light on again!!!!!

[rob172cup]

my engine manegement light is on again. its been on twice before, the first time was just after i had my exhaust and sports cat put on so i thought it must be to do with that so i took it to renault and they said it was fixed. then it came back on and they told me it was my cat that is knackered so i just picked it up and the light was off so i was happy but its just come back on and ive done that test you can do and it came up with the letter t which i read on here means an injection fault has been detected for a min of 4 secs.
how accurate is that test and whats up with my car is the fault the reason my light is on or are they not related help please

 

[rob172cup]

oh and im sure the cat is not fucked

 

[rob172cup]

?

 

[edde]

Its a very accurate test don't help diagnose it much but thats the ECU speaking there.
Did you disconnect the second lambeda sensor after the cat?

 

[rob172cup]

no but it ive aked k tech and they said the light should not come on

 

[edde]

no but it ive aked k tech and they said the light should not come on

You do need to disconnect it.
Some peoples cars set the emmsiosn light off with the second sensor fconnected after a few seconds some don't do it for months.
There no reason to have the second sensor connected.

 

[rob172cup]

so why does it have a hole for it? and does the light just stay on if its not connected

 

[Dink]

is it a 100 cell cat?

as my light is on all the time so looked it up and you need a 200 cell if you OBD 2

 

[rob172cup]

its a jan speed cat i got it from k tech

 

[Jesske]

The second sensor has to measure a reasonable lower value than the first. I have a +-30 cel cat without the gap for the second sensor. You only have to place the second sensor in a small tube and tape it under the car. The light won't come on. If you just tape it under the car (not in a tube) the light will come on sometimes, but will go out again

 

[rob172cup]

whats this cel cat thing?

 

[rob172cup]

anyone

 

[edde]

The cat thingie is how many holes the cat has a decat has 0 as there just one bit hole the 172 has a restrictive cat with a cel of 400 the 182 has a 200 cel cat from memory. The smaller the number the less restrictive.

 

[rob172cup]

so what is the janspeed cat anyone know?