Crank Position Sensor / Tachometer

[tweak1029]

I just replaced my timing belt, etc., front bearings, and rebuilt my front calipers. During all of this I forgot to check out my cps because I hadn't been using the car. I doubt the cps has any problems or the car wouldn't run / run well (It's a 1992 5SFE, maybe pre-OBDII cars are different). Car runs perfectly and the MIL is off. How can I test the tach? It reads way too low, especially in the cold. But the tachometer's performance doesn't vary directly with coolant or engine temp, it seems to lag behind and perform better as the cab or dash temperatures increase.

I've considered grounding it, but I'm afraid that will put too much current through it and make things worse. Is grounding it safe? What should the resistance be?

[jsroller]

Originally Posted by tweak1029

I just replaced my timing belt, etc., front bearings, and rebuilt my front calipers. During all of this I forgot to check out my cps because I hadn't been using the car. I doubt the cps has any problems or the car wouldn't run / run well (It's a 1992 5SFE, maybe pre-OBDII cars are different). Car runs perfectly and the MIL is off. How can I test the tach? It reads way too low, especially in the cold. But the tachometer's performance doesn't vary directly with coolant or engine temp, it seems to lag behind and perform better as the cab or dash temperatures increase.

I've considered grounding it, but I'm afraid that will put too much current through it and make things worse. Is grounding it safe? What should the resistance be?

mine was doing the same thing (92 camry 5sfe) cold weather no tach, after car warmed up tach would start working, could never figure it out so i got another tach out of junked car and replaced mine worked great for about a month and starting to slowly show incorrect RPM's again i am thinking something in distruburtor not working correct according to wire diagram that is were it gets its signal from .

[tweak1029]

That's an idea. The Wiring diagram says the ignitor powers the gauge. Perhaps something is wrong with the ignitor that damages the gauge. Or perhaps it's all in the ignitor. I'll probably check it out tomorrow after I finish with the struts on the Olds.