Well after getting the 78's head back together...I was getting a little bored tonight. So I decided to go after my slow reading tachometer. I had hoped that the speedometer and tachometer on our S4 Spiders had the same type of adjustment screws as seen in the Milanos. Well....the short of it....they do! Hot diggidy Dam! as we say in KY. So here comes the skinny on both!
John M
How to fix your slow reading speedometer or tachometer on 91-94 Spiders
JohnJohn M said:
Great article!. My '91 never reads over 2800 RPM, but seems normal at low idle. Am I looking at a different problem that what you are describing here?
Hey Brad:
That was exactly what my 92 was doing. So go fix her. Be sure to glue the calibration screw back in place once calibrated.
Best Regards,
John M
That was exactly what my 92 was doing. So go fix her. Be sure to glue the calibration screw back in place once calibrated.
Best Regards,
John M
BTW Brad:
I was in your Commonwealth yesterday. Down to Richlands. Far western part of the state. Just a beautiful place to see especially along the southern part with the mountains.
Best Regards,
John M
I was in your Commonwealth yesterday. Down to Richlands. Far western part of the state. Just a beautiful place to see especially along the southern part with the mountains.
Best Regards,
John M
The 86 is the same. I removed the trimpot from the speedometer and added a length of telephone wirw to it. the trimpot now rests by the fuse box. This helps in finding the correct setting, however, as in my case, I had to go to Max to get a decent reading (no resistance left on the pot). My speedo is now accurate to about 60-65mph, but after that will barely move above 70mph. It is my belief that some electronic components age ungracefully and the trimpot only helps in the early stages of speed dementia. 
tonyg, sunny NJ
tonyg, sunny NJ
Thanks guys!
On the glue to use. It would appear that Alfa used ....seriously..... hot glue on top of the calibration screw. I actually used some 3m trim/emblem adhesive from the black tube. Just enough to keep the screw from rotating once set.
Best Regards,
John M
On the glue to use. It would appear that Alfa used ....seriously..... hot glue on top of the calibration screw. I actually used some 3m trim/emblem adhesive from the black tube. Just enough to keep the screw from rotating once set.
Best Regards,
John M
Hey Brad:
My speedo was working correctly so I simply set my tach off my speedo in fifth gear. My tach was reading up to around 2500 rpm before the calibration. The conversion of speed vs tach in 5th gear is 22.14mph per 1000rpm. Warm idle will be around 800rpm. Here is a chart for the conversion on Rob Favali's page:
http://www.favali.com/Fluids.htm
Neither the speedo or the tach go to zero. They are pegged above zero. If you need to set your speedo too, I would suggest either getting a digital multimeter /w tach output to set the tach or using a gps to set the speed. Then you can use your conversion to set the other. On those calibration screws, its basically about getting out any corrosion. So note the initial position of the screw, move the set screw back and forth several times through its full range, hit with some contact cleaner/dielectric grease, and reset to the original position and see what you got. Once you get the calibration down, be sure to glue her into position.
Best Regards,
John M
My speedo was working correctly so I simply set my tach off my speedo in fifth gear. My tach was reading up to around 2500 rpm before the calibration. The conversion of speed vs tach in 5th gear is 22.14mph per 1000rpm. Warm idle will be around 800rpm. Here is a chart for the conversion on Rob Favali's page:
http://www.favali.com/Fluids.htm
Neither the speedo or the tach go to zero. They are pegged above zero. If you need to set your speedo too, I would suggest either getting a digital multimeter /w tach output to set the tach or using a gps to set the speed. Then you can use your conversion to set the other. On those calibration screws, its basically about getting out any corrosion. So note the initial position of the screw, move the set screw back and forth several times through its full range, hit with some contact cleaner/dielectric grease, and reset to the original position and see what you got. Once you get the calibration down, be sure to glue her into position.
Best Regards,
John M
Did it all last night. I'll reintall today to see what happens. The only frustrating thing is I got a fingerprint on the face of the tach which will not clean off, so use surgical gloves if you do this job if you are all thumbs like me.
All back together and it works great. Thanks for the all the instructions John. Now all I have to do is figure out how to fix the blinking air bag light as opposed to just removing the bulb.
Woo Hoo! Another success. That airbag light is simple to fix. Get the code. I bet its 26. A good task to accomplish prior to resetting the airbag light is to loosen the screws securing the impact sensors and retighten. Probably the majority of airbag light flashing senarios come from improper grounding of the sensor. And the sensor appears to be grounded through those screws. Also good to visualize the wires from the sensors to the harness. Gubi.....didn't you find chaffed wiring?
