Tachometer going out.

Buickguy123

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Going to work this morning 60 mph on the freeway I noticed the tachometer not working. Car run ok. Just now car started up fine and teach was off for 5 miles then came on but dropped to 0 for a split second before shooting back to 1600 RPMS. 60 MPH cruise control on. Did this about 5 times. Car ran fine. No SES. I keep reading that perhaps the crankcase position sensor is potentially failing.?
 

Alan 55

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2001 Buick Park Avenue, previously owned 1997 Park Avenue
Going to work this morning 60 mph on the freeway I noticed the tachometer not working. Car run ok. Just now car started up fine and teach was off for 5 miles then came on but dropped to 0 for a split second before shooting back to 1600 RPMS. 60 MPH cruise control on. Did this about 5 times. Car ran fine. No SES. I keep reading that perhaps the crankcase position sensor is potentially failing.?
This may have a connection to a potential CPS sensor issue or could be unrelated in my opinion. I would drive it and be alert to any new symptom or condition that may occur.
 

BuickGirlFromMars

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I had cut outs of my tach, with no adverse running or starting issues, for weeks before i had to let my car cool to start it and it would stall at random infrequently. I lived with the issue of stall and no start for about a week and then my crank sensor went in that weekend. then it broken on my new harmonic balancer. then i towed my car up my big ass hill, put a napa sensor on and the original harmonci balancer, and it was trouble free till my recent exercise in anger, pain, sadness, and swearing about a month ago when it was all fixed.

That sensor was a damn AC delco too. Freaking cheap aftermarket balancer..

But, key difference here, my tach NEVER read incorrect or bounced, it was dead on or 0. I had a code related to the 18x circuit of the crank sensor.
Have you checked for codes? If no code or reason to suspect crank sensor, your dash cluster is 99% likely the problem. you can verify this with using a 20$ scan tool from walmart and checking tach in the live data while comparing to the running car tach

if they match, your crank sensor or interuptor system has an issue or the wiring to the PCM and it
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Buickguy123

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I had cut outs of my tach, with no adverse running or starting issues, for weeks before i had to let my car cool to start it and it would stall at random infrequently. I lived with the issue of stall and no start for about a week and then my crank sensor went in that weekend. then it broken on my new harmonic balancer. then i towed my car up my big ass hill, put a napa sensor on and the original harmonci balancer, and it was trouble free till my recent exercise in anger, pain, sadness, and swearing about a month ago when it was all fixed.

That sensor was a damn AC delco too. Freaking cheap aftermarket balancer..

But, key difference here, my tach NEVER read incorrect or bounced, it was dead on or 0. I had a code related to the 18x circuit of the crank sensor.
Have you checked for codes? If no code or reason to suspect crank sensor, your dash cluster is 99% likely the problem. you can verify this with using a 20$ scan tool from walmart and checking tach in the live data while comparing to the running car tach

if they match, your crank sensor or interuptor system has an issue or the wiring to the PCM and it
Ok so today I had to repair the radiator lines into the radiator just below the radiator cap. Then drove the car one mile to a store. I came out and no start. No turn over nothing. So, I got on the ground and wiggled the harness into the CPS making sure it was tight etc. Behind the harmonic balancer of course. Turned the key over and the beast started right up. So, alas, I am going to pull the tire off and the harmonic balancer and will replace the sensor. Clean it all up. Do I need a puller on the 93 PA? I believe so. YouTube videos. LOL
 

Buickguy123

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Cold solder joints can cause intermittent operation of your tach. If it was your CPS trust me your car would NOT be running consistently well.
Today and twice in the last few weeks the car would not start. The first two times I jumped the battery with car two and both times it started up. Today, I wiggled the harness wires to the CPS and jumped back into the vehicle and is started right up. Teach still acting odd so I am sure the CPS is an issue. Will replace both the harmonic balancer and the CPS. 93 PA SC ultra do I need a puller? Thanks!
 

BuickGirlFromMars

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f53387ab45f77db49eab416695d2ccb2.png
the very fact wiggling the wiring and it started instantly after means i would start my diagnostic at visually inspecting the harness for the sensor..
 

