White2505

obvious first things are:- what have you changed recently? many faults comeback to something I have wired up which seemed correct at the time in the cold light of day but when the lights are switched on or the electric heated rear window is switched on suddenly starts doing funny things!! something shorted around the ignition switch, headlight switch, any smells of burning? or seen any smoke recently which you could'nt trace at the time? Where are the relays for your headlights, have they got water in them, corroded contacts etc etc

so, if the the thermotime switch is faulty I could potentially be adding extra fuel once upto normal operating temperature via the 5th injector. However surely at this point I'd be running rich and see this through fouling of the plugs?? (or of course the 5th injector would not work when the engine is cold)

nice one cheers

Hi, mfa is already goosed on mpg, this is from actual fuel usage and actual mileage covered. Most people seem to be average in the mid-high 30's unless they're having troubles so I know my fuel consumption is WAY too high. there is no lambda sensor cos its a 1.8 valver. I just don't see how i can use almost twice as much fuel as the average without obviously running rich???

mine is also missing that pipe off the back of the airbox and runs absolutely no probelm at all.

So I'm currently getting about 20mpg out of my valver. There are no fuel leaks, it has new injectors fitted and dioes not appear to be running rich, I recently had mixture checked and the plugs look real nice so there is no evidence of over fueling at this point. idle is good and power is okay though not great. ECU is known to be good as it's recently been swapped out. I have a replacement CSV on its way also. so the question is how can I be using SO much fuel without running rich.

Ben, if thats a brown wire in a black outer sheath then it goes to a sensor (that looks like it may be temperature sensor) on the left front airbox end of the inlet manifold/head. My post this afternoon is to ask what the hell this sensor is and what it does as I have no idea!!

okay peeps, 1.8 16v, where's the thermo time switch hiding then?? also there appears to be what looks like a temperature sensor bolted to the end/side of the inlet manifold near the airbox with a brown wire coming off it. Is that what it is and where does it go to/What does it do?? thanks Andrew

sounds like a thermostat stuck either fully or part way open to me

Can't help feeling that based on the initial accurate reading of the mfa and the definate change once the temperature is met this is something more than the clocks. Once combined with the poor mpg it definately suggests to me something vacuum related in the engine bay having a wobbler onve the engine starts to warm up.

If it's the same as the 16v golf engine then I think its underneath the water pump in a metal 90degree housing.

apologies 1.8 16v

okay so after some more driving the following appears to be the case. 9/10 times the mfa starts offering what appears to be an accurate mpg figure. (around 10-18mpg depending on how cold the engine is starting from) however once the engine temp reaches about 65-70ish the mfa steadily climbs to 99.9mpg. this suggests to me that something within the vacuum circuit which is temperature dependant has thrown a wobbler. initial thought is the isv although, the old girl is idling just fine and I would have thought that if the isv had gone nuts then my idle would have gone to rats, especially in this super cold weather. (unfortunately I don't have a spare so I can't easily swap it out just to see.) My fuel consumption is also knackered (20 mpg tops) I'm not running rich and the 4 fuel injectors have just been replaced so are known good. Any suggestions greatly appreciated.

just re-read the previous page of posts. just to make it clear for everyone, you MUST declare as part of the process who was driving the car at the time of the alledged incident ( this is a legal requirement and if you can't 'remember' then any punishment eventually falls to the keeper of the vehicle anyway IIRC) If you were driving and claim someone else was to avoid the punishment you then commit another offence of perverting the course of justice which can potentially carry some significant consequences in court!! not intending to be a killjoy but you do need to bear in mind the consequences of this deliberately intended action after an initial offence of the moment.

As a rule of thumb, normally, if they're gonna take your licence then you are asked to attend court for it to happen. (so you can't drive afterwards and claim you never knew you were banned!) once it goes as far as a formal ticket then 30mph over the limit is the magic figure** where the courts are looking (depending on circumstances) to apply some form of driving ban (anything from days to months). ** unless you're actions are deemed to be particularly negligent/dangerous at which point police representations about your actions made to the court may increase the 'standardised' penalty typically applicable in those circumstances. example would be travelling at 40 in a 30 typically landing you with a 3 pointer but doing that outside an infants school at chucking out time whilst wheelspinning for efect would likely see you receive a much heavier penalty hth

okay latest update and time for you knowledgable types to put on your thinking caps please, I have swapped out the ecu today and the same problem persists. I KNOW the vacuum pipes themselves are not leaking. I also figure if I'm losing vacuum to the MFA display then surely I must also be losing vacuum to the ecu. This in turn must surely be throwing out the timing meaning I'm losing power/economy. The brakes are working extememly well so I know I've got vacuum to the master cylinder. So what should I be looking too next? What's the most likely candidate for the failed piece and why do you think that?

