Emissions

[Mole]

Right, my car has failed its MOT, and a re-test all coz of emmissions, ive replaced the cat, which lowered the emissions on the 2nd run down by about 1% (still at 1% vol of CO (3 times the legal limit))

Today i cleaned up the lambda sensor in vinegar to eat away at the carbon, so thats back on there now, looking at the picture of common faults with lambda sensors here: http://www.lambdasensor.com/main/mfaults.htmhttp://www.lambdasensor.com/main/mfaults.htm - mine looks like picture B, rich fuel mixture caused by a failure in the air/fuel metering system.



Anyone have any ideas on what i can do to get this sorted? really need to get this done as i passed my driving test, and it needs to pass an MOT to get tax

 

[Mole]

anyone got any ideas, any car mechs here able to throw some ideas at me, got the whole of this weekend to rectify problems myself

 

[BRUN]

try a full tank of optimax and some fuel system cleaner..........

its been known to work in the past.........

oh and obviously get the car hot before you take it in.....

did the guy at the MOT say it was running rich ?.........how dirty is your air filter ?........when did you last change your plugs etc etc

 

[Mole]

the guy didnt tell me anything, he said the next tihng to try is to give it a full service, but as everything got changed only about 2k ago i see no need, air filter is very clean, pretty much new.

Thinkin of trying some redex in the tank, been told that works good.

i took the lambda sensor out yesterday and checked its condition, quite heavily coated in carbon, which would show either its old, or its running rich

 

[BenR]

Fuel system cleaners wont work as they are reduced to burnt waste and carbon as they pass through. Effectively the detergents they contain are worth nothing.

Its simply and injection fauly probably down to something like your coolant temp sensor, map or potentiometer coupled with your lambda as it should of corrected to stoichiometric when running closed loop.

 

[JAY172]

fuel system will clean the elements before the cylinder though wont they(injectors,pipes,valve seats) but there affectiveness is debatable. does the engine run ok in general? have you knocked the cat with your hand to check if the internal element is collasping(eg-you would hear it rattle as you knocked it). you can check the voltage output of the oxygen sensor with a mulitimeter but its needs to be plugged in with the engine running(voltage should vary constantly between approx 250mv>850mv) .check this with engine hot though as the oxygen sensor readings dont change for the first 5mins or so of engine running from cold. this is the only check you can do as the sensor works on a chemical reaction so you cant do resistance checks on it.Check/change coolant temp sensor and map sensor.

 

[Mole]

i spliced the connection from the signal wire of the lambda sensor and took readings using a multimeter, they fluctuated from 1100mv right down to 0mv, never stayed in a set point, im going to test it again tomorrow after i get an extention lead back, got a proper multimeter whichll record high low and average readout, if thats of any use.

I may be tempted to just goto a scrappers and pinch the whole inlet side of things, plus just rip off a lambda sensor just to test against, if this works then im ok for that.

When the engines warm, it fluctuates a bit on idle, wouldnt say its too lumpy, but the gearstick does its little shaking thing.

I noticed when i took the lambda sensor out to check it physically i checked the wiring, and noticed it had been crimped and replaced by someone else with a universal 3 wire sensor, connections seemed fine, may have been replaced the same time as the cat, which had a stamp on it saying WK 36/98 (week 36 of 1998 i wonder)

 

[JAY172]

the reading will constantly fluctuate up and down that is normal. max readings a little high though but this could just indicate a rich mixture and not nes a sensor fault. normally when the oxygen sensor fails the figures dont fluctuate. the figures are fluctuating as they should but are the sensor seadings accurate as the max figure is a bit high. if your going to the scrappies i would change the oxygen sensor and the map sensor. coolant temp sensors are very cheap so you could get a new one of those. hasnt the local garage got any code readers etc to check the injection system and its sensors.

 

[Mole]

yea couple of places round here do fault diagnostics, bout 30 quid they want.

I shall do a check 2moro of resistances on the certain sensors i can, may find something wrong with the injector or something.

Havent got any real money until this friday (payday) got 67 quid in the bank, and 30 notes in cash.

