LAMBDA Woes

LAMBDA Woes

Author
Discussion

KenInOntario

Original Poster:

97 posts

107 months

Tuesday 25th April 2017
quotequote all
I had my freshly rebuilt engine installed into my car, but only to find lambda woes

I used the diagnostic software which showed essentially 0 volts on Lambda 2. I think the mechanic may have connected the sensors the wrong way around before as well.

Regardless, it caused over fuelling, and killed one of my cats.

I ordered 2 new sensors, and 2 sensor connector wires, as the old ones were fried. I ran the wires and connected them into the loom.

But no matter what I check so far the Lambda 2 is still not working. I teste the sensors, both are good.



I checked and there is 12v going to the sensor, and the ground seems to be ok as well. So the issue must be on the blue signal wire for Lambda 2.

Any pointers on what to do next? I am getting overfuelling again. I don't think I will be able to fix this in time for her MOT on Thursday frown

KenInOntario

Original Poster:

97 posts

107 months

Tuesday 25th April 2017
quotequote all
Cleared the old fault codes.


Fired her up, still no LAMBDA 2 frown

I diod not wait for the Red AFR error to appear again


Englishman

2,219 posts

210 months

Tuesday 25th April 2017
quotequote all
Have you traced the lambda 2 wires back to the ECU connector to ensure continuity? If all ok, can you borrow another ECU to try?

Other than that, the adaptives should be as close to zero as possible when idling @~90C. Should be able to achieve that by a adjusting the throttle screw and resetting the throttles by the software. If you can't get close to 0% maybe you have an air leak bypassing the throttle assemblies?

KenInOntario

Original Poster:

97 posts

107 months

Tuesday 25th April 2017
quotequote all
Is the connector easy to get to?

I have a 2nd ecu. Will it work with my immobilizer?

NCE 61

2,386 posts

281 months

Tuesday 25th April 2017
quotequote all
Lambda to ECU wiring diagram on the My Tuscan site Link

Earthing the lambda sensors directly to the chassis rather than the ECU can improve the signal.

NCE 61

2,386 posts

281 months

Tuesday 25th April 2017
quotequote all
Lambda wiring modification Topic

Englishman

2,219 posts

210 months

Tuesday 25th April 2017
quotequote all
KenInOntario said:
Is the connector easy to get to?

I have a 2nd ecu. Will it work with my immobilizer?
The ECU is behind the pedals on the Tuscan, held in by a couple of wing nuts. You need to be a contortionist to get to it, but once released it is simple to remove the connector.

You will need the pinout on the ECU for continuity checks (now attached)

Assuming the spare ECU you have is the same variant, it will be a straight swap. The immobiliser is separate circuit and will not be affected.

Edited by Englishman on Tuesday 25th April 20:45

KenInOntario

Original Poster:

97 posts

107 months

Wednesday 26th April 2017
quotequote all
Ok, looks like I got that issue fixed.

The Leads for 4 & 6 were in the wrong spot on the coil.

I cleaned all the connectors, took the plugs out, cleaned them. 4 & 6 were black, flooded etc etc.

And got her running, but the Adaptive levels seem off.

Also, when I blip the accelerator, the revs don't drop, but rise momentarily before dropping. Any ideas?

I have not taken her out for a drive yet, to be honest still terrified lol!!!


Englishman

2,219 posts

210 months

Wednesday 26th April 2017
quotequote all
Well done, looks much better and should be fine to take for a drive.

The mismatch in adaptives point to the throttles being slightly out of balance. Could cause the rev issue too. There are lots of threads on how to correct this but you will need a Syncrometer or similar.

KenInOntario

Original Poster:

97 posts

107 months

Wednesday 26th April 2017
quotequote all
I have a syncrometer,

got all the throttles at 6.5 - 7 CFM at an idle of 900rpm.

I thought that as well. I just rechecked, perhaps one is sticky? I had them refurbished by Powers who also rebuilt the engine. (Great guys btw).


KenInOntario

Original Poster:

97 posts

107 months

Wednesday 26th April 2017
quotequote all
Redid the throttles again

Still increases RPM when I take my foot off the peddle

Englishman

2,219 posts

210 months

Thursday 27th April 2017
quotequote all
Yes, tricky to get the adapatives exactly the same at idle, but very close balancing on each cylinder can be done with a lot of patience!

One chief mechanic at a dealer I know well said that after balancing with a Synchrometer they do the final adjustment to the balance between the front three and rear three cylinders by adjusting the screw slightly to get the adaptives as close as possible.

As for the revs, is the throttle cable sticking at all? If so, often due to fraying at the pedel end.

KenInOntario

Original Poster:

97 posts

107 months

Thursday 27th April 2017
quotequote all
Not the able, seems that the butterfly for the #1 cylinder does not return to the same position as the others straight away, takes about 1-2 secs for it.

I checked, idled it, used my hand on the throttle, rev'ed up. When I moved the #1 adjuster bracket up with my finger it instantly returned to perfect idle.

I think it needs some adjusting again.

Basil Brush

5,080 posts

263 months

Thursday 27th April 2017
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It could be the small spring in the linkage between one and two. I had one that had gone a bit weak and wasn't holding the butterfly closed against the stop screw.

KenInOntario

Original Poster:

97 posts

107 months

Thursday 27th April 2017
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How did you fix that?

KenInOntario

Original Poster:

97 posts

107 months

Thursday 27th April 2017
quotequote all
The engine aside from that seems to be running well now. Still just breaking her in though for the next 900 miles


Basil Brush

5,080 posts

263 months

Friday 28th April 2017
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KenInOntario said:
How did you fix that?
As a temp fix I stretched the spring out a bit but I'm going to replace them all.

KenInOntario

Original Poster:

97 posts

107 months

Sunday 30th April 2017
quotequote all
Think I found my issue, there are no springs on the adjuster screws.

A set of 5 on their way from the UK

m4tti

5,427 posts

155 months

Monday 1st May 2017
quotequote all
Where was the engine rebuilt.

KenInOntario

Original Poster:

97 posts

107 months

Tuesday 2nd May 2017
quotequote all
Powers. Dom & Andy have been brilliant, Dom already sent me springs before I even figured out they were missing.

I would not have been able to get the rebuild etc , and running sweet without them.

I am in Canada, and cannot thank the lads for their help & patience.