I did the T56 swap a while ago and love it! I have had an idle problem though which really didn't show up till after the swap. Here's the thing, I didn't hook up my speedo yet because I don't feel like paying for the calibration box yet. I have been searching through EVERYTHING in the engine compartment to fix the idle problem except for a custom chip, which I don't think should be neccessary to get it to idle consistently.

I saw this in the tech section -

"If you car has an electronic speed sensor, make sure you find an electronic speed sensor from a V6 tranny & install it in your "new" tranny or you will stall at every stop being the car will have to "hunt" for an idle being it does not know what speed the car is at."

Is the lack of a speedometer causing my eratic idle? Thanks for any help!

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88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

 

I did the swap a couple months ago and I havn't had an idle problem yet. I have an electronic speedo and it wasn't hooked up for about the first week. Now I have the Cyberdyne calibration box and it works great.

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I finished the samw swap in my 85 Camaro, but my engine was carbuerated. I installed aftermarket gauges(an electronic Autometer Speedo) so I used the sender that came in the T56. I think I need to buy the Cyberdyne box so my cruise control will work. I do know that the VSS Buffer sends a speed signal to the ECM. I don't know how the comnputer would act if it didn't receive a signal at all. If I recall the sender in the T56 is around 256,000 pulses per mile where the one in the 700R4 was around 4000 pulses per mile.
I would try hooking up the speedo sender and seeing if that helps. You could still disconnect the speedo, just after the buffer. Hopefully someone else knows an answer for sure.

HTH,
Dave

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Better to keep one's mouth closed and be thought a fool, than to open
it and remove all doubt.(Mark Twain)
Homepage of VTCamaro/Arntzman
Need Wiring Diagrams??
darntz@vt.edu

 

Where is the buffer located?

------------------
88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

 

Yes the article is correct. The computer has no idea what speed youre at, so its trying to judge based on the other inputs like throttle position and MAP. It cant quite figure it out, so it'll have a crappy idle and you'll get bad gas mileage.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

What confuses me is that it idles GREAT when I start it up, even when it's already warm from previously running it. Then, when I move the car maybe a quarter of a mile it starts to go crazy. But how does it know that the car has moved to even look for a speed? Nothing is hooked to the trans. I'm just wondering how it can idle great forever if I don't move the car, but then get screwed up when i move it. Is there some other sensor somewhere that knows the wheels have moved or is it maybe the rpm changes?

------------------
88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula