| DeLvxe |
Wed Sep 22, 2021 12:11 pm |
|
Hi all, Hoping to resolve an annoyance I have with my van. I have a '91 with a 2000 EJ25. I recently (9 months ago?) had a new wiring harness put in from Autoventures to resolve an intermittent starting problem as well as a couple other gremlins. The van runs great, but the tach and the reading from my OBD2 port don't agree on the actual RPMs. My OBD reader consistently reads about 600+ RPMs higher than the tach.
1. Since my tach reports about 200 RPMs at idle and 3400 RPMs at 75 mph, am I safe assuming that the ECU is reporting the correct RPMs? - more like 800 RPMs at idle and 4,000 at 75 mph.
2. If my tach is reading low, what could be causing this and how to fix? It was reading correctly before the new wiring harness.
Thanks |
|
| veloandy |
Wed Sep 22, 2021 2:03 pm |
|
Does your tach get its signal from the tach pin from the Subaru ECU, or is it wired to the ignitor as described here?
Have you checked the tach signal wire for excessive resistance? |
|
| skills@eurocarsplus |
Wed Sep 22, 2021 2:54 pm |
|
talk to jeff
his newest signal converter box has provisions to adjust the tach output, i just forget how to do it |
|
| wesitarz |
Wed Sep 22, 2021 3:18 pm |
|
Too funny I just adjusted mine.
02 2.5 Subaru, my tach was reading about 200 rpm higher than my TorquePro app. There is an adjustment on the back of the tach under a label. Peel it off and you can fit a small flat blade screwdiver in the hole to engage the potentiometer. You can see the slot with a light. Turn very slightly left (looking at the back of tach) to decrease, right to increase. Test at idle and higher say 2500-3000 rpm. I had the whole unit out and only attached at the 14 point connector. I found it easier to engage and turn it with it disconnected and trial & error to get it close. |
|
| skills@eurocarsplus |
Wed Sep 22, 2021 4:28 pm |
|
i have adjusted VDO tach's by your description in the past
jeff has made his interface box adjustable for various tach signals so there is no need to mess with the tach itself (unless there was a issue before)
jeff's box addresses this adjustment |
|
Powered by phpBB © 2001, 2005 phpBB Group
|