Best Regards,
John M
A good task to accomplish prior to resetting the airbag light is to loosen the screws securing the impact sensors and retighten. Probably the majority of airbag light flashing senarios come from improper grounding of the sensor. And the sensor appears to be grounded through those screws. Also good to visualize the wires from the sensors to the harness. Gubi.....didn't you find chaffed wiring?Best Regards,
John M
Man, what *didn't* I find...
Yeah, the wires to one of the sensors were chafed through down to the conductor. Fixed that, but kept getting intermittent errors. So I replaced the front sensor torx bolts with longer hex bolts and added a star washer underneath the sensor and a lock washer above it. That fixed the grounding and most of the problems, but it would *still* crap out on me every now and then.
I knew the problem had to be in the front because I could sometimes make the light start blinking by slamming the hood. The final piece of the puzzle was the three-wire connectors just off of the sensors. Basically they suck, and in my car they loosen very slightly over time until they cause a connectivity failure. Rather than cut them off and replace them, though, I've had good luck just pressing them firmly together and then wrapping the two halves of the connector with electrical tape to hold them tight.
Been a few months now and so far it seems to be working well.
Yeah, the wires to one of the sensors were chafed through down to the conductor. Fixed that, but kept getting intermittent errors. So I replaced the front sensor torx bolts with longer hex bolts and added a star washer underneath the sensor and a lock washer above it. That fixed the grounding and most of the problems, but it would *still* crap out on me every now and then.
I knew the problem had to be in the front because I could sometimes make the light start blinking by slamming the hood. The final piece of the puzzle was the three-wire connectors just off of the sensors. Basically they suck, and in my car they loosen very slightly over time until they cause a connectivity failure. Rather than cut them off and replace them, though, I've had good luck just pressing them firmly together and then wrapping the two halves of the connector with electrical tape to hold them tight.
Been a few months now and so far it seems to be working well.
You and that little gem have been through it Gubi. Guess what I found on the floor.....brake fluid. I haven't exactly figured out where its coming from, but the bottom of the barrel of the master is barely wet. Its always a little something. Remember all that polishing I did?.....well finally got sick of keeping up with it, pulled the wheels, and they are on their way to sunny Newbury Park, California for a little R & R so to speak. I am looking forward to retiring the buffer for awhile!
Best Regards,
John M
I haven't exactly figured out where its coming from, but the bottom of the barrel of the master is barely wet. Its always a little something. Remember all that polishing I did?.....well finally got sick of keeping up with it, pulled the wheels, and they are on their way to sunny Newbury Park, California for a little R & R so to speak. I am looking forward to retiring the buffer for awhile!Best Regards,
John M
John M said:Woo Hoo! Another success. That airbag light is simple to fix. Get the code. I bet its 26.
Best Regards,
John M
John,
As I have only had the car a couple of weeks and haven't forked over the $140 yet for a manual, could you give me a hint at to where this impact sensor is located? Also, when you say "get the code" do you mean via the diagnostic connector to a code reader (which I don't have of course) and if so what kind of reader would you recommend.
Brad,
No code reader needed. See my link a few posts up for the procedure.
Front sensors are two silver boxes about 1x1x2. They are mounted to the top metal frame crossbar in front of the engine. Each one is bolted down with two secure torx screws (star shaped hole with a pin in the middle) and has a three-wire cable and connector coming off of it.
No code reader needed. See my link a few posts up for the procedure.
Front sensors are two silver boxes about 1x1x2. They are mounted to the top metal frame crossbar in front of the engine. Each one is bolted down with two secure torx screws (star shaped hole with a pin in the middle) and has a three-wire cable and connector coming off of it.
Hey, Brad,
you and I ought to do this together this weekend. The wife's 164L has an airbag error and I've been looking for the sensor wire connector. Patchin says it's at the right end of the dash, but I haven't taken the small panel off to look for it. The early '90s Spiders and 164s supposedly have the same airbag controller and codes. I have the cardisk with the airbag procedures and video demo, and you're welcome to borrow it. It uses a Spider as the demo car, by the way.
Michael
you and I ought to do this together this weekend. The wife's 164L has an airbag error and I've been looking for the sensor wire connector. Patchin says it's at the right end of the dash, but I haven't taken the small panel off to look for it. The early '90s Spiders and 164s supposedly have the same airbag controller and codes. I have the cardisk with the airbag procedures and video demo, and you're welcome to borrow it. It uses a Spider as the demo car, by the way.
Michael
Did I ever tell you guys that the first time I reset the airbag light,....the dam thing went..
BAM!
Just kidding guys.
