MOT Failure - Emissions
Discussion
My Griff has just failed its MOT due to emissions 
Admittedly the lambda sensors were disconnected (the engine has to run without them until I can get it rolling roaded to remap the Tornado ECU) but the lambda readings were within the appropriate limits so the MOT station didn't think they would make a difference.
Everything was fine apart from the CO reading which was 4.65% instead of 0.30%. Do we think that reconnecting the lambda sensors (done this morning as it was too hot at the MOT station) will make it pass or does this point to another problem? Could a faulty coil (it was leaking oil from the connection) cause this?
Also, they spotted a puddle of coolant sitting on top of the water pump. It has reappeared on the 5 mile drive to work this morning. Does this involve replacing the water pump gasket or is it more likely to be the pipe immediately above it that leads to the inlet manifold?
The words "TVR" and "For Sale" are being threatened!
Ian A.
Admittedly the lambda sensors were disconnected (the engine has to run without them until I can get it rolling roaded to remap the Tornado ECU) but the lambda readings were within the appropriate limits so the MOT station didn't think they would make a difference. Everything was fine apart from the CO reading which was 4.65% instead of 0.30%. Do we think that reconnecting the lambda sensors (done this morning as it was too hot at the MOT station) will make it pass or does this point to another problem? Could a faulty coil (it was leaking oil from the connection) cause this?
Also, they spotted a puddle of coolant sitting on top of the water pump. It has reappeared on the 5 mile drive to work this morning. Does this involve replacing the water pump gasket or is it more likely to be the pipe immediately above it that leads to the inlet manifold?
The words "TVR" and "For Sale" are being threatened!
Ian A.
No the exact story with the chipping is as follows:
The car was chipped (Tornado) and run on a rolling road by Mark Adams. The inlet manifold, trumpet base, trumpets and camshaft were then changed (involving a full engine rebuild). When the engine was put on an engine dyno, it was running very lean at the top end. Mark Adams said that this was due to the increased breathing not being met by increased fuelling by the ECU. The ECU needs to be remapped.
The temporary solution was to run the ECU on a non-cat map (higher fuelling) by changing the tune resistor from white to green. The cat's were also disconnected to stop the ECU from being confused. The theory was that it would still pass emissions tests!
Thus when it failed the MOT, I reconnected the white tune resistor (lower fuelling but I wasn't revving it high enough to make a big difference). It still failed its MOT but the cats could not be reconnected as the connection is right next to the red-hot exhaust manifold. However, the lambda reading was in range so the MOT station did not think that reconnecting them would make any difference.
The best solution is probably to get Mark Adams to retune the chip but a) I've just spend £2500 on an engine rebuild, £850 on insurance and £160 on tax and b) I doubt I can get an appointment with Mark at short notice.
Ian A.
The car was chipped (Tornado) and run on a rolling road by Mark Adams. The inlet manifold, trumpet base, trumpets and camshaft were then changed (involving a full engine rebuild). When the engine was put on an engine dyno, it was running very lean at the top end. Mark Adams said that this was due to the increased breathing not being met by increased fuelling by the ECU. The ECU needs to be remapped.
The temporary solution was to run the ECU on a non-cat map (higher fuelling) by changing the tune resistor from white to green. The cat's were also disconnected to stop the ECU from being confused. The theory was that it would still pass emissions tests!
Thus when it failed the MOT, I reconnected the white tune resistor (lower fuelling but I wasn't revving it high enough to make a big difference). It still failed its MOT but the cats could not be reconnected as the connection is right next to the red-hot exhaust manifold. However, the lambda reading was in range so the MOT station did not think that reconnecting them would make any difference.
The best solution is probably to get Mark Adams to retune the chip but a) I've just spend £2500 on an engine rebuild, £850 on insurance and £160 on tax and b) I doubt I can get an appointment with Mark at short notice.
Ian A.
SGirl said:
IPAddis said: b) I doubt I can get an appointment with Mark at short notice.
You can but ask. I got an appointment at very short notice with him - about a week. It would've been even shorter had the rolling road not broken down the day before I was due to show up!
Mark is at power engineering tommorow, I've got a car booked in, so phone him now you might get a slot if your lucky.
Tim
Could you not just de-tune it for the MOT, and put it back where it was after getting the bit of paper?
That is how I got my Griff through it's last test. The view of my garage was that it was running sweet as a nut, so why fiddle too much! Therefore a quick tweek of something (I don't know what) brings it within limits, but it does not run so good, round to the MOT station, pass, back to garage, put what ever it was back to where ever it came from and voila!
