Rewiring tach and speedo after engine swap

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Jan 19, 2010 | 12:58 PM

buymytransam

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Joined: Jun 2002

Posts: 42

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From: Syracuse, NY

Car: 2005 Audi A4 Avant

Engine: 1.8T

Rewiring tach and speedo after engine swap

I converted my 305 TBI to a carbed 350. I know some of you will develop a twitch, stand on your computer chair, point at your monitor and scream "WHY WOULD YOU DO THAT!?!?!?!" I did it because I wanted to. Here's my question: How do I make the tachometer and speedometer work again? After removing the ECU, swapping motors, etc., my tach and speedo do not move. If anyone has any ideas how to make them work (reliably) again, I would appreciate your advice very, very much.

Lenny

Jan 19, 2010 | 01:18 PM

NINÅ

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Joined: Jan 2006

Posts: 3,341

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From: Mooresville NC

Car: LOWERED ♦ CRIMSON METALFLAKE

Engine: ► 400 KUBES ◄

Transmission: 765R4

Axle/Gears: EATON POSI 4.56

Tack It Back On

The tach does not need the ECM.

You knocked a wire off during the swap.

Locate the WHITE wire in the harness near the distributor.

It needs to go to the coil primary.

◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!

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If People Drove Any Slower They’d Be Going Backwards

When you see fog lights on in good weather beware. Low performance driver ahead.

How bout those nitwits too scared to drive without headlights in the daytime,

and the nitwits that need headlights for a little rain

.
.

Jan 20, 2010 | 03:11 PM

Pocket

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Posts: 8,117

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From: NC

Car: 91 Trans Am

Re: Rewiring tach and speedo after engine swap

Agreed

Read this
https://www.thirdgen.org/forums/ltx-...p-3rd-gen.html

If you originally had a TPI/V6, then you need a buffer box. If you were originally TBI, the buffer box is stock and should work just like is the ECM was still connected