|
700/900 Series General Forum for the Volvo 740, 760, 780, 940, 960 & S/V90 cars |
Information |
|
RPM/tach signal wireViews : 2280 Replies : 13Users Viewing This Thread : |
|
Thread Tools | Display Modes |
Apr 23rd, 2019, 14:05 | #11 |
Premier Member
Last Online: Apr 9th, 2024 21:44
Join Date: Jul 2009
Location: Holywood
|
The voltage is the back emf from the coil primary, probably more than 25V (or -25 maybe). You'll not have much accuracy trying to measure a pulsed signal on a dc meter.
There is a 5v rpm signal between the ignition and fuel ecu, and this can be converted into the required level with a relay coil and transistor. You have to do this for wasted spark mods typically. |
The Following User Says Thank You to TonyS9 For This Useful Post: |
Apr 24th, 2019, 08:34 | #12 | |
Master Member
Last Online: Oct 8th, 2022 22:22
Join Date: Sep 2016
Location: Auckland
|
Quote:
|
|
The Following 3 Users Say Thank You to aardvarkash10 For This Useful Post: |
Apr 24th, 2019, 22:20 | #13 |
Member
Last Online: Jan 1st, 2023 16:44
Join Date: Mar 2017
Location: Blackpool
|
Ah, I didn't know I could do that, might give that a go instead as I'm having trouble getting the shift light to work and not sure if its just a faulty product or not... Thankyou!
|
The Following 2 Users Say Thank You to Mattty For This Useful Post: |
Apr 24th, 2019, 23:37 | #14 | |
Premier Member
Last Online: Yesterday 23:44
Join Date: May 2012
Location: Lakenheath
|
Quote:
I suppose they've designed and written the instruction manual for the new generation of cars with one coil pack per plug, all individually controlled, timed and triggered by the ECU which somewhere along the lines will still have a timing sensor that would generate a signal. Good job you don't have contact breaker ignition and no tachometer, you'd have really been in the dark about it!
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
The Following User Says Thank You to Laird Scooby For This Useful Post: |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|