Emission problem

[Basilly]

Hi, my 1.8 1999 lean burn 7A-FE struggles on emissions, done approx 140k miles, yearly 6000 mile service by me just before MOT (plugs, oil, filters). Last year it sailed through emissions but this year failed quite badly on emissions. We replaced the Cat and O2/Lambda sensor and it passed but the guy had to work hard for it to pass by revving the nuts of it, at it for about an hour. We have had the car since new and my wife, the main driver, drives it like a pussycat and honestly never goes over 60mph. I consider the car to be in very good condition and would like to hang on to it, especially as we have had it 18 years. The engine starts first time, no smoke, gets through a little oil but the 7A-FE engine design meant it always did.

Last year pass   CO  0.03 (limit 0.2), HC 34 (limit 200)

This year fail     CO  0.57 (limit 0.3), HC 199 (limit 200)   I don't know why CO limit was 0.2 last year

After new Cat and O2/Lambda

This year,  FAST IDLE   CO  0.65 (limit 0.3), HC 240 (limit 200)  SECOND FAST IDLE CO 0.18 (limit 0.3)  HC 40 (limit 200)  PAAASSSSSS

Can anyone give me pointers as to what might be wrong.

Cheers in anticipation

[frankie406]

Is there a charcoal canister in these engines? Try some millers additives might help

[mickburkesnr]

Is the thermostat working properly? My Corolla's 4E-FE just about passed last year but only after it warmed up. The thermostat had failed open so it would run very lean until it got warm.

Other than that, maybe clean the throttle body and run some additivies through the engine like @frankie406 suggested.

[Cyker]

It's probably deposits building up in the engine; It'd be worth running a few tanks of Shell FuelSave or V-Power through it in the months approaching the MOT next time to see if that helps. You could also try that TeraClean thing - Seemed to help in Wheeler Dealers when they were having similar issues with emissions.

An 'italian tune-up' has also been shown to help in some cases too, esp. if the engine is otherwise in good condition ;)

Always driving an engine gently can actually hurt it as it allows stuff to build up and it never gets burnt off or blown out; It is partly why modern emissions-controlled diesel engines are so much less reliable than their older cousins.

Kinda reminds me of the first time I drive my dad's old diesel Focus - He never pushed it, so the first time I floored it down an on-ramp it threw so much soot out the back it looked like the smoke screen from Spy Hunter!

[Konrad C]

Is the vacuum switch pulling the lever to the inlet valves. To fix the problem, I pulled the hose off the vacuum switch, then moved the lever to the stop, held it there while reconnecting the hose. This was done with the engine off. When the engine is started, the vacuum will pull the lever to the right position. The pictures are after I set the lever position and when idling. It opens gradually when the throttle is pressed.

I hope this helps. 

 

[Konrad C]

I forgot to add, that i changed the exhaust and catalyst , but it did not make any difference to the emissions. The vacuum fix above did. 

[Basilly]

Quote

 

Wow, many thanks everyone. I will sit down and digest the info.

[Mike169]

A company I know used a local garage for their MOT's but the diesels usually failed on emissions so they booked their diesel vehicles in with a garage about 30 miles away and thrashed them getting there and holding the vehicles in 3rd gear on a fast road they used. The result was they cleared out the exhaust system and then MOT passes were not a problem then. Mike.

[Konrad C]

If I was well ( got a cold), and still had my old 7AFE, I would take photos or make a video to demonstrate the procedure I used to set the vacuum. It is simple to do. Other checks i would do, is to make sure the leanburn sensor cable is routed safely between the cooling and air-con fans - mine got caught and damaged in the air-con fan when I switched it on. I repaired it, then later obtained a spare sensor. Even with spare catalytic converter (year old and new), and sensors the car struggled to pass. That is why I go back to the vacuum switch operating the inlet valves. See this post - 

Overall if the engine is in good shape and the emission system okay, genuine Denso Iridium spark plugs, new air filter, recent oil/filter change, the exhaust catalyst and sensor swap - none made no difference!
Give an update to your progress - and don't get a cold! 

