EP3 K20 owners. All please reply, both standard and modified


Rich777 said:
If it's been modified then I'm thinking down the lines that it needs tuning now. I'd imagine the slightest change to the engines VE will cause problems as the engine has been tuned by the intake cam angle as well. I could be wrong though. See what "Vtec6000" thinks about this statement as he's the pro tuner on here. It may just be running lean in a certain area... From what I know they're quite sensitive engines (hence why they make so much POWAAAA).
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You could be right on the running lean. At part throttle at low rpm's they will want a good bit more fuel when you free up the breathing. If you could monitor 02 trims when it's occuring it may point this out.

Another thing is the VTC solenoid. I've experienced one to go bad on a K series. Basically it was under and overshooting the target cam angle, this kind of fluctuating made the power delivery very rough
 
OK now this might be completely off because my experience comes from my remote control cars, but the same thing happens when the engine on the RC car is running too rich. It only ever happens at low RPM because at higher RPM the engine is simply capable of burning the excess fuel efficiently enough (although the power is decreased). In any case the mechanics and basic principles are still the same. If air intake and exhaust have no effect then it probably is fuel management related - can be both ways, not enough fuel is just as bad as too much!
 
Ive got this issue with my ep its not magorly noticeable but can notice it regularly. Im a standard air box still catted no other mods other then a b pipe and a n1 style backbox. Hope this helps
 
Had the exact problem with my ej9 when first bought it 8 years ago. The d14 was completely stock. Then I thought I'd install a fuel pressure regulator beeing envy at a mate with a starlet seeing gains. Anyhow this solved the problem and didn't bring any gains for the history.
 
Have you tried buying a oem O2 sensor? I have read up that the cheap ones are rubbish, only enough to turn the management light off. Oem are dear but worth every penny.
 
ive seen this appear a lot...but only on cars with changed air filter and removed catalist...
 
Sounds very common.

For the record i have changed the O2 sensor for a brand new genuine Honda version.

This leads me to wonder if our setup is causing it to be magnified slightly as with a 2.5 cat back system you would loose slight low rpm torque. Perhaps our is disrupting the fueling but where the pipe work is between the 2 magnifying the hesitation.

OEM manifold and cat
Magnex B pipe 51mm dia
Spoon style back box 62mm dia

Maybe a 2.5" cat back would reduce the issue slightly??

Whats the thoughts on this?
 
t.schultz said:
If it is happening a lot more during cold start, I would look at the IACV.
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Its not so much cold start more once its between needle moving/off cold choke and normal operating temp.

Alway does it once its been parked up go in the shops it cools a little then will do it.

It does do it when hot but not as often or normally as violent
 
Small update

Check you throttle cable tension.

Ours was very slack and this is my theory behind the hesitation.

The car still coughs (probably due to mods) most EP3's do this. What makes it noticeable is the throttle tension. When slack and at light throttle this "cough" causes a slight rock in the engine which is a enough to shut the butterfly in the throttle body which momentarily cuts fuel and makes it hesitate.

Now when the throttle cable is tensioned this cough does not allow the throttle to shut and cause the stutter. Thus making it very hard to now notice. It's a massive improvement 90% I would say and does not bother me at all now. Once fully up to temp car is beautiful and actually feels slightly faster wot so maybe we where never at 100% throttle position with the slack cable.

Not sure why Honda make them set so slack? Apparently it's common... One theory is to prevent wot when running in....

Anyway my advice if you have this problem adjust your throttle cable before spending any money!!!
 
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ijwhiteman said:
Small update

Check you throttle cable tension.

Ours was very slack and this is my theory behind the hesitation.

The car still coughs (probably due to mods) most EP3's do this. What makes it noticeable is the throttle tension. When slack and at light throttle this "cough" causes a slight rock in the engine which is a enough to shut the butterfly in the throttle body which momentarily cuts fuel and makes it hesitate.

Now when the throttle cable is tensioned this cough does not allow the throttle to shut and cause the stutter. Thus making it very hard to now notice. It's a massive improvement 90% I would say and does not bother me at all now. Once fully up to temp car is beautiful and actually feels slightly faster wot so maybe we where never at 100% throttle position with the slack cable.

Not sure why Honda make them set so slack? Apparently it's common... One theory is to prevent wot when running in....

Anyway my advice if you have this problem adjust your throttle cable before spending any money!!!
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Thanks for this, I will check mine, as I have this exact problem all be it only under 2k... light throttle. Mine has done it from 2 days after owning it when it was stock and still now its lightly modded... I was hoping fitting kpro would solve it... I also notice when gearing down from high revs the revs do not drop evenly... they sort of stick for a split second... quite un nerving when going quickly, possibly could also be due to slack cable???
I'm about to fit RBC and 70mm t/b so hope all will be well once fitted and mapped.
 
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