Running issues

1. lucasboi69 L-plater Joined: Jul 2009 Petersfield Posts: 35 Saxo Vtr 52 Plate In Black

   #1 12th October 2010, 19:54

   hi got a vtr mk2. engine missfiring and running rich., have got a code of fuel trim and also lambda sensor 1. changed sensor and still have problem. changed double relay under ecu. only getting lambda sensor 1 code back up. any other ideas? thanks
2. burgerfeet Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does

   #2 12th October 2010, 20:38

   Quote:

   Originally Posted by lucasboi69 hi got a vtr mk2. engine missfiring and running rich., have got a code of fuel trim and also lambda sensor 1. changed sensor and still have problem. changed double relay under ecu. only getting lambda sensor 1 code back up. any other ideas? thanks

   The reason fuel trim and lambda have come up is because the lambda sensor is producing results that suggest the car is rich and as a result the ECU is adjusting the mixture i.e. fuel trimming, in an attempt to lean the mixture off. Becuase it can't lean it off sufficiently it will flag it as a fault.
   
   The real problem you have is the misfire. When a misfire occurs, unburned fuel is detected by the lambda sensor as an excessivley rich mixture. ECU trys to compensate but can't. So in summary, don't look at the lambda at all until you have cure the misfire....this is your fault, nothing else.
   
   This is the problem with fault code readers if you are not technically familiar with engine management systems...what the code reader say must be right...not the case in the majority of cases. Don't worry I know garages that spend thousands on this kit and do not know how to interpret the data.
   
   Hope this helps....
3. lucasboi69 L-plater Joined: Jul 2009 Petersfield Posts: 35 Saxo Vtr 52 Plate In Black

   #3 12th October 2010, 20:53

   yer but the only thing is. if i disconnect both lambdas it runs perfectly. ihavent got a miss fire atm but it seems to hesitate a little some times. tried a new coil on there and made no difference.
4. burgerfeet Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does

   #4 12th October 2010, 21:47

   The ECU will now put its own value in place that try to compensate for sensor errors. Without live data from ECU or carrying out proper testing it is a finger in the air now.
5. lucasboi69 L-plater Joined: Jul 2009 Petersfield Posts: 35 Saxo Vtr 52 Plate In Black

   #5 12th October 2010, 21:59

   no other sensors that i could try??? has been idling strangely too. most the time its ok but sometimes it idles at 1500
6. burgerfeet Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does

   #6 13th October 2010, 09:10

   try disconnecting other sensors like MAP and coolant first. Don't disconnect the crank sensor as the car won't run. Make sure the lambda is connected back up when doing this.
7. lucasboi69 L-plater Joined: Jul 2009 Petersfield Posts: 35 Saxo Vtr 52 Plate In Black

   #7 13th October 2010, 17:57

   changed ect sensor few days ago, and i know that it wont run with no crank sensor, took out icv today n it was caked in shit cleaned it up put it back in and also cleaned map sensor, hopefully that solves it