Lambda Problem Saxo VTS

[ScottyD-VTS]

Fitted a Stainless Steel System to a mates VTS.

But stupidly we had the lambda hole welded up thinking that there was no lambda in manifold for a ph2 vts. Dont ask why

Obviously when we took the Old Exhaust apart there was a Lambda.

Now we have a problem that the car isnt running right.

Manifold Lambda is in a GMC sleeve, if i connect the Centre Section Lambda and put that in a GMC Sleeve also will the car run alright again?

Just now its only running with 1 Lambda and the car is overfuelling badly.

Can he still drive it or will it cause problems with the engine?

Thanks in Advance

[mattg]

I only have 1 in mine, the one in the manifold is still there as its 1st bank which will cause problems without out, second bank lambda isnt a problem if you dont have one, i dont have the second bank one which is supposed to go in the cat as mine is decatted too and runs perfect without it, engine management light flicks on now and then but had it tested and runs perfect.

My mate had a problem with his 1st bank lambda and it caused all sorts of problems so would defo need one in the manifold mate.

[gd16]

Not entirely sure i've followed what your saying, so can you can you confirm;

2 lambda sensors.
The one that is normally nearest the engine (one that normally reads emissions first) is in the GMC sleeve
Next lambda sensor is screwed into the exhaust system.


Is that correct?

If so - its wrong. The second sensor should see cleaner air than the first one (as standard it assumes the CAT is working due to this). The way you've got it plugged in the second sensor is seeing more emissions than the first - so its probably trying to lean out the fuelling quite a bit.


Any issue with the fuelling will cause engine damage. Just a matter of how big the issue is and how much its driven.

[ScottyD-VTS]

Whats happened is the First Lambda Bank1 is in the GMC Sleeve reading clean air. but there is no lambda connected at bank 2.

Car is overfuelling badly and cutting out on idle.

The reason the first lambda is in the sleeve is because the hole in the manifold was welded up as we didnt think there was a lambda in the manifold.

So how can we fix this if we put both lambdas in a sleeve each should this then let the car fuel normally?

[mattg]

Right this is getting confusing lol.

So you have one in a gmc sleeve in the manifold then, and havent got one where the cat would be.

If there is a decat fitted has it got a hole for a lambda or no?

Cant see the second one giving you problems mate, only the one in the manifold would cause issues with idle and fuelling etc.

Just checking now, dont mean to sound silly but have you unpluggd both sensors and got them mixed up, ie put bank 2 sensor into manifold etc.

[Alex]

You need the first lambda in the manifold, thats the one that the ecu uses to regulate fuel.

The second one just pops up a warning light if emissions are high, doesn't effect fueling.

[gd16]

The first lambda sensor needs to read the emissions. No way around it. (Unless you want to go standalone and get it properly mapped therefore no need for the sensor).

The second one i'm not entirely sure if you can just unplug or not. You can get away with having it plugged in but put in the sleeve.


Lambda sensor is read by the ECU for everything except full throttle. So if the ECU can't read the signal its going to go into limp home mode and try and make things as safe as possible so you can't damage the engine.



Not really too important where the lambda sensor is plugged in - but the first sensor MUST be plugged in.

[ScottyD-VTS]

Right this is getting confusing lol.

So you have one in a gmc sleeve in the manifold then, and havent got one where the cat would be.

If there is a decat fitted has it got a hole for a lambda or no?

Cant see the second one giving you problems mate, only the one in the manifold would cause issues with idle and fuelling etc.

Just checking now, dont mean to sound silly but have you unpluggd both sensors and got them mixed up, ie put bank 2 sensor into manifold etc.

Sorry Mate i kno its confusing just weird.

Right The First Lambda Sensor the one in the manifold is plugged in and screwed into a GMC Sleeve

And there is No Lambda sensor on the centre section.

When i fitted the system the cars idle was a little rough but no EML on and no cutting out. Now the EML is on an is cutting out.

Im worried that because the first lambda isnt screwed into the manifold because it is welded is the cause of the problem. Not sure how we can fix it if the holes welded up?

Make any more sence?

[mattg]

Yes it makes sense now mate lol.

If there i no hole for the second sensor just leave that one as its not needed.

Like everyone else has stated too the 1st sensor needs to be in the manifold so it can pick up readings etc, you defo need the 1st sensor in because both sensors are different and the 1st one is the important one for the running.

[ScottyD-VTS]

Right Damn thats a bit of a problem. Any way to by pass it as there is not really anyway to get the lambda into the manifold now that its welded up?

Only option i can see is to drill the weld out and re tap it?


Any other ways would be very helpful cheers

[mattg]

Thats right mate, you need to get the 1st bank sensor into the system.

Only option like you said with no holes in it is to drill out the weld and tap it and then screw the sensor in.

[ScottyD-VTS]

Thats right mate, you need to get the 1st bank sensor into the system.

Only option like you said with no holes in it is to drill out the weld and tap it and then screw the sensor in.

jesus thats going to be a bit of a mission

definately no alternative way?

[mattg]

Not that i can think of tbh mate, you need the 1st bank sensor in the system some how to pick up the readings so the ecu can calculate the correct settings.

[gd16]

Either that or find an old exhaust system, cut out the boss that the lambda sensor screws into (make sure its the correct thread etc), then cut a hole inyour system and weld the boss in place. Had to do that to my manifold as it only had one hole for a lambda sensor and i needed two (one for ECU, one for AFR guage)