Help! Car hesitates to accelerate

[furansu]

I have 2002 DC5 5 Speed Manual.

Car History:

I have replaced some parts with aftermarket parts. These are the modification i did at one same day.

Aftermarket header
Aftermarket catalytic converter
Aftermarket exhaust system

Aftermarket clutch and pressure plate
Aftermarket light flywheel

All done professionally by a qualified mechanic. The car went normal after the mods without any sign of problem.

6 months after the modification, I started to feel the car hesitating to accelerate, and the rpm goes up slower than usual. The V-tec doesnt activate because it's difficult to get up to 4500 rpm and above without making the engine work so hard.

The rpm seems to flutter/stutter its way up when i'm accelerating or press the accelerator while i'm driving. It seems to me that i have lost a lot of power.

After that the CEL came on and i checked it using my OBD2 Scanner. It shows P 1162 in the screen and it turns out that the primary oxygen sensor is buggered. I changed it with Denso oxygen sensor and resetted the ecu. The CEL never come again until now.

I also changed the spark plugs but it didn't help.

Initially i thought my car went into limp mode due to the rpm limitation (below 4500). However i was able to rev up to 6000rpm using first gear (which takes longer time than usual and a lot of engine noise) which indicates i'm not in limp mode.

The car is still hesitating to accelerate until now. I think the problem lies in the fuel system, whether the fuel pump is buggered or the fuel filter is clogged up and need replacement. The ecu could also be malfunctioning and give an bad signal to the pump.

What do you guys think i should check on

[fuzionz]

Is the eng idling fine? not missing or anything?
How did the spark plugs look when u pulled it out?
Does it accelerate normally in Neutral?
What brand catalytic converter is it? Could be blocked or melted.. Get a mate to rev it for you and see if the exhaust is flowing?

[trism]

What about when you free rev it? As in, in neutral.

Sounds like a fueling issue.

Also, has the fuel filter ever been changed?

If not, that'd be the first thing to change.

Im not sure if its an in tank or external filter, but if its in tank, id replace the fuel pump at the same time.

[TypeS]

So the CEL's back on?

Find out if its still P1162 or something else.

[gensport]

before changing anything, check the basics.. fuel pressure at the rail, put a timing light on it and record what it does when revved. These 2 things will point you in the right direction. CAS, and TPS will pull fault codes, but the fuel system won't. could be something as simple as old/lazy coil or leads. So check them all... a multimeter is your best friend. (and a fuel pressure gauge)

[nugget]

fyi

before when i drive, it would go from normal and then at abt 2500rpm, it would hesistate and stutter for like 200 rpm and then rev finely to redline

took out the injectors and got them cleaned..

engine revs smoothly now to redline. no more hesitation.

[gensport]

good stuff

[furansu]

Here's an update: I brought my car to Honda dealer in the morning to get it checked. I was supprised that the lady in the reception told me that the mechanics nor the head mechanic couldn't find any problem in my car. They said it was normal when idling and driving. I don't think that is fully true, i can definitely feel there is a loss of power especially when there is no V-tec kicking in. So i'm picking my car up tomorrow.

In the meantime i will do what you guys suggested. Catalytic could be melted or clogged but it's relatively new approx. 1 year. However i'll check with my bro to rev it in neutral. Usually when i rev it in neutral, the engine is very responsive especially with a change to light flywheel. But now there seems to be a 1/2 second delay.

The fuel filter hasn't been changed since i own the car back in 2009. I think it's most likely the culprit, if not it's good time to replace anyway.. I think gensport has made very good suggestion there, but i don't know how to check the leads/coil. Am i able to measure the fuel pressure from the OBDII scanner? If so, what is the normal fuel pressure for idling and WOT?

I always do my own service at home, but i always change the common ones. So some of the parts will be worn out already.

Cheers guys for the great advise, will update you more for sure.

[dc2r-0636]

Might not have a big enough spark.. Coilpacks might be on there way out bro

[gensport]

fuel pressure is different from model to model, usually around the 40psi mark, but find out what it should be. checking it at the fuel rail not only checks the pump and filter but also the pressure reg. a quick cheat is to use flat nose pliers close off the return line and give the eng a quick rev, if it responds very differently.... there the prob is... Leads should be MAX 20.000ohms per metre. on a honda i would expect to only have about 3 to 5 thousand ohms resistance. Coils are tricky. the easiest way is to take 1 lead off the plug and the injector plug (so you dont pump fuel into that cyl) start the eng and carefully hold the lead just off the rocker cover, or a bolt head. when you see the spark jumping, slowly move the lead away to make the spark jump further until it stops. (maybe a good pair of insulated pliers would be good for this one) if you can do this for about 2-3cm then the coil is ok. if its multi coil, repeat for every cyl. a poor coil will have trouble at 2-3mm
hope this helps

[gensport]

cats and blocked exhaust are easy to check.. a neutral rev is sometimes an indication, but there is no load on the eng. a drive up the road... see how it goes, then drop the pipes and the first flange... and sneak a drive up the road (if you can lol) will tell you immediatly.

also back on the fuel system, a flow rate should be checked as well. car (and aftermarket pump) manufactures give lt-per-min figures.. easy to check with a container with measurements.

[AK Type R]

spark leads are not common to go in a k series, id say check the spark plugs themselves and make sure that you lightly sand the black charcoal of the end of the plug before putting back in, also get your tps sensor checked and IAC valve these are the more common problems with these engines might help to pull the hole throttle body off and check each part individually .. if your not to much of a diy person yourself give Adrian from Toda a call and book in an appointment he will definately know your problem. His number is 0401 869 524 .. Hope that can help ... also give your throttle body a clean up using a generous amount of carby/efi cleaner and whilst the car is off spray some into the tb whilst the throttle is completely open then turn car on repeat process turn off and clean throttle body with a rag .. Note : your car wont start first go after cleaning your throttle body so keep trying to start , it will eventually kick over .. Cheers