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

draggin86 · 11-30-2009, 01:45 AM

So i am planting my L31 vortec 350 in my c10 with my 4L60E transmission. So i have been told if you use the new 90-91 blazer or suburban gauge cluster you can use input from the transmission.. my question is how to i hook up the input to the cluster.

Thanks
Billy

Jonboy · 11-30-2009, 09:35 AM

From what I understand, the electric speedometer uses three inputs. There is a 12+, ground, and a signal from the PCM. All three of these will plug into the rear of the cluster, and just need to be connected accordingly. At least this is how I understand it.

78-5.3 · 11-30-2009, 05:51 PM

there will be one one coming from the PCM it will hook up too the speedometer

draggin86 · 11-30-2009, 06:30 PM

Copy that guys thanks for the insight i have my speedo coming.. im just torn weather i should mod the OEM harness or to do a standalone.. the standalone seem to be pretty pricey ranging from $400-700 not including a tune.. waitforme said they would tune for 85 bucks so this is where im at right now.. the painter has the truck so i have some time.

78-5.3 · 11-30-2009, 07:49 PM

Quote:

Originally Posted by draggin86

Copy that guys thanks for the insight i have my speedo coming.. im just torn weather i should mod the OEM harness or to do a standalone.. the standalone seem to be pretty pricey ranging from $400-700 not including a tune.. waitforme said they would tune for 85 bucks so this is where im at right now.. the painter has the truck so i have some time.

try brendan at lt1swap.com

draggin86 · 11-30-2009, 10:08 PM

Quote:

Originally Posted by 78-5.3

try brendan at lt1swap.com

I just emailed him see what he says

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.

Jonboy · 12-01-2009, 10:10 AM

Using that VSS, what type of drive gear is used? I looked on the JTR website, and got more confused. It looks like you have to add another gear to the output shaft of the trans to get it to work. I also looked at the S&P modified tailshaft, but figured I could spend $450 a better way.

68 TT · 12-01-2009, 12:54 PM

Quote:

Originally Posted by Jonboy

Using that VSS, what type of drive gear is used? I looked on the JTR website, and got more confused. It looks like you have to add another gear to the output shaft of the trans to get it to work. I also looked at the S&P modified tailshaft, but figured I could spend $450 a better way.

Depends on the year of the trans. The newest one I used the dual output VSS on with was a 93 4L60 that came behind my LT1 so it still had the plastic speedo drive gears not the newer trigger wheel ring design. Most likely the switch happened with the change to the 4L60E so it won't work with what you have, sorry for the confusion.

You could always switch to a non-electronic 4L60 / 700R4 to save a pile of cash up front but the tuning features of the electronic trans are pretty cool and I'm not sure how the PCM would interface with the non-electronic trans to control TCC functions or how you would get the TV cable to connect to the vortec throttle body.

Sounds like you are much better off using the electronic speedo and keeping the 4L60E.

78-5.3 · 12-03-2009, 09:09 PM

IF its it has 4l60e then isnt the ecm edited for what the rear end ratio and what tires size thats what happen to me they want to know what rear end i had and tire sizes

68 TT · 12-04-2009, 10:10 AM

Quote:

Originally Posted by 78-5.3

IF its it has 4l60e then isnt the ecm edited for what the rear end ratio and what tires size thats what happen to me they want to know what rear end i had and tire sizes

You are correct. With the 4L60E you change settings in the programming to account for gearing and tire diameter.

draggin86 · 12-04-2009, 04:39 PM

Hey guys i do have the pin put of my truck i was thinking of getting the GM shop manual for the motor i pretty much have it figured out from what i have found online and a few other places. as for the transmission it is the newer electric speedo tranny just like the ones that would come in a 5.3L i dont feel like wasting money on converting the tail shaft and calibrating the gear sets to get it right when i change the wheels when it could just be tuned.

Thanks for the help guys!

11-30-2009, 01:45 AM	#1
draggin86 Registered User Join Date: Aug 2004 Location: Folsom, Ca Posts: 573	electronic speedo? So i am planting my L31 vortec 350 in my c10 with my 4L60E transmission. So i have been told if you use the new 90-91 blazer or suburban gauge cluster you can use input from the transmission.. my question is how to i hook up the input to the cluster. Thanks Billy

11-30-2009, 09:35 AM	#2
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: electronic speedo? From what I understand, the electric speedometer uses three inputs. There is a 12+, ground, and a signal from the PCM. All three of these will plug into the rear of the cluster, and just need to be connected accordingly. At least this is how I understand it.

11-30-2009, 05:51 PM	#3
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	Re: electronic speedo? there will be one one coming from the PCM it will hook up too the speedometer

11-30-2009, 06:30 PM	#4
draggin86 Registered User Join Date: Aug 2004 Location: Folsom, Ca Posts: 573	Re: electronic speedo? Copy that guys thanks for the insight i have my speedo coming.. im just torn weather i should mod the OEM harness or to do a standalone.. the standalone seem to be pretty pricey ranging from $400-700 not including a tune.. waitforme said they would tune for 85 bucks so this is where im at right now.. the painter has the truck so i have some time.

12-01-2009, 02:25 AM	#7
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	#9
68 TT Still plays with trucks Join Date: Jul 2009 Location: Spokane, WA Posts: 3,556	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. __________________ miSSed opportunity - ground up creation of an AWD 1994 454 SS that never was http://67-72chevytrucks.com/vboard/s...d.php?t=795577 69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been 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 79 Malibu TPI 350 4L60 w/ Z28 steering & sway bars Last edited by 68 TT; 12-01-2009 at 12:54 PM.

12-01-2009, 10:10 AM	#10
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: electronic speedo? Using that VSS, what type of drive gear is used? I looked on the JTR website, and got more confused. It looks like you have to add another gear to the output shaft of the trans to get it to work. I also looked at the S&P modified tailshaft, but figured I could spend $450 a better way.

12-03-2009, 09:09 PM	#12
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	Re: electronic speedo? IF its it has 4l60e then isnt the ecm edited for what the rear end ratio and what tires size thats what happen to me they want to know what rear end i had and tire sizes

12-04-2009, 04:39 PM	#14
draggin86 Registered User Join Date: Aug 2004 Location: Folsom, Ca Posts: 573	Re: electronic speedo? Hey guys i do have the pin put of my truck i was thinking of getting the GM shop manual for the motor i pretty much have it figured out from what i have found online and a few other places. as for the transmission it is the newer electric speedo tranny just like the ones that would come in a 5.3L i dont feel like wasting money on converting the tail shaft and calibrating the gear sets to get it right when i change the wheels when it could just be tuned. Thanks for the help guys!



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