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How many pulses per minute does the original vss for cruise control (the one mounted behind the speedometer) in the mid 80's elcos produce? I am running a 1994 LT1 in my elco with a 2004r, I would like to be able to get a vss signal to feed the pcm but I don't know how I can do this. Has anyone had experience with this type of setup?
 

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I don't know, I cant even remember if I have cruise??
several ways to go, heres some readin..
http://www.jagsthatrun.com/V8-chapters/V8-tpi-Speed-Sensors.pdf

1. The two-pulse (2000 pulses per mile) square wave (D.C current or direct current) used on all TBI

engines thru 1992, all computer-controlled-carbureted engines, and on 1985-1989 TPI engines.
I assume the ccc signal was the same, but I don't know??:sly: hope that helps. where's Darbysan??​
 

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Yep- 2K Pulses per Mile.
 

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WT, easiest way is to get an adapter that mounts where the speedo connects to the trns. If you like a project, I have seen online where someone opened up the back of the speedo and did a conversion to give 4000 PPM out of the stock speedo. It was quite clever, but of course then you would loose the 2k ppm for your cruise.
 

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Don't have 200r4, but have 700r4 question. Purchased a problem child, trying to work out the kinks. Currently my speedometer is off, reading 40 mph, when doing approx. 60. Was wondering how much of an affect this has on the ecm.
 

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Speedometer Calibration Program - Method #1 - By Bowling
This program provides the necessary information needed in order to determine what transmission speedometer gear is needed in order to properly calibrate a speedometer. This method is purely calculations-based, and will yield very accurate results.
One important piece of information which is required is the number of revolutions it takes your speedometer to register one mile. On most modern cars, this may be found on the bottom (or elsewhere) of the speedometer face, usually in very small numbers. Look for something like 940, 960, 1000, or 1020, or something close. This number is the number of speedometer cable revolutions (or equivalent in the case of electronic sender units) to increment the odometer one mile. Most speedometers (modern ones) are 1000 revs/mile, and this is a good starting number to use.

Another vital piece of info is the speedometer drive/driven gear ratios, the gears inside of the transmission or transaxle. The drive gear is the one which is turned by engine power, usually mounted right on the transmission output shaft. The driven gear is the one which is "driven" by the "drive" gear, and is connected to the speedometer cable or electronic sender. The numbers entered in the program are the integer number of teeth - just count 'em up.

The program will compute the best driven gear given a particular drive gear, or the best drive gear given the driven gear value. Remember that there are only set combinations available, which you can find out from the parts store or dealer. Also remember that gear tooth numbers are integer values.

http://www.bgsoflex.com/speedo1.html

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User Input:
Speedometer Revolutions Per Mile:

Rear Tire Diameter in Inches:

Differential Gear Ratio:

Want to Find : drivendrive Gear.

Drive or Driven Gear teeth (opposite to selected above):

Press this button to submit a computation: .

To reset the form input: .


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Algorithm:
 

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Currently my speedometer is off, reading 40 mph, when doing approx. 60. Was wondering how much of an affect this has on the ecm.
Depends on what ECM and induction you have. Need more info. Basic issues would be Torque Converter Lockup, but could also affect other things depending on induction.

Not to hard to change driven gear on the 700r4, but with that much difference, may have to change drive gear too. You could try changing the driven gear first to see how close you can get it.
 

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Guess I was a little vague on my previous post, so here is some more info: 383 with trick flow heads, sanderson headers. The TPI setup from 91 IROC which came as a kit from Street & Performance out of Mena Arkansas, ecm:01227727. Previous owner told me he put 4.11 gears in the rear end. Figured I needed to at least change the driven gear, to try to get the speedo close, but if it has no affect on the ecm, no rush. I am at the bottom of a steep learning curve with efi, so I was going to take it in for a tune up. But if I need to change the driven gear before, I will. Thanks for all the input. I am sure that this is just the beginning of the questions.
 

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It will have some effect, but mostly in the Torque Converter Lockup. Might be throwing off the TPS tables some ( Too much throttle for the indicated speed), but I think that is secondary. Might want to ask the question over at Thridgen.org ( be prepared for the Newbie Flame or two!).
 

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Thanks Darbysan, will give Thirdgen a shot. Exhaust does smell a little rich. HKDUP87, tried the program you suggested, now I am even more confused. It told me I needed to go to a higher gear, which I thought would actually reduce the speed. Currently have a 42 tooth driven gear (granted it is worn down a lot) with a 17 tooth drive gear (in good shape). I did the "raise one tire and do one full tire rotation, driveshaft rotated approx. 1.66 times, which I think gives me a 3.42 rear gear (one more piece of bad info from previous owner). I have 26 inch dia wheels. The calculator told me I needed a 45 tooth driven gear. If anyone has any input or heard of this before, chime in.
 

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Looking in my 77 Olds shop manual the 400 transmission used a 45 tooth gear Blue with an 18 tooth driven gear Lt.Blue with a 205 70 15, a 44 tooth driven gear Dk.Grey with a 215 70 15. These are shown with a 3.23 differential.

The 400 was the non electronic control, non overdrive trans that developed into the 700R4 so the gears should fit. You might be able to find one at a local trans shop in your area

Hpoe this helps

Steve
 

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Yep- 2K Pulses per Mile.
Is the 2K pulses per mile, analog or digital (sine wave versus square wave).

I am looking at making a 3d printed piece (I will likely be using Taulmann 910 for the 3D material) that bolts (I will print the bolts out on the 3d printer also) around the outside of the drive shaft (near the transmission tailstock). I have removed the ECM for controlling the original EM4E carb and distributor. Carb was replaced with mountain man qjet and HEI with vac and mechanical advance.

I would like to get my cruise control working again using the signal from the 3d printed piece with steel (or perhaps neo magnets) imbedded in it. My understanding is if I use a hall effect switch (generally three wires) then I will get a square wave. Alternatively, if I use a variable reluctance sensor (two wires) then I will get a sine wave.

PS I am aware that I can use the existing speedo cable, speedo, optical sensor and buffer to fix this problem also.
 
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