85 GTV6 Speedo Issues

gtv6ma88 · #1 (**permalink**) 10-12-2009, 03:11 PM

My 85 GTV6 Speedo works intermittenly, I attempted to pull it out, but fluid began to flow so i immediatly put it back in. Is this suposed to happen? seems that having to change the transaxle fluid for this job is a little much. Also, just to make sure i am pulling out the right component, it is the two sets of wires that are on the front of the transaxle, not the rear. Any tips would help out going. to leave it alone until i at the least get some redline fluid to replace whatever comes out.

steveh29 · #2 (**permalink**) 10-12-2009, 11:02 PM

I have the same problem with my 1986 model. The speedo sensor in the transmission is on the driver side just near the back and has 3 wires coming from it. You may find this link useful.

http://www.alfabb.com/bb/forums/alfe...eter-inop.html

Yes, oil will leak out if the sensor is removed so you need a rubber stopper or a spare sensor to put in there to stop the drainage. I happened to have a spare transmission from a Milano and the Milano sensor will fit (but will not work electrically). I used it to stop the oil drainage while I inspected my original sensor.

I cracked open the speedo itself and found some questionable solder joints but re-soldering them did not help. I was always going to cut open this sensor and see what was inside (and rebuild if possible). However, I didn't want to carve on my only example. I am getting irritated with it not working properly so I'm getting motivated to figuring out the problem.

Hope this helps.

**bayalfagtv6** · #3 (**permalink**) 10-14-2009, 09:55 PM

steveh29,
You say the Milano sensor won't work? i hope you are talking about the 2 wire type and not the later 3 wire sensor that was fitted to the later 85-86 GTV6. I have a 3 wire on my GTV6 late 85 production and hope to purcahse a Milano 3 wire type to fix the problem of speedo not working.

steveh29 · #4 (**permalink**) 10-16-2009, 02:44 PM

Well I've never actually tried it because the Milano speedo sensor has a different connector on it and the wires are different colors. So I'd have to do a bit of testing to figure out which wires match up. I was under the impression that although it physically fit, it was not compatible electronically. If that's not true, I'm going to do the swap myself.

**alfaparticle** · #5 (**permalink**) 10-16-2009, 08:04 PM

The Milano sensor must be used with the oscillator/amplifier box. The sensor is passive and does not generate an electrical impulse. It is an inductor in an oscillator circuit. The inductance changes as the gear tooth (or whatever) passes in front of it and stalls the oscillator. The oscillator restarts as the gear tooth moves out of range. This series of bursts of high frequency oscillations is converted into a PWM signal that drives the speedometer.

I am about to learn about GTV6 speedometers. I may be wrong, but I thought that GTV6's do not have the oscillator/amplifier. If that is the case, then the sensors are different.

**bayalfagtv6** · #6 (**permalink**) 10-16-2009, 10:13 PM

Would like to know about the difference, I was under the impression that a Milano speedo sensor would work. I do know that the Milano had a black box in line with the sensor. I just thought that the sensor was incorporated into the later style GTV6 speedo, like I got. I would like more info on this since my 85 GTV6 speedo has never worked since I had the car. Speedo has been tested and rebuilt by PAspeedometer, checks good. Do you think the amplifier box in line with the Milano sensor would work.
Sorry about the thread hijack........

**alfaparticle** · #7 (**permalink**) 10-17-2009, 05:58 AM

I don't know the answer to your question yet. I bought an 85 GTV6 last weekend and it needs a replacement speedometer so I expect to know more, soon.

steveh29 · #8 (**permalink**) 10-19-2009, 12:26 PM

I don't believe the GTV6 has the black box in line with the sensor. I'm about to dig into mine. Driving around this weekend with it going off and on was the last straw. (Or maybe it was my wife telling me we were speeding and I couldn't prove her wrong!) Either way, here are some more interesting links on the subject that can help build your speedo knowledge.

ALFAGTV6.COM • View topic - Input Shaft Affect Speedo Reading ?

ALFAGTV6.COM • View topic - Speedometer Sensor Question

ALFAGTV6.COM • View topic - GTV 2.0 SPEEDOMETER PROBLEM

ALFAGTV6.COM • View topic - Speedo on GTV6

**bayalfagtv6** · #9 (**permalink**) 10-20-2009, 11:33 AM

thanks steveh29,
I think that the 4th link answers my question, link within link says use milano amp box with milano sensor and an late 85, 86 GTV6 speedo and it will work. The only thing tha bugs me is it says the splines in the transmission were change with the introduction of the milano gearbox. Does this mean that it will not read accurate.
Well, I do have all the parts so will try it and see what happens.....

steveh29 · #10 (**permalink**) 10-21-2009, 11:07 PM

I'm curious how it turns out. I think the different splines only apply to the gear driven speedo - not the induction type that we are using. Hopefully it'll work for you. Otherwise I think we're both in the position of buying the Dakota Digital box to modify the signal to get proper readings - which actually might be nice so you can calibrate the speedo.

Again, good luck and I'm anxious to hear how it works out.

**bayalfagtv6** · #11 (**permalink**) 10-22-2009, 04:51 AM

wouldn't mind spending the bucks to get a Dakota box if that will fix the problem. I saw the threads at GTV6.com and it seems to work. I should have my 85 finished by the weekend, I've got the Milano amplifier and new Milano speedo sensor. Will post results next week.

**Graham D** · #12 (**permalink**) 10-22-2009, 08:14 AM

gtv6ma88: The speedo wires are the two at the rear of the gearbox; the ones at the front are for the reverse light switch. Before you run off to spend your money, tighten the wiring connectors. If it's all nasty under there - likely - a can of brake cleaner will be helpful. There should be - once-upon-a-time - a rubber boot covering; pull it back and there should be a black plastic two-wire terminal block. Pull it away, disassemble the wires from the block - if you don't know how, ask - , with a pliers tighten the connectors and reassemble. Worked for me on my '84.

gtv6ma88 · #13 (**permalink**) 10-24-2009, 06:52 AM

Graham: I was under the impression it was the two wires on the fwd part of the gearbox. i pulled this out and fluid began to flow so i put it back in. I also pulled the sensor from the rear two wires and no fluid came out. I am pretty sure it is on the fwd part of the gearbox, but i could be wrong. will put up a pic later to get it clarified... thanks

**Graham D** · #14 (**permalink**) 10-24-2009, 08:20 AM

Oops, my bad! In my memory or lack thereof, I had them turned around. The forward unit is the speedometer sender and the rear one is the reverse light switch. None the less, do tighten the connectors before you replace as it cured my problem; wildly erratic speedo - sometimes on, other times not and sometimes 100 mph in a 40 zone!

gtv6ma88 · #15 (**permalink**) 10-24-2009, 08:27 AM

ok thanks ! ill try it out here today and let you know how it goes.