Also i need to find a bolt that holds the anti roll bar to the wheel section, as the top of my left hand side one has sheared the top off itself and didnt get flagged up on the MOT, but as its failed its re-test i better get that changed

 

[edde]

Have you though about having another place testing the car?

Or ask the tester if £50 cash in hand would "fix" the problem.

 

[Mole]

well if its running rich then i could be saving on a bit of fuel lol

if it comes to it, ill replace all the inlet electronics stuffs, injector, sensors with ones i get from a scrappie off a mk1 ph3, and hope they all work, and run it thru a CO test

 

[BRUN]

be careful mate as sensors you get from the scrappies might be f**ked too and in the long run it will cost you more in money and time !

 

[Mole]

well its the cheaper option at the moment, still working up figures on a loan but i need something to drive about in, i plan on having the parts out of 2 clios, theres a place near me with 7 clios in with energy 1.4 lumps in em,

when i get some spare cash ill replace most of the sensors anyway.

should tie me over for a couple of months atleast

 

[BRUN]

well a very common fault is a buggered coolant temp sensor

check that your map sensor has the pipe connected to it properly and its clipped/mounted in properly

 

[Mole]

ahhhh coolant temp sensor, could this be damaged by the engine overheating? i found that the fan didnt trip in on my car at all, so i changed the thermostatic switch and it works now, but if this coolant sensor is damaged then it could be that

 

[JAY172]

Quote: Originally posted by ATOMiC-UK on 17 April 2004


yea couple of places round here do fault diagnostics, bout 30 quid they want.

I shall do a check 2moro of resistances on the certain sensors i can, may find something wrong with the injector or something.

Havent got any real money until this friday (payday) got 67 quid in the bank, and 30 notes in cash.

Also i need to find a bolt that holds the anti roll bar to the wheel section, as the top of my left hand side one has sheared the top off itself and didnt get flagged up on the MOT, but as its failed its re-test i better get that changed

do you mean the bolt that goes through the anti roll bar bush and holds it to the wishbone? complete bolt/bush kit from renault about £8. coolant temp sensors corrode through on the inside. you can check the resistance of it when the engine is cold and see if the resistance reading matches up to the resistance reading given in the repair manual for actual engine temp.there will be a chart which shows what resistance equals what temp. if the engine is cold but the resistance of the temp sensor corresponds to that of a warm engine then youve found your problem.

 

[Mole]

only 8 quid, not bad, i couldnt find anything on the dialogys about the price, but its on the right hand side, if i put it on full lock the the left i can get to it, its right at the back, looks like it takes a hex socket on top, and its a normal bolt on the bottom with a few rubber bushes.

Would it fail its MOT if this bolt had its head sheared off, as i guess its all to do with steering etc?

Ill get all the sensors i can checked tomorrow, including the injector itself.

 

[JAY172]

edited my last post. i meant wishbone not subframe. anyway if the mot bloke had seen it then it should have failed.

 

[Mole]

ok so thats another thing on my list to get done lol, cant seem to find the part on dialogys, saying that i end up just giving it stupid engine codes etc just to bring up diagrams lol.

 

[Mole]

just reading thru the haynes manual, talks about the coolant temp. sensor, i think this is working correctly as its the same sensor that tells ya on the dash how hot ya car is. ill test it to make sure thou

 

[BRUN]

mine appeared fine, i replaced it with one from Renault and the car ran better

 

[Mole]

Just been testing the sensors i could, checked the coolant temp. sensor and its open circuit, which would show its buggered, would this have such a big influence over the richness of the mixture to cause bad emissions?

Injector measured 1.2ohms which is normal, checked the air temp. sensor, was within tolerance.

 

[Mole]

just had the car running, without the sensor plugged in, runs normally but as youd expect, the guage doesnt go up... but if i plug it back on and start it up again, the guage works normally.. this dont make sense because i tested across the sensor pins, and its open circuit.

anyways heres a short clip of my dash, u can hear the engine, and about 20 secs into it, u hear the engine dip, which it does quite alot, is this normal?

thanks

http://www.steven-petersen.pwp.blueyonder.co.uk/car/DSCI0010.AVIhttp://www.steven-petersen.pwp.blueyonder.co.uk/car/DSCI0010.AVI (2mb)

 

[BRUN]

if its buggered mate get it replaced

its a very common problem on those engines so one from a scrappies wud prob b buggered aswell

 

[Mole]

i plan on doing so, its just weird that its getting a signal for sending the temperature readings to the display on the dash, yet taking a resistance reading from it, i get no reading, totally open circuit.

