HOW 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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Tach question
4 posters
944Hybrids: 924/944/968 and 928 V8 Conversions :: Technical Stuff (other than motors) :: Electrical Mods
Page 1 of 1
Tach question
Ok, the tach worked before the conversion. I found the wire on pin 3 of the center cluster plug. The ecm has 1.3volts at idle to ground (computer case) But tach still doesn't work. Am I missing something here? Does tach need something else. My tach is wired into a 4 pin red plug (pin#2 grn/bk)on the passenger side.I disconnected the plug from the harness going to the Porsche engine. All I should have to due is hook the tach wire from the ecm to it? No dice.Any ideas?
dallas- Posts : 69
Join date : 2009-07-10
Location : stratford ct.
Re: Tach question
Dallas-
Basically the tach needs 3 connections: 12volt power, groound, and a low voltage signal (from the ECM).
It sounds like you have sourced the ecm signal correctly, as it should be a very low voltage output. It will have an AC frequency that is proportional to the engine speed, but you probably cannot measure that unless you have a very expensive DVOM or Oscilloscope. To verify that you are on the correct 4 pin connector, you could pull the instrument cluster and try to figure out which connectors go to the tach, but that will not be easy as many connectors are not marked and the back is one big circuit board for all of the instruments. So I guess the next steps would be to try to determine if power and ground are available to the tach. Do the other instruments within the cluster seem to work? That's all I can suggest. I know my harness is different from yours, but the one wire from the ECM to the Tach worked perfectly for me.
Good Luck.
Basically the tach needs 3 connections: 12volt power, groound, and a low voltage signal (from the ECM).
It sounds like you have sourced the ecm signal correctly, as it should be a very low voltage output. It will have an AC frequency that is proportional to the engine speed, but you probably cannot measure that unless you have a very expensive DVOM or Oscilloscope. To verify that you are on the correct 4 pin connector, you could pull the instrument cluster and try to figure out which connectors go to the tach, but that will not be easy as many connectors are not marked and the back is one big circuit board for all of the instruments. So I guess the next steps would be to try to determine if power and ground are available to the tach. Do the other instruments within the cluster seem to work? That's all I can suggest. I know my harness is different from yours, but the one wire from the ECM to the Tach worked perfectly for me.
Good Luck.
Bridar- Posts : 52
Join date : 2009-08-12
Location : Asheville, NC
Re: Tach question
I didn't get out to work on it today, but yes all other guages work. My car has that mpg guage in the tach and it swings to right when I start the car. I fear the tach is bad now. Stranger things have happened I guess. I have another cluster that I might try before I yank the cluster. I'll post my findings. Thank you.
dallas- Posts : 69
Join date : 2009-07-10
Location : stratford ct.
Tach failure
I hooked my pcm tach output (88 NA) to pin 2 (Gr/Blck) in the 8 pin connector and the Tach worked ok.
2 years on and the tach quit working. Do the Porsche tachs handle the LSx tach signals well? Wiring checked and is OK.
2 years on and the tach quit working. Do the Porsche tachs handle the LSx tach signals well? Wiring checked and is OK.
simon123- Posts : 125
Join date : 2013-07-26
Re: Tach question
i believe admin posted that the ls ecm works on a 4cylinder signal so it works with the 944 tach easily. just hook the wires directly up to it. if u do a search u should be able to find it.
shokwave30- Posts : 68
Join date : 2012-02-02
Location : Iowa
Tach died
Shock wave
Sorry I don't need to look anything up.
The tach has worked OK with the LS1 in my car for two years, now its died. Question I asked was about life expectancy of tach in this configuration. Do they prematurely fail?
Sorry I don't need to look anything up.
The tach has worked OK with the LS1 in my car for two years, now its died. Question I asked was about life expectancy of tach in this configuration. Do they prematurely fail?
simon123- Posts : 125
Join date : 2013-07-26
Re: Tach question
oh ok. thought u needed to know which wires to hook up or how to hook them up. or a schematic to help out dallas. no worries here.
shokwave30- Posts : 68
Join date : 2012-02-02
Location : Iowa
Tach failure
Follow up to my Tach failure, I purchased a cheap Chinese tach on Ebay and used it to confirm I had a good tach signal from the computer. Pin 2 on 8 pin connector in passenger footwell.
Then I sourced a used 944 Tach on Ebay, face looked identical to mine until I took my original out and saw a bunch of electronics and a shift light. Well the shift light never worked anyway so the replacement (without any electronics) was installed in the cluster and it works fine. Problem solved.
Anybody want a shift light tach for parts?
Then I sourced a used 944 Tach on Ebay, face looked identical to mine until I took my original out and saw a bunch of electronics and a shift light. Well the shift light never worked anyway so the replacement (without any electronics) was installed in the cluster and it works fine. Problem solved.
Anybody want a shift light tach for parts?
simon123- Posts : 125
Join date : 2013-07-26
944Hybrids: 924/944/968 and 928 V8 Conversions :: Technical Stuff (other than motors) :: Electrical Mods
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