[T3] Car Runs Great, but Why?

[Bobsnotch at aol.com]

In a message dated 3/2/2011 4:27:40 P.M. Eastern Standard Time,  
j_jonik at yahoo.com writes:

.Bingo!  All performance problems disappeared!...EXCEPT that it  was still 
somewhat tricky to set the idle to make acceleration  smooth.   To see what 
negative changes there would be, I unplugged  the Temp Sensor at the Air
Distributor.

Then, double Bingo!... The  car now feels like new.  It idles regularly, 
accelerates without any  hesitation (no need to rev a little), and it now 
starts right up on the first  key turn.   With the Cold Start Switch unplugged 
and un-hosed, it  needed at least a few key turns to prime up the fuel lines. 
But not now.   Don't understand that.   I've finally, bravely, gone out on 
the  interstates and...well...it's just fine.  No troubling fuel smells, or  
fuel leaking from heater box clamps etc. And, the oil level is staying 
right  at its level...no fuel getting into it.

I asked about unplugging that  Temp Sensor not too long ago and was told 
that doing that makes the Control  Box think the engine is cold, and that this 
would lead to higher fuel  consumption.   Can't check that because I don't 
know previous MPG  anyhow.

So, what explains this?  Why would sensor plugged in make  car perform
worse?  This must be a clue to something.    I  tried two other 
sensors...but they made it a little worse idling and  hesitating etc than the original 
one.

No...I haven't yet tested sensors  in hot oil to check ohms.





That temp sensor just leans out the fuel mixture. With it unplugged, it's  
causing the system to be 10% more rich than normal. The normal reading (with 
an  ohm meter) is 300 ohms @68*F. This is specified in the Elfrink FI 
manual. I  believe as the air temp goes up, the resistance drops (like the head 
temp  sensor). I don't know what the lower limit is though. Ray Greenwood 
told me that  he normally unplugged his during the summer (it gets damn hot in 
Texas in the  summer), and would plug it back in, in the fall.This helped 
drivability issues  in very warm weather, and kept the system from running 
lean. Another approach is  to balast the head temp sensor (factor approved 
mod), using a 200 ohm resistor  in series (set up to plug into the connection 
for the head temp sensor to wiring  harness).
 
Since it running pretty decent, why don't you drive it the 13 miles to the  
mechanic, and see if he can reset the idle?  

Bob 65 Notch  S with sunroof and IRS (Krusty)
71 Notch (Krunchy)
64 T-34 Ghia  (Wolfie)
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