electronic speedo? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sailed2japan · 12-01-2009, 02:25 AM

If you decide to mod your existing harness I suggest getting the original schematic and drawing out where you are going to tie inyour new harness. A little extra time in the planning will save alot of time in the "oh, $h!t"

Jonboy · 12-01-2009, 09:47 AM

Quote:

Originally Posted by sailed2japan

If you decide to mod your existing harness I suggest getting the original schematic and drawing out where you are going to tie inyour new harness. A little extra time in the planning will save alot of time in the "oh, $h!t"

x2. Whoever swapped the engine in mine skipped this step. It would have made life quite a bit easier, but I am looking forward to sorting it out.

I went ahead and picked up an electric cluster too. Hopefully I can get the gauges to work now.

68 TT · 12-01-2009, 10:01 AM

I don't know what kind of signal the L31 vortec PCM is looking for from the VSS but on the LT1 & TPI swaps I have done they both worked perfectly using a dual output VSS from a 93 vintage Caprice cop car. VSS-231 at NAPA if I remember right.

It has both the mechanical speedo output and the VSS output on it so I was able to keep the stock cable driven speedometer but still give the ECM/PCM what it needed too. The mechanical side was to drive a speedo cable driven radar gun. I know it is the wrong type of signal for a TBI swap but since the L31 is port EFI I figured it might work with it too.

The same VSS unit fits into a 4L60, 700R4 and a T-400.

12-01-2009, 02:25 AM	#1
sailed2japan Jonny Join Date: Apr 2008 Location: Outside the Box, Austin,TX Posts: 741	Re: electronic speedo? If you decide to mod your existing harness I suggest getting the original schematic and drawing out where you are going to tie inyour new harness. A little extra time in the planning will save alot of time in the "oh, $h!t" __________________ 1966 C30, Cummins, stacks, and a flat bed in progress... "Honor.....simply put, A veteran - whether active duty, retired, national guard or reserve is someone who, at one time in his life, wrote a blank check made payable to 'The United States of America', for an amount of 'up to and including his life.' That is Honor, and there are way too many people in this country who no longer understand it." -AEC Hundley USNR

12-01-2009, 10:01 AM	#3
68 TT Still plays with trucks Join Date: Jul 2009 Location: Spokane, WA Posts: 3,570	Re: electronic speedo? I don't know what kind of signal the L31 vortec PCM is looking for from the VSS but on the LT1 & TPI swaps I have done they both worked perfectly using a dual output VSS from a 93 vintage Caprice cop car. VSS-231 at NAPA if I remember right. It has both the mechanical speedo output and the VSS output on it so I was able to keep the stock cable driven speedometer but still give the ECM/PCM what it needed too. The mechanical side was to drive a speedo cable driven radar gun. I know it is the wrong type of signal for a TBI swap but since the L31 is port EFI I figured it might work with it too. The same VSS unit fits into a 4L60, 700R4 and a T-400. __________________ 69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been https://67-72chevytrucks.com/vboard/...d.php?t=484426 69 K20 lwb TBI 350 4L60E NP208 14-bolt Dana-44 w/disc 68 Camaro SS / RS 500hp 439 inch roller cam big block 4L80E Last edited by 68 TT; 12-01-2009 at 12:54 PM.



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