Mad_Coachman

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Today and twice in the last few weeks the car would not start. The first two times I jumped the battery with car two and both times it started up. Today, I wiggled the harness wires to the CPS and jumped back into the vehicle and is started right up. Teach still acting odd so I am sure the CPS is an issue. Will replace both the harmonic balancer and the CPS. 93 PA SC ultra do I need a puller? Thanks!
It's a PITA. I've done two over the nearly twenty years that I have been dealing with this platform of car. Try to secure your wiring as Buick Girl is suggesting.
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Buickguy123

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View attachment 29766
the very fact wiggling the wiring and it started instantly after means i would start my diagnostic at visually inspecting the harness for the sensor..
Yes I will unplug that harness and clean the connector. I washed the car last week and I like to spray underneath the vehicle. Could be water got into the connector. Will spray WD 40 and clean the connector. Thanks!
 

Buickguy123

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It's a PITA. I've done two over the nearly twenty years that I have been dealing with this platform of car. Try to secure your wiring as Buick Girl is suggesting.
There are many videos on YouTube showing how to remove or replace the harmonic balancer to get to the sensor. None of the videos are very complete like a Chris Fix video. Some are using the ignition to unloosen the bolt? Interesting...
 

BuickGirlFromMars

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Yes I will unplug that harness and clean the connector. I washed the car last week and I like to spray underneath the vehicle. Could be water got into the connector. Will spray WD 40 and clean the connector. Thanks!
you and your WD-40. dont use WD 40 on plastics liek the connectors, its a petroleum cleaner in the simplest terms, you may degrade the plastic if not ruin it. its old and tired. use a proper ELECTRICAL CONTACT CLEANER spray. CRC, house names, etc all produce a spray for it. EVEN wd-40 brand!!!! It actually is a nice one ive compared it to 2 brands and prefer theirs.

WD40 is to be used on metal parts to clean up things not plastics to dry. Electrical contact cleaner has solvents which speed up evap HUGE and are completely safe to rubber and plastics(or most of them)
when i say it evaps fast, it evaps fricken fast. WD40 doesnt like to evap much. then use silicone grease to seal connector again
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Buickguy123

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you and your WD-40. dont use WD 40 on plastics liek the connectors, its a petroleum cleaner in the simplest terms, you may degrade the plastic if not ruin it. its old and tired. use a proper ELECTRICAL CONTACT CLEANER spray. CRC, house names, etc all produce a spray for it. EVEN wd-40 brand!!!! It actually is a nice one ive compared it to 2 brands and prefer theirs.

WD40 is to be used on metal parts to clean up things not plastics to dry. Electrical contact cleaner has solvents which speed up evap HUGE and are completely safe to rubber and plastics(or most of them)
when i say it evaps fast, it evaps fricken fast. WD40 doesnt like to evap much. then use silicone grease to seal connector again
Yes WD 40 is not for electrical. I actually prefer liquid wrench much more than WD 40 to remove old rusted bolts nuts etc. Anyway, I jacked the car up and removed the tire. I was not able to unplug the harness connector to the sensor. Seems you have to remove the harmonic balancer to get to that. Question? Where does the wire run to as it leaves the sensor? I did change the fuel filter as I was down there anyway. Not sure that was bad but $12 why not? The car is starting. Same security light on for 32 seconds before going out. Same off again on again squeal from Supercharger at times. When warmed up it goes away it seems? The tachometer upon start up is dead for about a half mile to 3 miles then works normal but jumps around at times.
 

Buickguy123

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Sound wisdom. Will clean up that connector today.
When you changed your CPS sensor twice did you use any grease on the harmonic balancer before putting it back on? I ask because in one video the guys put grease on the balancer. How about coating the tough bolt with anti seize before reinstating? Lots of videos on YouTube on this and very few are very complete. The talk about a "key" when putting the HB back and that confuses me as well. Thanks!
 

BuickGirlFromMars

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When you changed your CPS sensor twice did you use any grease on the harmonic balancer before putting it back on? I ask because in one video the guys put grease on the balancer. How about coating the tough bolt with anti seize before reinstating? Lots of videos on YouTube on this and very few are very complete. The talk about a "key" when putting the HB back and that confuses me as well. Thanks!
the bolt is TORQUE TO YIELD and coated with antiseize by GM. If you put anything on the threads, at all,your modifying the amount of torque a torque wrench can report its putting on. in the case of tightening, it can cause it to be too easy to turn, thus allowwing overtightening which theoretically could compromise the bolt since its stretching to begin with, and that could cause it to fail or snap on install

The bolt also should not use an impact

The key is woodruff key, used on shafts to keep a hub from being able to turn, there is science to it but you see a lot on small equipment like lawn mowers and mechanical shafts that dont use flanges
also called a keyway, saginaw P pumps used to have a bolt and they had a key, its just a small bit of oval like metal that slightly recesses on shaft and pulley or dampner slots over it.

