Emissions

[Guest allenr03]

Hi Guys

 

I took my car for a pre SVA MOT today (A good excuse to take it for a drive.)

 

All went well apart from the emissions test. I changed the Ford Lambda sensor for the correct Rover MEMS sensor but the best reading I could get to was 1.13 - which sucks.

 

The MOT man suggested that the sensor wasn't going far enough into the exhaust and as such wasn't getting hot enough to do its job. Anyone got any ideas about fixing this or suggest anything else?

 

I thought about grinding 1/4" (or more) off the nut that holds the sensor on to get the sensor head into the exhaust gases but I'm worried about getting everything to seal up afterwards if I do that.

 

The other fail point I had was the front brake pipes which foul the coilovers on full lock. The pipes fitted to my car have brackets mounted to the lower wishbone but I don't see them on anyone else's car! Any ideas/pic most appreciated.

 

While I was there I got the suspension geometry set up properly and I was really surprised just how accurate the thrust line was.

 

Driving the car was great but I need to stop driving it like a diesel!! Just need to sort these bits and get it SVA'd then I can practice (within the legal limits obviously!!)

 

Rich

[Andy Spencer]

Is the lambda sensor heated? If that is the problem, it may be worth trying a heated sensor. Don't know whether its a wideband or narrow band but Bosch do a universal wideband sensor for about £70 here. I'm currently looking to convert to wideband for ECU self learning but I guess that's not an issue for you. They also do heated narrow band sensors that may be compatible.

 

I'm sure I've seen issues with superspecs and lambda readings before - may be worth a search.

 

Andy

[Guest allenr03]

Yeah its a heated sensor, I only changed it last night following advice from other SS builders. I found several threads on the interweb stating that universal zirconia sensors aren't suitable for a MEMS ecu so I bought the right one. Wiring was the same as the Ford version so it was an easy swap. Maybe the heater wiring isn't connected properly! I'll investigate later I think. Then get the grinder out :-)

 

Rich

[Guest salty_monk]

Lots of problems with Lambda's on SS.... Also a lot of info on here if you search for it.

 

Dan

[Guest Giggling_Buffoon]

Richard,

 

Lots of us have had real problems with emmissions (took me 5 SVA tests to get it sorted out, eventually fixed 4 problems including engine loom and duf ECU)

 

was the 1.13 reading the BET or the natural idle reading (were you holding is at 2500 to 300 rpm or just at idle?)? if it was OK for the BET but no good at idle then there may be an ECU issue which other people have had.

 

you should not have to take off any metal from the exhaust nut. List of things to do first as follows.

 

1. Is the lamda sensor working? Simple check - you should have two white wires that are the heater (ignore these for the moment) and a third wire connected to earth. The fourth wire connects to the ECU. Check that the voltage output from this 'switches' when the car is running (see Just Lambda website for a more techincal explanation). Also make sure that the wire connected to earth has a good connection, the engine harness I had was rubbish, with 3 wires that had no continuity!

 

2. Is the ECU detecting the lamda sensor?

Get someone to interogate the ECU at a garage to confirm that there is no fault code being generated by the ECU, and confirm that the idle stepper motor is working properly.

 

3. Is the ECU working properly?

The RH ECU is a bag of nails, and is made to a price rather than a performance spec.... Send the ECU to Avon Diagnostics and get them to confirm that the ECU is working properly. If its not see if they can give you the MEMS immobiliser override box an get a Rover 820 or 220 ECU.

 

4. Apparently a new engine needs to run for a number of hours before the lambda reading starts to come into the right value. I'm not sure if this is a myth, but I know that on my final SVA test we ran the emissions test for the best part of 2 hours, with the readings getting closer and closer to a pass for the natural idle running until it just tripped over the pass line.

 

Cheers,

 

Chris

[Guest allenr03]

The reading was for BET not idle, we never did that test, the expansion tank wasn't big enough so we stopped!!

 

The ECU idles irratically, AVON have already had it and tested it and I needed the imobilser to get it work! I have found an ecu from a 220 on ebay that is reconditioned with a warranty and I thought about buying it as a spare. (£85 didn't seem too bad.)

 

The idle did get better after driving 20 miles to the garage to be honest and I did only put the lambda in last night.

 

I'm going to do some tests on the wiring on Sunday to see if I can work out whats going on.

[TonySuperSpec]

Sounds to like the lambda relay !

 

Is it switching ?

 

No point in working on any other aspect if the relay is not switched in ..

 

The relays from RH are questionable regarding the contacts

 

I tested mine and then tossed the lot and bought good new ones, the RH ones switched but no contact, oscillated on coil activation so intermittent contact.

 

tony g

[Guest allenr03]

Sounds to like the lambda relay !

 

Is it switching ?

 

No point in working on any other aspect if the relay is not switched in ..

 

The relays from RH are questionable regarding the contacts

 

I tested mine and then tossed the lot and bought good new ones, the RH ones switched but no contact, oscillated on coil activation so intermittent contact.

 

tony g

 

Something else to test tomorrow:-) Do I just look for an output voltage from the relay when the engine is running? I learn quick but ask stupid questions!!

[TonySuperSpec]

Relays sequence on as engine starts

 

Can't have lambda when not running...

 

Look for the relay supplying constant 12V or there abouts .. Its the heater supply switch om +a feed back to the ECU saying its on.

 

 

Tony

[e666]

Hi Richard

 

Sorry to hear about your problems. I'm guessing you've checked the obvious things like vacuum hose connected etc cos that can cause havoc with the engine idleing/running.

 

There is only one thing to add to all of the above: When I got mine tested I got different results depending on which tail pipe the nossle was pushed up . Top pipe I got 1.007 bottom pipe I got 1.3! Fortunately the SVA man went for the top one in the end.

 

e

PS good to put a face to the Avatar at Stoneleigh

[Guest allenr03]

Hi Ian

 

Yep it was good to put faces to names and websites!!

 

I've checked all the easy stuff and its all ok, i'm going to check wiring continuity etc, if thats ok I'm going to dismantle the exhaust and rebuild it making sure it has lots of exhaust paste on! It was about 6 weeks between assembly and firing up the engine so I'm not sure the paste will have worked properly.

 

After that (once I have the exhaust off) it'll be grinding the nut down that holds the sensor in so the sensor head goes in further.

 

Then book it in for a retest and drive the 20 miles to the garage I chose to use:-) Hopefully it'll pass then.

 

Can't do anything until Friday now though, I'm stuck in a meeting for the next 2 1/2 days in Bournemouth :-(

 

Rich

[Guest allenr03]

I've checked everything I can. The lambda relay seems to be working, the sensor is in tightand the wiring continuity is ok.

 

I took the sensor out and ground down the retaining nut, I reckon about 8mm has come off:-) Refitted the sensor and resealed the first joint in the exhaust. When i fired it up the engine seems to run better. It runs fast (1500rpm) for about 30seconds then settles down to 900rpm. The throttle response seems better and the exhaust isn't leaving soot on the garage floor so I suspect the mixture is leaner now.

 

Hopefully my modification of the nut has done the trick!!

 

I'm going to book the car back into the garage for a retest and find out.......

 

SVA on 5th June soI hope its ok!

 

Rich