I have an eg si with a d16z6. Sometimes, not everytime, when my car is warmed up it feels sluggish and slow when I get on it. In the morning when I get on it, before the car warms up, and I know i shouldn't, it feels fast and haul ***. What could the problem be?

I've already ran lucas oil fuel injector cleaner. I know I have a valve cover leak and a distributor o-ring leak. I changed the oil last month with some mobil 1 10w30 syn. My car has 190,000 miles on it, would changing it to 10w40 help? thanks for reading guys

 

O and please don't say get a b-series. I will get one when my transporter job is stable, but for now I'm gonna stick to my d16z6

 

whats the tempature of daytime morning compared to your afternoon commute from work?

before the car warms up, your vehicle is running in a richer state. richer is mroe fuel. more fuel is more power.

 

I dont know, i live in cali so the weather is like mid to low 60's in the morning. In the afternoon when its warmed up, its around mid to high 70's. Do I need to seafoam my injectors??? or replace them?

 

What is the condition of the plugs, wires, distributor cap, and rotor? Have you checked whether the cat is clogged?

 

Plugs and wires look good, i know that the part where your screw the distributor cap on is cracked at each screw point, didnt check the rotor yet, will check when i get a chance

 

anyone else have any ideas?

 

So....it runs fine in Open Loop, but not in Closed Loop. That screams 02 sensor

You're welcome

 

open loop?? close loop?? i guess i will check the o2 sensor

 

Open loop is when the car warms up and idles without the assistance of the 02 sensor. The AFR (air : fuel ratio) is regulated by the computer. When the car reaches closed loop (when it is warmed up and the RPMs drop), the computer uses the 02 sensor to regulate the AFRs. If the 02 sensor is shitty, it is going to give odd AFRs causing the car to run like crap. Make sense?

 

disconnect it to confirm. obviouslly your cel will come on.

the vehicle should run better in your case.

 

I like simple but informative tests like this one. Just a thought. Not sure, but if the car doesn't run better, might the problem instead be caused by a bad ECU rather than a bad O2 sensor?

 

try checking your ignition timing. when my timing was off you could only notice it when the engine warmed up and goin past 3000rpm. thought it would be sluggish all the time but only did it when the engine was at normal temp

 

It's certainly possible, but chances are that an O2 sensor would go bad before an ECU. I had a similar issue on my EP3 and it was the O2 sensor, however I had a CEL along with my lack of power.

 

Yeah, I would tend to agree. I was just wondering what the possible problems might be if the engine did not run better after unplugging the O2 sensor.

 

Ah, I apologize, I misread. The ECU would still be one of the last things on my list of potential problems, but I it is certainly possible.

 

So....whats my prize? Let us know how it works for you

 

imma unplug the o2 sensor, then ill letcha know

 

i love how threads get there purpose. asked a simple question people give thoughts. and answers come flying at ya. great work guys.

 

Yeah guys, it was my o2 sensor. Im gonna get that changed. Thanks for all the help honda tech homies. **** feels quick again too. Now I have 3 more questions.

First one is I noticed that my car poofs out a small poof of black smoke when its shifted into gear. I let someone drive it. Does that small poof of smoke mean that I need a new catalylic converter too? Im asking because I need to get it smogged quick, either that or I pay someone $130 to pass me.

Second, is it ok to run my car with the o2 sensor unpluged until i get a new one?
the downside is my gas mileage goes down i believe.

My last question is, when i change my o2 sensor, how do i get the check engine light off? Was it that i had to unplugg the negative cable?

Thanks for all the help again guys

 

any answer?

 

1. Not sure on that one, and I'm not going to condone any "paying for passing"...lol.

2. Yes, you can run it with the 02 sensor unplugged, but as you expected you will sacrifice performance and mileage.

3. Generally unplugging the negative battery terminal and waiting a few minutes will "reset" the ECU. Mine went away all by itself, however K-series and D-series may be different in that respect.

Glad you are getting the problem fixed!