Looking for Lambda

[griffter]

I've got a wild and crazy idea - try to get lambda feedback working on my precat.
I've already got lambda bosses in my Dulford stainless manifolds.
If memory serves, I should have the lamda wiring in place, tied up in the loom somewhere.
So...all I need is a pair of lambda sensors and a tune resistor (possibly and a cat-map fuel chip).

Can anyone tell me where to start looking for the lamda connectors and loom? What colour are the wires? What do the connectors look like? Anyone know from experience where they were concealed on the precat loom? Or were they simply cut off?...

Any other comments welcome - thanks!

[Ozstyle]

Hi,
the lambda connectors on the loom are close to the rear of the rocker covers. You will need the extension cables that plug into the connectors in the loom. The extension cables run along the engine between the rocker covers and the inlet manifold and down the front of the engine block on both sides. The lambda sensors plug into the the extension cables in the vicinity of the front supension.

Oz

[griffter]

Thanks! Extension cables from a RR breaker perhaps? Or are they TVR specific?

[Pupp]

PM me if you don't track any down near to you... have some used sensors that should be ok and some extensions spare too

[HRG]

You can make any connections you need with bits from here:

http://www.vehicle-wiring-products.eu/VWP-onlinest...

They stock all the TVR interconnects.

[rev-erend]

Surely a crazy idea..

The MOT man may now test you car for the much more stringent emissions test - which you will fail as you have no cats.

I'm pretty sure there were quite a few griffs made around 93 that are sort of on the cusp of the test.

What are you trying to achieve ?

[nicktowe]

rev-erend said:

Surely a crazy idea..

The MOT man may now test you car for the much more stringent emissions test - which you will fail as you have no cats.

I'm pretty sure there were quite a few griffs made around 93 that are sort of on the cusp of the test.

What are you trying to achieve ?

An MOT man who knows what he is doing will not test the car more stringently just because it has Lambdas. If the car passed MOT's before lambdas it should pass them afterwards. The critical issue is the date the car was registered.

[blitzracing]

griffter said:

I've got a wild and crazy idea - try to get lambda feedback working on my precat.
I've already got lambda bosses in my Dulford stainless manifolds.
If memory serves, I should have the lamda wiring in place, tied up in the loom somewhere.
So...all I need is a pair of lambda sensors and a tune resistor (possibly and a cat-map fuel chip).

Can anyone tell me where to start looking for the lamda connectors and loom? What colour are the wires? What do the connectors look like? Anyone know from experience where they were concealed on the precat loom? Or were they simply cut off?...

Any other comments welcome - thanks!

The idea is far from crazy, Ive done this on my Ginetta, but there are some minor pitfalls as well. Firstly the catalysts fuel map constantly cycles the air fuel ratio around 14.5:1, which is the optimum point for minimum polution. This can be a little lean for and engine designed in the 1950's and can introduce a snatchy throttle response at low throttle openings, but some TVRs do it and some dont. On the plus side, a leaner mixture will improve the MPG significantly over the origional TVR non cat fuel map, that is set to run at 12:1 or so all the time, and on my car I gained about 6 mpg!. Performance wise the throttle response is not quite as good on the catalyst map, as it takes a moment for the ECU to switch from closed loop fueling at 14:1 to open loop at 12:1, but anything above 3400 rpm or 3/4 throttle the fueling is the same either map. If you want the best of both worlds, then make your tune resistor switchable with two resistors. You need a 3.2k ohm and the 470 ohm currently fitted. You wire them in series, and put a switch across the 3.2k. With the switch on, it runs the non cat map, off the cat map. Put the switch in the dash, and simply set it before you turn on the ignition and away you go. You will get error code 21 generated in the ECU, but it does not effect the running at all. Connector wise I have not been able to get the barrel type connectors any where used by Range Rover to fit Lambdas, so ended up cutting the loom and using spades, but be warned the Lambda cable itself is screened audio type cable with a very fine core, so you really need to solder some take off wire on to it to connect to the new connectors. I have also a range of TVR fuel chips if you need one. Bit more here:

http://www.g33.co.uk/fuel_injection.htm

Mark

Edited by blitzracing on Friday 4th July 20:11

[Ozstyle]

Hi,
I believe the extension cable is TVR specific - I replaced one a while ago and got it from a TVR dealer. I think the lambda probes on a range rover plug straight into the loom plugs as the lambda probes screw into the exhaust near the rear of the engine block.

Oz

[blitzracing]

You can get new probes for less than £20 from the 'states, but they dont have the unique connectors, so you have to use your own. If anyone does know where to get the Lucas / Amp barrel connectors Id be most interested.

Mark

[griffter]

rev-erend said:

Surely a crazy idea..

The MOT man may now test you car for the much more stringent emissions test - which you will fail as you have no cats.

I'm pretty sure there were quite a few griffs made around 93 that are sort of on the cusp of the test.

What are you trying to achieve ?

My car was tested last week, and bizarrely came up on the computer as 'first used Dec 2003' - so it was subject to a cat test, which it failed, and then because it is pre '96 was subject to the non-cat test (that's the rule for pre 1996 cars I believe). It's still incorrect procedure though as the car was registered Feb '92 so should never have gone through the cat test. It's the first year it's happened so I think the MOT computer info must have been 'updated' since last year...

Anyway why am I doing it? Because I've nothing else to do! I've done absolutely everything I want to to the car - it is FINISHED!

Blitz implanted the idea and I rather like it. I can always ditch the system.

Thanks for all your replies. Pupp, YHM.

[blitzracing]

griffter said:

rev-erend said:

Surely a crazy idea..

The MOT man may now test you car for the much more stringent emissions test - which you will fail as you have no cats.

I'm pretty sure there were quite a few griffs made around 93 that are sort of on the cusp of the test.

What are you trying to achieve ?

My car was tested last week, and bizarrely came up on the computer as 'first used Dec 2003' - so it was subject to a cat test, which it failed, and then because it is pre '96 was subject to the non-cat test (that's the rule for pre 1996 cars I believe). It's still incorrect procedure though as the car was registered Feb '92 so should never have gone through the cat test. It's the first year it's happened so I think the MOT computer info must have been 'updated' since last year...

Anyway why am I doing it? Because I've nothing else to do! I've done absolutely everything I want to to the car - it is FINISHED!

Blitz implanted the idea and I rather like it. I can always ditch the system.

Thanks for all your replies. Pupp, YHM.

If you are tinkering, its worth your while getting a lambda gauge or analogue test meter in the cockpit and strap it across the lambda probes, so you can really see what the fueling doing- its quite interesting and you dont need a rolling road to trim the fuel pressure etc. Basically anything that can read from 0-2 volts will do, and I used a stereo audio power LED display that worked pretty well with some minor mods. (Then I could see both banks)

http://cgi.ebay.co.uk/ELECTRONICS-PROJECT-KIT-22-L...