Why is my tach quiting

thunderturd

Registered User
My tach will drop to 0 for a second or sometimes a minuit, but the car keeps running. Is this a problem in the dash or somewhere else. Even when I pound on the dash there is no difference.
Thanks!!
 
I think I remember someone else on here had the same problem , it was a bad crank sensor as I recall, but it is very likely I am wrong. :p
 
VostocK said:
I think I remember someone else on here had the same problem , it was a bad crank sensor as I recall, but it is very likely I am wrong. :p
Yup.. you're wrong. A loss of a crank sensor signal (PIP) will cause the engine to stop. The loss of a cam sensor signal (CID) can cause bucking and/or a wacky tach. A failing DIS can cause a loss of the tach signal, but yet the engine will run just fine.
 
:( Boy, i am in a lot of trouble, My engines dies every now and then while driving on the street or freeway, it bucks sometimes, and i can remember atleast a few times when the tach doesn't move from "0 RPM" yet the car is idling.. Guess i should get ready to pay an arm and a leg for all those three parts.. :( :(
 
SuperCoupe007 said:
:( Boy, i am in a lot of trouble, My engines dies every now and then while driving on the street or freeway, it bucks sometimes, and i can remember atleast a few times when the tach doesn't move from "0 RPM" yet the car is idling.. Guess i should get ready to pay an arm and a leg for all those three parts.. :( :(

Cranks sensor is about 30 bucks
Cam sensor is about the same.
DIS module is going to hurt, about 200.

I suggest starting by hitting the local computer parts store and getting some good heat sink compound. Replace the old stuff, i.e. clean the DIS and mount on the passanger side accessory bracket. See if that helps.

Then replace the cam sensor and crank sensor. They are fairly easy. The cam sensor is 2 bolts and a plug. The crank sensor is 3 bolts, 2 screws and a plug.

If non of that helps then replace the DIS.

If you go this route, please let us know what worked. I have a similar problem, my tach drops out for a second and I get a 122 (I think) code, which points to the crank sensor. The car has been doing this for years. Replacing the Cam sensor didn't help, but replacing the crank sensor lessened the frequency and length of time the tach drops.
I'm hoping to not have to replace the DIS anytime soon either. I've spent far too much money on this thing in the last 9 months. The only way I will ever get my money's worth out of what I have had done is to drive it for another 5 years.
 
SuperCoupe007 said:
:( Boy, i am in a lot of trouble, My engines dies every now and then while driving on the street or freeway, it bucks sometimes, and i can remember atleast a few times when the tach doesn't move from "0 RPM" yet the car is idling.. Guess i should get ready to pay an arm and a leg for all those three parts.. :( :(

Probably your crank sensor. I have read where you can change it without pulling the balancer. If you pull the balancer it should be changed too.

I have the same problem with my 2nd SC with 84K on it. The car just randomly dies while driving like you cut the ignition with the tach dropping to 0 instantly. Starts right back up though. So I have a BHJ balancer and underdrive pulleys I am going to install in June when I do some major maintenance.
 
All of these 3 things will eventually, over the life of the car, need to be replaced. The cam sensor is the easiest and cheapest to to fix. DIS modules can be found for less than $200 and the crank sensor is the hardest to replace. Before you dive into that though, be sure to check that the HB main bolt is not missing and that the crank pulley is not wobbling when the engine is running. If it is really the crank sensor, it's possible to replace it w/o pulling the HB. :)
 
BIGJOHN0352 said:
I bet that it is your dis i just had the same problem


I suppose the right first question is: Have you run the codes yet?


I already have already changed the DIS sensor on mine. For under $30 I changed it first before deciding it was the crank sensor. Also my car has over 80K on the original balancer and crank sensor I am going to change them both.
 
I ment your DIS module when your tach goes dead tap your dis module its mounted on top of your a/c compresor i bet it will start working for a short time the zone has the module for like 150.00 :)
 
BIGJOHN0352 said:
I ment your DIS module when your tach goes dead tap your dis module its mounted on top of your a/c compresor i bet it will start working for a short time the zone has the module for like 150.00 :)


LOL I meant Cam Sensor on mine.... I might just put my spare DIS on. I changed it before I found my brand new but defective injector on my other SC. I bought the DIS at Schucks for $89 last fall. I just checked and now they have it at $241 on the web site... :mad:

NAPA
Item#: ECHTP502

Price: $ 134.00
 
Last edited:
Cam sensor is so easy, change it in 5 minutes. Crank Sensor can be changed w/ balancer on the car, I have done it, but I had to go to sears and get a set of small craftsman ignition wrenches 5.5 mm two bolts hold it on not 3 bolts and 2 screws like someone else said. Take off the plastic balancer guards and you can get at it from under the front of the car, its not extremely hard to do, I put it on after I put on my balancer. If you pull the balancer off its MUCH easier w/ a 5.5 socket but I recommend leaving the balancer on unless you are doing other work in that area that requires removing it.

DIS modules are $90.00 at Auto Zone.
 
Looks like I'll try the crank pick up, I've already changed the cam sensor and the DIS. Also it seems to buck every once in a while when the engine is cold, could the crank pickup play a role in that also?
Thanks for all the replies everyone!
 
The first thing i am going to change is the crank sensor, then if that doesn't work, i'll change the cam sensor... Hopefully sometime in June i'll change the crank and see what happpens.. Thanks guys...
 
Back
Top