View Full Version : HELP?! I need to replace a cam position sensor on a 91 Buick Park Avenue 3.8L


1FstChevy
10-16-2009, 03:24:58 PM
As the title states, I have a friend that described the symptoms of a failing Camshaft Position Sensor on their 91 Buick Park Avenue, so I offered to replace it for them tomorrow at noon!!! :confused:

I've been searching high and low for a guide online but haven't found one, I've read it's a fairly straight forward and easy to complete task so I'm hoping too much disasembly isn't required. I own 1000+ Craftsman sockets but I'm hoping it only takes 10 or less!!!

Fortunately for them the sensor itself is only $30+ from Napa and I'm only charging them cost since they're exchange students who just bought the Buick to use for a year, so it would be nice to avoid buying an instruction manual too...

Any help is appreciated as I am tight on time!!! Thanks! :bowtie:

dioismyhero
10-16-2009, 03:56:38 PM
SEND ME THE LAST 8 OF YER VIN AND I'LL PULL UP A DIAGRAM

DIOISMYHERO@YAHOO.COM

BondoSpecial
10-16-2009, 03:56:58 PM
autozone has the haynes manuals online for free. Let me see if I can link you to the specific images for the cam sensor on that car. If not i have the hard copy manual for the h body gm cars in the garage

79camaro2001
10-16-2009, 03:59:23 PM
It's not hard to change it.

I found a website dedicated to these 3.8L motors with the buicks and they had a complete step by step for changing it out.

Darn if I remember the site but I got it printed out.

1980_Z28
10-16-2009, 04:01:18 PM
It is right below the water pump


REMOVAL AND INSTALLATION



Disconnect battery ground cable.
Remove water pump pulley attaching bolts, then the serpentine belt and water pump pulley.
Disconnect sensor wiring connector and remove sensor retaining bolt.
Twist and pull sensor to remove.
Reverse procedure to install and prior to installing new sensor, lubricate sensor O-ring

BondoSpecial
10-16-2009, 04:05:06 PM
I dug up my haynes manual and took a picture of it for you, it shows a pic of the cam sensor's location as well.

Here ya go

http://farm3.static.flickr.com/2579/4016716271_30e43804d8_o.jpg

Fawn
10-16-2009, 04:19:31 PM
This is a Ryan 79 question for sure. Wait till this evening when he gets home from work.

Twisted_Metal
10-16-2009, 04:49:36 PM
What are the symptoms... Did it throw codes showing a cam sensor problem?

I hope it's the cam sensor and not the crank sensor.... The crank sensor is more of a chore.
(I had a crank sensor go bad on a 91 Olds 3.8 engine and I paid someone to do that one.)

68400BIRD
10-16-2009, 05:01:54 PM
It should be just plug and play. These are hard to diagnose unless it has a hard code. For the most part it will either miss, hard start, or not start at all. It could also be a crank sensor. I changed out both of mine last year in less than 15 minutes a piece with a 10mm socket.

pdq67
10-16-2009, 05:21:01 PM
Are you guys talking about the old-fashioned timing spots the old point dizzy engines have that are now electronically picked up by the ECU??

pdq67

Mike N
10-16-2009, 11:37:09 PM
Have seen where the magnet falls off the cam gear also. The cam sensor comes off rather easily, just one bolt with a 10mm head. When it's off turn the engine over with a breaker bar and look in the sensor's mounting hole until you see the magnet that trips the sensor. Verify the magnet itself is still there, and not just the holder.

The pisser is if the magnet is gone, you need to remove the timing cover to retrieve and repair it.

1FstChevy
10-17-2009, 01:07:15 AM
Woah all this information is super helpful! Thanks a bunch everyone, especially to TPI Camaro for photographing and uploading that image. :D

If all the above is true then this should be a pretty straight forward fix, I was just dreading that it would be inside the timing cover like my buddies VW.

To 10second81: As far as turning the engine over on a "modern" car (or as modern as 91' is to something from the 70s with a carb) like this is there any trick to it or just slap the breaker bar on the crank and rotate?! Checking to verify the magnet is still there is a good idea!

As far as the symptoms it runs great, idles smooth but every so often it'll just die either while coasting at any speed, or sometimes while idling at an intersection, then it takes usually 15 minute or sometimes much longer until the CPU will let the car be started again. I haven't seen or attempted to diagnose the car in person but the symptoms matched that of 2 other cars I know that required the camshaft position sensor be replaced, that and upon Googling this issue it looked like this is a typical issue for the Series I 3800...

pdq67
10-17-2009, 04:16:20 AM
This crap is why my 496 will have a point dizzy on it.

W/ real copper wires to the plugs!

pdq67

Mike N
10-17-2009, 03:05:53 PM
Woah all this information is super helpful! Thanks a bunch everyone, especially to TPI Camaro for photographing and uploading that image. :D

If all the above is true then this should be a pretty straight forward fix, I was just dreading that it would be inside the timing cover like my buddies VW.

To 10second81: As far as turning the engine over on a "modern" car (or as modern as 91' is to something from the 70s with a carb) like this is there any trick to it or just slap the breaker bar on the crank and rotate?! Checking to verify the magnet is still there is a good idea!

As far as the symptoms it runs great, idles smooth but every so often it'll just die either while coasting at any speed, or sometimes while idling at an intersection, then it takes usually 15 minute or sometimes much longer until the CPU will let the car be started again. I haven't seen or attempted to diagnose the car in person but the symptoms matched that of 2 other cars I know that required the camshaft position sensor be replaced, that and upon Googling this issue it looked like this is a typical issue for the Series I 3800...

Slap the breaker bar on the crank nut and rotate by hand.

Your symptom sounds like either the crank sensor or ignition module is heating up and momentarily failing. Loss of signal from the cam sensor won't cause the car to stall. It's used for starting and firing the injectors in sequence. What happens if the cam sensor craps out while the car is running is the injectors will go from firing in sequence to gang firing (read: all fire at the same time). In addition, the check engine light will light and code 41 will be stored.

1FstChevy
10-18-2009, 01:38:15 AM
Success, it's fixed! Long story short the cam shaft sensor only took 15 minutes to do and 10 of that was finding it. All said and done though it took 6 hours, 1 new battery, (the new cam position sensor obviously) a new ignition module and the unit with the points on top of it! ;) Advice to anyone working on location with a dead car, don't accidentally launch your newly assembled ignition module @ $170.00 into the pavement! At one point one of the exchange students described the breif mayhem as just like that in "a bad American movie" but fortunately nothing died.

Half the 6 hours was driving around to get the needed parts but hey the car runs like new, it's not my car so it didn't cost me a dime, and despite myself insisting it was a favor I still got free dinner and made all of $35.00 ha hooray right!?

Thanks again for the assistance NastyZ friends!