Problem with 3.1V6 (Ignition related)

[Jeff M]

> Well, an update...    I reseated the memcal and it started up fine when
> cold (it was about 60 outside).  It ran great until the engine temp hit
> around 210 and then it started misfiring and eventually stalled.  Now I
> only have spark on the 2-5 coil.  The other two aren't firing at all, and
> the engine aint running all that hot hehe.  To me this seems like a module
> problem, but I can't understand how I can have three bad ones in a row.

Though I do not know all that you have done and fixed I will make a few
suggestions based on work I have done to a few 1990 3.1L.

Injectors fail/become shorted and this takes out the ECM (overload the
drivers) which shows up when things (engine and ECM drivers) heats up after
use.  Even if you have replaced all the injectors, the ECM drivers will
still be weak and susceptible to acting up again.  Also the crank sensor is
one to act up after a time.  Grounds are critical as in any car so check
these and especially the ones at the tranny to block bolts in front of the
engine, and the ones near the timing chain cover/back of lower engine block.
The cable that runs to the module can become pinched as it passes through
some tight/hot areas so check these by pealing back the wire loom.  Also
motor mounts top and bottom can cause a ground loop problem if they are worn
out enough to allow metal to metal contact but yours sounds more heat
related.

That is about all I can remember at this time, good luck and keep us posted.

Jeff M




















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