The Oldsmobile Connection

bobshow · Joined: 26 Jun 2004 Posts: 51

hi everyone.. have a little problem did a code check and up came 24. vehicle speed sensor..could you please tell me where this part is located..the car runs great,the check engine light comes on when i first start the car cold i put in drive and it goes out after the first 100. feet..is this part hard to replace????i have a 1987 cuttless ceria 3.8.. you guys are great love this site.thanks so much

Turbocharged400sbc · Joined: 18 Aug 2004 Posts: 318

on the front wheel drive GM's the VSS is located on the Right Front axleshaft area of the transaxle-take off your pass front tire (helps but not required---remember, JACKSTANDS!!!) and follow your axle to the transaxle and on top will be a verticle sensor sticking up (with a two or three wire connector) unplug the connector and look at the connector closly and make sure that a wire isn't broken/loose connection. NOW for my experiences sake (the DOH! factor!) follow the wires up and make sure that the wires dont runn next to your ignition/(spark plug wires!) a recent tune up is usually a dead givaway-but old plug wires can give off EMI too! if the VSS wires go near them (closer than an inch or two -move the sparkplug wires/VSS wires to fix that issue-it can help to shield them by putting alum foil around the VSS wires and grounding it. then start it up and see if it happens(dont forget to plug sensor back in) you may need to clear ECM memory but i dont think i ever had to.

The clue is that when you start the car the light comes on (cold engines require higher ignition voltage-and old wires or missrouted ones might leak voltage to nearby VSS wires) but when you start rolling the light goes out. a VSS putts out a certain number of PPM (pulses per mile) as it is what is called a Hall effect sensor this tells the ECM how fast the car is going for the tranny shift points as well as your speedo (electronic).
With your car started and in "Park" the ECM will "see" (from the EMI of the ignition wires) that you are "moving" when it "KNOWS" that you arent, this will trigger the light-but after you putt it into gear and start rolling and the VSS pulses build up higher voltage it wont "see" the EMI and cancel the code (still in memory though!). If your VSS itself was broke the light would stay on while you drive and your speedo wouldn't work/or fuction erratically.

I have dealt with this problem on a couple of cars and it is relativly easy for someone to check on their own and see if it goes away!

the other possibility (i have seen it also) is that the sensor is shorted/too high of a resistance and that it takes the car moving for it to build up enough voltage for the ECM to "see" once it does it will cancel the light. THIS is a job for Ohming out the sensor and maybe hooking up an Occilliscope to check that it's putting out a good signal (the shop will run it in gear (on a lift/jackstands) to make sure that it works at low/high speed)

Hopefully I havent wasted your time if you have a Rear Wheel drive car (i dont remember and RWD Cutlass CIERA'S-but i might be nuts! LOL)
but if you have the FWD this all applies! I hope I could help ya out.
PS--most of the cars with the first problem were "tuned up" by their owners-or-my buddy knows how so i gave him a 12 pack to doit. LOL---Feces occurs! so it's easyto correct if it is the problem.--it just takes a little time!

you can sometimes get to all of the wires from under hood but you cant really see them this way so removing the tire helps!

Oh I might as well say that if it's a RWD the VSS is in the rear of the transmission 6-12 inches in front of where the driveshaft enters the tranny. let me know how it all turned out!? i'll chack up on the thread OK?
Later man, Schlim

bobshow · Joined: 26 Jun 2004 Posts: 51

took car to shop.for vss.they tole me that the car 1987 cuttless ceria does not have a vss.still have a code 26.are they on drugs????

Turbocharged400sbc · Joined: 18 Aug 2004 Posts: 318

87 cutlass ciera is it the FWD? (they made the RWD to 87-88) but not as a Ciera? i believe it does have a VSS (no speedo cable-but I might be smokin somethin) didja blink during the codes? 87 is the GM's with the C^3 (command Control Computer) system and thay do have VSS's unless you somehow have a transition year but i doubt it, have you looked fer it? let me know more---schlim

bobshow · Joined: 26 Jun 2004 Posts: 51

car does have a speedo cable...found out it might be the park nutrel switch

bobshow · Joined: 26 Jun 2004 Posts: 51

had a new fly wheel installed and stater replaced.thats when it all started

Brando · Joined: 06 Jun 2003 Posts: 3067 Location: Michigan, USA

Yes, 87 does have a vehicle speed sensor, checked out my Haynes 87 Delta 88 Manual and it has a Vehicle Speed Sensor.

TOC Admin
Brando

Turbocharged400sbc · Joined: 18 Aug 2004 Posts: 318

definatly possible if the tranz range switch is screwy-teeth go on your flywheel huh? had the same thing on my sbc (got a new flywheel and got a cast iron nose for the starter) the alum nose cracked and was letting the starter mandrel bend and eventually wiped all the teeth out!
glad that it's working out fer ya though-sorry i wasnt much help!

88 Coupe · Posted: Mon Aug 30, 2004 6:30 pm Post subject:

Quote: had a new fly wheel installed and stater replaced.thats when it all started Hi bobshow, hello all
This item would have been usefull at the start of the thread, as it contains the answer.
When the work was done, something that was disconnected was not properly reconnected.
Have the shop that did the work check it out.
Regards, Norm

Turbocharged400sbc · Joined: 18 Aug 2004 Posts: 318

or entirely possiblt that when they yanked the tranny (to do flywheel) they broke something and didn't realize it! the VSS might also be where the speedo cable comes outta the Tranzaxle. I (when in my first year) have missed electrical connecters when yanking something and then finding it unplugged it-just as possible i might have broken it if i wasnt paying attention! like Norm said go back to the service station and explain what has been occuring since your work was done-dont rant/rave (never helps matters)-and an honest shop will check it out.
schlim