I have a 1990 240 (instrument cluster K10042).
I replaced the odometer gear from www.odometergears.com.

I followed the replacement procedure: http://www.hyperocity.com/volvo240/volvoodometer.htm

I carefully reinstalled the speedo in the instrument cluster ensuring that the (3) and (1) stake-conductors inserted correctly into the speedometer. Started the car and after ~2-3seconds the speedometer goes to 120 mph (The max, "pegged").

Has anyone ever had this same occur?

 

I am facing a similar situation, and am currently searching the forums. I have a 1991 245, non-turbo & automatic. Specifically, I was trying to track down why some lights were lighting up in the dash at strange times that didn't make any sense to me... long story short, it sounds just like this: https://volvoforums.com/forum/volvo-...rnators-54206/
Anyway, before I found this, I took apart the dash. upon re-assembly, whenever I move the key to position II, the speedo pegs at 120. I can't figure out what I've done. While the 240 is setup differently from the 1989 740 instrument cluster, which I am very familiar with, I can't isolate what is going on here. But i'll keep looking & post back here if I find any solutions.

 

Shoot, I thought we had a new speed secret here; my 240 sure won't peg the speedo..

Seriously, I haven't heard of that particular problem, but if it was me I'd be rechecking my connections, especially the one that goes on the speedo. Could you have gotten that one on backwards? If everything else is working normally, that would be my first guess.

 

hey, I've seen 110 MPH on my 240.. GPS confirmed it even. yeah, was on a long down grade, with a tail wind, and the car completely wound out. on flat lands without a tail wind, I've never seen over about 105.

 

I'm pretty sure the speedo ain't backwards--it is an electronic connection that can only be attached in one direction. I will probably start a new thread for my car instead of hijacking this thread. I'll post a link to it when I do. but I want to test a few more things before I put it up.

 

Meh...it ain't threadjacking when the o.p. is a year and a half old...more like resurrection...
Besides, any 240 speedometer reading 120 mph is always newsworthy!!

 

So, an update to let people know where I am at. I did a bunch of searching around the forum and found the solution to another problem I was experiencing, but was going to work on later--I had the classic 240 flickering of idiot lights that i figured out were the tell-tale signs of a bad alternator. So, out it came, and sure enough, the brushes pretty much look like they are done.
In the mean time, I've put the instrument cluster back together, and it is sitting in the lifeless 240. What are thoughts on putting the car key to position II without the alternator in, just the battery running things? I'm hesitant to try & if I can get the alternator fixed real soon, it will be moot.
Anyway, I doubt the speedo going to 120 is related. But... i've seen stranger things on the 740 i worked on a lot that made sense later, but not at the time.
In regaurds to the alternator, has anyone replaced the brushes without replacing the voltage regulator? I asked that question here: https://volvoforums.com/forum/genera...gulator-55007/
Peace.

 

New alternator brushes worked wonders for other things. But... no change in speedo. It is stuck at 120 the moment it comes on, and the odometer doesn't add mileage. Perhaps new gauge is in order.

 

So, I am back to working on the 240, again. Who knew that after four months, the speedo problem would _not_ magically go away? Reviewing where I was when I left off, I think I am going to try to get a new gauge and replace it. The thing is, it worked fine until I took the dash out. It seems most likely that I did something when replacing it... but I cannot figure it out. Any thoughts? Has anyone ever burnt out the speedo when re-installing it? Any help would be great.

 

Electronic Speedometer Notes


Good Luck
Fred

 

Thanks darkdelta--those notes are great. I just need to track down an oscilloscope... The local pick and pulls keep crushing all the old volvos... so repair may be the best option. Ebay has some, but prices for what i've found seem rather high.

Your diagrams and charts should be of great assistance. I'll let you know how it goes.

 

I just wanted to post that I did solve this problem. I moved discussion of that over to the page where I discuss my car. (see post #4 and on)

https://volvoforums.com/forum/volvo-...1-244-a-61233/

In a nutshell, I fried the integrated circuit. Replacing it gave me functionality again.