Hey guys, I need your help, please. I bought a V6 2.8 MPI Berlinetta, the car is working fine, no engine check light on, nothing, the think is that the Digital speedometer is not registering the speed, it means, the dash is working, I can see 0 Miles, the cars mileage but it does not register the speed. Here are some pictures of the tranny tail where you can see a black piece, it should be the Speed sensor. Take a look, so you can give me your opinion, also there is an unplugged wire, it has 2 connectors, 1 Volt, and it comes from underneath the distributor. I am gonna post them in different replies because the forum engine does not allow me to post more than 1 pic per message.

 

More pictures

 

Is it the cruise control plug?

 

The unplugged wire....... it comes from under the distributor.....do you know where it should plugged in?

 

And the magic year of the car is ... ?

Not -quite- sure on Berlinetta dashboards, but that doesn't look like an electrical VSS in the tailshaft. It looks like it's expecting a speedo cable- especially because the end of it is threaded! What I'm confused about- you said:

So you're saying that the odometer works but the speedo doesnt? So you can see extra miles counting up on the odometer as you drive? Or did I misunderstand that?

And my guess at that connector is that it was meant for an AIR (smog) pump... an emissions piece that someone could have removed- but I don't know the year of your car.

Do you know if the transmission was swapped out before you got the car?

Welcome to the forum, by the way!!

 

Electric Speedo:

 

That extra plug looks like it goes on one of the sensors on the TB...IF i recall correctly......although I'm not sure which one off the top of my head.

 

The cars year is 85, yeah I know it is so confusing, that is why I am asking you guys, I do not know if the former owner wanted to convert it from digital to analog.
It is just like that, what I tried to say was that I can see all the numbers in the digital display, the 0 Miles (speed) and the car mileage.

 

Nope, I cannot count the miles that I run on the car. Even more, there is no cable or wire going to that black piece at all.

 

Ovrclck350, there is no wire going to that VSS, am I right? how does it work?, and where is it connected to, ECM or Speed Sensor Buffer?

 

No clue if they swapped the tranny......

 

ok the year of his berlnetta is either 85 or 86
the plug thats unplugged is not the iac or the tps.... looks like one that goes under the coil/egr area?

 

it may even be the oil pressure sender wire that plugs into the oil filter housing

 

It looks like it comes from underneath the distributor, lets say, 5 and 6 cylinders, there are a bunch of wires around there, it is too difficult to follow it all the way to its end.
The analog gauges are all working fine, Fuel, Oil, Temp, Battery.........do you say the wire should be connected around the oil filter, right?

I am thinking they wanted to know if the car could run with analog speed sensor, what if I get a digital speed sensor and put it in there? could it work?
Probably this guy have no clue about speed sensors and he bought the wrong one. Is there any way to know if he changed the transmission tail?

 

First off, mine did have wires going to it, the connector is at the top, yellow and purple IIRC.


MY car has the VSS (that sensor pictured) go directly to the ECM which sends the electronic speed itself to the speedo. There is no Vehicle Speed Sensor Buffer (lil yellow box)



Your Berlinetta is an electonic digital speedo YES, BUT it still has a cable. The cable goes into a yellow box which converts the signal to an electric signal for the speedometer. your cable is either missing or unhooked.

 

So how do you hook it up to the yellow box?, I mean, from cable to wires....what kind of cable should I buy so?

 

Could it be plugged into the disconnected wire that I shown you guys, or where it should be connected at? Thanks for all your help!!!

 

Thank you guys for your help, I am starting to know about my car ........
Do you guys where do I have to hook it up at? I mean, from the transmission tail up to...?

 

That was my guess for the VSS! Does that car have cruise control?

But, that unhooked connector isn't for the throttle body; throttle body has one 3-pin connector (TPS) and one 4-pin connector (IAC), and that's it. The oil pressure sensor for the dash on an 85-86 is one wire. The oil-pressure-fuel-pump-switch is two wires, but doesn't look like that connector; it's a blade-type connector. That's why I think it's for a smog pump- doesn't the AIR/smog pump have a connector on it? Watafo, does it look like something used to "hang" off a bracket beneath the alternator?

 

Yeah, the car has cruise control, you can see the pic of it in one of my first posts. That is right, it is in the back of the alternator, around the ignition coil........could it be for the Speed sensor?

 

Now I have found that those 2 connectors are for the speed sensor unit........Now, lets clear it out, I got a tranny tail with cable driven sending unit, and a 2 connectors wire that goes to the speed sensor buffer under the dash.......any suggestions anyone?......What should I do now?.......change the tranny tail or figure it out to become it into a digital speed sending unit?......

 

How did you determine the two-pin connector is for under the dash? And I'm not sure what that 3rd picture is from the top of this message... not sure how it relates to cruise control. Maybe someone with cruise control (I don' t have it) can help out.

So, I'm gonna step out of this message but basically, you want to look under your car for a disconnected speedometer cable. The mechanical cable should have been run alongside the fuel lines, underneath the car on the driver's side. Check out the metal clips that hold the fuel lines to the driver's side underneath the car- see if there's a cable there, OR, see if there's an "empty spot" in the clips where a cable used to be.

You need to get your old cable unit working in order for your factory speedometer to work. Yeah you could convert to an electronic speedometer, but then you'd have to change out your dashboard for an 89-up Camaro's. There's gotta be some remnant of the cable somewhere on that car.

I guess someone with a Berlinetta GM Service Manual needs to step in- or, watafo, you can buy a GM Service Manual from http://www.helminc.com , and sometimes they pop up on eBay for a used one.

Good luck!

 

Yup Tom, the third pic is about the cruise control and TCC torque converter cluch. This car has digital speedometer, the speed buffer is under the dash, right where the front left wheel is located. Now, the thing is, some guy changed the digital speedo sending unit or changed the whole tranny or the tranny tail to a cable driven one. Now I need to know how to change that cable driven speedo sending unit to a digital speedo one. Both of the units, (cable driven one and digital one) work with the same speedo gear of inside of the tranny.
So, the only thing I need to know is, what kind of problems I could find when changing from cable driven speedo sending unit to a digital one.