rich running 3b coupe

[simons2]

Hi guys , my 91 3b coupe runs rich when hot and the temp gauge doesn't work , I guess it is a temp sender but any help pointing me to the right one would be appreciated , it is home fried , de catted and running a cone filter

[rs200]

rich mixture don't depend on MFTS. lambda probe or F96 sensor (white one on back of the head) can cause rich mixture . take a look on wires , maybe one of them don't have good contact.

[simons2]

Thanks , will have a look , which one feeds the temp gauge ?

[simons2]

Just replaced lamda , no change

[andy10v]

The gauge works off the MFTS (check the mfts plug as well), the 3B ecu does also use the MFTS.

[ian4455]

Just remembered i also change the sensor on the rear of the head along with lamda sensor. Its the smaller of the two - 2 pin, think its was called a G62 or something, I actually posted a section on here similar to your question running rich ! The larger one sits under the intake and sends the signal to the temp gauge !!

[simons2]

Rs 200 said the white one is f 96 , does that ring a bell , looks like I might need both

[s2driveruk]

small one on back of the head is G62 coolant sensor...I had crappy starting and idle when mine went south

[simons2]

Plus some #$% head has just keyed her , ahhhh

[ian4455]

My car seemed to run fine unit i upgraded to RS2 Hybrid spec 3b. Started ok when cold and drove ok until it started to get warn then black smoke & wouldn't tick over.

[ian4455]

Plus some #$% head has just keyed her , ahhhh

Sorry to hear that some people need a good kicking for doing such a thing.

[simons2]

Still runs well when hot , so looks like both those sensors or wiring , says something when a 20 year old car still provokes jealously

[rs200]

sorry I change it with something else .. it is G62. newermind how it calls .
if the MFTS are bad ,they can also reduce your boost on 0.4bar , and you must have 0.9bar on stock .
but I will say that lambda is bad 99%.

[simons2]

Ok , is there a way that I can test it ?

[simon20vq]

Got the same problem myself. Rough when cold sweet when hot. Just change the G62 on the back of the head and it appears to have sorted it. I think you can test it by checking the om's. I had a spare so just swapped it over 10min job.