2600 Rpms to zero!!

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.

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

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

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?

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.

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

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

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.

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







http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
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.

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.

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.

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. :dunno:








http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
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 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!

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.









http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
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.

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.

[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?

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

CKPS GM list price is $52.00 USD for OEM and Autozone has it for around $26.00 USD, Wells brand.








http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
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.

I paid about $30 for the sensor. I had to get the 1/4'' x 28 x 3'' bolts at NAPA, and had to buy the HB puller for $15 at oreillys.

I paid about $30 for the sensor. I had to get the 1/4'' x 28 x 3'' bolts at NAPA, and had to buy the HB puller for $15 at oreillys.


Glad you finally got it sorted out. Is it fixed? :biggrin:











http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
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.

yeah, I spent more time tracking down to dumb bolts than doing the job. With the instructions on that link, it was a snap.

I've got the same problem with my 01 GT... but it's really been weird. First off, my ABS warning light and trac off lights came on simultaneously... It was off, the next time I started the car, but as I was going around a corner braking lightly I noticed a pulsating pedal. A few miles later, the lights came on again. I thought this was a problem with the ABS and took the car to the dealer for service. They said I had a bad hub... and it cost several hundred dollars to replace. The very next day, the light came on again, I immediately called the dealer who had me bring the car in right away so they could check the error code in the computer. I did and they informed me that it indicated a problem with either a hub or the rack & pinion steering or both. I decided to continue driving it this way because I couldn't afford another several hundred dollars. Then my battery died and I replaced it myself. After that, no more ABS warning light OR pulsating pedal. However, two weeks later, the tach died while driving on the freway, and the service engine and trac off lights came on at the same time. It felt like power had been reduced a bit and when I accelerated, the engine pinged. Again, this condition went away after shutting the car off. and restarting it. This happens frequently now, but the service engine light doesn't come on any more, and neither does the ABS light which makes me wonder if those bulbs have burned out. All in all, it reminds me of having to restart my computer when it crashes. So tell me does this sound like this crank position sensor problem? What does it have to do with the trac off light or ABS or rack & pinion? I thought it might be a grounding problem, but decided to check this forum first... glad I did now. seems that I'm not the only one who has experienced this.

Turn the key on no start check the bulbs. Get it scanned for history or pending codes, post back. Make sure battery terminals and grounds are tight. Not a cks problem here.

I've got the same problem with my 01 GT




It is a classic crankshaft position sensor (CKPS) problem. Get it replaced and your problems will disappear.

Well, I've checked the bulbs and they are indeed working fine, so I'm not sure how the ABS problem went away unless I inadvertantly fixed an electrical problem when I replaced the battery. I guess my next step will be to get the history/pending codes and see what story they tell. I would assume that if the CKS fails, then the computer would not be able to do it's job properly and that would result in the pinging issue when the tach goes out. Is there a ground for the CKS that could be a problem, rather than the unit itself? One other odd quirk that I've not mentioned so far... every once in a while, the horn honks all by itself (it's a stout horn too!) I'm not sure if there's a short there that may be related or not.

Well, I've checked the bulbs and they are indeed working fine, so I'm not sure how the ABS problem went away unless I inadvertantly fixed an electrical problem when I replaced the battery. I guess my next step will be to get the history/pending codes and see what story they tell. I would assume that if the CKS fails, then the computer would not be able to do it's job properly and that would result in the pinging issue when the tach goes out. Is there a ground for the CKS that could be a problem, rather than the unit itself? One other odd quirk that I've not mentioned so far... every once in a while, the horn honks all by itself (it's a stout horn too!) I'm not sure if there's a short there that may be related or not.

One thing you can do is remove the electrical connector to the CKPS. Check for corrosion. If present clean both jack & plug sides with electrical contact cleaner and let dry. There should be a total of 3 - 4 pins and one is ground. Normally, when the CKPS goes bad the 18X pulses output feeeding the ignition control module and tachometer is bad and the circuit is hard to troubleshoot.

If you are lucky odb-ii DTC error codes will be present indicating the sensor for sure but half the problems I've seen and helped a lot of people on the forum out with did not have any or a SES/CEL light. The pinging is probably related to the CKPS problem.