Just read the FAQ for the first time EVAR!

[93rev2sev]

I beleive this to be incorrect information. It is located in the FAQ(that no one reads)

Since the CPS is also used to operate the tachometer, a common warning sign is the tach dropping to 0 while still driving down the road and not registering anything while the engine is being started


The tachometer will register RPM (about 300) when you crank it...even with a bad crank sensor.

 

[SuperHO]

odd, when my CKP went to shit, the tach just looked at me like "what" and didn't even twitch.

 

[93rev2sev]

I thought that too...then I bought the silver 93MTX last February. It had what the PO called "a timing issue". It would crank and crank but not start. I don't think he knew how to check for spark, but when I got it home, it would crank and the tach would go up to about 300. Maybe 400... But there was no spark...none whatsoever. When I saw there was no spark (my brother was cranking it, from the drivers seat) I asked if there was any tach movement. He said there was about 400 RPM. I actually switched spots with him to see the tach move. I couldn't beleive it. I swapped DIS with my car...same deal. 3-400RPM and no spark. I didn't care. It was -3 and I was convinced a crank sensor would do it.

I didn't so much as remove the coil cover to check connections. I went right to Autozone and bought a Crank Sensor. Installed it, cranked it and it purred. Keep in mind this was February of last year...very freaking cold and windy. I didn't do anything that wasnt required to change the crank sensor and see if there was spark. I only had 7 plugs wired. While the engine was singing it's off key notes, with no damper pully or timing belt guide(for about 3.5 seconds), I heard "SNAPSNAPSNAPSNAPSNAP". There was spark now.



Because of that cold...I didn't bother to unplug it to see if I still had RPM. Suffice it to say I'm in a similar frame of mind now. Someone else can go check...or look it up and tell me I'm full of it.

Edit : I guess this thread can be moved until it's confirmed either way.

 

[01SVTSnakebite]

I thought that too...then I bought the silver 93MTX last February. It had what the PO called "a timing issue". It would crank and crank but not start. I don't think he knew how to check for spark, but when I got it home, it would crank and the tach would go up to about 300. Maybe 400... But there was no spark...none whatsoever. When I saw there was no spark (my brother was cranking it, from the drivers seat) I asked if there was any tach movement. He said there was about 400 RPM. I actually switched spots with him to see the tach move. I couldn't beleive it. I swapped DIS with my car...same deal. 3-400RPM and no spark. I didn't care. It was -3 and I was convinced a crank sensor would do it.

I didn't so much as remove the coil cover to check connections. I went right to Autozone and bought a Crank Sensor. Installed it, cranked it and it purred. Keep in mind this was February of last year...very freaking cold and windy. I didn't do anything that wasnt required to change the crank sensor and see if there was spark. I only had 7 plugs wired. While the engine was singing it's off key notes, with no damper pully or timing belt guide(for about 3.5 seconds), I heard "SNAPSNAPSNAPSNAPSNAP". There was spark now.

I guess this thread can be moved until it's confirmed either way.

Because of that cold...I didn't bother to unplug it to see if I still had RPM. Suffice it to say I'm in a similar frame of mind now. Someone else can go check...or look it up and tell me I'm full of it.

WOW, now THATS an interesting story lol

 

[93rev2sev]

WOW, now THATS an interesting story lol

The cold makes me

 

[Huntervf]

I've seen it go both ways with the CPS... tach drops COMPLETELY away while driving yet the car still runs along fine. Vice versa, car dies out and the tach still registers. If the CPS hasn't completely failed you can get an intermittent problem which can give symptoms above. Since the tach IS driven by the CPS, having it drop out to zero and not move when you crank the car can in fact be a very good indication that the CPS is bad, but it's not a 100% foolproof symptom. The only real sure-fire check is to in fact pull codes. 9 times out of 10 even an intermittent CPS problem should set a code.

 

[St Louis SHO]

Hmm, then the 4 times I've seen a bad one don't, I must be the 1 of 10.

 

[platoribs]

Hmm, then the 4 times I've seen a bad one don't, I must be the 1 of 10.

James,

I believe the math for your situation is something like 4 out of 40, you just need to work on more cars dude!