Scorpio Speed sensor question

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john keefe
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Re: Scorpio Speed sensor question

Post by john keefe »

Kinda' old fashioned speedo check... Drive steady at 60mph, watch the odometer and time it for exactly one minute. If its on, your odometer will turn over one complete revolution (10/10's). If its off a touch, don't worry as its not unusual for mechanical systems like these to be close, but not totally accurate. Most times, they were geared for closest approximation for city speed limits.

If its off a lot, you may be able to switch the driven gears with another color. I'm sure there's some archive in some group's XR or T5 website showing # teeth vs. driven gear color. But, I wouldn't assume the VSS won't work without trying that first.
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brokencase
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Re: Scorpio Speed sensor question

Post by brokencase »

Its all good John. I tested it yesterday with the cellphone navigation. The reluctor sensor outputs the same number of pulses per rev as the original Scorpio Hall effect sensor. I re-used my original gear. These aftermarket sensors do not come with the gear.
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Ed Lijewski
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Re: Scorpio Speed sensor question

Post by Ed Lijewski »

"One thing I notice with the polyurethane bushings - the front tires squeal a little on tighter turns. Maybe they will break in."

I installed new non-poly TCAs two weeks ago and also noticed a small brief squeal on certain tight turns/surfaces.

YMMV
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john keefe
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Re: Scorpio Speed sensor question

Post by john keefe »

Good to know your solution works!

Funny the stuff you entertain yourself with on long cross-country trips... nothing to do sometimes but stare at the odometer turning over, calculating fuel mileage, speedo errors, and effect of other gear ratios in your head. Anything to stay awake. And, of course, there's the totally bored, "wondering how accurate the "Miles To..." highway signs are." :D

I know a guy who somehow swapped in a Mustang 2.6 or such rear diff ring and pinion in his XR. Great mechanic. But, he wanted the most mileage possible on his monthly drives to his shack in Montana. Claimed he was getting 38+mpg, cruising at 75 mph, and watching the 2.3 turn over at 1100-1200 RPM or something silly like that, the whole way.
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brokencase
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Re: Scorpio Speed sensor question

Post by brokencase »

I didn't do this because I needed the entertainment John. I did it because I wanted the odometer and cruise control to work, and not to mention it gets real irritating to have the fuel computer screaming at you every time you start the car up.

If I find myself with free time over the winter I will see about making a printed circuit board for this circuit and make it available for other A4LD Scorpio owners.

If folks could sound off in this thread the desire for this then that might give me a better ideal of the demand and if it is worth the effort.
I would not expect many US Scorpio owners would be interested (because there are not that many) but there may be more in Europe that might desire this solution.

I have a CNC that I can do printed circuit board routing on. I could cookie cutter a whole bunch of them in one shot on the machine.

I'm thinking one other thing. I should have made a way where the module is fastened to the bolt that holds the Vss into the trans.
Something like a bracket OR cut the square tube so there was an extra tab with a hole in it.
There is a bit of extra wire and I worry that if my zip ties let go then the wires might foul into the u-joint/rotoflex at the back of the trans.
Zip ties have been known to fail...

All in the interest of making this a more permanent solution....
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Ed Lijewski
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Re: Scorpio Speed sensor question

Post by Ed Lijewski »

I'm in for one.

Some Scorpio owners might drive more often and/or longer distances if they knew your fix was available.

I'd even buy a few (6), just because the demand for these will be there eventually...on both sides of the pond.

YMMV
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john keefe
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Re: Scorpio Speed sensor question

Post by john keefe »

Hey Brokencase, this is pretty cool. Thanks for the link to the CDI tech page. I may be interested in one of your adapter/circuit-boards if I end up keeping this a4ld.
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brokencase
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Re: Scorpio Speed sensor question

Post by brokencase »

Well, my solution has survived one week with no issue. Fuel computer is registering mpg around the same as it was previously.

I'll try to make a few PCB boards over the holidays
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DAReese
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Re: Scorpio Speed sensor question

Post by DAReese »

I'd be interested depending upon the cost.
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brokencase
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Re: Scorpio Speed sensor question

Post by brokencase »

OK, so we have three individuals interested...about what I expected.

BTW, Here is another version of the MSD project article with the original pictures..
http://www.not2fast.com/ignition/cap-dis-ignit-cdi.pdf

I am tempted to make another one for the Scorpio. The main reason is that this MSD makes a lot of spark firings at the lower rpms.
It really smooths out the idle of the engine. It also makes the engine start very easily.
At least this is what it did with the Sprite - in fact, the Sprite no longer needs choke even when it is started when it is really cold out.
On the original point system the Sprite would gurgle and sputter upon initial starting/running. Now it's just hmmmmmmmm. It never skips a beat.

But these are the only advantages, up at the higher rpms there is not much difference with MSD

However the article warns in the intro about 6 and 8 cylinder engines, stating the ignition cable dressing has to be really good to avoid cross firing.

It makes a real aggressive spark. When I first put it on the Sprite, it was not a week or so later that it bore a hole through the old "bakelite" plastic of the original distributor rotor. Basically the spark found it's new way to ground through the distributor drive shaft. Took a while for me to figure out what was going on. I then found a guy who makes new rotors for the old British sports cars out of modern plastic and this solved that problem. It's been fine ever since.

To take best advantage of the hotter spark you are inclined to open the plug gaps, but when you do that the spark starts looking for other ways to get to ground (since you made it harder to jump the gaps). So all the other ignition components have to be in tip top shape.

I am sure the MSD also eats up the plugs about 8 times faster. So its best to run platinum or even iridium plugs.
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