HomeHOW TO DO AN ADVANCED SEARCH.
Mon Jul 08, 2013 3:56 pm by Admin
For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.
When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).
After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …
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Pcm tach output
4 posters
944Hybrids: 924/944/968 and 928 V8 Conversions :: Technical Stuff (other than motors) :: Electrical Mods
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Pcm tach output
matt889 Thu Aug 18, 2016 9:23 pm
Hi I'm running into a little problem . I'm trying to wire my tachometer to my pcm but it doesn't have to wire on the pcm my model is a 2005 savanna 2500 model with a 4.8 engine drive by cable . The pcm on the green connector doesn't have a white wire in the slot 10 .my question is has anyone seen this before? Do I add a wire and get it tuned in or do I need to do something else to work with the original tachometer ? I also don't get A signal on my data wire for the obd2 port but that is not my priorities now. My car is a 1986 944 NA late dash
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
Re: Pcm tach output
sharkey Thu Aug 18, 2016 10:48 pm
not all harnesses will have wire for the tach output, as most send the tach over the data bus. you can simply add the wire to the harness and have the tuner turn the tach output on in the ecm when the security stuff is being removed.
sharkey- Posts : 714
Join date : 2014-11-21
Age : 39
Location : Abbotsford BC
Re: Pcm tach output
matt889 Fri Aug 19, 2016 6:07 am
And for the serial bus not sending any data to my scanner? My pcm was already flashed now I can't get any data when I plug my scanner on the green wire
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
spence- Posts : 684
Join date : 2009-07-21
Age : 41
Location : St.Catharines, Ontario, Canada
Re: Pcm tach output
matt889 Fri Aug 19, 2016 5:41 pm
I used the serial class 2 data wire (green), an obd2 power and the ground . My scanner turn on from my power ND ground just no communication
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
Re: Pcm tach output
sharkey Fri Aug 19, 2016 11:27 pm
i believe you need the high speed data bus wiring at the obd2 plug. id have to dig around some more to know for sure.
edit:
did some more looking, apparently that pcm only uses serial data to communicate with the scan tool. my guess would be that your pcm isnt powering up, check your constant power source, switched power and grounds.
edit:
did some more looking, apparently that pcm only uses serial data to communicate with the scan tool. my guess would be that your pcm isnt powering up, check your constant power source, switched power and grounds.
sharkey- Posts : 714
Join date : 2014-11-21
Age : 39
Location : Abbotsford BC
Re: Pcm tach output
matt889 Fri Aug 19, 2016 11:35 pm
On my pin out there is only one data line weird wire is green I will have to confirm the pin but it's in the 58 dark green
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
Re: Pcm tach output
matt889 Wed Nov 02, 2016 9:00 pm
i got the obd working and i added a tach wire and no rpm is showing -.- is a resistor needed for a late dash ? i have pluged my tach wire to the greeen wire of the 8 pin connector under passenger side
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
Re: Pcm tach output
sharkey Wed Nov 02, 2016 9:12 pm
the pcm needs the tach output turned on in the tune. the factory gauge cluster (if it had a tach) gets its tach signal through the data bus.
sharkey- Posts : 714
Join date : 2014-11-21
Age : 39
Location : Abbotsford BC
Re: Pcm tach output
Hotrodz of Dallas Fri Nov 04, 2016 9:13 am
matt889 wrote:i got the obd working and i added a tach wire and no rpm is showing -.- is a resistor needed for a late dash ? i have pluged my tach wire to the greeen wire of the 8 pin connector under passenger side
Depending on what year your ECU is, you may have to install a pull up resistor. I've hooked up the tach wire direct on 98-01 ECU's, but on 03-up I had to install a pull up resistor to make the tach work.
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: Pcm tach output
matt889 Sun Nov 20, 2016 7:42 pm
got the tach working 
thanks now i need a tune ...
thanks now i need a tune ...
matt889- Posts : 214
Join date : 2015-04-03
Age : 35
Location : canada Quebec
Re: Pcm tach output
sharkey Sun Nov 20, 2016 9:26 pm
what did you do to get it to work? it could help others in the future
sharkey- Posts : 714
Join date : 2014-11-21
Age : 39
Location : Abbotsford BC
944Hybrids: 924/944/968 and 928 V8 Conversions :: Technical Stuff (other than motors) :: Electrical Mods
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