ep3 stutter/bogging

[dross123]

Hi guys, just bought an ep3 and it has a few problems, when slowing to a junction revs drop below 500 and it almost stalls, it has never actually stalled yet though, i should say at this point it has a decat and a aem induction kit.More worrying though is it sometimes hesitates and holds back when trying to accelerate and yesterday when in 4th at about 30mph at wouldnt accelerate at all, felt like it was going to conk out as anything above constant throttle it actually slowed down, changed to 3rd still wouldnt accelerate and then changed to 2nd and it cleared its throat and off it went, eml is on and the only codes are o2 sensor code which has now been joined by a catalyst efficiency code, is it the decat causing these issues?thanks.

 

[Chris.]

Could be a whole host of issues. Bogging down could be heatsoak if it's the indicution kit that sits in the engine bay.

You really shouldn't be running a decat on these cars without having it mapped, it's a narrowband O2 sensor and the ECU won't be able to adjust fueling correctly.

I'd start by replacing the decat with a proper cat, reset the ECU and see if you clear the fault code for the O2 sensor. If not, get a new one from Honda only, do not buy cheap or you'll buy twice.

If you're then still having issues replace the induction kit with a decent closed box system such as OEM or Mugen.

You may also have a dirty idle control valve or even a stretched timing chain.

 

[Loxy]

Search on the forum for cleaning IACV or idle control valve.

Secondly check your throttle cable for slack.

Decat won't be helping and as the EML is on, it is likely to be in limp mode. If the car isn't mapped to the decat, take it off.

EDIT: Beaten to it by Chris. :lol:

 

[dross123]

Ok, will have to weld a new flange onto the cat that came with it as its gone, see where i am then.

 

[dross123]

Seems to be doing this on hot starts where the car has been sitting less than an hour, did it today again and when i put my foot down more just missfired for about ten seconds then suddenly took of and then i would have to lift again as i was in traffic, then it was back to the same.Once i got out of town and could give it some revs it was fine, real pig to drive in traffic when its like this.Have calipers to measure the cat pipe to get another flange for it.

 

[dross123]

Forget that last post as it is now doing it even from cold.

 

[dross123]

Is there much chance of this being a stretched chain as sometimes i drive it and its fine then the next time its bad from the getgo, would have thought if the timing was off it would be bad all the time?

 

[Lewisgame]

You should only have a catalyst inefficient fault after a decat. Any other faults will need to be diagnosed and fixed.
Running a decat shouldn't give any running issues. Not recommended though as how the engine management works it could cause some lean running on wide open throttle. Part throttle no problem.
Low engine revs, stalling or engine 'hunting' when at idle is a sign of the idle air control valve not working correctly. Generally they stick and need removing and cleaning. This can cause further running issues that you maybe experiencing.
Unlikely to be a stretched chain. That would give you a constant running issue and not intermittent.


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[dross123]

Just realised that its a code for the front lambda not the rear, the person that sold me the car told me the eml was on due to the decat so i wasnt paying much attention to it but the code is for the pre cat lambda not the post, could this be the issue?

 

[mike.h]

Without input from the pre-cat lambda the engine has no programmed way of knowing what the oxygen content of the exhaust stream is, fuel delivery will be a mess

 

[dross123]

I have ordered a ntk one, also ordered a lambda cheater for the rear one until i get the cat fixed, will see how it is then, thanks.

 

[Chris.]

NTK? Do you mean NGK? You should only get one via Honda, anything else will likely fail in a matter of months.

 

[dross123]

Ntk and ngk are the same company and are oem for some hondas i am led to belive, cant afford nearly £200 for a lambda from honda.

 

[Chris.]

Ntk are an arm of ngk i think and are oem for some hondas i am led to belive, cant afford nearly £200 for a lambda from honda.

You may be lucky but most people that buy the cheaper ones end up replacing them within months as they end up failing. I did say this in my first reply.

 

[dross123]

Well it would seem that it was just the pre cat lambda, arrived today and fitted straight away and its perfect now, god its a good car when its running right.Cant believe how bad it was running with this fault, never seen a faulty lambda make a car run so rough, the last few days it has been bad all the time.It was actually becoming difficult to drive it was so bad, just shows how much these cars rely on the information from the lambda to adjust fueling.