help please

[baz105e]

not osf but i took a car in for mot today and the lambda was through the roof 1.319 can anybody tell me wether this is too rich or too lean>?? and i've put a cat on since the test. will this bring the lambda down enough without any tweaking on the carb .............ps the car was single point injection but i've dumped it for a nice meaty carb .....ta

[Tom]

putting the carb on is probably why its off mate - would it not have been a closed loop sysytem with the single point? i.e the lambda tells the ecu to adjust fuelling whether its rich or lean

[baz105e]

yep. but now the ecu only controls the spark. the single point was a piece of sweaty horse poo, so now there is no lambda sensor no single point but still has a cat and a carb. when i bought it it had a diesel turbo bolted to it with a fooked engine. i just stuck to the carb that the lad who had it before me put on it(solex twin choke)

[Muttley MK2]

High lambda can be a result of a hole in the exhaust system.You can have a cat that works perfectly but still have a lambda reading that is too high or too low. Do not think that adjusting fueling alone will cure this.Inlet air leaks can also affect lambda.What car are we talking about here? Carbs do not work well with the mot emissions test thats why all modern vehicles run fuel injection. The current limits for co hc and lambda are probably beyond the reach of a carb with no o2 sensors

[baz105e]

its a peugeot 106 1.4 1993. heres the full readout from mot

first fast idle test.

rpm 2000 - 3000 2394

ppm max 200 391

co 0.3 max 1.6

lambda .97 - 1.03 1.319

 

2nd fast idle test

rpm 2800

ppm 111

co 0.17

lambda 1.208

theres no probs with ppm or co just the lambda do you think that if i richen the carb it will do owt ??

[Muttley MK2]

The problem you will have is that the increments in fueling that are possible on a carb are only effective at idle. Once you go onto any other rev range you cannot change owt without changing jet sizes! This is far too crude an adjustment for the size of change in fueling that you need. This is why ecu controlled injection is needed to comply with todays strict limits on emissions. Sad but true

[baz105e]

Bugger lol. better nip down the scrappys tomorow in the anglia and get parts for spi . :thumbsup:get it through the mot and rip it streight off again

[Muttley MK2]

Thats prob the best idea