2600 Rpms to zero!!

[Bacoman]

I have a 1997 Grand Prix SE 3800 for the past two years and its been a great car. For the past two months I have been having a problem that I can't seem to figure out. It happens when driving on the hiway, the rpms will go from 2600 to zero, the car seems to downshift, sometimes thats all that happens but occasionally it shuts down. I put it in netreul and turn the key and it restarts and the rpms are back to normal.
Anyone have this type of experience.
I have a 2000 GP GT and have never had this happen.

[GTP Dad]

Two possible causes, crank position sensor going bad or the speed sensor in the transmission. Start with the CPS.

[richtazz]

I agree, it's more likely a crank sensor.

[PerfesserCoffee]

I've got the same problem and assume I need to replace the CPS on my 1995 Grand Prix GTP.

On Rock Auto, I'm given the choices of:

a. STANDARD MOTOR PRODUCTS PART # PC7
7X SIGNAL (CRANKSHAFT SENSOR)

b. ACDELCO PART # 213148 SENSOR, CR/SHF POSN2 BLAD TERM-SIDE OF BLOCK

c. ACDELCO PART # 213234 SENSOR,CR/SHF POSN 24X TO ECM-BEHIND BALANCER

What parts do I need to complete the task for my car?

[richtazz]

On your 95, you'd be best off to replace both, as there is no easy way to determine which is causing your problem. The one behind the balancer is the most likely cause, but I'd change both.

[PerfesserCoffee]

Okay, thanks, richtazz! I'll do that.

Where is the one located that is NOT behind the balancer?

[the.dude]

I think the same thing is what I am experiencing. I'll be going do the road and there is something like a surge in the acceleration then my tach shows 0. The car still run fine and nothing else is dufferent that I can see. When I restart, everything is fine.

I have a 98 gtp 135k. Any help is apreciated.

[BNaylor]

Originally Posted by the.dude

I think the same thing is what I am experiencing. I'll be going do the road and there is something like a surge in the acceleration then my tach shows 0. The car still run fine and nothing else is dufferent that I can see. When I restart, everything is fine.

I have a 98 gtp 135k. Any help is apreciated.

Sounds like classic 24X CKPS going South. Also sometimes the TRAC OFF light will illuminate when it cuts off in addition to the tach going to zero. Here's a procedure to give you an idea of the work involved if you prefer to DIY.

http://mykidz.net/GTP/CrankPosSensor.shtml








Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[the.dude]

TRAC OFF... how'd ya know?!? Now I have TWO reasons that this light comes on. I've had wheel hubs going out all around the thing. Every time I run over railroad tracks the ABS / TRAC OFF pops on.

[the.dude]

ok, I got the harmonic balancer removal tool from oreillys and the dumb thing doesnt fit the car. not sure what to do now, I am a foot. Everything in this kit is too big.

[BNaylor]

Originally Posted by the.dude

ok, I got the harmonic balancer removal tool from oreillys and the dumb thing doesnt fit the car. not sure what to do now, I am a foot. Everything in this kit is too big.

What's too big the puller or bolts? The one Autozone has fits.









Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[the.dude]

the bolts were to big, and the puller has a pad on the end that won't fit in the balancer hole. auto zone has loaned theirs out. Guess I need to learn patience. Hard when you dont have a car!

[BNaylor]

Originally Posted by the.dude

the bolts were to big, and the puller has a pad on the end that won't fit in the balancer hole. auto zone has loaned theirs out. Guess I need to learn patience. Hard when you dont have a car!

What a bummer! Sorry to hear that. I know what you mean....lots of patience.

I'm glad I have 17 Autozones within a 20 mile radius. One of them is bound to have the puller available. Oh well.










Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[the.dude]

Just so you can all have a laugh at my expense...

I went to Autozone tonight in my wifes car to just buy the puller I need. I planned on getting everything I need to finish this job tonight so tomorrow, when I have no other vehicle here, I don't have to worry about it. Well, I get the puller with the right bolt (still wrong bolts for the 3 small ones by the way), Pay, get in the car...

It won't start.

Turned out to be the positive battery cable was badly corroded and it just needed cleaned out. But it was still quite a headache. Her 97 Monte Carlo has the battery buried under everything short of a cup holder.

While I am on it, does anyone know why the 'security' light would randomly come on in the Monte Carlo? I would ask in the forum, but compared to this one, it is useless. I am hoping it was related to the bad connection to the battery.

[Bacoman]

[quote=bnaylor3400]Sounds like classic 24X CKPS going South. Also sometimes the TRAC OFF light will illuminate when it cuts off in addition to the tach going to zero. Here's a procedure to give you an idea of the work involved if you prefer to DIY.

http://mykidz.net/GTP/CrankPosSensor.shtml

Thanks for the detail instructions. Any idea on what the parts will cost to replace the CKPS?