Running rich emissions fail - Civic Vti (b16a2)

pk10216

Little bit of back round. Civic vti coupe 1.6. When it went for the test first time round i had no cat, but just put it in anyway to see if anything else would show up anyway car failed on emissions as i expected (and not by much). Got a second hand cat and had it fitted, tested again car failed with much the same co reading (fail on high idle).Thought second-hand cat dodgy so bought a brand new cat had it fitted and had the car tested again today. Yesterday i put some diptaine in tank and took car for a good half hour spin and again this morning before test so the car was red hot. Car once again failed on high co.

low idle 0.41 vol% --- above 0.50 fail (PASS)
HC - 256
Lambda 0.99 --- not between 0.97-1.03 fail (PASS)
High Idle CO 0.58 vol% ---- above 0.30 fail (FAIL)

Took it to a garage that do emissions testing after and they reckon the car has running too rich and has previously been remapped or chipped and i should get a new ecu. I hugely pissed off that i can't get it to pass. car is costing me a small fortune to try and get an nct. any ideas lads on how to fix???

Gary ITR

Sounds like you need an o2 sensor. Whats the code on your ecu? If its an ek4 Civic thr stock ecu cant be mapped or chipped

pk10216

Was thinking it couldn't be chipped. It is an ek4 99 VTI coupe. They never checked for codes in garage just ran the emissions test and said either lamdba or new ecu. Car is running very rich when he mechanic put the accelerator to the floor there a nice bit of blackish smoke.Hope its not injectors or some serious. Do you think try and replace lambda sensor first?

Gary ITR

pk10216 wrote: »

Was thinking it couldn't be chipped. It is an ek4 99 VTI coupe. They never checked for codes in garage just ran the emissions test and said either lamdba or new ecu. Car is running very rich when he mechanic put the accelerator to the floor there a nice bit of blackish smoke.Hope its not injectors or some serious. Do you think try and replace lambda sensor first?

I meant the physical code on the ecu itself

Sounds like its running pig rich, lamda shouls sort it

pk10216

Took a look at the ecu no code or barcode on it just a plain silver box. I'll try lambda. Could you recommend anywhere cheap?

Leonard Hofstadter

It can't be running rich if the lambda value is 0.99 - that's almost ideal:)!

pk10216

now i'm confused. should i bother replacing lambda or not?

kona

When were the plugs, oil , leads, filters changed last?

ZENER

I used to own a 1991 Integra XSi with a B16A 1.6 DOHC vTEC engine (sweet car ) anyway a common tweak to that engine was to turn the TPS (Throttle Position Sensor) a few degrees so the ECU would think the accelerator was pressed further than it really was so it would inject more fuel. That coupled with an improved air filter or induction kit gave a bit more power.

If the car used to belong to someone who was clever with cars (you mentioned the CAT had been removed ?) they may well have done this tweak. The result would be a richer mix once the pedal was pressed leading to a higher reading I think.

The TPS is on the left of the throttle body in this photo.



Ken

kona

ZENER wrote: »

I used to own a 1991 Integra XSi with a B16A 1.6 DOHC vTEC engine (sweet car ) anyway a common tweak to that engine was to turn the TPS (Throttle Position Sensor) a few degrees so the ECU would think the accelerator was pressed further than it really was so it would inject more fuel. That coupled with an improved air filter or induction kit gave a bit more power.

If the car used to belong to someone who was clever with cars (you mentioned the CAT had been removed ?) they may well have done this tweak. The result would be a richer mix once the pedal was pressed leading to a higher reading I think.

Ken

In that case the idle would be higher than usual, just wasting fuel.

ZENER

kona wrote: »

In that case the idle would be higher than usual, just wasting fuel.

The idle was controlled by the ECU ignoring the TPS until it was activated. I've done this myself so I know the effect.

Ken

Gary ITR

ZENER wrote: »

kona wrote: »

In that case the idle would be higher than usual, just wasting fuel.

The idle was controlled by the ECU ignoring the TPS until it was activated. I've done this myself so I know the effect.

Ken

It doesnt increase power though. I can tell you that for sure and it also causes long term problems.

Sorry op your lamda does look ok, if somebody was fiddling with tps it certainly could be the cause. Have your mechanic check the ignition timing too

kona

ZENER wrote: »

The idle was controlled by the ECU ignoring the TPS until it was activated. I've done this myself so I know the effect.

Ken

I did my thesis on fuel injection, my system the TPS was fitted, then the ecu was calibrated to the TPS position.

If this wasnt done the TPS would over rev the engine. Altho having said that I didnt use a stepper motor.

pk10216

timing belt water pump and oil and filter done about 3 weeks ago. spark plugs about 3 months ago. if its any help

pk10216

oh and the spark plugs were fairly badly fouled when they were changed.
which would suggest its been running rich

JP 1800

The car is running rich but not by much, a dirty air filter or some air restriction. A slight misfire will also give higher CO readings. Can diagnostic codes be gotten from the ecu?

Mar4ix

not sure particularly about your car, but i know some people set timing earlier, make them aka more sportier. check if timing correct.

ZENER

Are there any engine mods to the car - induction kit, performance cams? There are a lot of aftermarket mods for these engines and if you got it S/H do you know its history ?

Adjusting the TPS by a few degrees was definitely a tweak mentioned on a few of the performance websites around at the time - not a drastic adjustment but just a few degrees.

It was also common to advance the timing by a degree or two and to replace the injectors with those from the Type R or use adjustable cams. Of course it's also possible a previous owner drove the crap out of it ! Is it a JDM spec car by the way ? Does it idle ok at around 750 RPM ?

Ken

pk10216

Car is a uk spec import (not a jap). Only mod is an induction kit, previous owner never mentioned anything else so dont believe it has uprated cams. I don't think its the timing as the the belt was only done about 3 weeks ago and surly this would have been spotted. Checked idle it seems to be steady below 1000. anybody recommend a good garage to take it to in Kilkenny-Carlow-Waterford area that's not going to rob me? or anybody looking to do a nixer

Gary ITR

pk10216 wrote: »

Car is a uk spec import (not a jap). Only mod is an induction kit, previous owner never mentioned anything else so dont believe it has uprated cams. I don't think its the timing as the the belt was only done about 3 weeks ago and surly this would have been spotted. anybody recommend a good garage to take it to in Kilkenny-Carlow-Waterford area that's not going to rob me?

Sorry I was posting on mobile last night.

Sometimes owners of these cars fiddle with ignition timing (not cam timing which is your belt) this is done by moving the distributor. Others mess with TPS and throttle body. All of these things can lead to running rich. How healthy is the car otherwise? Using oil?

pk10216

Car is running fine other wise lots of power and good pull from vtec . uses a bit of oil but nothing serious, have to top up every few months. Only thing that went wrong was Idle air control valve failed but had that replaced and car was fine.I had the car put on emissions test yesterday at a garage after nct the mechanic said try a new lamdba but if ye guys reckon thats a waste of time I'm at a loss what to do now

Gary ITR

Have him check the ignition timing