do some
>> swapping out AND intend to replace the ignition switch anyway as it IS old.
>>
>> Can I assume that at this point the ECU and FP are OK and that it's
>> likely a relay, ignition switch, and or connections in between ?
> An ign. switch is a handy spare part. The fault may very well lie at
> ignition switch
> or points in between.
>
> Check and clean all grounds. Including strap between drivetrain and
> frame, front of transmission and at battery post and to frame.
>
> Since the ECU is what turns on the FP relay, I'd start with all grounds to ECU.

OK, Thanks all good advice, and I AM planning on replacing the ignition
switch as good measure.
>
>