Honda Civic EJ9 1.4i failing NCT emissions

rizzodun

I recently sent my 98 Civic for the NCT, it failed on emissions, got it serviced, and told it was the cat, got a new generic cat welded in, garage said emissions were fine, put 120 miles up since then and got it retested, now it's failing worse again, the guy in the NCT centre told me he had a problem with one he had himself, ended up being the ECU, so, I'm wondering what sort of money it would cost to replace this, or if anyone here could shed some light on this problem?

Car has not been tuned, absolutely, bog standard.

burke027

My first bit of advice would be to get what is wrong with it correctly figured out by a competent mechanic. It could be any thing from a air mass to the timing being a tooth out, dont jump in with statements like that when you are unsure.
Sorry rant over
I just hate when people come into the garage and say this kinda stuff to me. When it could be anything wrong.

rizzodun

burke027 wrote: »

My first bit of advice would be to get what is wrong with it correctly figured out by a competent mechanic. It could be any thing from a air mass to the timing being a tooth out, dont jump in with statements like that when you are unsure.
Sorry rant over
I just hate when people come into the garage and say this kinda stuff to me. When it could be anything wrong.

While I appreciate the time you took to write your reply, while I may not have specified, this problem has happened a year ago, everything you mentioned above was checked by a competent mechanic, it was sorted by a new cat at the time, the ecu suggestion was made by a mechanic now retired, who came to that reasoning based on the history I had told him, but who couldn't tell me price. I'm planning to ring a Honda specialist tomorrow and wanted a guide to see if the job is worth doing if it is the problem, I don't want to pump money I can't afford into a potentially w**ked engine. Please don't think because I posted here that I'm some thicko who thinks I know more about cars than I actually do, that's the sort of reaction I hate from garages. Rant over.

burke027

Maybe you should of mentioned that in your post. I hope you do get it sorted but i doubt its the ecu to be honest.

Waterson

Can you post up your emissions test results from which we could draw some conclusions. Thank you.

rizzodun

Waterson wrote: »

Can you post up your emissions test results from which we could draw some conclusions. Thank you.

Low idle (760rpm) 0.24%

High idle (2810rpm) 0.52%

That was before service and cat replaced, garage said high idle was about 0.01% when tested after service, don't have other nct centre readings as the guy was good enough to cancel test so I wouldn't have to pay, just said its much higher than before.

Honda dealer said its probably not ecu, to try fuel additive and drive it hard to blow out engine and cat, maybe some build up of carbon before service? This is bugging me as its the second year for this.

Nissan doctor

What were the lambda and HC readings?

The would thing I would note is that if your mechanic was as knowledgeable as you say, being certain that he has checked everything properly, then he wouldn't have fitted a generic weld in cat as the majority of these are utter rubbish.

jimmyw

what about the lambda (Oxygen) sensor(s), were they tested at all? Might they be giving wrong signals to the ECU?

rizzodun

Good point nissan, I however am not an expert on cats so have taken his word on it, he does have a good reputation, lambda reading was 93, hc was 90ppm

I may have caused some confusion with this thread to be honest, so I'll give you a full history.

Last year:

Failed NCT on emissions (high & low idle way off charts)
Replaced Lambda with new, reduced readings but not below pass, and a second hand cat, reading in garage was passing, tested two weeks later, failed on same.
Replaced second hand cat with new one (bolt on, non-oem part) passing in garage, passed nct.

(I have no readings for this as unfortunately misplaced all NCT reports, and the mechanic who did original work has since moved to Aus)

This year
Failed NCT on high idle only
Car serviced (car had been overfilled with oil by a friend who needed it for a run to Dublin about a month previous which I'm told may not have helped)
Reading taken in garage, still failing around same mark so cat replaced, reading taken in garage, car passing
Failed NCT one week later (120 miles) on high idle again, worse than before, but still passing on low idle.

There was black sooty residue on the back of the car which I attributed to the overfilling of oil, does not seem to have come back since service.

I understand this is not much to go on, but the garage I used seems to have a good reputation, I am no car expert so in the end have to trust that he knows what he's on about. I'm just trying to shed some light on any solution to the problem. The mechanic who suggested the ECU is not the same mechanic who did the repairs, but happens to know a member of the family and is also trustworthy, even if now retired.

dieselbug

I think you you need to go back to square one on this and start again. If possible you need,
4 gas readings.

hc, co, o2, co2. Also fuel trims, injector times and what the oxygen sensor readings are, before cat and after. Gas readings before the cat would be great, if possible. A decent independent garage should be able to do this and will give a good idea on the best way to move forward. Ask for a printed report on the results.

Aftermarket cats are a waste of money imo and generally will only get you through one nct test. Genuine cat will cost you in the region of 300 to 400.

rizzodun

Thanks diesel, hopefully will get some time tomorrow to start with that, half the problem is I use the car for work and have some crazy hours which makes it hard to get it in for enough time to have a real good look over. Seeing its a similar problem two years in a row made me wonder that it may not be the cat, aftermarket or otherwise, but something else, and no honda dealer close by, such is the state of the motor industry these days, even though they couldn't pin it down when talking to them over the phone. Frustrating or what?!?

George Dalton

rizzodun wrote: »

such is the state of the motor industry these days, even though they couldn't pin it down when talking to them over the phone. Frustrating or what?!?

Nobody will be able to diagnose it over the phone, or via the internet for that matter.

enumbers

you have failed to provide full information the lads have ask for co,hc and lamda readings from the test so they can help you with this issue. There is no possible way to definitely diagnose an emissions issue over the phone

rizzodun

enumbers wrote: »

you have failed to provide full information the lads have ask for co,hc and lamda readings from the test so they can help you with this issue. There is no possible way to definitely diagnose an emissions issue over the phone

The Honda dealer was given full info over the phone regarding readings as on the nct test sheet, the second failed test I was unable to give readings as I said before the guy cancelled the test to save me the fee, and thus, could not print the readings, its going in on Monday so hopefully the problem will be identified.