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Post by Stiggy on Oct 19, 2017 12:47:32 GMT
I would call that a good fail, not too bad in other words. I've only ever had one had fail on emissions it was down to a faulty MAF, we replaced the lambda as you would assume its that at fault but it made no difference. A tiny air leak in the exhaust can suck a little air in that causes the reading to show too much un-burnt oxygen.
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Post by scottmev on Jan 10, 2018 8:05:40 GMT
Hello Ian,
Unlucky on the Fail - hope you get it resolved quickly.
Two questions:
1) Where did you go for the IVA?
2) I am contemplating my rear exhaust, how happy was the IVA man with the extension to use for the rear box. I want a Measure like this as I only really want to use the standard box for IVA?
Many Thanks Scott
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Post by ian360 on Jan 14, 2018 12:40:35 GMT
Scott - Iva was in Nottingham.
exhaust was no problem, as long as you keep in the limits as per manual for exterior projections and all mountings are covered blunted or greater than 2.5 mm they can’t fail you
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Post by ian360 on Jan 14, 2018 12:59:02 GMT
My next problem! car has been at my garage for a month trying to sort out the emissions. So far we have- tried 2 cats, the second from an mx5 replaced temp sensor checked and confirmed lambda working ok. checked all the wiring to all components we still can’t get the emissions low enough on CO. We have fluctuated between 2.8 and 3.2 without it stabilising. the garage said there was 5 litres of oil in the engine as opposed to 3.5 so they drained and changed filter. They think it might be that the 20 or so miles run with this excess is the problem and it needs burning off on a good run. yesterday I did that, 50 miles, and checking immediately CO was 3.7 but no better. garage is stumped - and these are not back street cowboys they look after all my cars and specialise in performance marques. the only difference to the donor is the charcoal canister and solenoid has been removed. other things to note - the car runs lovely, no mis firing or spluttering, ticks over all day at 800rpm, doesn’t overheat fan comes on and off as required. i took the plugs out today to see what they looked like 
Do these give any indicators? i can’t see the point in putting it in for a retest given we aren’t confident of regularly hitting value. Maybe just keep it as a track car? one final thing I noticed this morning after checking around, there was exhaust smoke coming out of the flexible exhaust pipe section. Also water droplets. This is immediately before the big back box silencer. If that’s failing would it affect result? I don’t know if this has happened in last few miles? |
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Post by snowbird1 on Jan 14, 2018 15:16:34 GMT
Plugs look good.
Water is the normal product of combustion, when the exhaust is fully warmed up it is emitted a invisible steam, a bit cooler and it is visible water vapor and cooler still as liquid water. The exhaust leak may upset the O2 reading on the emission test but not the CO.
If the HO2S is switching consistently COs should be lower than 1% even without a cat. Are you checking the reading at the ECU - unfortunately the Mazda does not have an O2 sensor terminal in the diagnostic connector (Toyota does!)
Have you checked fuel pressure, rich fueling can be caused by high fuel pressure, the ECU does not monitor fuel pressure - it just 'assumes' it is correct! On earlier cars check vacuum to the pressure regulator or restrictions in the return line.
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Post by mikeeyboy on Jan 14, 2018 18:03:46 GMT
I have used a 1.8 mk2. I noticed in the wiring that the solenoid for the charcoal has a wire that runs to the ECU, so it must have some function electronically?
On my car I have removed charcoal and kept the solenoid but looped it so that both sides are sealed, the hose from the inlet is then blanked.
My car has not passed IVA, so cannot say for definite it is ok on emissions, but, if I unplug the solenoid from the harness the car runs rich and smokes more. If I plug the solenoid back in and loop it this issue goes away.
Might be worth a punt?
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Post by ian360 on Jan 15, 2018 10:53:20 GMT
snowbird - thanks reply it all seems a bit complicated for a novice like me! We are only checking emissions at the exhaust pipe. If you can explain in laymans terms how to check as per your suggestions I'll have a go!
mikeyboy - I've ordered a replacement solenoid for charcoal canister and connector as I know this was cut out of the loom and everything removed. It's a fairly simple job to put it back in and loop the pipes to see what happens.
