terrible idle.

[blackbooty]

morning peeps, some advice or ideas needed.

been having weird stuff going on that i think is all linked.
started with check engine light comming on... running sweet, no probs.
changed o2 sensor , light went out a couple of days later, and stayed off for a couple of days before comming back on.

then petrol consumption rocketed, was 90miles for £20, went down to 50 miles to £20. ouuuccchhh. (still running smooth)

3 or 4 days later, i started her in the morning and got a terrible idle, bouncing all over the place. 400 rpm bouncing up to 1200 dropping to 600 upto 1500 , holding at 2000 back to 800 ect ect.

she starts instantly and as soon as shes upto running temp all probs dissapear, other than an occasional cough.

i have replaced (new run) elbows from in-man to by the turbo, changed maf, changed o2 sensor , changed evap valve and evap cannister ???

checked engine fault codes and got these..(hence all the above swaps).

541. evap valve fault.
121. maf sensor signal absent or faulty.
231.long term fuel mixture weak or rich at part load.
232 " " " " " " " idle.

ps. after swapping the maf sensor back (done it a few times) i forgot to connect the multi plug and stared her and she ran exactly the same as when it was connected ????

im thinking ...RE. 121...that the car doesnt realise that the maf is connected or there.
even when i changed it for a known good unit.

im stumped and dont know what to try or test.
i dont have enough confidence in the car to take her on a 70 mile round trip to a main dealer.

any thoughts ?

wayne

[mike 850]

hi, an air leak would throw the fuel trim thing, i had that on mind last week , it lost boost and everything, it ended up being the hose going to the throttle body split where it joins to the idle valve, you can only see it when you take it off!! id say check all the hoses, and the little elbow on the inlet, these could all effect the idle
hope this helps

[blackbooty]

hi, an air leak would throw the fuel trim thing, i had that on mind last week , it lost boost and everything, it ended up being the hose going to the throttle body split where it joins to the idle valve, you can only see it when you take it off!! id say check all the hoses, and the little elbow on the inlet, these could all effect the idle
hope this helps

thanks for that mate.

well..... monday night i changed the o2 sensor back to the one that was originally on the car.

yesterday morning, she ran like a dog again (hense the post) ,
took dog for a walk (ran awfully), went to the driving range (ran awfully)
went to the golf coarse (blah blah) , left her there for four hours.....
started beautifully and ran sweet ?????

just went out to try her after standing all night, and shes just started and idled like shes just come out of the factory ?????

what the **** ? is it poss that the fuel ecu takes time to work out theres a new o2 sensor in place ?

i really cant work this one out (not that im complaining, back to full strength)