strange emissions at MOT

[phipck]

iv made not of the circumstances which these issues occur,

1. the fan cuts in at 90deg (or there abouts) and cuts out when its dropped below, so i would suggest the stat is opporating the fans rather than a faulty coolent temperature sensor.

2. when the fan cuts in there is a loss of engine power, no stalling, but emmissions sky rocket and electrics dim. The car has a good battery which the car fully charges, so i dont believe it is battery or charge related. I am going to look into the earthing as it could be an issue with the efficiency an earth. (if anybody has an engine bay earthing diagram that would be cool)

3. i recieve a bank 1 lambda error occasionally, this typically happens before the car is up to temperature, so cannot be caused by issue 2 as the emmissions are perfect when the fan isnt running. This happened both before and after a new replacement lambda. Its possible the new lambda has a fault, but seems like a strange coincidence that the new and old exhibit the same fault, i wonder if its possible for a fault elsewhere can cause both to display the same problem?

I have no experience with electronic testing equipment so im looking to teach myself, as it will be clearly invaluable with this car! any suggested reading  would be greatly appreciated.

[Testor VTS]

Could you check the current drain of the fan? (connect a multimeter inline the fan's live feed - find the plug of the fan, or it's fuse in the fuse box)

[phipck]

thanks for the help chap

[wheeler]

Could you check the current drain of the fan? (connect a multimeter inline the fan's live feed - find the plug of the fan, or it's fuse in the fuse box)

Remember most normal multimeters are only fused upto 10A on the current measrement setting, probably a bit too low for an engine cooling fan which is normally fused at 30A. An amp clamp would be more suited to checking the fans current consumption.

[phipck]

cheers again for the suggestions, i did a lot of youtube'ing to get my head around the use of a meter and also looked at what an amp clamp is etc and i realised i had one in amongst all my tools (not knowing what it was i didnt realise i had one) but i found it only does AC current, which is pretty useless and probably why it was donated to me by whoever i got it from!

anyway with my newly learnt multimeter skills ive checked  the voltage on the battery while the car is running and charging, this sits at 14v pretty much all day long, and when the fan cuts in the voltage drops down to 12.3v, creeps up to between 12.5 and 13v while the fan is on then as soon as the fan cuts out its straight back to 14v.

now i understand that the fan will cause a draw on the system as its quite a hungry electrical component, but its sucking the life out of the engine and other eletrical parts. Is there meant to be some kind of resistor holding the fan back? something that limits the fans draw that may have failed. Im keen to get an AC/DC amp clamp as it will help greatly with a range of hobbies and work that i do, so i may soon be able to test that side of things.

cheers again guys for your guidence

[welshpug]

sounds like a bad earth or lazy alternator, it should be able to hold circa 14 volts with any load.

[The Wrinkly Ninja]

I don't believe so.

That alternator is rated at either 80 or 90A and that fan alone could be pulling off nigh on a quarter of that on its own. I wouldn't have thought that cutting in and bringing the voltage down to that level was so bad. Ideally, it should be 14.5 of course, so perhaps it is a little down, but I doubt it's the cause of all this hassle.

I still go with the idea that this is down to the coolant temp sensor.

[phipck]

if i can get to the fan i shall check the connections, a bad earth would be easier and more immediate a check. I understand your previous discription of the issues a coolent temp sensor can be involved with, for instance the -44 deg issue, so i will be looking at replacing as a matter of course, just need to find out which one my 1.4LX uses.

cheers again

[The Wrinkly Ninja]

3 possibles.

All Phase I   1338 66  Maroon plug
Early Phase II  1336 A6  Blue, 3 pins, till RP 09456, then
Remainder, 1336 A7  Green, 2 pins.

[phipck]

magic, i will check when before i start the car in the morning. 

[phipck]

finally got round to checking and its a blue with three pins, only two of them have wires attached though which is interesting. does anyone know if thats meant to be right?

anyway, where would the reccomended place be to get one of these as im finding it a little more complicated locating a blue 3 pin, as there seems to be many many blue two pin's

[The Wrinkly Ninja]

Your definitive answer is to either search the Service.Citroen database for your VIN and find the exact item fitted to your individual car.
Your local dealer will also do that for you and find you the right one - offhand, I think they're only about 20 quid anyway.

Just possible someone's replaced a 2-wire sensor with a 3-wire one.

[phipck]

some progress with the over all issues, although i am still yet to sort the coolant sensor. I mentioned i was having the lambda error pop up periodically, changing the cat didnt make much difference to the frequency (a little less often i suppose) and after the cat replacement i noticed that the back box was blowing a little, possibly brought on by gas actually reaching the backbox now!   

so i ordered and replaced the backbox as the old one was rattly as hell with bits of old cat and the baffles coming away inside and since that was replaced not only does the car pull better but i also havent had the error come back. Im guessing that without the correct backpressure the gasses wernt being evacuated correctly meaning the lambda couldnt read correctly. Before changing the backbox i could place my hand on the tailpipe and make a seal, gas would escape elsewhere in the system. But now i cant even get my hand down onto the pipe which is much better.... so another possible answer to the question of what causes a lambda error can be added to the long list.... "a blowing exhaust back box"!

fingers crossed that the coolent sensor resolves the poor running when the fan engages. 

[phipck]

hey guys, a little progress with this. It turns out that a previous owner installed a Kenlowe thermostatic switch and relay due to some issues they were having.

Bear with me as im new to electrics! The fan gained its power direct from the fuse box via the fused themostatic switch, the relay takes power direct from the same location also and is switched when the aircon is activated, so aircon and thermostatic cooling work.

the issue is that when the fan cuts in it is drawing too much power, possibly due to the direct feed from the fusebox without any resistance? also because of this massive draw of power it starved some systems of electricity causing poor running while the fan was running.

Now the fuse which was inline should have blown (rated at 15amp) but instead it bridged and continued to take much higher ampage, so much so that last weekend the lead wire for this setup failed. Hence my discovery of this setup.

so i rebuilt the curcuit, taking its feed from the battery instead and using a 30 amp fuse (was reccomended) the circuit functioned, the fan operated and the car ran better than it ever had.

Untill the 30 amp blew.

So i grabbed a scrappy fan, thinking that maybe the old fan had  shorted internally, which might explain the high power draw. but this resulted in exactly the same issue, blowing the 30amp fuse in a short space of time.

so now im thining the original circuit had resistors and relays involved... could this possibly be reduce the power draw enough to function correctly?

or should i just get a fan designed for whats been installed?

[The Wrinkly Ninja]

Now we're getting down to the nitty-gritty.

There's no need at all for a Kenlowe on there -  no wonder the power drain was knocking everything out - massive overkill on a little engine like that.

You may have had either a single or 3-speed fan on there - the latter would have had resistors and relays in a small pack on the rear of the rad. Is the motor OEM or a dedicated Kenlowe replacement? I'm guessing the latter as the original shouldn't have pulled that power.