re. Help..no spark when warm

[Ben Swann]

Eric,

I admit, that is one of the things that through me for a loop.  I ran
around in circles checking our fuel pressures, injectors,  etc.

The problem started out when my wife usually drove the car.  She'd usually
have no problem on a one destination trip.  Invariably I'd get a call, from
some place where she went after work or an appointment.  Anyway, I'd come
and get her and of course, get in the car and turn the key and it would
start.  My comment to her was jokingly,  you just aren't turning the key
right.

A few months later the ignition switch crapped out for good.  It was easier
to find the problem then.  It is easier to troubleshoot something when it
is completely broken rather than marginal.  I suspect the ignition switch
got flaky when hot.  The way the key was turned and released also made a
difference.  Actually, the final chapter in this was when the car would
start, and the engine would rev to 2000ish RPM.  I started diagnosing the
ISV circuit at that point.  No somehow the ignition switch flakyness did
this.

Also, I suspect some of the current tracks would be operational (X/Load
reduction) while others like Ignition positive might not be.  This made it
more difficult to isolate the ignition switch.

After replacing the switch, I have not had one recurrence of the problem.

Anyway, the short answer to your question is the switch got flaky when hot.

I don't know what the MTBF is for these, but I would consider suspect it
when the car get to 150Kmiles and unexplainable things start to happen.

Ben

On Friday, July 19, 2002 11:00 AM, Eric_R_Kissell at email.whirlpool.com
[SMTP:Eric_R_Kissell at email.whirlpool.com] wrote:
> Ben,
>
> How does the ignition switch show up as a good cold start but no warm
start
> issue?
>
> I am chasing something similar, so I am interested in the science behind
> the phenomena.
>
> Thanks,
> Eric Kissell
>
>
> ______________________________ Reply Separator
_________________________________
> Subject: re. Help..no spark when warm
> Author:  Ben Swann <bswann at worldnet.att.net> at INTERNET
> Date:    7/19/2002 10:48 AM
>
>
> [Greetings,
> The no-fuel-pump-when-warm condition has been traced to a no-spark when
warm
> condition... the spark being the "safety circuit" that enables the f.p.
> The car ('87 5KTQ) starts cold, and will run all day if not stopped.
After
> being off for 5 minutes, (and bridging the f.p. relay) the car cranks for
> several seconds, fires and dies when the starter is disengaged...
> i.e. the key goes from starter to run position.
> Sound familiar?
> Now that I think on it.. could it be tied to the ignition switch?
> Any BTDTs seriously welcomed. I'm in the process of moving, and need to
move
> the car ASAP.
> Many thanks.
> Mark Woodland]
>
> Mark,
>
> Here's hoping that the not so obvious culprit you will find is the
ignition
> switch.
>
> BTDT - drove me crazy as it was not so obvious, but I posted on this
similar set
> of problems several months back.
>
> Ben
>
>
>