Is there any way to change what pulse VSS must be used inside the PROM.

 

I've read that it can be changed within the bin, but check this post out I found in the archives. There is a link within this post you will probably want to check out that goes into detail about the swap. https://www.thirdgen.org/messgboard/...ML/000660.html

I'm having a similar problem where I'm trying to get my VSS from my '86 "7165" style VSS to operate with my current 7730 setup. I believe the '86's used a 2000ppm sensor whereas the 7730 ECM uses a 4000ppm sensor. Supposedly there is a road speed parameter that needs to be changed in the BIN.

Anyone else have ideas?...I'm curious as to the exacts myself.

------------------
86 Trans Am WS6 Black with tinted windows, shaved door handles
ZZ4, Mini-ram, true duals, LT4 HotCam, AFR 195 heads.
***Too many other mods to mention***

"In the future, cities will become deserts,
roads will become battlefields, and the hope of mankind
will appear as a stranger" The Road Warrior

 

With the 7730, you cannot adjust the VSS "Pulses per mile" below 3,600, thus it will not work. I do notice that the 7730 has a "bit switch" regarding a "MAG sensor" which may work.

The problem is the algorithm GM chose does not let it get less than 3,600 rpm. You basically have to look at 1) changing the VSS to a 4,000 type; 2) get a Cyberdyne box to make the neccesary adjustment for the ecm; or 3) physically modify the machine code instruction set (no easy task and beyond most DIYer's capabilities).

It is a pity that GM made the lowest limit so high. You can increase it as high as 900,000+ but not below 3,600.

 

Thanks, Howell efi hooked me up with a cable driven 4-pulse unit. Solved my problem.

------------------
'88 IROC TPI 355, '69 truck 4-bolt, fully balanced, 9.75:1 compression, fully ported '70 truck heads(for now), Harland Sharp 1.6 Roller Rockers, Comp Cams CS 252AH-12, ported '86 TPI converted to speed density, Crane AFPR, Flowmaster 3in. exhaust, Edelbrock TES headers, all emissions equipment is still intact, plan on burning my own chips, many more mods and parts on the way as time and money permits =(
Best E.T. with TBI 305: 16.11 @ 82mph
Haven't been to track with new motor
If you have any questions on converting from TBI to TPI email me at jdkchevy70@yahoo.com
In memory of Dale Earnhardt, I'll miss cheering for that black #3 on raceday!!!

 

Gleen,
Is that "MAG sensor" "bit switch" available on TunerCat? If it is I can't find it. Oh and your right, that has to be selected for the conversion from a 165 ECM to a 730 ECM.

John




------------------
86 Camaro Sport
383 Speed-O-Motive Crate Engine, Raptor 700R4 Tranmission, Trick Flow Twisted Wedge G2's, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine Belt Setup, Dual IROC Fans, Jamex springs, 16" IROC Rims, 36mm/24mm Sway Bars, Global West Steering Brace. Hotchkis Rear LCA's,Panhard Bar and SFC's.
My Camaro Project

 

You guys don't have to go much farther than the GM parts bin for this one. I caught a glimpse of a combination cable/mag speed sensor insert for the 700r4. It looks just like your cable insert, but has a 2-pin connector that has the vss sensor built in for use with the later SD computers. Yes, both a cable hookup and an electronic speed sensor all-in-one. I believe these were used on 91 or 92 police cars with a 700r4.

------------------
1987 Trans Am GTA WS6
-5.7L SuperRam
-4L60-E Transmission
-3.73 SRD

1988 Pontiac Grand Am
-3800 SFI V6
-125-C Transmission

1985 Pontiac Fiero SE
-3800 Supercharged
-125-C Transmission

Domestic Terrors Car Club Online

[This message has been edited by MadMax350 (edited April 20, 2001).]

 

The MAG speed sensor switch you are speaking of for the $8D program is for a Permanent Magnet pickup VSS. This switch is present for use with the Beretta V6 cars (used the 7730 ecm) in which a reluctor wheel - mag sensor pickup was used. The signal here is an AC voltage pulse. The 90-92 Camaro VSS was a different type of pulse (DC I think), which is not compatible with an AC signal. I had to change the setting of this switch, in my car, in order to get the 7730 SD computer to work with my VSS reluctor-style pickup that comes on the 4L60-E transmission.

 

Thanks for the info MadMax350. I am sure there are a lot of people that will want to try that.

John, I have defined the "Mag Bit switch" in a special TDF that I created called "XXX.TDF". It contains the Mag Switch (plus some other useful switches), the controls for "Low Octane" that I mention in another post, plus a few other interesting Constants to help control other things.

I have forwarded this to TunerCat for incorporating into future releases of the 8D.TDF. TunerCat and I had a discussion on this a while back as to what would be the best way that this "experimetnal" tdf could be distributed to other 8D.TDF users. After some discussion, TunerCat agreed that if I forwarded these "experimental" TDFs to them, they would gladly forwarded to other 8D.TDF users simply by contacting them and requesting it. It is "experimental" and it is a "additional" tdf to the 8D, it does not replace it.

Also, I have created a version of the 8D that displays Farhenheith instead of Celsius in the temperature contstants called 8D4.tdf.

If you wish to get a copy of XXX.TDF and/of the 8D4.TDF, just e-mail TunerCat and explain that you heard that Glenn91L98GTA from www.thirdgen.org has submitted these two "experimental" TDFs and you would like a copy of them. Just remember they are "experimental" so any errors are not TunerCat's problem. But, I am sure the TunerCat would be interested if anyone notices any errors in them.