1998 HONDA CIVIC TRANSMISSION FLARE

  • Tiny
  • ihbigred
  • Member

Interesting that "advancing" the sensor caused the shifting flare to dissolve mostly. Makes me believe even more that it's a PCM issue being that we have been able to resolve the flare by "tricking" the computer of what really is occuring.

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Monday, September 10th, 2012 AT 6:58 PM
  • Tiny
  • rberq
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Well I agree it is a PCM issue, but what are the chances of getting THAT fixed, since apparently these computers are not reflashable? I program computers for a living, and I'd love to get my hands on the code for this computer, but again what are the chances? My car acted as if there were two separate computer events: one telling the transmission to disengage 2nd gear at about 2600 RPM, and the second telling it to engage 3rd at 3000 RPM, so the flare happened over the 400 RPM range from 2600 to 3000. Under harder but still moderate acceleration, the "disengage 2nd gear" event was delayed until 3000 RPM and there was no flare. So that gave the the idea (after several years!) To fake out the computer by tweaking the TPS to simulate harder acceleration. Strangely enough, it not only raised the RPM for "disengage 2nd" but seemed to lower the RPM for "engage 3rd". Bringing the two together made it all better.

I'm intrigued by the earlier poster who got good results by using a potentiometer to simulate lower resistance (higher coolant temperature) at the ECT sensor. A jumper between the two sensor leads, with the proper resistor, could (I think) change the resistance of the sensor circuit appropriately. Again, it's a way to fake out the computer, but it sounds like it could give cleaner results than the TPS adjustment. Guess I'll have to do some direct-current-physics research to find the proper resistor -- high school physics is pretty far behind me now, so I think it can be done but I don't remember the equations!

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Monday, September 10th, 2012 AT 11:19 PM
  • Tiny
  • rberq
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Oops, sorry ihbigred, I see the "earlier poster" with the potentiometer was you. I had only skimmed the thread and I missed the problem about cold starts with the potentiometer installed. According to my shop manual, 150 ohms represents a very hot engine, coolant at 212 degrees or higher. Also since the ECT sensor does not respond straight-line to coolant temp, my simple idea of a parallel resistor in the circuit probably would not work -- I still have to think that through. 1/R = 1/R1 + 1/R2.

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Tuesday, September 11th, 2012 AT 12:39 AM
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  • rivermikerat
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Resistance in a parallel circuit = (R1)(R2)/R1+R2

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Tuesday, September 11th, 2012 AT 2:05 AM
  • Tiny
  • ihbigred
  • Member

Rberq,

I'm glad someone else has gone to some steps to try and resolve this! Yes, sadly an in series or paralell resister would not resolve the problem due to cold starts, but! If someone was willing to do some circuitry they could create a cool little black box to change the resistance at operating temperature! I'm an engineer with some minor background in circuitry, but I am elbow deep in grease with my V10 automatic conversion to Cummins diesel w/ manual transmission : ) With this box someone could either post how to make it, or make some pocket change on the side. I got the same result seeing the engine was running "hot" by seeing the resistance to temperature curves for the cts sensors.

FourOur,

I went to the website and browsed a bit, but am not sure if you're suggesting we buy some diagnostic tools?

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Tuesday, September 11th, 2012 AT 11:37 AM
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  • KHLow2008
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FourOur is a spammer and he is history now.

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Wednesday, September 12th, 2012 AT 8:49 AM
  • Tiny
  • ihbigred
  • Member

It's sad that some people don't know how to make a good honest living.

Thanks for resolving that KHLow

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Wednesday, September 12th, 2012 AT 11:33 AM
  • Tiny
  • KHLow2008
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You're welcome.

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Wednesday, September 12th, 2012 AT 2:08 PM
  • Tiny
  • 427ZL1
  • Member

I have the same issue. Anyone consider a worn out transmission? Your trans is slipping due to wear. Even a Honda wears out.

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Wednesday, February 13th, 2013 AT 4:20 PM
  • Tiny
  • ihbigred
  • Member

Thanks for the input and I had considered that, but if you will read through the entire thread you will read that we were able to remove the problem flair in two ways: 1. Trick the car into thinking it is running warmer than actual and, 2. Changing the ecm to a vtec model and doing the "minime" conversion. I've never personally seen a transmission that was worn out act like this. Maybe you can shed some light on which component is worn?

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Wednesday, February 13th, 2013 AT 4:37 PM

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