Rep Power: 0

Good morning/afternoon/evening Civ nation. I have an odd engine problem with a 3rd hand 2003 Honda Civic SI (Canada) 1.7L Vtec.

I have done quite a bit of forum searching and found alot of idling issues but not quite like mine.

Bought it for a good price, body is excellent however it has an issue, as follows:

Car starts up fine when cold. The odd time when I give it some gas in neutral the RPM's will hang for a second before dropping down.
Pull away, drive the car for 10 minutes or so (or until car is at a warm operating temperature) and pull in to the mall. Go inside for 15 minutes and come back out while the car is still warm and start it, and it will start bogging down, hesitating, the RPM's will drop and when its about to fall on its face it will snap out of it and away it will go, without issue.

Come to a stop and go to pull away and when I give it some throttle, the RPMS wont move, it is not responding to any throttle. Turn the car off and back on and away it will go, no issues at all.

This doesnt happen every single time but it is often enough that I will be putting some money into it. Before I bought the car we tried for 2 hours to get it to bog out and it wouldnt. But the other day I didnt take it out for long at all and it acted up. It has a mind of its own.

The car was for the right price, hopefully it will be a relatively cheap fix and ill be laughing.
More details:
Car exhaust stinks
Needs oil change
230,000 KMS
Was getting O2 Sensor High Voltage code on my reader, only happened once, has not came back after clearing.

Any suggestions to help mitigate the amount of parts in question?
The car is going to be driven to a mechanic in the next little while, and see what they can dig up. Will be doing timing belt and water pump.

Cheers!

 
Rep Power: 517

Primary sensor? Replace it.

Replace with the correct brand sensor though. Whatever brand the factory installed (DENSO or NTK)

 
Rep Power: 0

Funny enough when I was talking to my mechanic about the bogging issues and mentioned o2 sensor he said it wouldnt be that.
A salvage yard has them for $25, might be worth slaving in an old one to see if it makes any difference.

 
Rep Power: 517

Your mechanic?







I've seen it many times.

It's usually hard to catch it in the act with a scanner hooked up, and since it only lasts for a few seconds it's even harder to make a data recording and pick out the bad parts of the data, and then sift through all that data and nail it down to a single cause.

Just unplug it and drive it around, drive it through the situations you KNOW it would have stumbled in......If it runs ok that way then replace with NEW.

Good chance an old used one will have the same problem. Or different problems.

 
Rep Power: 209

Automatic or manual transmission?

I know this may sound odd but, the next time it does what you are describing turn the headlights on and see if it idles any differently.

What does the exhaust smell like? Any smoke when under load or blipping throttle? If so, what color? Does it smell like fuel or rich running condition. Does it smell sweet (coolant).. possible head gasket issue. Does it smell like burnt oil? .. valve seals or oil rings.

Inspect and tighten all chassis and engine ground connection points

Have you tried and ECU relearn?
1) disconnect negative terminal
2) turn on bright headlights to drain residual charge
3) engage brake pedal (brake lights) to drain residual charge
4) wait 5 minutes and shut off lights, radio, interior lights, a/c and any other electrical device
5) reconnect negative terminal
6) start engine and let idle until radiator fans engages (roughly 10 minutes) and do not turn on any electrical devices.

 
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had issue for years. Summer winter warm or cold. No rhyme or reason does it intermittent sometimes numerous and other times days weeks not doing it. Had it to a trusted garage left it for a week. They drove as service car and it only did it once for them. He thinks electrical but would not code and they have no real idea what’s up. Changed fuel pump asst early in the game. No joy. Tank was crystal clear clean. Still pondering. Not much help to you
cheers
tom