Hello everyone,

I recently bought a 2002 Honda Accord Coupe V6. The car has 97,000 miles.

When I met the ex-owner the engine was warm already, so the car did not display the problems I’m about to tell you.

Car was kind of neglected, service history up to 60,000 miles at the Honda dealership (last in 2011), after that he just had the oil and the oil filter changed every now and then at a generic shop. A few days ago I collected the car back from the Honda dealership where they changed all 6 spark plugs, transmission fluid and various belts (including the timing belt) among other things. I hoped this generous service would fix the problem but it didn’t.


So, the following happens after a cold start:

1- Car starts up right away with no hesitation, engine settles at around 1250rpm (steady). It jolts very slightly.
2- I start making my way out of the garage: car is huge for European standards and my parking lot is quite tight. After a couple of backs and forths to get out of my spot the engine idles steadily at around 850-900rpm with no hesitation yet the jolts as per point 1 are still present.
3- Now the problems arrive. I climb up the first ramp, a few more manoeuvres, engine slightly warmer (but still cold), the car would want to idle at the usual 750rpm however it can’t, vibrates and jolts fairly bad, idle falling down to 250-500rpm. The car then tries to raise it to 750 but it just falls back down to the unusual 250-500rpm range. It even stalled once.
4- I drive for 1 or 2 minutes, engine and coolant warmer. When I stop, at a red light for instance, the idle is at 750rpm but it’s not really steady, sometimes falls to 500-600 then goes back up. Car still shakes and vibrates however less than in point 3.
5- I continue driving, let’s say for another 5 more minutes. Now the coolant is in the correct operational range, when I stop the car is able to maintain 750rpm but the jolts are still present.
6- When the car is completely warm then idles beautifully at 750rpm, no vibrations or jolts whatsoever. If the radio is on would be hard to tell whether the engine is running!

I cold started the car observing the engine with the hood open and I did not hear any hissing noises.

Any ideas?

I hope my explanations were clear enough, please be patient I’m not a native speaker

If there’s something unclear let me know and I’ll try again. I even made a couple of videos and will upload them should you deem them useful.

Thanks in advance!

 

A couple of things to check or do:

1 - before replacing anything, literally go over the vacuum and other hoses looking to see if there is anyhting disconnected or cracked. Replace those. Especially around the intake and throttle body. Vaccuum leaks can cause issues
2 - Look for leaks - oil leaking onto something can cause weirdness. Starting at the top of the engine, check around the distributor and underneath to see if there is anything. clean connections that might have oil in them. Checking around the intake areas again, there are definitely places that can leak on the back part of the engine.
3 - Fluid levels - go over the basics here: check transmission fluid, engine oil level, power steering fluid level, radiator - just covering basics but one never knows.
4 - Clean throttle body
5 - IAC - This is a usual suspect. You can clean it and see if it helps, or simply replace it.
6 - Scan car for engine code and see if anything is showing up. Just because there is no light doesn't mean there couldn't be an issue showing in the computer
7 - Possible other idea - after all that, reset the computer and let it relearn your idle.

 

Hi 99stockcivic, thanks for your help.

1- I’ll try again. Unfortunately this car in Europe was rare back in the early 2000 so the parts are not really easy to find nowadays.
2- As per point 1, I’ll try again. But everything seemed pretty clean to me. To be fair, when I picked up the car at the dealership the other day I was informed they fixed a small coolant leak next to the head, even though they didn’t specify anything else.
3- fluids are ok, plus they just got replaced less than a week ago and I rechecked them.
4- first thing I did, so it’s clean.
5- good idea. Again not easy to find it here so will have to clean the one I have making sure I don’t damage the gasket otherwise it’ll be a problem.
6- perhaps it’s me being dumb but I couldn’t locate any OBD port? Maybe the car is too old and has an old system for diagnosis?
7- would you mind telling me how to do that?

Thank you,

FB

 

Hmmm...no expert on UK cars, but I thought it was here:
https://www.justanswer.com/honda/8rd...obd2-port.html

scroll down to see pic. Should be against croner of drivers' door and footwell area.

For reseting, I simply would get one of the cheap apps and reset with your phone via bluetooth.
Examples of scanners that will help you examine and reset computer are here:

You want this and something like this:
https://play.google.com/store/apps/d...hl=en_US&gl=US

 

Thanks for your help, I did locate the 2 and 3 pin connectors. It is possible to read codes without a scanner however I have no codes, so jumping the 2 pin connector is of no use.

I ordered a set of fine brushes to clean the IAC valve. I also found the replacement gasket for it, funnily enough it is the same as the Honda Goldwing 1800 motorcycle, which in Europe is more common than an Accord Coupé. Tomorrow I’ll try to buy it at the dealership as if I order online I’ll pay more in shipping costs than for the gasket itself.

 

Could the OBD-2 connector be on the other saide of the car? In a left hand drive car, its' on the opposite corner.

 

Could you turn the air bypass screw out 1 whole turn? If it is fighting for air cold , give it some. See if the condition changes.

 

Thanks for your help guys.

My car has no OBD2 connector but just the 2-3 pin setup, however there’s a 3 pin to OBD2 adaptor on Amazon.

The screw on my throttle body is blanked! Like there’s no screw as per your picture.

Anyway I managed to clean very very thoroughly the IAC (which, by the way, was not in bad shape at all). Problem is still there. At this point I am starting to suspect that the problem is more electrical rather than air/fuel.

So this is what I bought:
https://www.autodoc.co.uk/ngk/1041459

 

It is a 2002 and it does not have an OBDII? Did they even make them like that?

I think you need to look again.

 

Yes, I was also confused but I swear I can’t see it.

If you give a glance at the link 99stockcivic shared on post #4 that’s the same setup I have. Bear in mind the car is European (although built in the USA) so probably there were no requirements for it? I don’t know, but the user on the other forum had the same issue.

 

Right so there have been some developments.

This morning I was driving the car uphill, since it needed some extra power to maintain the cruising speed I was at, transmission lowered a gear and the engine was running at around 3000rpm, however the car sputtered briefly and a loss of power followed (no response to the gas pedal), then it became “drivable” again, but the CEL came on. I stopped and turned the car off and back on. CEL off.
I connected the 2 pins to pull the codes without the scanner, then turned the ignition on without starting the car. I’m getting code 22 which is linked to a VTEC oil pressure switch. Oil is new and enough.

Now, can a VTEC oil pressure switch cause the symptoms I described in post #1? I still haven’t received the new plug wires.

 

Ok another update as I had to drive a bit more today.

There is now also a code 70; which is the transmission. D4 light blinks 8 times rapidly. Anyone knows what that means? Transmission works fine IMO and has always worked the same throughout my ownership, so don’t really understand the fault? No CEL on, only when jumping the 2pin connector. Code wasn’t present when I checked the previous one.

I also tried to further diagnose the code 22 issue. Again while “pushing” the car a bit more than the usual the CEL lit up. No new codes however while the CEL is on the car won’t go beyond 3000/3500rpm. If I switch the car off and then back on, there is no CEL, and the car will again rev over the 3000/3500rpm. However there is no VTEC, so it seems there is indeed a problem with that system?

Thanks

 

Yes, that VTEC can cause exactly that issue.