Throttle position numbers Scan Gauge Bostig

[Microbusdeluxe]

I have the Bostig Zetec engine in my 1989 syncro with a Scan Gauge hooked up to it. Today reading the Scan Gauge owner's manual I noticed that I can set it up to read the Throttle Position measured as a percentage. So I did that and it shows an idle setting at 17% which I guess is ok. It idles smoothly right at 1000rpms.

The question is that entering onto the freeway with the pedal on the floor all I get is 67%. Doing internet due diligence I've learned that some cars don't show 100% at WOT, like I was expecting. So what do other Bostig people see on the Scan or Ultra Gauge. Thanks.
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'69 Squareback RIP
'65 21 window deluxe sold before the price spike, damn it.
'70 rhd bay now a taxi in South Sudan
'81 Westy sold
'89 hightop Westy Joker syncro 16" now with Bostig!

[uberaudi]

Can't say much for a Bostig, but I had the same question regarding my ABA TPS, which happens to max out at 76%. I was thinking of course, that's why my extra swap power is limited, but unfortunately it seemed to be on par with other ABA throttle bodies out there. Why they're not all calibrated for 100% is a bit misleading, lol.
At one point early in the swap I lost almost all power untill I realized that my TPS was maxing at 13%, which was easy to diagnose as a loosened throttle cable.
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'84 Adventurewagen 1Z TDI, '08 Audi Avant Quattro 6spd BHW TDI

[Microbusdeluxe]

Answering my own question. I learned that the Scan Gauge reads out the throttle position even when the engine is not running. That makes figuring out if a cable adjustment is really opening it up a heck of lot easier and quieter for the neighbors.

Fooling around with the linkage by hand it pegs out at 92% with the butterfly vertical so that's WOT. Adjusting the linkage at the intake I was able to go from 67% to 82% while maintaining my 1050 RPM idle. Trying to adjust it under the pedal didn't improve the situation; to get a higher number while flooring it meant the idle was in the 2500 RPM range, no bueno.

Took it for a ride and noticed a definite increase in power, zoom, zoom.
_________________
'69 Squareback RIP
'65 21 window deluxe sold before the price spike, damn it.
'70 rhd bay now a taxi in South Sudan
'81 Westy sold
'89 hightop Westy Joker syncro 16" now with Bostig!

[Silverghost500]

Could the extra percentage from 82% be found with a new throttle cable? Perhaps the one you have has stretched some?
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1986 Volkswagen Vanagon Westfalia "Von Westy"
Honda K24A conversion
3-Speed Automatic

Von Westy YouTube Channel
https://www.youtube.com/channel/UCbhyZYxJEQrUuLnMbLleeIA

[Pchill2]

Once you've confirmed that you are able to achieve WOT when the pedal is all the way down, and you confirm that when you remove your foot from the pedal, the throttle body fully closes, you can perform an idle relearn.

The scangauge will probably still show the offset percentages for TPS after the relearn has been performed but at least your ECU will have the voltage scalar for correct fueling.
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87 Syncro Westy
Honda K24 swap

[Microbusdeluxe]

Thanks for the tips. It is possible the cable has stretched. As far as the butterfly closing, that's the problem. I can't get true WOT and the butterfly closing up nice. It's one or the other.
_________________
'69 Squareback RIP
'65 21 window deluxe sold before the price spike, damn it.
'70 rhd bay now a taxi in South Sudan
'81 Westy sold
'89 hightop Westy Joker syncro 16" now with Bostig!

[Pchill2]

If your throttle cable has stretched, you should be able to adjust it back to spec either under the pedal or at the throttle cable bracket at the throttle body.

If that is not working for you, it might be worthwhile to confirm you have the correct throttle body that Bostig spec's out for their swaps.

If your throttle body pulley is too large in circumference, you wont get the correct angular rotation for a given linear cable travel.
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87 Syncro Westy
Honda K24 swap