the case of the unstable idle finally solved!

[Soma576@xxxx]

Hey all,

at long last i am pleased to report that i have solved the mystery of why my 
car never wants to settle down at idle!! the problem i have had for over a 
year is that when my car is warmed up, it always liked to fluctuate between 
500 and 1000 RPM, always wavering back and forth, never staying still like a 
normal car should. i replaced lots of original parts including the whole 
ignition system plus ignition coil, getting the fuel system evaluated and 
adjusted by grady, playing with the throttle linkage, etc etc. nothing 
seemed to work. i finally had the ignition timing checked again and this 
time after some investigation it was found that my car was suffering from a 
pre-advance condition at idle, which according to the shop manual shouldn't 
be happening. when we checked around we found that the ignition vacuum 
canister which is located directly behind the fuel distributer was not 
operating correctly. it was causing the ignition advance solenoid to 
energize prematurely causing the off-timing effect at idle. this is 
something i never would have suspected or discovered if the timing hadn't 
been checked!! we found that when we disconnected the middle vaccum line to 
the canister and plugged it, the car returned to normal timing at idle and 
the idle stabilized!! it was a beautiful sound!! today i got a new canister 
from Grady and installed it and VOILA! problem solved. 

now i just need to get my mixture checked again cuz i swear i am still 
running a little rich...

anyway, if your car seems to be perfect except for the idle never wanting to 
stabilize, you might try this test to see if your canister is broken too. 
just one more thing to check!!

Andy

Soma576@xxxx
1982 DeLorean DMC-12 VIN#11596
Fargo, ND 58102


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