falconman

Ok, so my car seems to be having problems with the tach. according to the gauge, it idle's at ~1100 rpm. I know it's not that low from sound, and also know that it's reading high throughout the rpm range. it sounds at about 2500-3000rpm when it's redlining. I'm not sure where the rpm sensor is either, so a location on that would be helpful also. Are there any problems in the area these cars are prone to? If not, does anyone have an opinion on this?

Also, while I'm asking, it seems to have a problem every now and then, usually when it's cold outside, with idling and staying going. Once it heats up, it doesn't have this problem, but now, if I rev it and let completely off of the gas, it will die. And recently, it seems to be backfiring. I'm guessing it's the timing, but wanted a second opinion.

Thanks,
Andy

sofakingdom

iTrader: (1)

The "tach" (trim option) fails in these cars by reading high. I have several of them; one reads more than double the true RPM. I have heard of them reading much higher than that.

There used to be a writeup on this site somewhere about what to do to fix it but I can't recall where. It involved using a variable resistor to determine the correct value for a certain thick-film one the factory used as a trimmer and cut with a laser to get to the right value, which is not stable and then changes value over time. You remove the original, use the pot to find the correct value (make it read right), then solder that value of resistor in place of the old one.

falconman

you lost me there^.it could just be cause I have no idea how tachometers work, but yea, I'd need some further explaining on that.

thanks

hotro1988

Take a look at this link it gives a generic description of the proccess need to calibrate a tachometer.

falconman

thanks

zenish

https://www.thirdgen.org/forums/elec...meter-fix.html .ignore the title.it works on all years.