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Bucking/hesitation issue, fine at wot?

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Old 10-13-11, 08:10 PM
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TX Bucking/hesitation issue, fine at wot?

Ok, just got my car running, the issue is with light throttle loads, it will jerk extremely violently in any gear. If I go wot, absolutely no bucking or anything, I'm really lost as to what could be going on. Car is an s4 t2 with a jdm s5 engine retaining s4 electronics. No emissions stuff on the car.
Old 10-13-11, 08:34 PM
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My friend is having this exact same thing happen on his s4 t2 with a fresh oem rebuild.
Old 10-13-11, 08:36 PM
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Originally Posted by MrGoodnight
My friend is having this exact same thing happen on his s4 t2 with a fresh oem rebuild.
Did he fix it? I'm lost.
Old 10-13-11, 09:14 PM
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TX

http://www.youtube.com/watch?v=hnNcVJ8k3zA
here is a video I made, it's me just lightly pressing the gas. Tps does exactly 1k ohm at idle/rest and ramps up smoothly to like 4.3k ohms.
Old 10-13-11, 09:24 PM
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my car is doing the EXACT same thing and i dont know how to fix it

I'm trying a new fuel filter tomorrow + injector cleaner.

Plugs and wires are brand new
Old 10-13-11, 09:28 PM
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Car is fast as **** at wot but almost everywhere else it's completely useless. It just stutters and does weird ****.
Old 10-13-11, 10:09 PM
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No vacuum leaks? Any other mods??

My car does this... But only when it is not warmed up before driving.
Old 10-13-11, 10:23 PM
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suck see another tps,, these mid throttle hunts are often caused by open circuit or shorts within the tps wiper movement
Old 10-13-11, 11:18 PM
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TPS had no dead spots/shorts in its travel. I made sure to check it slowly. Oddly enough I don't have a tps set screw, I'm really confused about that. No vacuum leaks that I know of, the only mod is a downpipe. Rest is bone stock.
Old 10-14-11, 12:13 AM
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Then how did you set the TPS?
Old 10-14-11, 12:17 AM
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It originally was pulling 1.6k at idle, the little round ramp the tps rides on was slightly bent to one side, I just bent it back and it pulled right at 1k. Does this make any sense? Sorry for the crappy terminology.
Old 10-14-11, 12:29 AM
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Does this sound like a proper way to set the TPS?
Old 10-14-11, 12:39 AM
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Oh of course not. I'm just confused as hell that there is no set screw. I was just straightening something that was bent that happened to bring it back into the resistance range it should be in. This is my first rotary, I've never had anything with this style of tps, it's weird to me.
Old 10-14-11, 12:43 AM
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When the throttle linkage pulls completely off of the TPS it occurs around 3000 rpm. Do you think it's a coincidence that you have no problem after the linkage releases from the TPS but you do have a problem before so. Most bucking, hesitation issues which occur when accelerating is due to a faulty/misadjusted TPS. You need the screw.
Old 10-14-11, 07:40 AM
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Having the same issue with my S5 NA. Mine isn't quite as bad but there is a fluctuation in the rpms at light throttle. I suspect the tps even though it is set properly I found no dead spots.
Old 10-14-11, 09:36 AM
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Does this look like everything is there or not?
Old 10-14-11, 09:48 AM
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/\ you have an s5 TB,, someone has pulled the narrow TPS,, and your running on the wide range
( and that is the issue ! )
you do have the adjust screw,, but it has minimal/nil effect on setting the wide range sender
( which is for the eomp control inputs )

i would suggest moving that TPS and its clip onto the other bracket space so it runs on the narrow cam
( and thus is fully open much earlier )
Old 10-14-11, 09:51 AM
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Great, I've got two s5 throttle bodies. Are all s4 throttle bodies the same or do they vary between na/t2?
Old 10-15-11, 12:29 AM
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I just went ahead and bought an s4 t2 throttle body and tps, I think this will solve my problems.
Old 10-17-11, 10:21 PM
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Hey, you have 2 s5 throttle bodies with matching tps? I need a set of working tps for an s5, which consists of 2 tps (1 narrow and 1 wide).
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