today I mostly failed the mot. (sigh) couple of niggly bits (no real biggy there) but previous owner had lowered the car sufficiently that the front tyres are rubbing against the inner wheel wells at the front on full lock. have just ordered some 40mm drop springs for front and rear which should also address the problem of the car currently having almost no suspension travel at all, which on the b roads round here was not only shaking the c apart but was likely to end up as a dentists apoointment for me to have the fillings that had shaken loose replaced. Down side is the C will look like a 4x4 compared to now!

replaced the fuel injectors with the mercedes ones which where an ebay steal. lost one of the fuel injection bolts in the engine bay (sigh) spent about an hour looking for it....... finally found it. connected everything up and hey presto quite a bit more urge and a nicer idle. The first two injectors had a fair bit of skanky oil build up on them. The breather return into the airbox had been bleeding oil into the airbox and I'm reasonably sure this was the cause. I removed that problem though a couple of weeks back so this should not re-occur. Also I read the thread regularly as I like to hear what little things other people have been upto. Lets me know I'm not alone in lying on the driveway underneath the car when its 0 degrees out!!!

Sounds like a wire got trapped whilst installing the new motor and the insulation has chaffed through over the period of that week until it's reached a point of constantly touching a +ve supply wire to earth hence the immediate and constant fusing. Sounds to me as though, unfortunately, the motor is going to have to come out to check the wiring behind it. Sorry :(

Just reread your post the blowing fuse for the fan motor is likely to be a seperate problem altogether. The reversing light failure is most likely to be a seperate fault acting as a red herring!! Try disconnecting the +ve power lead to the fan motor itself, replace the fuse and try activating the fan switch. If the fuse stays good this suggests the fan motor itself is faulty. try turning it by hand (has it seized? does it feel REALLY stiff to turn) this suggests the bearings have seized or something similar) was it squealing prior to the fuse blowing or did it sound like it was struggling to provide any air flow?? let me know how you get on.

I had a similar problem with my reverse lights. On top of the gearbox is a black housing held on by two bolts which has a connector coming out of it. This connector goes to a small switch inside the housing. When I took the housing off there was a mild steel circular cup which was bolted in the centre to the selector mechanism (this presses against the switch and turns the reversing lights on. The bolt had worked loose and thus the mild steel cup was not applying any pressure to the switch within the black housing and so not activating the lights. 10 minutes with a socket set MAY solve your problem. If it's not the circular cup, whilst you have the black housing off the selector mechanism try manual pressing the switch (with it still connected obviously) and se if the reversing lights come on (don't forget you will need to have the ignition switch in the on position) hopefully should be this simple

Ahhhh, kerching (sound of light bulb going on overhead!!) I have ordered fresh o rings from gsf which did not arive today so used the old ones as a temporary measure. The old injectors were definately S*****d as the replacements even with the manky and hard old o rings are a fairly dramatic improvement in tractability and acceleration (will never know now whether the mercedes injectors were a performance improvemnt over standard as the old ones were SO bad. Once the new o rings are fitted I'll be much happier but it still seems a bit wierd that the injectors just press home and are otherwise unsecured!!

okay this may sound like a stupid question but how are the fuel injectors fixed in? I just got a killer deal for a set of replacement fuel inectors, I looked at getting the old ones out and they just rotated around and around. Then I realised they wern't held in by anything other than friction and a good tug on them just pulled them straight out of the seat . This surely cant be right so what am I missing and how much is it likely to cost :roll:

all the vacuum pipes have been checked and are definately okay. each of these pipes connects to something and it must be that something that's causing the problem. This begs the following question there is a vacuum pipe coming out of the ecu unit on my valver, now if I've lost vacuum to the clocks giving the 99.9mpg issue then I must have lost vacuum elsewhere in the system and am I now losing power/optimum timing??

all pipes have already been checked. is there something that the pipes connect to that allow the enigne to run smoothly that still gives this effect??