It works. Just i turn the car on, and it won't move. It says i have 0 RPM when im idling. LOL

What could be causing it? I mean i know it works, but it seems likes its a notch down, or something.....

 

So it functions and rises with RPMs, just it's too low over all? Or does it not function at all?

 

Same questions as above...

If it is just off, chances are at some point in time the needle was removed and may not have been put back on properly.

If it isn't working at all... I believe that the tach signal comes from the CMP (camshaft position) sensor.

 

It works. But if i turn the car on and its not moving. It goes all the way to zero.

 

C'mon man give us some elaboration, I still don't really get what your tach is doing when... When you're driving down the highway, at say 70 mph, a normal 4.3 blazer in good shape should be doing right around 1800-2100 rpm. What does yours show.

And at start up, you say it goes all the way to zero...but the tach started out at zero with the car off, so are you saying the needle did not move? Or are you saying you cranked it, the needle reved up with the engine start up, THEN went back down to zero (pegged)?

Post at least 2 sentences now

 

When im idling, it goes to zero.

oh and it says less than 1500

So i know something isnt right. and thats me doing like 85 down the freeway.

 

It is possible that the needle is loose as well. This happened in my cousin's neon. I used my scan tool to monitor RPM from the PCM and then stuck the needle back on in the right position. Has worked like a charm since then.

 

So i should hook up a scan tool(that i dont have) and monitor the RPM's like im driving. And then deassemble the front gauge's Pop off the needle and put it where it should be?

Any other ways around that?
lol

 

I mean...I guess you could just guess what your RPMs are..


Or fix the needle like you wanted.

 

IF the needle is just loose, then the ONLY way to accurately put it back on is to know what the RPMs are. Now whether you use a scantool, an inductive pickup with a DMM capable of displaying RPM, or some other means of finding the true RPM of the motor, well, that's up to you.

Idle RPM in park fully warmed up should be between 500-600RPM. If that is close enough for you, pop the dash apart, remove the 'window' on the cluster, and pop off the needle. With the engine running, fully warmed up, put the needle back on pointing at approximately 600RPM.

If that doesn't work, then you either have a RPM reporting problem (CMP) or a cluster problem. The only way to tell after that is to use two of the ways of getting RPM I listed above; scan tool and another means of measuring RPM directly off of the motor. My Fluke 88V has an inductive pickup that can show the RPM. If the PCM matches the multimeter, you problem is in the cluster. If it doesn't, then somehow your CMP sensor is feeding mis-information to the PCM without the PCM tripping a code.