Mechanics

GEO PRIZM ENGINE PROBLEM

1990 Geo Prizm • 120,000 miles

Have a 90 geo prizm LSI sedan with the 1.6 L. Did alot of repair to engine, now I need to reset the idle correctly. Where can I pull the RPM signal from? Is there a plug that comes off the distributor? I really have not looked yet.
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Carpetman1759
October 23, 2012.




Do you have a distributor driven ignition system if so hook up the TACH on the neg. Side of the coil and ground


Tiny
Rasmataz
Oct 23, 2012.
I know you pull it off the negitive side of the coil but the coil on this motor is internal inside the cap.? There has to be a port somewhere under hood to get it from. This car does not come with a tach option in any model until 92.I would like to put a tachometer on it if I can find a connection.
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Tiny
Carpetman1759
Oct 23, 2012.
Kk-Try this

Warm engine to normal operating temperature. Turn engine off. Remove cover from Data Link Connector (DLC) located on left strut tower. Connect a tachometer to battery and terminal No. 19/IG (Black wire) of DLC. Good Luck


Tiny
Rasmataz
Oct 23, 2012.
OK! I found the data link box, but it is not look like your picture. It only has 17 pins in it. It also has a rubber pull off cover on a pin mounted outside of this box that is marked 1G -. I don't know if that is what you are talking about. Also my prizm is a 1990 1/2 model vin 6 if that matters.I want to make sure before I start sticking meters into wrong connections and short something out. Been there done that! Thanks.


Tiny
Carpetman1759
Oct 25, 2012.
Slap the Tach meter on that and read off-


Tiny
Rasmataz
Oct 27, 2012.

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