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Any idea where engine speed sensor is?

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Old Apr 8, 2010 | 10:25 PM
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Default Any idea where engine speed sensor is?

Need help on locating the engine speed sensor that sends signals to the tachometer. Just installed a salvage engine into a 96, and everything working great, except tachometer not responding. Before I pull out the instrument cluster to diagnose, perhaps it would be a good idea to make sure this engine speed sensor is plugged in right (or functioning).

Thanks in advance.
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Old Apr 9, 2010 | 05:18 AM
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the tach signal comes from the ignitor. if it wasnt plugged in then the engine would be running like crap. there are 2. 1 for each cylinder bank. so its either a wiring problem or the tach is bad. if the tach worked before id check every connector on the engine harness asuming you used your old harness. if you used the one that came with the engine could be a bad wire.
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Old Apr 9, 2010 | 09:23 AM
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Thanks Williamb82, it was working before. And yes about engine running crap if there weren't any engine speed signals. Will get multimeter out to diagnose/find bad wires.

Added: After a longer drive tachometer is alive again. Probably a less-than-good connection somewhere when putting the engine back in.

Last edited by ck90211; Apr 9, 2010 at 10:30 AM.
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Old Apr 9, 2010 | 11:37 AM
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yeah, prolly just have a plug that had a bad connection due to too much dielectric grease in it or something. at least you didnt have to go chasing wires. that can be fun. lol. heres what my 84 looked like when i built the engine harness for my megasquirt 2.

http://www.cardomain.com/ride/2042690/18
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Old Apr 9, 2010 | 02:34 PM
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Does the Tach signal come from the cam position sensors?
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Old Apr 12, 2010 | 08:24 AM
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no. ignitor. or if for some reason your wanting to install an aftermarket tach you can grab te signal from the neg side of either coil. just make sure that your tach is set for a 4 cyl, not an 8 cyl. each ignitor/coil is running half the engine only.
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Old Apr 13, 2010 | 06:05 AM
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Originally Posted by Thermactor
whoa, mr. celica supra! Great to have you in the LS section!
lol. didnt know you had an ls. just got mine a few weeks ago. still sorting some issues out. needed a new daily so figured id get a 1st gen ls400 and ride in style and comfort. and the bigger rods incase this car gets the turbo bug too!
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