Cheap AF Gauge

[John Sims]

For those of you famillier with my recent problems, I am in the throws of sorting an AF gauge. Despite Mr Cannells recommendations I have gone narrow rather than wide band and will probably regret it ultimately. I have taken the view that some warning is better than no warning at all.

The gauge, now winging its way from the States is a natty 10 LED jobbie which apparently is completely black when not in use.

Unfortunately it would seem that it lights up all the bars from the bottom upwards as a climbing scale, rather than the bar as appropriate to the condition, but it is only as a warning - and only cost $69

I sourced a standard Lambda sensor from Euro Car Parts, at £30. This is a tad cheaper than my OPC with the Porsche one at £110. Apparently, the only difference is the Porsche one has the Porsche plug on it for the Porsche loom. As I'm only using the sensor with the gauge, the plug doesn't make any difference anyway.

Now all I need to do, once all the goodies arrive, is to get them in the car.

 

[Diver944]

Great, I've been waiting for a guinea pig to install an AFR in a non cat car that does not have a factory lambda []

Let us know how it goes John?

 

[944Turbo]

I think Gareth on titanic has just done it too so he may be able to give some good tips,
Tony

 

[John Sims]

OK, Lambda link has arrived.

It has three wires - one to the sensor and 2 for the Lambda heater - as if it wasn't hot enough already!

Can one of you fine people tell me what sort of current draw I should allow for on the Lambda heater and any clues as to where I might nick a suitable feed from?

Thanking you in anticipation,

 

[Diver944]

ah......now that I do know, or have an idea about anyway.

The cars with a cat and lambda as standard use a three pin plug that is just behind and to the right of the lifting point at the back of the engine (where you have your MBC John [] )

Cars without a cat just have a blanking plug in the socket (well mine does) so you could tap into that. By a stroke of good fortune when I bought a S/H headlamp I discovered that the headlamps use exactly the same three pin plug, so if you want to keep your underbonnet looking standard (yeah right [][][]) you could try a breakers yard for an old plug.

 

[John Sims]

The plot thickens...

OK chaps, is this the unused lambda sensor plug?

Assuming it is, what is the wire in the blanking plug for?

Again assuming it is the lambda plug I guess it must be earthing the sensor lead. Garath on Titanic noted that connecting up a lambda to the plug provided all manner of odd running (how I know that feeling). To avoid this, again guessing, if I cut the sensor wire going to the DME/KLR earth the one from the box, I can then use the sensor wire to feed my guage.

It all sounds too simple? [8|]

 

[944Turbo]

That is the plug, I am not sure exactly, mine was already connected up as I had a cat.

I vaguely remember with it unplugged I couldn't get any voltages with a multi-meter.

I guessed which one had the info by the sex of the plugs and then tested it connected ( iused a thin wire tucked into the connector), it was giving sensible info 0.5V IIRC range is 0-1V connected my AFM cable.

Which connections does the short go across?
My 'heater' connections were the 2 pins of the same sex the opposite sex pin was for the sensor.

Tony

 

[John Sims]

I bought a S/H headlamp I discovered that the headlamps use exactly the same three pin plug,

They do but, apparently speaking to Porsche-Apart, they are the wrong sex.

Unperturbed I've ordered on old Lambda sensor (£15) from which I will whip off the lead and connect it to my new sensor ready to plug into the affore mentioned plug - still cheaper than a full Porsche sensor by £50 []

Additionaly I've ordered a daffy of plugs, a fuse board and a shed load of heat shrink as, having partly linked into the DME/KLR wiring, I'm now going to re do it neatly with plugs etc to gain acces to the Lambda wire and generaly have a good tidy up.

 

[John Sims]

As noted in another post - the bung won't come out of the turbo up pipe. Despite heating it to cherry red (and melting an allen key) it wouldn't budge.

Any ideas?
Is there a more appropriate place within the exhaust to mount the Lambda?
Is there an easier place to weld in a ferrule to take the Lambda?
Am I better off just getting a replacement section of exhaust with the the bung removed?

Whilst I appreciate there must be a delay, being further down the system, is there any issue in putting the Lambda in the rear section? Porsche Lambdas do preheat so there shouldn't be a delay in activation - I assume.

 

[944Turbo]

Did I mention it was left hand thread??? [] [][][]




Only jesting []

I guess as you are only using it for reference and exhaust gas travels fairly quickly it could go almost anywhere but I think if it was mine I would go for as close to the factory fitting as possible so somewhere in the same section? or maybe after the turbo so you dont have to worry about the swarf.

Tony

 

[John Sims]

Talking to Simon at ESS today, I think I might go for a non-silenced de-cat pipe and have a ferrule put in that. I just need to work out where the best/most convenient place for the ferrule would be.