Rev gauge problem 1.5d mk1 saxo - Saxperience

mitko9510 · 11th March 2018, 11:10

Hello guys! I have this problem since my dad bought the car 3 years ago and i think it is time to get fixed if possible.. Basicaly when the car starts the rpms go from 0 to max and back to 0 and dont work anymore.. When you turn the key and keep it in the position where the starter still works sometimes the revs work for a moment (until the car switches to alternator ).. I used to be quite sure it was a snapped cable from the elternator since there is a purple-ish cable with e thin yellow or green stripe right in the middle, but after opening the clocks unit to change bulbs none of those cables matched the color of the one found in the engine bay( the snaped cable is right near the alternator, between the engine and the radiators).
I am sorry for making this thread so long or if it is in the wrong section.

MartinObviously · 11th March 2018, 14:06

Quote:

Originally Posted by mitko9510

Hello guys! I have this problem since my dad bought the car 3 years ago and i think it is time to get fixed if possible.. Basicaly when the car starts the rpms go from 0 to max and back to 0 and dont work anymore.. When you turn the key and keep it in the position where the starter still works sometimes the revs work for a moment (until the car switches to alternator ).. I used to be quite sure it was a snapped cable from the elternator since there is a purple-ish cable with e thin yellow or green stripe right in the middle, but after opening the clocks unit to change bulbs none of those cables matched the color of the one found in the engine bay( the snaped cable is right near the alternator, between the engine and the radiators).
I am sorry for making this thread so long or if it is in the wrong section.

The tachometer is driven from the flywheel sensor, not the alternator.

Replace the flywheel sensor and check the wiring to it.

mitko9510 · 11th March 2018, 14:48

flywheel sensor and crankshaft sensor is the same right? ( im not rly good at the english translation of mechanics and i am really sorry)

MartinObviously · 11th March 2018, 15:33

Quote:

Originally Posted by mitko9510

flywheel sensor and crankshaft sensor is the same right? ( im not rly good at the english translation of mechanics and i am really sorry)

Yes they are the same thing.

3 pin orange connector on a mk1

cost about 15 euros

mitko9510 · 20th March 2018, 17:42

changed it with a new one , but the problem stays. All the wiring is kind of messed up but all cables go where they are supposed to and are not worn or melted, the grounds are not rusted. Changed the rpm gauge few times with 100% working ones and the needle does the same( sometimes on startup moves on some weird ways with voodoo and dies). All other gauges and lights on the board work, all fuses and relays are fine... I am not good at those stuff and it took me 2 nights and a day to check everything but im sure in everything aside from the dash since its the only thing left.. or maybe i missed something.. tomorrow i'll drop the steering wheel and check the board if it has some damage since i never payed too much attention on it.

I am sorry for the late reply, but had some nasty fever and couldnt open my eyes.

MartinObviously · 20th March 2018, 22:34

Quote:

Originally Posted by mitko9510

changed it with a new one , but the problem stays. All the wiring is kind of messed up but all cables go where they are supposed to and are not worn or melted, the grounds are not rusted. Changed the rpm gauge few times with 100% working ones and the needle does the same( sometimes on startup moves on some weird ways with voodoo and dies). All other gauges and lights on the board work, all fuses and relays are fine... I am not good at those stuff and it took me 2 nights and a day to check everything but im sure in everything aside from the dash since its the only thing left.. or maybe i missed something.. tomorrow i'll drop the steering wheel and check the board if it has some damage since i never payed too much attention on it.

I am sorry for the late reply, but had some nasty fever and couldnt open my eyes.

Hope you are well now!

The rev counter problem is a strange one, there is clearly an issue with the wiring. maybe there is corrosion in the engine bay on the connector at the chassis leg?

mitko9510 · 21st March 2018, 00:04

I'll check it tomorrow when i wake up. Overall the bay looks like its new car aside from some small stains from oil.

mitko9510 · 23rd March 2018, 07:54

the weather is awfull... managed to find 2 snapped cables green purple-ish and a red one in one of the cable holding plastic hoses... when the snow melts i'll try to find where those 2 are going.