Think my TPS died...need confirmation

Squeaky back brake? Hard to control at 30mph/40kph?
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Random00
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Think my TPS died...need confirmation

Post by Random00 » Wed Mar 08, 2017 5:06 am

I don't have access to a ECU cable. (2012 SM-T ABS)
Symptoms. Engine power dies suddenly like a light switch, then returns. Usually happens at roughly 5500 rpm, but sometimes lower, sometimes higher. If you pull in the clutch, engine idles normally...it doesn't die, it just idles. No FI light. When testing, in Neutral with side stand down or up, there's a "stutter" at 5500 rpm. If you rev quickly you can get past it. If you rev slowly, it "hangs" at that rpm and the engine coughs and sputters, and eventually goes up to 6000 rpm and revs freely. The problem "usually" happens at 5500 rpm, but not always, sometimes 3500-4000, sometimes 7000, but mainly in the 5000-6000 rpm range. Again, no FI light and I don't have a ECU cable.pm

I've tried "resetting" the ECU with 15 minutes of idling, to no effect. Problem still happens. Problem happens most often when engine is warm/hot. Less so when cold.

I've "burped" the fuel system(opened fuel cap) , and the problem happens right after, so it's not a clogged vent pipe or vacuum in the fuel system. I'm on 71 miles on this tank, so I doubt it's bad gas, or it would have shown up long before now.

From everything I have read, it sounds like a bad TPS or bad wiring going to TPS. It doesn't appear to be fuel filter or fuel pump related, as I can get the engine to give good power above 7000 rpm.

Is there anything I've missed?

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nrvous
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Re: Think my TPS died...need confirmation

Post by nrvous » Wed Mar 08, 2017 12:45 pm

I had similar symptoms and it was a bad TPS http://youtu.be/G3XcJu_MdpE
Last edited by nrvous on Fri Sep 22, 2017 10:08 am, edited 1 time in total.

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Re: Think my TPS died...need confirmation

Post by jhalfhide » Wed Mar 08, 2017 12:52 pm

Might be someone near you with a cable. Where are you located?


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Re: Think my TPS died...need confirmation

Post by nrvous » Wed Mar 08, 2017 1:13 pm

jhalfhide wrote:Might be someone near you with a cable. Where are you located?


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I had TuneECU connected and there were no errors visible so it might not help.

Random00
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Re: Think my TPS died...need confirmation

Post by Random00 » Wed Mar 08, 2017 2:01 pm

jhalfhide wrote:Might be someone near you with a cable. Where are you located?
Los Angeles (Torrance).

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Re: Think my TPS died...need confirmation

Post by Random00 » Wed Mar 08, 2017 7:02 pm

After sleeping on it, I'm actually thinking the problem isn't the TPS, but is spark related. It would explain why the problem appears to be load based (the harder you accelerate, the more likely it happens), the sudden acceleration surge "after", and the backfire's out of the exhaust "after" it happens. If it was TPS, it would cut fuel AND spark. Since I'm getting an acceleration surge and backfire after, I'm thinking I've got a dodgy plug/plug wire/something ignition related.

I'll be doing a teardown/examination this evening, and testing components as I go.

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