S2000 Under The Hood S2000 Technical and Mechanical discussions.

Running in open loop?

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Old Mar 6, 2009 | 07:55 PM
  #1  
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Default Running in open loop?

Sorry for long entry...trying to be as detailed as possible..

Hi all, I've been having the infamous bucking/hesistation/kangeroo problems..theres alot of threads out there about it..and I believe I pretty much read every single one.. Anyways...

I'm experiencing problems and it sounds pretty similar to the one on these threads..Heres a quick list of things that was happening..

1st..Accelerating from 1st gear..sometime it would feel as if you just ran into a wall..kinda like when u release the clutch and not enough gas...when you are learning to drive a stick shift....intermittent problem

2nd..When cruising with a steady foot on the pedal..it would feel like you would loose some power as if you released the gas pedal then go back to normal..even tho your foot is still steady on the pedal....intermittent problem

3rd...When accelerating and pressing the throttle more then half way feels like it starts to not throttle anymore..for example...normally you would press the throttle and it would go from 0%-100% instead, it goes 0%-50%-40% or something of that matter but after a certain point in pedal travel about 50% it is less throttle and flattens out for the rest of the travel....consistant problem

4th...When coming to a stop or shifting to neutral...before it would drop to about 700-1.2k and go back to normal idle around 850-1000, now it drops to about 200-500 and sometimes stalls out..it struggles alot at about 200 trying to fix itself and sometimes it does..and sometimes it doesnt and just dies...was intermittent..now always happening

Troubleshooting I have done:

1. Map Whack : Removed map sensor, Gave it a couple of not so soft taps, reconnect the sensors multiple times to try and remove corrosion on contacts, ziptie the connector, Clean the passage way on the TB and cleaned IACV.

2. Test TPS sensor : I think mines is broken..I probed pins 1 and 3 and got a voltage reading of .45v and when I open the throttle plate the voltage did not change..pretty weird..same for resistance I cant remember the readings I had on the resistance...I have ordered a new throttle body which will replace the TPS and MAP sensor..I will see what happens after I swap those out.

3. Removed backup ECU fuse : Just wanted to try this and this is how I am driving the vehicle now, It runs and idles very good now. With the fuse in..it just drives very bad..need to figure it out..also with the fuse in..while the car is struggling to idle the exhaust smells VERY VERY bad like fuel..perhaps running very very rich?

Now I was wondering why is the car not having idle problems without the backup ECU fuse...as opposed to having the fuse in...

Couple of questions:
1. Is this considered OPEN Loop to drive without the back up ECU fuse?
2. Does this bypass sensors? If so, Which ones?
3. Any ideas what my problems might be?


Car specs:
2002
43k miles
New plugs (5k Miles ago at Honda dealer)
AEMv2 Intake (Filter was cleaned about 2k Miles ago)
Fujitsubo Exhaust

And that is pretty much it...

Any help will be greatly appreciated..Thanks..
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Old Mar 6, 2009 | 08:22 PM
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You probably need to replace the MAP entirely.

I doubt it is your tps...they main symptom I've seen from a bad tps is that the car simply won't rev past 3-4k rpm.
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Old Mar 6, 2009 | 08:30 PM
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So all those symptoms could be caused by a bad MAP sensor?
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Old Mar 7, 2009 | 06:34 AM
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Yeah...the MAP tells the ecu how much air is coming into the engine.

But I see you've already ordered a new TB...see if that fixes the problems. If not, I would swap the MAP next.
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Old Mar 7, 2009 | 07:14 PM
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REPLACED THROTTLE BODY WHICH REPLACES TPS AND MAP SENSOR PROBLEM IS SOLVED..THANKS TO s2kaddicted for the throttle body and Xviper for helping me in the background !! GREATLY APPRECIATED!!
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Old Mar 7, 2009 | 11:55 PM
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thank you for updating thread, its good for people searching for answers in the future.
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