big problem! help !!! - Saxperience

spencer_cammedvts · 1st March 2006, 20:10

using waaaay too much petrol. seems to be sine i made the filter mod but thats probably just me.

im gettin like 85 miles to £15 so thats like 170 to £30.

proper worrid now. also this may be some thing to do with it but everytime i put my clutch in to change gear my car revs up a further 500-600rpm before the revvs start to die down. this is after iv shut off and the clutch is in.

anyone know what this could be?

please help iv got no money and really cant afford to pay loads out if its somethin serious. some one please re-assure me!

Scott^p · 1st March 2006, 20:41

normally drinking fuel can be put down to faulty lambda sensor causing it to run in "limp home" mode

spencer_cammedvts · 1st March 2006, 21:31

DO YOU THINK IT COULD BE ANYTHIN TO DO WITH MY AIR INTAKE SENSORE AS I HAD TO EXTEND THE WIRING ON IT TO ACCOUNT FOR MY FILTER BEING MOVED TO THE FRONT. I MAY HAVE GOT THE WIRES THE WRING WAY ROUND!

Ratty · 1st March 2006, 22:40

arnt they coloured? the car jumping revs when you change gear is telling you that the ecu is putting more fuel in when the load on the engine changes (just like turning on heaters, lights, radio sub amp and the batter gets hammered so the stepper kicks in to make the car idle properly)

So thats a def sign that something isnt right, sadly that something could be anything. Get a multimeter out (if you dont have one then buy one) and check voltages on sensors at idle, ie air temp, lambda, coolant temp etc. Post here and ill tell you, make sure the car is at normal temp first though

spencer_cammedvts · 2nd March 2006, 00:02

the wires on the air intake sensor are both white and when i snipped them to extend em i hadnt got a clue which was which! it does also seem that the flat spots throughout the rev range are a lot more obvious now. before the filter mod was made i used to get 320 miles to a full tank. now im luck if i get 250! its got to be somethin to do with the filter mod. or it could have started when i put the 4 branch on? i had to extend the lambda sensor then!

thanks for ya help ratty. always much appreciated!

woodsy · 2nd March 2006, 00:28

didnt the lamber sensor reach over the back of the gearbox i found that out
personally i wouldnt cut and extend any wires unless i really needed to like when the knock sensor and pressure sensor wires melted so i replaced them

"SCOTT" doesnt limp mode only allow you to drive at 50 mph or something daft like that

to be honest mate i relised my fuel went down a bit when i put a mod filter on
think this was due to a heavy right foot and the filter sounding ace

spencer_cammedvts · 2nd March 2006, 03:24

just got back from college and there is a motor vehicle engineerin course on in the same room as me. i nipped over to the teacher of the course and explained the problem.

he said it would make a big difference if the wires were crossed. he said it sounds as though my engine is running could all the time.

what he meant by this is what you'd know as the automatic choke that kicks in when you first start the engine isnt shutting off. so the car is over fueling all the time. he says he doesnt think its my lambda sensor as that alone wouldnt make the mileage as bad as it is at the mo.
He also said that some of it could be to do with the change of air temp from where it goes past the sensor at the front of the car to when it actually goes into the throttle body after its gone through the piping.
IMO the temp wouldnt change that much in the distance of the piping. (a couple of foot!)

does all this sound right ratty? or anyone for that matter!

spencer_cammedvts · 2nd March 2006, 17:53

i just dont want to go snippin wires again if its not gonna do anything!

Scott^p · 2nd March 2006, 18:09

Quote:

Originally Posted by woodsy

"SCOTT" doesnt limp mode only allow you to drive at 50 mph or something daft like that

not necessarily, if its the lambda thats at fault then the ecu doenst know whats going on in the engine, for all it knows it could be running super lean and be ready to die. So it reverts to "limp home" which basically means it pumps a shit load of fuel in to ensure the engine doesnt detonate, giving poor performance and shite consumption

Ratty · 2nd March 2006, 18:18

and it doesnt sound like your automotive class really know how sensors work lol. Inlet Air Temp and Coolant Temp sensors are of the resistive type ie 1 wire for earth and the other for the signal, i dont think it matters which wire it connects to on the actual sensor as they are not powered.

if you extended the wire on the lambda then id say that was the problem, the wires are sheilded and are very sensitive ie you shouldnt cut them, id get a new lambda and route it correctly.

Ratty · 2nd March 2006, 18:20

and no it wouldnt make any difference, a 10 degree increase in temp is something liek 1-3% loss of power, thats got nothing to do with fuel, lambda has lots to do with fuel, specially at warm up and below a certain rpm, if the lambda things the car is leaner than it is, at warm up and idle, and transient conditions ie not full throttle it will put too much fuel in (and since the lambda thinks the fuelings right the ecu doesnt correct it).

spencer_cammedvts · 2nd March 2006, 18:37

iv just changed the wires over on the IAT sensor and took her for a spin. NO FLAT SPOTS ANY MORE! so thats one aspect of it sorted not sure if it will make much difference to the fuel though!!! how much am i looking at for a new lambda then? or even a second hand one as i think it would be best to replace it anyway if if the cuts in the wires may have changed somethin!?

l1ukeRS · 2nd March 2006, 19:23

which 1 do you need? will 1 off a mark 2 do the job? if it does i can get u 1 for a 10er +post
let me know
or Ratty will a mark 2 lambda b ok for this shud be the same surely does it matter which 1 2?

spencer_cammedvts · 3rd March 2006, 13:35

yer mate that would be sound if it fitted. but im not sure well see if the ratster can tell us!

madfubar · 17th March 2006, 13:05

high revving-turn off car,disconnect automatic choke sensor(colour lilac),wait a short while,reconnect it and u should hear 2 or 3 clicks from the ecu.try car again,it should b ok....it worked 4 me!!!

spencer_cammedvts · 17th March 2006, 17:46

nice one mate! where is the auto choke sensor? on the throttle bosy or the ecu or what?
any help would be great!

madfubar · 21st March 2006, 07:01

sorry m8 i aint been here 4 a while, you should find it on the throttle body close 2 bulkhead if i remenber rightly!!!

jpa214 · 22nd March 2006, 04:21

Joined: 21/March/2006
Member No: 9166
Posts: 1 Posted: 21/March/2006 at 23:14 | IP Logged

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hi there please can anyone help me,ive just bought a saxo vtr,and my throttle is sticking on it when i put my foot all the way down,and i have no idea what it is,also the butterfly sticks when doing it,please help
any one
jpa214