I have a 1990 CRX Si with a stock tachometer indication problem. At idle the tach reads 2000 rpm's and my timing light is reading only 750 rpm's and when I go through the power band the highest the rpm's will go is 3500 and it goes very slowly. Any help would be greatly appreciated.

 

ttt

 

sounds like a couple of problems,
first if your car wont "rev" past 3500 rpm then your ECU is going into limp mode, are there any CEL's flashing (there should be)? or is this related to the tach just not reading correct, like does the motor stop at 3500 rpm or does the tach stop there?

second is this tach issue new or was it always this way?
and is the tach off by 1000rpm all the way through the range?
if it is consitant then you could possibly adjust the needle. I have done that before, take the cluster apart to get access to the tach. Yours needs to be adjusted down so turn it counterclockwise (you will hit the pin that stops the tach at zero, but just gently pull the needle up and over the pin). You will feel some resistance when the needle gets to the "home" position (where the needle rests). Then just turn it a tiny bit more past that point to adjust down, and then pull it back over the pin and test, rinse and repeat until you get it right. Oh and if you turn it too far counter clockwise just turn it clock wise to around where 9000rpm would be and it should hit some resistance there, and then just push it a tad more to adjust it up.


Modified by grog at 6:31 PM 8/6/2008


Modified by grog at 6:36 PM 8/6/2008

 

Thanks for your help and reply. The second reason is correct being the factory tach doesn't go past 3500. The engine rev's up smoothly with no issues just the tach reads off by 1000's of rpm's.

 

I am not positive but maybe someone else can chime in and let me know if im right or wrong but I believe it could also be a bad ground (check the one by the thermostat housing) or also it could possibly be the ignitor in the dizzy going bad.

Just a few more options that it could be...

Have you done anything at all under the hood lately? wash it? mess with anything?

 

What exactly is the dizzy? Nothing has been touched under the hood since I bought the car. The previous owner swapped the original D16 for a sohc ZC motor. I will check the grounds as you mentioned. Thanks

 

dizzy=distributor