 

[JAY172]

Quote: Originally posted by ATOMiC-UK on 18 April 2004


Just been testing the sensors i could, checked the coolant temp. sensor and its open circuit, which would show its buggered, would this have such a big influence over the richness of the mixture to cause bad emissions?

Injector measured 1.2ohms which is normal, checked the air temp. sensor, was within tolerance.

open circuit means its definatly faulty,did you check the right one though as the gauge and ecu on older cars use separate sensors. this would affect the engine running so replace it if its open circuit.

 

[Mole]

heres a picture to show what i tested, it had the same socket on it as the thermostatic switch, looks identical really... anyways this shows u what i tested... hopefully its the right one otherwise im an idiot lol

http://www.steven-petersen.pwp.blueyonder.co.uk/car/sensor.jpg

 

[JAY172]

the white one is the injection temp sensor. the one youve marked as unknown.

 

[Mole]

hmmmm seems the haynes manual doesnt point that out, or atleast i cant find it, althou i must admit, the E type engine isnt very well documented in there, time to check the dialogys. thanks Jay172

 

[Mole]

the haynes manual refers to that sensor, which is the sender guage sensor as the coolant temperature sensor?? help this is proper doing my head in, i just want a car that works!!!

bloody renault



Jay172 have u got a proper diagram to show which sensor is which, i cant find jack sh*t on the dialogys

 

[Mole]

right as i cannot edit my last post, no button there to do so

checking dialogys, the sensor marked as unknown looks like:

77 00 866 055 SENSOR 41.51

whereas the one i checked was (i think)

77 00 737 571 SENSOR W/T2PINWHI 20.10

althou looking from the picture, id say that the latter one (Sensor W/T2PINWHI is something different, as the one i tested gave no results, on resistance, which stopped the temp. guage on the dash from going up when getting hot)

help please lol

 

[JAY172]

the brown connector/sensor is for the instrument panel gauge. the white sensor/connector is the injection coolant temp sensor. youll know if youve got the right one because its got a stupid metal clip that holds it on and makes it a right pain to get the connector off.

 

[Mole]

ahhh nice one mate, seems the haynes manual never documented that then.

I might just book it in for a fault diagnostic test and see what that tells me, dont want the garage doign the work if i can do it myself, as for that anti roll bar bush kit, is there a part number i can goto reno with?

cheers again Jay, youve been extremely helpful with my car problems lol

and thanks to everyone else with their input

 

[JAY172]

most garages will charge you a set diagnostic fee of about £35 and whatever they find you could replace yourself as youve said. i could get you the part number for the bush but seeing as youve got to go and fetch it you might as well just let them look it up. make sure you take your reg or chassis number with you so they can look up the correct part. all the numbers out of the oval shape on the chassis plate would do as well.

 

[Mole]

how can they use the reg number to trace back my car? can dialogys do that? or do they use another system they use?

 

[JAY172]

all the vehicle details are avaliable on the renault dealer net (icm part) by just putting in the reg number.

 

[Mole]

ive just phoned 3 garages that can do code reading, and they say that its unlikely they can just tell me whats wrong with it, I myself dont have the cash to pay for it to be left in the garage to be serviced on whatever.

Can anyone confirm that it will actually pin-point my problem? Is it worth taking it to a renault dealer to ask them to do a fault diagnostic on there, and how much would they charge?

 

[Mole]

right got home, and tested that unknown sensor, resistance changed with temperature, and running it without the sensor plugged into the connector, made the car sound like it was really going to die!!

got about 5k, but as its rather cold out here i would say thats about right, got it down to 2k after having the engine on for a few minutes....



so what should i do? im thinking of replaceing the sensor and then putting it thru the test again

any ideas?