[Basilly]

Thanks everybody for all the advice

Hi Konrad, last night I found your earlier post (2014) ref the Vacuum switch. This morning when the engine was cold the lever was hard against the stop. I removed the hose and there was a very audible release of gas followed by me going Ooops. I held the lever against the stop, reconnected the hose, let go of the lever, the lever then moved away from the stop, started the engine, the lever now back against the stop, turned the engine off, lever still against stop, engine appears to be running normally. Unless anyone says different I have to assume the Vacuum switch is OK??

[Basilly]

Just to clarify, the gas noise may have been a vacuum rather than release. Definitely a gas noise though.

Cheers

[Konrad C]

12 hours ago, Basilly said:

Just to clarify, the gas noise may have been a vacuum rather than release. Definitely a gas noise though.

Cheers

That's a good sign. The vacuum is holding. When the engine is running, when you rev the engine, the vacuum should move the lever from the stop. I previously made the mistake of detaching the hose when reattaching the level at the pivot. I did not notice the correct position until my emission problem occurred. 
I would do as other say and run some additive or clean the induction side. Also check for leaks since the car is 18 years old. One item that I looked at but could not remove was the charcoal canister on the left-hand side of the engine bay. Not sure how much difference and how much to replace. 
When you get a chance after running any treatment, see if you can get an updated emissions check. 

[Basilly]

   Looking around the net the carbon canister doesn't really pop up, no one seems to sell them. Further research told me it is only meant to suck up fumes when stationary. When the engine is running any fumes are directed back to the engine (not sure if that puts my mind at rest or not), could maybe lead to a rich mixture, who knows, then again the O2 sensor might correct this. Because of the above and the fact that access is a little fiddly I am going to choose to leave the carbon canister alone and look elsewhere. I am going to check that the vacuum lever works when the engine is revved. I have put some REDEX fuel additive to clean the injectors etc hopefully after a few weeks I see a difference. I will probably also change the radiator thermostat because its cheap and easy to do. I don't have easy access to an emission test machine so unless I get more suggestions, I will apply all the great ideas people have given me and book the car in for a 3 month early MOT having had a service with new plugs and good quality fuel etc. If any of you guys can add to this plan then it would be greatly appreciated. As soon as I have any useful feedback/success I will let you all know.

Cheers

[frankie406]

Use the millers ecomax far better stuff than redex

[Basilly]

Will stick some "millers" in once the redex has washed through

Thanks

[mickburkesnr]

13 hours ago, frankie406 said:

Use the millers ecomax far better stuff than redex

Just looking at this, as I was thinking mine could do with some.

On Halfords they list it down as saying it adds two octane numbers. Would buying a tank of V Power or the Super-duper Unleaded sold at some forecourts do the same job in cleaning?

[Basilly]

I am no expert but could either do any harm?

Message for Konrad, Revved the engine and the Vacuum arm was popping in and out, wasn't gradual just either in or out, seems ok to me.

[frankie406]

3 hours ago, mickburkesnr said:

Just looking at this, as I was thinking mine could do with some.

On Halfords they list it down as saying it adds two octane numbers. Would buying a tank of V Power or the Super-duper Unleaded sold at some forecourts do the same job in cleaning?

Yeah wouldn't do any harm..unfortunately there is no v power here in northern Ireland(not that I've seen) to compare it.

[mickburkesnr]

46 minutes ago, frankie406 said:

Yeah wouldn't do any harm..unfortunately there is no v power here in northern Ireland(not that I've seen) to compare it.

Ah yeah I forgot about that. 

[Mike169]

Hi All.

Just wanted to mention Petrol like V Power fuel is more expensive as it has more additives in it, cleaners basically, so in itself it the cleaning agents themselves don't actually burn like diesel/petrol  so technically it actually reduces your mpg but because the extra cleaning agents enhances the performance of your vehicle by cleaning it's internals it in theory will give you more mpg.

Personally I put in usual fuel, never supermarket stuff, but every other or third fill up I put in the dearer stuff as I believe it helps to keep the engine cleaner on the inside.

Mike.