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Registered
Join Date: Sep 2004
Location: Burlington, Ontario
Posts: 631
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Tach not working 73 2.4
Hello, after starting my freshly rebuilt 2.4 I'm finding that the tach is not working. It was working before removal. Before I get too deep into the schematics can anybody recommend any quick checks?
Thanks, Joe |
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11-25-2005, 07:20 AM
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Registered
Join Date: Apr 2001
Location: Linn County, Oregon
Posts: 48,535
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If you're still running points, check the gap...points are the trigger signal for the tach.
__________________
"Now, to put a water-cooled engine in the rear and to have a radiator in the front, that's not very intelligent." -Ferry Porsche (PANO, Oct. '73) (I, Paul D. have loved this quote since 1973. It will remain as long as I post here.) |
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11-25-2005, 07:22 AM
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Join Date: Sep 2004
Location: Burlington, Ontario
Posts: 631
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Yes, I am running points but the car is running fine. Are you suggesting a connection in the distributor.
Joe |
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11-25-2005, 07:24 AM
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Registered
Join Date: Apr 2001
Location: Linn County, Oregon
Posts: 48,535
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Yep...the tach signal come from the points...where it reads the revs. A mechanic once told me that if points were gapped improperly, or even dirty, since they aren't high voltage, the tach signal can be interrupted. I dunno how it works when converted to pertronix or crane. I converted to Pertronix in my car, but also went with a RS dizzy because of the original "back-wards points" set-up on the '72 "S". Once it got that complicated, I just wrote a check to a shop. Prior to that, if my tach started acting weird, I'd run clean paper through the points, cleaning up minor oil, and bingo...tach would work again.
__________________
"Now, to put a water-cooled engine in the rear and to have a radiator in the front, that's not very intelligent." -Ferry Porsche (PANO, Oct. '73) (I, Paul D. have loved this quote since 1973. It will remain as long as I post here.) |
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11-25-2005, 07:34 AM
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Registered
Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,772
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Double check the black/purple wire connection. On mine, it is a piggy back deal and can lose the signal easily. Check all grounds since you just installed the engine. And, I don't know what this has to do with the tach specifically, but you did reinstall the tanny ground strap, right?
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11-25-2005, 08:34 AM
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Registered
Join Date: Sep 2004
Location: Burlington, Ontario
Posts: 631
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Thanks guys, I will check it out on Sunday. It's got mighty cold up hear in the last few days. Supposed to warm up Sunday. It'll give me a chance to track down a few pesky leaks as well.
Thanks, Joe |
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11-25-2005, 09:44 AM
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Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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A 6 - 12 Volt test lamp can verify the validity of the tach signal at the Black/Violet wire on the back of the tach. If you don't have a blinking lamp during cranking ... backtrack through both 14-pin connectors. Clean all connections with Brakleen and a brass brush. Don't use abrasives or emery boards!!! After degreasing ... 9% pickling vinegar on a Q-tip is good for removing corrosion, followed by rinse with distilled water. Faston connectors should be 'snug' on their tabs to remove or install. Slight crimping on the sides of the female connectors [don't close thee gap entirely] to improve loose connections. After tach is functional again ... apply silicone grease such as Dow Corning 4, 111, or, 112 to all connections to protect against future corrosion.
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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11-25-2005, 01:41 PM
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