I went through all the wiring and everything is good the plugs are on the right sensors and when I rented the track I took the tb off of my street hatch with the map and tps from that car and put It on the race car and it still messed up. So I wouldn't think it was the map or the tps sensor. I have searched for an answer looking at each sensor and can't find anything as to what is happeneing. I'm going to get a video on YouTube so I can put a like to it. Then u can hear what the car does. It probably won't explain why but who knows at this point. We have thought about putting the car on a dyno and having the problem happen while it's on the dyno and see if the guys at the shop can pinpoint what it is. But a dyno run around me is $450 plus then whatever labor ad parts they have to fix. Don't really what to spend it if I don't have too.

 

When you checked the wiring for the TPS, I assume that you checked for continuity from the TPS connector to the ECU. The thing is, that maybe one of the wires is only hanging on by a strand or two, and then opens up intermittently out on track - I read one thread where someone found the wire only hanging on by a strand or two. Did you move the wiring and TPS connector to see if the readings changed? I also remember reading about someone hooking up some extra wiring from the TPS connector directly to the ECU (in parallel/in addition with the existing wiring, I believe). I also did a search for 'tps wire' and the threads below look somewhat interesting. I'm not positive that the TPS/TPS wire is the issue, but the TPS signal fluttering when the problem happened makes it seem like an issue to me.

Have you had the motor and wire harness for quite a while, and just recently started having issues? I hope you figure it out. Good luck!! - Jim

https://honda-tech.com/forums/tech-misc-15/new-throttle-body-tps-help-2724743/

https://honda-tech.com/forums/tech-misc-15/help-w-tps-sensor-how-remove-1467499/

https://honda-tech.com/forums/tech-misc-15/car-loses-power-track-2426606/

https://honda-tech.com/forums/tech-misc-15/swapping-tps-wires-eliminates-1-8th-throttle-stutter-1142266/

https://honda-tech.com/forums/tech-misc-15/car-goes-baaaaaaaaaaa-ba-ba-ab-ab-baba-ba-ba-1-8-throttle-1135825/

https://honda-tech.com/forums/tech-misc-15/help-tps-voltage-issue-875367/

https://honda-tech.com/forums/tech-misc-15/dumb-tps-question-844198/

 

I've had the same wiring harness and ecu for 3 years in the same racecar. At the end of last year we put this new motor in and have had problems the whole year this season. I'll double check the tps and look at the wires again. I'm also going to check out those thread thanks for the help. This is my dad's car and I hate seeing him lead a race and the car acts up and he gets last because of it.

 

Posting in the Hondata forum makes good sense. Maybe they'll be able to help. I took a look, andhttps://www.hondata.com/forum/viewforum.php?f=19&sid=190f2757f9f1ac94ec32c0b2072 145c6 seems like the correct forum. I know that you also tried another ECU (P28), so even if their was some limit set in the S300, then the other ECU should have still worked, but it doesn't hurt to post the question in that forum. Having the car run OK with the engine coolant sensor unplugged still seems interesting. - Jim

 

I just tested the tps and I'm getting .42v closed and fully open I'm getting 4.36v. The volts increase steady and no jumping around. I wiggled the whole harness while test and it didn't change any thing. Could the vss cause this that's the only thing I haven't changed

 

As far as I understand it, the VTEC engagement looks at quite a few things with the VSS reading being one of them. One time at a track weekend, my speedometer was bouncing all over the place when I was driving thru the pit area, and when I got out on track, then VTEC wouldn't work periodically. I didn't have a spare VSS sensor with me for that weekend, but I think that I ended up going into the S300 Smanager, and changing the minimum speed for VTEC engagement from whatever it was (say 20mph) to 0 mph, so even if the VSS reading was fluctuating all over the place, then VTEC would still engage. When I got back home, the race shop that I go to found tat my VSS unit was actually OK, but the connector on top of it had a loose connection. I believe to test it, then just pulled the VSS unit, and with it connected, then spun it (by hand or drill?) and looked at the reading, and found the loose/bad connection. I'm not sure if that connection usually has a problem with corrosion or not.

I'm not sure if a bad VSS unit or reading would cause a misfire, but I believe that it would have an effect on the VTEC engagement depending on the minimum speed setting you have for VTEC in the S300 Smanager. - Jim

 

I replaced the vss and changed all the engine grounds. Tightened down the fast idle valve and car run good but it still messes up after couple laps. This is driving us crazy. We have an appointment at the tuning shop on Tuesday. We are going to take it down and put it on a dyno. Hopefully we can figure this out.

 

Did you figure out the problem??? I hope so!!

I was taking a look around, and reply #12 in the thread https://honda-tech.com/forums/acura-...hamber-475582/ is interesting in the black breather box causing a hesitation issue on track. Not sure if it applies in your case, but was interesting to see that info. Do you have extra breathers/vents on the valve cover, or are just using the stock system? On my car (2000 Civic hatch with JDM ITR - full race car - track only), I have extra breather tubes to the front of the valve cover, but was having some smoking issues on long left turns, and it turned out that there was a vacuum line from the back of the valve cover to the intake, so after that was capped off, that eliminated the smoking issue. I never had any hesitation from that though - just smoke during long left curves. - Jim

 

Please update. I am having the same issue. bogs right at 5800-6000rpms on load. I can blow thru it and rev to 8500 but if I keep it steady there, it misfires. track car use as well.

 

that's peak torque area. probably spark blowout. tighten up the plug gap a little, or get a stronger ignition system.
or it could just be a crap tune

 

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