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Discussion Starter #1
I had a non-starting issue which is now fixed and now just doing some timing adjustments. I got my manual and followed the instructions and set my timing to 10 without the spark computer vacuum advance line hooked up (I removed it and plugged it as the manual said). The car runs quite well but I was just trying to see exactly how much the vacuum advance affected timing so I also checked timing with the vacuum advance hooked up and noticed it did not change whether it was connected or not and kind of expected it to. I just don't know if the coolant temp input or the idle stop input to the spark computer affect whether or not vacuum advance works. The car is well warmed up (coolant switch open) and the idle stop switch is providing a ground to the computer. I was going to try changing both of these inputs and see if it changes but I thought I'd ask the question here.

Also in my troubleshooting to get the car started, I had the spark computer out and while out I put an ohmmeter on the two wires connected to the vacuum advance and they measured 70 ohms. I then used my hand vacuum pump to pump to about 18 inches of vacuum and kind of expected to see a change on my ohmmeter (open or shorted completely) but did not. I kind of thought maybe this was a valid test and determined the vacuum advance unit in the spark computer was bad, but this was all done without power and thought maybe I needed power to verify this test?? Anyways, I put it back in the car, and fixed a wiring problem to get it started but figure I may as well test as much as I can as I am very new to these 2.2l engines.

So basically wondering how I can test the vacuum advance module in the spark computer with the engine running and if there is also some kind of test to see what the coolant switch input does to the timing, if anything.

Thanks for any help/insight.
 

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One of the reasons you are not seeing any additional spark advance is you are missing something...
LOAD.
The system does not operate like a standard mechanical distributor system with a vacuum and centrifugal advance that move a plate according to engine speed and vacuum which increases/decreases spark advance.
The electronic spark control computer has to see numerous different things before it determines and changes spark advance.
The only reason you disconnect and plug the vacuum line to the ESC computer and ground the throttle switch is to be 100% sure you are at base timing.

To fully understand the Lean Burn System you will need to find a training manual that explains Principal and Theory of operation or an old Chrysler Tech that worked on these cars new.
Unfortunately with all of my training Lean Burn, GM Feedback Carb and FI, Ford VV Carbs and FI, Import Fuel Injection are no longer in my memory banks, the only reason I still remember Chrysler EFI and MPFI is I own one.

 

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Discussion Starter #3
Ok, that makes more sense than. I was just confused when it tells you to do something and then doing that doesn't make any difference. Now I know. Thank you so much for clearing that up for me.
 

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I'm not very familiar with the spark computer although I have 2, 1983 and a 1984

Previous member Angelo experimented with them on his Matchbox Horizon.

He even won some drag racing championships and put hundreds of 1,000's miles on it.

He was a carb expert and claimed they ran better without the vacuum line hooked up.

I never noticed any difference with the line attached or not.

Please keep us posted on your progress if you don't mind

I see a 1987 Charger one on Rockauto for $23.00!!

Thanks
Randy

 
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