[T3] cool weather idle hunt

Bobsnotch at aol.com Bobsnotch at aol.com
Tue Jan 17 16:53:15 PST 2017

In a message dated 1/17/2017 7:12:25 P.M. Eastern Standard Time,  
d.nohejl at gmail.com writes:

When replying, please  consider trimming your message. Thanks!  :)

O, boy, what a  mess!

Car started fine this morning but idled very roughly when cold. I  made a 
note to myself to adjust idle and timing after work in case changing  the AAR 
adjustment threw off the idle speed. I figured that was possible  depending 
on where the AAR was set when I last did the idle. 

After  getting off the highway on the way to work, the motor stalled every 
time I  took my foot off the gas but for one time when the idle stayed 
steady. After  work, it took five tries to start the car. Very unusual as it 
always starts on  the first or second try. I pulled out of the parking lot and 
stalled. I then  proceeded to stall every single time I let my foot off the 
gas but it drove  perfectly well on the highway. I got close to home and 
stalled at a light.  This time it wouldn’t start. It caught on one or two 
occasions but wouldn’t  fully fire up. Then, it’d crank and crank but nothing 
else. Of course it  started pouring rain after a few minutes…..

Anyway, I checked the  following partly by myself and partly once Jessica 
showed up (the benefit of  breaking down only 2 miles from home)…the list isn’
t in sequence:

—fuel  pump relay clicked and pump primed when key was turned
—FI power relay  clicked when key was turned
—MPS sensor plug wasn’t loose
—all injector  plugs were secure
—trigger points connector was secure
—injector grounds  and ECU ground at case center line all secure
—wires to generator were  secure
—12V to black/white wires from FI ground to T2 connector and 12V  from T2 
connector to ECU
—resistance of both temp sensors was  fine
—dwell was ok and everything in the distributor looked fine
—12V to  coil
—took out the ECU and verified that the plug wasn’t loose

It  was pouring out and I was staring at the ECU laying there in the cargo 
area  and decided to take the plunge b/c Jessica showed up with one of our 
spare  ECU’s. I plugged it in and the motor fired right up. Just to confirm I 
wasn’t  hallucinating, I tried the ECU I had just removed. No start. Tried 
pressing on  the harness in case it was loose on the card edge. No start. 
Put in the spare  ECU and it fired right up again and I drove home without any 

So all along my "intermittent warm idle lope" was the ECU  taking a dump 
until it finally died?!?! Is that even a  thing??
Well, I don't know if it's a sign of a dieing ECU, but it certainly  sounds 
like it's possible. At least having a spare ECU to put in and get the  home 
helped. I guess you'd have to try the replacement ECU for a couple of days  
to know for sure.

Bob 65 Notch  S with Sunroof
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