another FI mystery to chew on, something to do tonight Options

[drewvw]

my car runs pretty good, don't get me wrong....but its not perfect and the fact that its varies so drastically with temperature drives me a little batty.

so here goes

1) Cars runs awesome in extremely hot (80s-90s) weather and runs a little worse in the 60s-70s and stumbles all over the place like its too lean when its mid 60s or below.

1) I've timed it, pertronix, ignition seems to be in good working order.

2) Replaced intake temp sensor (thanks evil) and the ohm readings are the same, no change except if I unplug it altogether and then the stumbling stops do to it running more rich.

3) CHT measures 3057 when its cold and 57 when its hot. Seems to work fine

4) I discovered the MPS has been opened up, as the epoxy is gone.

5) edit: I've redone and clamped pretty much all of the vacuum lines

6) only varible seems to be outside temperature


solve my mystery and win a prize!

[SirAndy]

solve my mystery and win a prize!

what shape is your wire harness in? i had all sorts of trouble with my 1.7L. bit the bullet and bought 2 junk engine harnesses and made one good one out of three.
ran like new afterwards ...

what i found, some of the wires had broken inside the hard plastic covers, impossible to see from the outside!

i cut *all* the hard plastic and inspected all (and replaced the broken) wires, then put the wires back into the plastic and taped them shut with electrical tape.

used a voltmeter to verify *all* wires were working correctly.

took me a whole saturday afternoon, but it was well worth it.

if your harness is still the original, you'll be chasing ghosts forever and spent cubic $$$ on replacing parts that don't need to be replaced.

i'm certain 90% of the FI related problems people have are due to cracks and such in the wiring harness ...
(IMG:style_emoticons/default/wink.gif) Andy