View Full Version : vss sensor function with a manual transmission.

June 23rd, 2011, 05:48 AM
I want to use either a tko 600 or the new keisler rs600 manual transmission with a 0411 ecm. Is the vss needed for a manual swap ( some say no but others say yes)??
I know on a t56 the vss prevents the transmission from being shifted into reverse unless the car is stopped but does the vss serve any other function or can it be eliminated if the aftermarket transmission does not use a reverse lockout.

On ls1tech someone said their car would stall when depressing the clutch as the car returned to idle and adding a vss cured the problem.

I have a mechanical speedometer so if I were to incorporate a vss it would have to be a pass thru type such as dakota digtital 8 pulse generator

or painless 4 pulse generator

If not using an electronic speedometer, I have read that the pulse generated does not have to match what the pcm is programmed to expect - the pcm just needs to know when the car is coming to a stop.

Also some people say the 0411 ecm cannot be programmed for either an 8 pulse or 4 pulse generator using efilive ( but hp tuners does allow such programming) because the minimum pulse allowed using efilive is 10. I noticed efilive allows a correction factor to be applied to the speedometer calibration ( the table states that it is for only small errors in the speedometer). If the ecm needs to know the actual speed could I use this table to make a large correction to the calibration. For example, if i set the ecm to 40 pulse per revolution and then applied a .1 correction factor using a 4 pulse per revolution vss would the ecm calculate the correct speed.

June 23rd, 2011, 06:21 AM
Hello monzaaddict,

Sounds like an interesting project .... you didn't mention what engine you are using. In my opinion you will forever have driveability / idle issues without a VSS signal. If you have a mechanical (cable driven) speedometer, and it has been accurately calibrated (proper drive and driven gears) for your tire and differential gear combination - an in-line pulse generator is a quick and easy solution to provide a VSS signal to the PCM. EFILive can be used to adjust the input the PCM receives from the pulse generator output.

Also, for a manual transmission tune to function properly the PCM will require input from both a clutch switch and a brake switch.


June 24th, 2011, 07:39 AM
Thank you for your reply.

Also, for a manual transmission tune to function properly the PCM will require input from both a clutch switch and a brake switch.

I have both

I am building a 75 monza hatchback and have been acquiring parts to build a gen 1 383 with an aluminum motown block, afr 195 heads, a ported superram intake and the efi connection drive by wire / coil on plug conversion using a 0411 ecm but I have been bitten by the ls bug and I am considering putting this engine off to a later date and starting with an l33 aluminum block 5.3 with an ls6 intake, dbw with cruise control and using a 0411 ecm. I was planning on using a tko 600 but the rs600 that keisler is working on is more compact and appears to offer more shifter placement options ( I want my factory console).

Am I correct in my understanding that my mechanical speedometer is expecting to receive 1000 revolutions per mile which equals about 621 revolutions per kilometer. so, if using an 8 pulse generator than pulse per kilometer would be 4971.

Summit ( made by msd I think) http://www.summitracing.com/parts/SUM-G2887-1/?rtype=10 or http://www.summitracing.com/parts/SUM-G2887-2/?rtype=10 has a 3 wire hall effect 16 pulse per revolution pass thru vss. Would this work If I adjusted H0102 ( vehicle speed sensor pulses per revolution) to 16.

June 25th, 2011, 03:11 AM
Yes - essentially.

As long as your mechanical speedometer has been calibrated accurately - then an in line pulse generator will cause 4K / 8K / 16K (depending on type) pulses per mile to occur.

H0101 (pulses per mile) must equal the output per mile of the pulse generator (i.e this needs to be 4000 / 8000 / 16000) for the VSS and cable speedometer to be in sync.

H0101 cannot be adjusted directly - you can alter the tire diameter, final drive ratio, and / or VSS pickup teeth parameters - until H0101 displays the calculated value you wish. In a manual transmission application - you are finished after this - with an automatic transmission the shift speeds would need to be adjusted, BUT you cannot use the speedometer calculator for this task (as you have entered false data) - you would have to make these adjustments manually.


June 30th, 2011, 03:36 AM
Again I would like to thank you for your response. I have been looking at this more and I think the summit/msd vss I mentioned above will not work. It is a 3 wire square wave output type sensor. http://static.summitracing.com/global/images/instructions/sum-g2887-1g2887-2.pdf

The tremec tko and keisler rs600 are both ford based transmissions. Ford has a 8 pulse sine wave pass thru type vss available.
Can you think of any reason this would not work

Keisler includes an adapter cable that has a ford transmission connection at the bottom and a gm speedometer connection at the top.

June 30th, 2011, 02:16 PM
I have never used either of those particular products - so I can't state definitively if either would work - they may both work. With a cable driven speedometer transmission an inline pulse generator is generally the most cost effective and easiest to use / install.

Whatever unit you choose, as long as the signal is recognized by the PCM - you can accurately configure it using EFILive.


October 26th, 2011, 08:38 PM
What about using the original T56 VSS sensor & having a toothed wheel machined & mounted on the prop or driveshaft?? We have do this for crank sensors on some swaps like below

http://i1196.photobucket.com/albums/aa404/Blair_McWilliam/th_0f74f66a.jpg (http://s1196.photobucket.com/albums/aa404/Blair_McWilliam/?action=view&current=0f74f66a.jpg)

October 27th, 2011, 01:59 AM
Yes sir ... many ways of obtaining a usable VSS signal. JTR (Jaguars That Run) sell an external reluctor setup that mounts behind the yoke of the rear differential - essentially a driveshaft mounted system.

Some people will tap into the ABS signal from one of the wheels (generally the front wheels) as this system is a reluctor / magnet setup also.