TC 's and speedo readings

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Aug 14, 2002 | 07:10 PM

LiquidSnake

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From: Istanbul

TC 's and speedo readings

Hi to all;
I have a question for all A4 owners with aftermarket TC's :
I have a 98 Camaro with a Vig2800 and a few other friends haves LS1 y-body and f-body cars with Yank convertors.(Excpet for one 98C5 with a Yank 3500 convertor)we all have some speedo reading errors on high speeds.For an example my cars speedo work s very close to correct until 90-100 mph but after that point nobodys speedo reades correct mph.. i ve do some 4500+rpm s on the 4 th and speedometer still shows 110-115 mph quite funny...i ve tryed everythink(Hypertech adjusting,tire diameters,going back to stock programming...everythink...) but nothink works....anybody haves any opinions?Btw we never have a problem with our stock convertors.(i mean correct readings for the speedo)And nobodys trany is slipping.
Thanks in advance

Aug 15, 2002 | 07:35 AM

pekkaz

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Re: TC 's and speedo readings

I don't understand why a verter would have anything to do with speedo readings. If it does it must be some weird mechanism. Of course the engine rpm is higher in that speed range than with a stocker if it's not locked.

Aug 15, 2002 | 08:43 AM

Paul F

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From: Baton Rouge

Re: TC 's and speedo readings

Mert the speed sensor is on the output shaft of the tranny so there is no way the TC could be causing the problem. I know that my HPP III would not correct the speedo for 3.42s in my wife's car. We set it with LS1 edit and it was perfect, according to the dyno.

Aug 15, 2002 | 08:58 AM

Patrick G

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From: Victoria, TX

Re: TC 's and speedo readings

The speedo reads off of the speed sensor in the tailshaft of the transmission. If you are getting speedo skip, it's not because of the converter, but it's probably because the tranmission wiring harness connector or speed sensor contector has been disturbed when you did the converter swap.

The speed sensor just reads the rotation of the output shaft. It's all electronic. Check all conections. Spray them with electrical cleaner. If it continues, you may want to look into replacing the speed sensor. They're pretty cheap.

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Aug 16, 2002 | 10:13 AM

Ragtop 99

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From: Bethesda, MD

Re: TC 's and speedo readings

<blockquote>quote:<hr /> i ve do some 4500+rpm s on the 4 th and speedometer still shows 110-115 mph quite funny.. <hr /></blockquote>Was the converter locked?...it won't be locked if your foot is deep in the throttle. If is not locked, you are seeing the shift extension of your converter. Take ATAP and measure the converter output shaft speed. My guess is that it will be lower than 4500.

Aug 16, 2002 | 08:50 PM

LiquidSnake

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From: Istanbul

Re: TC 's and speedo readings

Paul @ Thunder

aul thank you for the info <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
I ll buy a seperate pcm from Valvegod and i ll send it to you.I think it ll be perfect.Also i ll test it for you on the 170+ mph <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
pekkaz : I dont understand 2 <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> . We all faced this problems right after the convertor swap .
Patrick G:Thank you for the good opinions and tips.A friend of mine haves a GM Tech II machine and he checked everythink + i put the stock convertor back on the car and speedometer shows the correct readings <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> btw : i hate my the car with the stock convertor i put the Vig back in for a few days later.
Ragtop 99 : Hmmm also thanks to you 2 for the nice tip.I ll check that asap! Btw you can bet that i floor it <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> (We are checking the top speeds with a radar gun)

Aug 17, 2002 | 01:55 PM

pekkaz

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Re: TC 's and speedo readings

BTW, do you guys have european spec cars ?
I just wonder how different the programming/PCM would be. According to the advertising european spec cars have 288hp... which may just be a number though.

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Aug 17, 2002 | 07:10 PM

LiquidSnake

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From: Istanbul

Re: TC 's and speedo readings

<blockquote>quote:<hr />Originally posted by pekkaz:
BTW, do you guys have european spec cars ?
I just wonder how different the programming/PCM would be. According to the advertising european spec cars have 288hp... which may just be a number though.<hr /></blockquote>%80 or more percent of the cars are direktly imported from USA.The rest is from Europa.But nobody wants to buy a Euro spec F-Body they are more than ugly! Vettes rear bumpers are ugly but you must seed the Camaro <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
My car is not a Euro spec car but i understand your point.
Engines are the same but the exhaust system is a little bit different same think goes for the pollution control .But everythink works well(Hypertech,LS1 Edit...)
(In the Switzerland and some other Euro countyrs they want different oem parts and mods for an example : You cant buy a Viper with stock side pipes! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> )