hi guys,
just wanted to ask a question about my citroen zx 16v. basically when im driving on normal (A) roads the car is fine, but half my journey is on the motorway and when i'm doing about 80mph for like 10 mins the orange engine management light comes on.
when i come off the motorway after about 30 seconds the light goes
off so it's only when the car is under load. i also clutched the car
while on the motorway and rolled for a few seconds and the light went
off so it's when the car is doing 4k or so for 10 mins or so.
anyone have any ideas? i'm hoping its not the cam belt warning light
or something?!
i tried asking citroen and they just said bring it in (so i probably
will but cant till pay day:|)
any clues would be great!
thanks
rich
engine management light (zx 16v)
Moderator: RichardW
This orange light is the engine management warning indicator - telling you that the ECU (engine computer) has detected a fault condition on the running engine.
The vast majority of problems is a faulty air/fuel mixture - possibly causing an overload to the catalythic converter (cat).
It can never indicate a problem with the cambelt - since this belt either works perfectly - or has splitted with an instant death of engine as a result. Only way to protect your engine cambelt (& engine) is to have the cambelt replaced timely at prescribed intervals - you never get any warnings.
What your Citroen garage has offered you is to do a read-out of the stored fault codes from the ECU - as any longterm faults causing the warning light to be lit - will be stored as a dedicated error code.
The code varies according to which component on engine the ECU has detected a faulty behaviour from - can then be used to trace down the problem.
Likely the problem is a faulty engine sensor or it's cabling.
The vast majority of problems is a faulty air/fuel mixture - possibly causing an overload to the catalythic converter (cat).
It can never indicate a problem with the cambelt - since this belt either works perfectly - or has splitted with an instant death of engine as a result. Only way to protect your engine cambelt (& engine) is to have the cambelt replaced timely at prescribed intervals - you never get any warnings.
What your Citroen garage has offered you is to do a read-out of the stored fault codes from the ECU - as any longterm faults causing the warning light to be lit - will be stored as a dedicated error code.
The code varies according to which component on engine the ECU has detected a faulty behaviour from - can then be used to trace down the problem.
Likely the problem is a faulty engine sensor or it's cabling.
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VisaGTi16v
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pain,
hi darren here from the zx mailing list
how did you de-cat it and did you notice any improvement? There was a discussion regarding doing this before on here and I think the general conclusion was that you would need a remapped ecu chip to get the most from it as the standard one wouldnt adjust enough to give you the extra power that would be available without the cat?
Darren
hi darren here from the zx mailing list
how did you de-cat it and did you notice any improvement? There was a discussion regarding doing this before on here and I think the general conclusion was that you would need a remapped ecu chip to get the most from it as the standard one wouldnt adjust enough to give you the extra power that would be available without the cat?
Darren
Rich -
The engine management system does not bother wether the cat is fitted or not - it simply controls the emission to avoid any overrich mixture possibly overloading the cat - wether or not it's fitted.
In other words : the ECU does not have a clue wether the cat is fitted or not.
Might be worth looking over the cabling for the Lambda sonde - not uncommon the cabling is damaged due to the harsh temperatures on the exhaust.
Note : You can not remove the Lambda sonde - even if the car is de-catted - the ECU is designed to work with information from the Lambda sonde.
The engine management system does not bother wether the cat is fitted or not - it simply controls the emission to avoid any overrich mixture possibly overloading the cat - wether or not it's fitted.
In other words : the ECU does not have a clue wether the cat is fitted or not.
Might be worth looking over the cabling for the Lambda sonde - not uncommon the cabling is damaged due to the harsh temperatures on the exhaust.
Note : You can not remove the Lambda sonde - even if the car is de-catted - the ECU is designed to work with information from the Lambda sonde.
yo dudes,
well on the ZX 16v i had before this one i didnt think i could remove the cat because the lamda sensor was after the cat (i was told by a few people this). this ZX i have is a few months older and the lamda sensor is before the cat so i just cut it off and put a through pipe on.
i think it did make a difference, but because i (think) i have a problem with my ACAV vacume system i dont think im seeing the true performance. basically my car is pretty slow before 4000rpm then it flies. it also seems to be using a hell of a lot of fuel compared to my old one.
could all my problems be down to this 'vacume' thing?
thanks
rich
well on the ZX 16v i had before this one i didnt think i could remove the cat because the lamda sensor was after the cat (i was told by a few people this). this ZX i have is a few months older and the lamda sensor is before the cat so i just cut it off and put a through pipe on.
i think it did make a difference, but because i (think) i have a problem with my ACAV vacume system i dont think im seeing the true performance. basically my car is pretty slow before 4000rpm then it flies. it also seems to be using a hell of a lot of fuel compared to my old one.
could all my problems be down to this 'vacume' thing?
thanks
rich
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VisaGTi16v
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no idea where mine is rich, i will look it will need putting back for MOT though? unless you go to a "friendly" one
is it getting up to temperature? mine was doing about 20mpg when the thermostat was knackered leading it to run cold the whole time and it ended up filling it with mayonaise as well. This cleared eventually after changing the thermostat. I guess as it thought it was cold it was chucking in far more fuel than it should have been.
it will need putting back for MOT though? unless you go to a "friendly" one is it getting up to temperature? mine was doing about 20mpg when the thermostat was knackered leading it to run cold the whole time and it ended up filling it with mayonaise as well. This cleared eventually after changing the thermostat. I guess as it thought it was cold it was chucking in far more fuel than it should have been.
Anders-
if you measure the signal voltage (or look at the pattern on an ociliscope) on an upstream sensor (when the engine is warm and in closed loop) it will constantlty fluctuate between aprox 100-800 milivolts,if you take the same measurement on a working downstream sensor you will get a constant reading,if the downstream sensor is giving the same readings as the upstream one then the cat is not doing its job (or there is an exhaust leak) and will bring the engine management/anti pollution light on.
i've never seen a car yet with just a downstream sensor.
if you measure the signal voltage (or look at the pattern on an ociliscope) on an upstream sensor (when the engine is warm and in closed loop) it will constantlty fluctuate between aprox 100-800 milivolts,if you take the same measurement on a working downstream sensor you will get a constant reading,if the downstream sensor is giving the same readings as the upstream one then the cat is not doing its job (or there is an exhaust leak) and will bring the engine management/anti pollution light on.
i've never seen a car yet with just a downstream sensor.
Thanks wheeler -
That's exactly what I thought. If the cat is working - you should in fact have no signal at all from the downstream sensor - in other words any signal from a downstream sensor means the cat is either ineffective or overloaded (or missing as the owner decat'ted the car [8D]).
That's the E4 emissions standard you're referring to - which means a "nil-emissions" regulation.
The reason I asked was that here in DK politicians are quite "interested" in owners tweeking their ECU's and decatting their cars. Guess future harsh regulations are close around the corner.
That's exactly what I thought. If the cat is working - you should in fact have no signal at all from the downstream sensor - in other words any signal from a downstream sensor means the cat is either ineffective or overloaded (or missing as the owner decat'ted the car [8D]).
That's the E4 emissions standard you're referring to - which means a "nil-emissions" regulation.
The reason I asked was that here in DK politicians are quite "interested" in owners tweeking their ECU's and decatting their cars. Guess future harsh regulations are close around the corner.