Press fit is another kind, interference application. This likely isnt what gm did because pressfit would require some SERIOUS forced to put a pulley on or take it off at this size. older P pumps were press fit, like what are on our cars with CB pumps :)

clean threads and shaft, use new bolt everytime installing a crank pulley. I used the old bolt to push the pulley on most of the way, not how its supposed to be done, but then i torqued it up with the new bolt to get clamping force.
 

Buickguy123

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the bolt is TORQUE TO YIELD and coated with antiseize by GM. If you put anything on the threads, at all,your modifying the amount of torque a torque wrench can report its putting on. in the case of tightening, it can cause it to be too easy to turn, thus allowwing overtightening which theoretically could compromise the bolt since its stretching to begin with, and that could cause it to fail or snap on install

The bolt also should not use an impact

The key is woodruff key, used on shafts to keep a hub from being able to turn, there is science to it but you see a lot on small equipment like lawn mowers and mechanical shafts that dont use flanges
also called a keyway, saginaw P pumps used to have a bolt and they had a key, its just a small bit of oval like metal that slightly recesses on shaft and pulley or dampner slots over it.

Press fit is another kind, interference application. This likely isnt what gm did because pressfit would require some SERIOUS forced to put a pulley on or take it off at this size. older P pumps were press fit, like what are on our cars with CB pumps :)

clean threads and shaft, use new bolt everytime installing a crank pulley. I used the old bolt to push the pulley on most of the way, not how its supposed to be done, but then i torqued it up with the new bolt to get clamping force.
I wish I could find a Chris Fix video on how to change the Crankcase Position Sensor. His videos are the best. Others are just bits and pieces. LOL
______________________________
 

Mad_Coachman

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Baldwin, New York
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2002 LeSabre Limited
Today and twice in the last few weeks the car would not start. The first two times I jumped the battery with car two and both times it started up. Today, I wiggled the harness wires to the CPS and jumped back into the vehicle and is started right up. Teach still acting odd so I am sure the CPS is an issue. Will replace both the harmonic balancer and the CPS. 93 PA SC ultra do I need a puller? Thanks!
I initially rented a puller from AutoZone when I did my first one about 15 or so years ago. You will need to purchase the proper screws to fit the pulley as that particular size was NOT in the kit. It's not an easy job.
Edit: if your wiggled wires and it started I would look into your wiring integrity before changing the sensor itself. You may have chafed insulation or flaky connections. It's not an easy replacement like a MAF sensor, cam sensor etc. etc.
 
Last edited:

BuickGirlFromMars

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t
I initially rented a puller from AutoZone when I did my first one about 15 or so years ago. You will need to purchase the proper screws to fit the pulley as that particular size was NOT in the kit. It's not an easy job.
Edit: if your wiggled wires and it started I would look into your wiring integrity before changing the sensor itself. You may have chafed insulation or flaky connections. It's not an easy replacement like a MAF sensor, cam sensor etc. etc.
autozone kit in the last couple years DOES have the right parts. I can confirm. Here’s mine. The kit is the same as the old one but with the three bolts there in the side. So now it’s useful for us lol
 

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Buickguy123

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I initially rented a puller from AutoZone when I did my first one about 15 or so years ago. You will need to purchase the proper screws to fit the pulley as that particular size was NOT in the kit. It's not an easy job.
Edit: if your wiggled wires and it started I would look into your wiring integrity before changing the sensor itself. You may have chafed insulation or flaky connections. It's not an easy replacement like a MAF sensor, cam sensor etc. etc.
Well even if it is the wire I will still need to remove the balancer to access the wiring harness. When you put the harmonic balancer back on what process did you follow? It has to be lined up a certain way? Something about a key? One fellow on YouTube just tightens it up with an impact wrench and uses loctight. Then some say you have to hold the balancer to keep it from moving? I started it up yesterday and it started right up but the tachometer stayed on zero for several minutes then started working. Seems to be the pattern. Supposedly there is a fuse related to the CPS? Thanks.
 
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