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Jumpings when I release the gas in a shift

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Old 07-03-08, 12:13 AM
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Jumpings when I release the gas in a shift

what could be wrong in my car, when im in second shift for example and i brake without putting on neutro the shift, my car starts to make like a little jumpings ... like if you were pressing and releasing the gas very quick and well i press the gas again it goes... obviously is not happening in very lows rpm (I know how to drive) it happens in 2000 rpm and less...

pd: I hope you understand what im trying to say, im not that good in english,if you dont ask me what you dont get,
thanx
Old 07-03-08, 01:39 AM
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The car bucks anywhere beneath 2000rpm?

It's an RX-7 thing, all of mine have done it; it's most likely your mounts.
Old 07-03-08, 02:02 AM
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Could be anything from a bad fuel filter to bad ground's or like dude above said loose or broken engine mount's.
Old 07-03-08, 03:22 AM
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Could be...TPS adjustment, throttle cable needs to be oiled, dashpot movement rough, anti-afterburn valve not working or air pump not working. It could be a lot of things, but if I had to pick one, I'd start with setting the TPS to 1 volt at warm idle.
Old 07-03-08, 07:17 AM
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One of the few functions of the TPS is to cut fuel when you let off the throttle. IF you let off completly it turns off both fuel injectors. IF you let off just a tash it'll cut just the front or just the rear rotor (for driveability reasons), I forget right now.

So this is one of the few times where you'd go to the FSM and ohm out the TPS thru its travel to see if it has any *opens* in the TPS. Best to use a analog meter to do that, but a digital will work.

'But when your through, and the engine is hot, do what was recommended above, set the TPS output to one volt at idle. That's if the TPS is any good at all.
Old 07-03-08, 10:00 AM
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oh ok thanks, could be the TPS cause my last TPS was bad and i just change it, but i just disconnected the other one and connect this one, i felt the car better bad could be is not set as you told me

DMM 1 ohms (fully warmed) disconnected, then when i connect it again and cranck the car it should be 1000ohms (without accelerating) till 5000ohms ( wide open throttle ) right??

im gonna do that.... maybe i should check the voltage wire that goes to the TPS i dont want my TPS gone bad again
Old 07-03-08, 12:32 PM
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If your going to check out the TPS to see if it's good or bad, you NEED to download the FUEL AND EMISSIONS section of the series five FSM and see which pins you need to be on when your ohming out the TPS thru its travel.

If the engine is fully hot, the output wire on the TPS connector will read approx one volt dc. It's the green/red wire on the harness side of the connector.That affirms the TPS is set right. It does NOT verify that the TPS does/does not have a *open* when the TPS plunger is moved from idle to full extension of the TPS's plunger.

Some jpgs out of the FSM for series five attached. The last one is the values of the TPS output, both narrow and full range, for a properly set TPS (engine hot when values are read either at the ECU or at the TPS connector).
Attached Thumbnails Jumpings when I release the gas in a shift-series-five-tps.jpg   Jumpings when I release the gas in a shift-seriesfivetpstwo.jpg   Jumpings when I release the gas in a shift-seriesfivetpsoutput.jpg  

Last edited by HAILERS; 07-03-08 at 12:54 PM.
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