rev counter issue

Topic: rev counter issue (Read 983 times) previous topic - next topic

rev counter issue

August 25, 2025, 04:55:53 PM

Right people, since solving my last wiring issue. ive now picked up a whole new one, just for fun

My rev counter has stopped working, initially i thought i was going to get lucky as a wire had fallen of the coil. The car also failed to run. i came back to the car today. Started an idled lovely this time, though i started it with the blue plug detached, not sure why but just did. now plugged in still fine, but the whole thing ran like a dog midweek, failed to even run when i tried Friday. but since ok

But during this time, the rev counter is failing to work, the wire to pin KL1 on the white plug seems to work just fine. Also volt testing it while running i get voltage drop on the multi meter, which is the opposite of how i thought it would work, but it shows power is there. Now when i do a continuity test from the pin to the other end of the track on board i get nothing, i assume this is my issue.

But there is no sign of any damage, and it worked when i had the wiring issue previous to this

So what are your thoughts please

Re: rev counter issue

Reply #1 – August 26, 2025, 10:22:44 AM

Based off your other post, you're in a CE1 car.
Not sure what you're referring to when you say KL1.

But I'd test continuity between B19 and the coil.
If there is a failure there, test between D26 and the coil.
That way you can see if there is a failure between the fusebox and the coil, or the fusebox internally.
If you have continuity between B19 and the coil, the chances it are it's your clocks internally (which is where you may already be looking).
It's odd how you say you have voltage and it drops, I used to think it spiked (quite high) to give an RPM signal.

Re: rev counter issue

Reply #2 – August 31, 2025, 11:09:39 PM

Quote from: Monkey on August 26, 2025, 10:22:44 AM

Based off your other post, you're in a CE1 car.
Not sure what you're referring to when you say KL1.

But I'd test continuity between B19 and the coil.
If there is a failure there, test between D26 and the coil.
That way you can see if there is a failure between the fusebox and the coil, or the fusebox internally.
If you have continuity between B19 and the coil, the chances it are it's your clocks internally (which is where you may already be looking).
It's odd how you say you have voltage and it drops, I used to think it spiked (quite high) to give an RPM signal.

Hi Monkey, mk2 golf stories sent me his spare clocks, i can confrim the rev counter works on that set when plugged in to my car. KL1 is the track number on the laminated circuit board

Now my set have no continuity between the pin on the white plug side and the 2 points that track goes to. where as the set on lone to me does, and of course works. So it looks like i have to find a working set and swap it over or change speedo etc.

Im not so sure soldering a wire to the LCB is a good idea, as i think i will just melt it, wire glue could work i guess

Any suggestions on how to repair them ?

Re: rev counter issue

Reply #3 – September 01, 2025, 06:52:21 AM

Ahh, I see. I was assuming it was a wiring issue with the car, not the clocks.

I've seen wiring repairs done on the plastic circuit board before, though I'd assume you have to be very precise where you apply the heat.
At this point, I'd have a go, you haven't got a huge amount to lose (as long as you have a spare set of clocks, that is!).

Re: rev counter issue

Reply #4 – September 01, 2025, 06:42:30 PM

well i guess i could try no matter what really, its quite simple, the pcb is already broken, repair or replace

Re: rev counter issue

Reply #5 – September 01, 2025, 07:26:13 PM

Monkey as i got your attention on this thread, my car is struggling to start. removing blue plug doesn't seem to matter. its turning and barely firing, when it catches enough its rough as anything for maybe upto a min, then slowly gets better and better, to the point its idling and revving as normal, will re start fine afterwards, then same story next day. any ideas please

Re: rev counter issue

Reply #6 – September 02, 2025, 08:00:41 AM

Oddly enough, I have the exact same issue with my quattro (basically a big mk2).
That runs on K-Jet, is yours the same, or digifant?

Re: rev counter issue

Reply #7 – September 02, 2025, 11:08:31 AM

Hi jacking a little but i have this problem. cold start is fine run the car for till slightly warm and leave it for a short while it is reluctant to start and will not tick over, hold the revs at 2000 for a short while and it then runs normally. I have replaced the blue temp sensor and the fuel pressure regulator no improvement. The isv buzzes away quite happily so I think that's ok. I am getting to the point where I don't know what to do next. What have either of you tried?

Re: rev counter issue

Reply #8 – September 02, 2025, 12:39:39 PM

Have you had the engine timed up at all?
I'd start there next, there's a procedure to time it up, that takes the blue sender out of the equation.

Also, there could be an air leak somewhere:
When it's cold, you're putting in extra air, so the mixture is more balanced, once warm, it's out and your under fuelling.
Get a can of brake cleaner and spray it around the inlet boot and vacuum, lines.
If it changes and picks up at all, you know you've got a leak.
Just be careful around the exhaust manifold.