Best Regards,
John M
BAM!
Just kidding guys.
Best Regards,
John M
I did not find that the airbag exploding facilitated a perceived operational improvement of the rev counting device. However, I did find some well placed impacts of human balled flesh upon a specific location on the dash pod did enhance peace and harmony and relaxation.....and this effect is exacerbated through the simultaneous release of a few choice well thought out words not typically heard at the national spelling bee.
Best Regards,
John M
Best Regards,
John M
Michael,MrT said:
Just sat down on the computer for the first time today. We spent the afternoon at the cart track with Rick, Andy, Tom, Skip, et al. What a blast! Fangio I'm not, but it was great fun. If you want to get together tomorrow give me a call. I'll email U.
More questions about speedo tach on a 89 Quad
Hi John and all
Still working on the speedo and Tach.
At the fire wall drivers side there is a metal box that the speedo cable goes into on the top a couple of wires come out. My question is this a signal enhancer that effects both the tach and speedo? I have a buddy in Toronto who has had similar problems and replaced this and it has fixed the problem
Barry
Hi John and all
Still working on the speedo and Tach.
At the fire wall drivers side there is a metal box that the speedo cable goes into on the top a couple of wires come out. My question is this a signal enhancer that effects both the tach and speedo? I have a buddy in Toronto who has had similar problems and replaced this and it has fixed the problem
Barry
Sorry about the hijack.
I still have this problem, too. I thought the sender in the engine compartment would have put out a single pulse train, and the speedo would count the rate and the odo would count the total, using the same input wires. This may not be correct, and your friend's experience may show that it is not correct. Thanks for the pointer.
I still have this problem, too. I thought the sender in the engine compartment would have put out a single pulse train, and the speedo would count the rate and the odo would count the total, using the same input wires. This may not be correct, and your friend's experience may show that it is not correct. Thanks for the pointer.
Hey Barry:
That's the pulse generator for the speedometer. It won't help your tach. But could be the piece needed to get your speedo going. With both of yours being out Barry, you need to look real hard at the wiring and especially the fuses in the fuse box. Check them with a multimeter. Check the grounds with a multimeter. Too coincidental...and makes me think fuse...common wiring problem.
Some thinking out loud:
Anyone know how to check and see if that pulse gen is working? I am thinking chuck up the drive cable in a drill and spin the cable in the pulse gen and see if it starts working. Could be that the drive cable running from the tranny to the pulse gen has rounded off its ends and not spinning. On reading the signal from the pulse gen....one should be able to connect with a digital multimeter set on tach read out and see if its working.
On the odometer not working....my thoughts are assumptions. We know that there was a bunch of these S4 spiders with the monopods that got new speedo/odo's due to speedo head failures. Like Michael said....speedo gets one signal driving both the speedo and odometer. If this failure is happening, my advice would be to pull it and send her off to Palo Alto Speedo repair. People have given testimony that they can repair them for a couple hundred dollars.
Their link:
http://www.paspeedo.com/
My bet on the odometer failure is that its a popped/fried some-kind-of-dohickie on the circuit board. I guess one could pull the head unit and ohm meter each of the components on the circuit board as well as ohm the path.
How do you guys like that good ole boys red neck fix'n!
Best Regards,
John M
That's the pulse generator for the speedometer. It won't help your tach. But could be the piece needed to get your speedo going. With both of yours being out Barry, you need to look real hard at the wiring and especially the fuses in the fuse box. Check them with a multimeter. Check the grounds with a multimeter. Too coincidental...and makes me think fuse...common wiring problem.
Some thinking out loud:
Anyone know how to check and see if that pulse gen is working? I am thinking chuck up the drive cable in a drill and spin the cable in the pulse gen and see if it starts working. Could be that the drive cable running from the tranny to the pulse gen has rounded off its ends and not spinning. On reading the signal from the pulse gen....one should be able to connect with a digital multimeter set on tach read out and see if its working.
On the odometer not working....my thoughts are assumptions. We know that there was a bunch of these S4 spiders with the monopods that got new speedo/odo's due to speedo head failures. Like Michael said....speedo gets one signal driving both the speedo and odometer. If this failure is happening, my advice would be to pull it and send her off to Palo Alto Speedo repair. People have given testimony that they can repair them for a couple hundred dollars.
Their link:
http://www.paspeedo.com/
My bet on the odometer failure is that its a popped/fried some-kind-of-dohickie on the circuit board. I guess one could pull the head unit and ohm meter each of the components on the circuit board as well as ohm the path.
How do you guys like that good ole boys red neck fix'n!
Best Regards,
John M
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