S2K@PR

Hi guys,

Sorry for the lack of updates but after installing the Boost Solenoid everything was set and ready to dyno the car, car was running great. The day after that, the car began having misfires issues. Until this day I haven't found the problem, so this has kept me from going to another dyno session.

The problem happens when you go full throttle and when it reaches 6k-7k rpms it misfires/bogs and the rpms wont continue up. A/F is 10.4 at then when the problem happens, the A/F goes to 11-12.This is happening at 15-16psi... If i go medium throttle the problem doesn't present itself, also doesn't happen when boosting 10psi-11psi.

Car has 43k miles (AP2 DBW)

We have checked/done:
-Changed to another set of new NGK Iridium 8's (gap to .025, previous set we're .030ish)
-Installed a relay connection for the Fuel Pump
-Done dozens of datalogs

Things we're suspecting:
-ID1000 (they we're installed in the car since 2012)
-Plug&play injector plug connectors (they we're installed in the car since 2012)
-Fuel Pump malfunction
-Convert Factory Returnless fuel system to a Return fuel system
-Bad Map Sensor? Got a P1129 (some weeks ago) never came back again. Map sensor is a SOS 4bar

Any other ideas?

tx2K

start with the PNP injector clips and go from there.

bobbyrandolph440

Shouldn't u got to copper V power?

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camuman

Gap them lower. If it ain't the pnp clips which I bet not gap down into the high teens. Should be fine then.

indi00

My stock coils after 70K miles, 10yrs+ blew after a couple months of boost. New RSX coils solved the problem.

cmn

I had similar problems last year, and found out it was dirt in the injectors. Got them professionally cleaned, and got the car re-tuned and it was all golden again. (Re-tuning was not because of the injectors.)
With the clogged injectors I could get the car to higher rpms if I was gentle on the throttle, but if I was a little too hard on the throttle the car just cut really hard at around 6000 rpm. Like it hit a wall...

RAIN H8R

Another thing to try is to reduce the ignition timing to almost nothing. Then while tuning you gradually increase it.

On my car with the sos tc kit i could run hardly any ignition timing without misfiring.

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Ptuning

I second this. Gap the plugs down to 0.018" to eliminate the possibility of a spark misfire first. You can always slowly re-gap them back up to a higher gap once you've nailed down the problem. I don't see you being able to consistently run more than a 0.022 gap on the "average" set of stock coils without misfires at that boost level. It is also unlikely that you'll see a power difference running a larger gap at that power level anyways. Honda makes a lot of great products, but unfortunately, S2000 ignition coils are not one of them. Good luck!

- Toan

S2K@PR

Thanks for the responses.

Modified gap to 0.018 and the problem is still there. Later today, a friend will lend me his coil plugs from his working stock '07 s2000 with 58k miles.

Does anyone knows what are the limitations on the returnless fuel system for 06-09?

blue monster

I was just going to say the same thing. I had a very similar problem with misfire at the top end. Replaced all four coils (8 years old & 51k miles) job done