Have a 90 Geo Prizm LSI Sedan with the 1

CARPETMAN1759

MEMBER
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.

Tuesday, October 23rd, 2012 AT 2:47 AM

5 Replies

RASMATAZ

MECHANIC
75,992 POSTS

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

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Tuesday, October 23rd, 2012 AT 2:53 AM

CARPETMAN1759

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81 POSTS

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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Tuesday, October 23rd, 2012 AT 1:58 PM

RASMATAZ

MECHANIC
75,992 POSTS

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

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Tuesday, October 23rd, 2012 AT 11:12 PM

CARPETMAN1759

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81 POSTS

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.

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Thursday, October 25th, 2012 AT 4:12 PM

RASMATAZ