Jon H
That is how I got my Griff through it's last test. The view of my garage was that it was running sweet as a nut, so why fiddle too much! Therefore a quick tweek of something (I don't know what) brings it within limits, but it does not run so good, round to the MOT station, pass, back to garage, put what ever it was back to where ever it came from and voila!
Jon H
jon h said: Could you not just de-tune it for the MOT, and put it back where it was after getting the bit of paper?
That is how I got my Griff through it's last test. The view of my garage was that it was running sweet as a nut, so why fiddle too much! Therefore a quick tweek of something (I don't know what) brings it within limits, but it does not run so good, round to the MOT station, pass, back to garage, put what ever it was back to where ever it came from and voila!
Jon H
Hell yes, that's exactly what I'm trying to do. Unfortunately, the question is what do you tweak!
The current theory (after speaking to Mark Adams) is that the lambda sensors really do make a big difference and that after connecting them and resetting the ECU (by unplugging it), it should pass with no problems.
Also, because the ECU has been slightly overfuelling on part-throttle (it's optimised for full throttle burns), there may be extra fuel/coke near the cat which will take a few miles to burn off.
Ian A.
i would have thought that if the engine has been rebuilt to spec, and the ecu "tuned" to run that engine, by mark...that it's up to him to put it "legal".
if, on investigation, a fault is found to explain the incorrect levels...a small remuneration would be in order.
let us know how you get on. I was gonna get mine done in summer.
good luck!
if, on investigation, a fault is found to explain the incorrect levels...a small remuneration would be in order.
let us know how you get on. I was gonna get mine done in summer.
good luck!
My Chim failed it's MOT yesterday, steering rack boots insecure and front brakes out of balance.
The dealer adjusted it all and had it re-tested for me today and I picked it up this evening.
Cost me just under £600 for a service and MOT.
Lee.
>> Edited by anonymous-user on Tuesday 21st January 19:50
The dealer adjusted it all and had it re-tested for me today and I picked it up this evening.
Cost me just under £600 for a service and MOT.
Lee.
>> Edited by anonymous-user on Tuesday 21st January 19:50
Yeah baby! Passed with flying colours.
Solution:
1) Reconnect lambda sensors
2) Ensure correct tune resistor for closed-loop mode
3) Reset ECU
4) Allow engine to heat up to ECU self-config temp
5) Take for burn up the dual carridgeway at 5000rpm
6) Apologise to other motorists for bleeding eardrums
7) Repeat 3-6 a couple of times to ensure correct ECU adjustment
The lambda is now 1.03 instead of 0.92 so it is running a bit weak now where it was runnning a quite rich before. However, that is at 3800rpm so at 6000rpm it's probably much weaker.
CO reading dropped from 4.65% to 0.01%, legal limit is 0.30%
Mark Adams hasn't tuned the engine since the rebuild so the initial failure is nothing to do with him. I also spoke to V8 Developments (engine builder) and they confirmed that it has to run in closed-loop mode to pass the MOT, hence why they gave me the appropriate tune resistor. It was just me that thought it would pass without.
So, to summarise, it's all good and a rolling road session with Mark Adams is in order.
Ta all,
Ian A.
Solution:
1) Reconnect lambda sensors
2) Ensure correct tune resistor for closed-loop mode
3) Reset ECU
4) Allow engine to heat up to ECU self-config temp
5) Take for burn up the dual carridgeway at 5000rpm
6) Apologise to other motorists for bleeding eardrums
7) Repeat 3-6 a couple of times to ensure correct ECU adjustment
The lambda is now 1.03 instead of 0.92 so it is running a bit weak now where it was runnning a quite rich before. However, that is at 3800rpm so at 6000rpm it's probably much weaker.
CO reading dropped from 4.65% to 0.01%, legal limit is 0.30%
Mark Adams hasn't tuned the engine since the rebuild so the initial failure is nothing to do with him. I also spoke to V8 Developments (engine builder) and they confirmed that it has to run in closed-loop mode to pass the MOT, hence why they gave me the appropriate tune resistor. It was just me that thought it would pass without.
So, to summarise, it's all good and a rolling road session with Mark Adams is in order.
Ta all,
Ian A.
SUPRAMAN said: My Chim failed it's MOT yesterday, steering rack boots insecure and front brakes out of balance.
The dealer adjusted it all and had it re-tested for me today and I picked it up this evening.
Cost me just under £600 for a service and MOT.
Lee.
>> Edited by SUPRAMAN on Tuesday 21st January 19:50
Lee, where was this?
Gassing Station | General TVR Stuff & Gossip | Top of Page | What's New | My Stuff