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xpernet · Posted: Mon Feb 28, 2005 6:36 am Post subject: Tach Problems

hey guys!

My tachometer is giving me a head ache! When ever i rev the engine to the max, with the pedal to the metal ( not for a long time ofcourse

) the RPM wont go over 4,000 RPM!!!

Its really bugging me and i want to fix it. I need to get a precise reading when the car is idling so i can adjust the car's idle abit. I tried to clean the contacts on the tach, and i have cleaned about every single ground i can find, but still no use.

Thanx in Advance

xpernet
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1977 Porsche 924
Sunroof Delete
Megasquirt II EFI & EDIS
Carrera GTS / 944 Body

"If one does not fail at times, then one has not challenged himself." Ferdinand Porsche

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

From my own experience, and others have said that they have had similar results, I will say that the in-dash tachometer is not terribly accurate. You will need a separate hand-held instrument to get a more precise reading. The calibrated instrument I used registered 900(+-)rpm, while the in-dash tach indicates 1050-1100. However inaccurate the in-dash unit is, I doubt that it is inaccurate by 2000-2500 rpm. If you are WOT and only 4000rpm, I'd just about guarantee that you have something other than the tach that is wrong (timing, fuel delivery, fuel mix, etc).

Another recent post of yours said that you heard a hissing sound. Sounds like a vacuum leak to me. Start simple, be methodical.
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'79 Eurospec 931

xpernet · Posted: Tue Mar 01, 2005 8:28 pm Post subject:

Thanx for the reply CMXXXI

I don't think i have a problem with the timing, but i have a problem with the Fuel delivery. I though that the Tach's problems where related to some problems in the electrics.

Ill try to fix the vacum leak this weekend and ill see if its going to give any results on the tach.

Regards

xpernet
_________________
1977 Porsche 924
Sunroof Delete
Megasquirt II EFI & EDIS
Carrera GTS / 944 Body

"If one does not fail at times, then one has not challenged himself." Ferdinand Porsche

Joes924Racer · Posted: Tue Mar 08, 2005 3:28 pm Post subject:

Wasover on rennlist & pelican parts and there like really exspensive to replace especialy the 44 ones. Ive also studied posts here on the board
on guages and what happens for a 25 year old car ...I want to know more on the combo guage setup though guess once you get resistance in the sys. they do that.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.