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Post by scottmev on Jan 15, 2018 12:33:11 GMT
Scott - Iva was in Nottingham. exhaust was no problem, as long as you keep in the limits as per manual for exterior projections and all mountings are covered blunted or >2.5 mm they can’t fail you Thanks Ian, I may go for this option as a temporary measure for the IVA save funds and wont have to get it trailered to a custom place. Cheers |
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Post by snowbird1 on Jan 15, 2018 16:23:29 GMT
I have used a 1.8 mk2. I noticed in the wiring that the solenoid for the charcoal has a wire that runs to the ECU, so it must have some function electronically? On my car I have removed charcoal and kept the solenoid but looped it so that both sides are sealed, the hose from the inlet is then blanked. My car has not passed IVA, so cannot say for definite it is ok on emissions, but, if I unplug the solenoid from the harness the car runs rich and smokes more. If I plug the solenoid back in and loop it this issue goes away. Might be worth a punt? I like to keep the EVAPs system (charcoal canister, purge valve etc.)intact as it prevents raw hydrocarbon vapors going into the atmosphere, however blanking it off should not make a difference to the engine running. The ECU may log a fault if it 'sees' an open circuit to the purge valve or no response from the O2 sensor when it cycles the valve. |
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Post by mikeeyboy on Jan 15, 2018 19:40:55 GMT
I have used a 1.8 mk2. I noticed in the wiring that the solenoid for the charcoal has a wire that runs to the ECU, so it must have some function electronically? On my car I have removed charcoal and kept the solenoid but looped it so that both sides are sealed, the hose from the inlet is then blanked. My car has not passed IVA, so cannot say for definite it is ok on emissions, but, if I unplug the solenoid from the harness the car runs rich and smokes more. If I plug the solenoid back in and loop it this issue goes away. Might be worth a punt? I like to keep the EVAPs system (charcoal canister, purge valve etc.)intact as it prevents raw hydrocarbon vapors going into the atmosphere, however blanking it off should not make a difference to the engine running. The ECU may log a fault if it 'sees' an open circuit to the purge valve or no response from the O2 sensor when it cycles the valve. Like I said, it's unproven, but I think the issue is on the solenoid side on mine. If you disconnect it from the loom the car runs rich. I've sealed the inlet pipe just for the sake of doing it. Whether removing it affects how it can pass IVA would be up for debate, but I notice a difference in how my mk2 runs without it. |
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Post by ian360 on Jan 16, 2018 20:33:32 GMT
Waiting for new solenoid to turn up thought i’d have a poke around the engine bay to make sure nothing was missing around the induction area. First check was the Maf sensor and not sure if what I’m finding is any relevance to my issue? here’s the connector 
The black wire is a good ground red / white is 12v supply when ignition on green / black have continuity to ecu but 0v on ignition With the engine started (cold) and voltmeter across the ground and green/blk wires there is a 0.02 reading on 20v setting. As I increase the revs no significant change to reading at all. i think from reading up this should increase steadily with engine revs and if it doesn’t the sensor is faulty? Of course only if the sensor isn't digital but then shouldn't there still be something like 5V on the signal wire? too cold to do much more tonight but can I ask if this is actually checking anything of relevance, if it might be causing my issue and what the remedy might be? i did replace the original donor air intake with a KandN filter and pipe but kept the donor sensor if that would matter? Many thanks |
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Post by ian360 on Mar 16, 2018 18:32:42 GMT
Not much more done recently except managed to run 80 or so miles with an engine cleaner but it made no difference to the emission test! Figured next easiest thing would be run a diagnostic check to see if anything shows up, bought the led checer but this has opened a new can of worms. Seems my connector is not standard? Here’s the diagnostic box 
It’s wired as follows - top row left to right: white ? white / green - FBS brown / yellow - TEN (Ecu 1L) black / white - 12v + 2nd row l to r: blue / black - SGND green / white - KLN (ecu 1D) 3rd row l to r: white / blue - TBS bottom row l to r: brown - FAB green / orange - IG black - GND lt green - FP Checked all wires for connectivity, think I need to jump TEN and GND, led lamp in 12v + and other side should go to FEN - don’t have this and used KLN but nothing comes out of the led. if any of this makes any sense could someone point me in right direction of what is right, wrong or waste of time! just to reconfirm engine is 1.6 logged as 1998 but import. Difficult to find any info specific to that year, either 1997 or 1999. Following the 1999 writing diagram from mellens.net thanks |
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Post by mikeeyboy on Mar 16, 2018 20:19:55 GMT
Did you sort the emissions issue? Mine failed at IVA last month with CO being out, everything else was in spec.
I replaced the cat for a type approved one and it sailed through on retest.
Do you have your test results to post on emissions ?
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Post by mikeeyboy on Mar 16, 2018 20:23:44 GMT
Edit, I had missed your post regarding swapping the cats already.
Mine failed at 0.5 fast idle, so was marginal!
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Post by ian360 on Mar 18, 2018 14:32:10 GMT
Recent emission test -
fast idle 2730 rpm
co 0.86 fail
hc 53 pass
lambda 1.050 fail
2 fast idle- 2800 rpm
co 1.46 fail
hc 376 fail
lambda 1.077 fail
natural idle 800 rpm
co 0.50 pass
these aren’t too different from earlier results before I changed the cat, so maybe that wasn’t the problem. Given the diagnostic looks a non starter I think I am going to change the lambda and see if that makes any difference. It seems to be the most common reason mx5 fail on emissions reading through various forums.
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