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 :confused:

[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

[Devine]

I had a similar sounding problem and it turned out to be a fuel pressure problem, in my case a single clip had come undone in the fuel pump or something stupid like that. If you have some free time lift up your back seats and undo the lid to the fuel tank and just check that nothing in the fuel pump looks out of place. It does sound like the car isn't getting the right amount of fuel mixture so when you go to accelerate it doesn't quite kick like it should, this could be cos the the fuel isn't at the right pressure level.

In regards to the fuel filter I was of the understanding that DC5's don't have a separate fuel filter, it's all built into the fuel pump. Is that right? If so you would have to get a whole new fuel pump..

[furansu]

I'm more starting to think that my converter is clogged up because i've been doing some research and found that some videos in youtube has similar problem. I can feel that my speed increase normally but the rev goes up very slow (it can hardly reach 4500). Let's say i usually have a max speed of 90 km/hr in gear 2 at 6500 rpm ish, but this time maxed out at 90km/hr at 4500 ish. So the gear ratio somehow changes. If you're still wondering what my situation is, please look at this guy's video;

http://www.youtube.com/watch?v=YpW3bjtDTqU

I will definitely check on my fuel system if that doesn't work out. But for now i'm gonna look for another Highflow Cat converter and perhaps another muffler. I've got a HKS Silent Hi-Power exhaust which have a silencer at the top of the muffler. I'm suspecting that it creates a lot of additional backpressure to compensate for the low noise. Hence i will need get one that flows through easier.

I'll update you guys more!

[furansu]

Hey, i've just had my car checked at Autobahn in which they checked all the stuff including under load and idling. Same as Honda dealer, they couldn't find any fault with the car. Three of their mechanics had a good test run on the road and they believed it was running well. None of the error came up when the OBD2 was put in. Hence I'm stuck as to how i can fix this problem.

I've had this car for 3 years now since it was bare stock and i know how it performed back then. I've felt the improvements after heavy duty clutch and light flywheel. The car felt very responsive and revs up faster . I guess the mechanics wouldn't know that since they've only tested the car on it's current state.

The car feels sluggish and less responsive. It seems like it's not getting the right mixture. Do you think it's possible that it is the throttle position sensor?

Is there anyone in Perth that would like to bring their Honda Integra and compare with mine? Preferrably DC5. Thanks a lot guys.

[dc2r-0636]

Get ur cat replaced with just a test pipe as it would be cheaper then a high flow cat, if its bak to its old self afta using the test pipe buy a high flow cat to make it legal

[furansu]

Ok another update,

I plugged in my OBD2 scanner and used the data logger function to record the following while i'm driving;

1. Short Term Fuel Bank 1
2. Intake Manifold Pressure
3. Engine Speed
4. Absolute Throttle Position
5. Bank 1 Sensor 1

The fuel system 1 status was "Closed Control using Oxygen Sensor - Normal" for the warming up period of the car. I'm getting a mix reading between rich and lean fuel trim bank 1 while i'm driving out of my house. Then somehow when i'm out on the street , the fuel system 1 status becomes "Open loop control - Warmup" which i'm sure it's already warmed up. It then goes back to Closed loop - normal again.

When i floor the pedal up to 4300 rpm the fuel system 1 status become "Open Loop Control due to driving conditions" which apparently makes the Short term fuel trim bank 1 to 0%. It then goes back to Normal again after a while. Then it goes to Open loop control- warm up again....

All this doesn't make sense to me, shouldn't it be Closed loop all the time? Did the ECU detect something critical that resulted the fuel system to become "Open loop control due to driving condition"?

Appreciate your feedback guys

[gensport]

put simply, open loop is tuning without the O2's, and closed is with. when you go to a certain throttle position, say 90%, you go open loop and run from a WOT map. if the ecu is staying in open loop for more than a couple of seconds (assuming the car is fully warmed up) then you have an issue between the O2 senors and the coolant temp. It doesn't mean those sensors are faulty, but the way the ecu is reading is. test sensors, plugs harnesses and ecu. i had a pajero (yuk) the other day, sluggish hard to start warm, using fuel, with a flat spot. Owner had put new O2 sensors and coolant sensor. after checking it out, where the coolant temp wiiring went through a gang plug further along the harness..... as i stated earlier, a multimeter is your best friend.