Hi,
Here's a challenge. Our Bx used to start fine, couple of rounds of the starter and she would run always. Recently we had some problems with the starter motor, I replaces the bushes([?]) and the problem was solved. However when I was testing the working of the motor I held it while connected and my gf turned the key, obviously nothing happened because it wasn't connected to the earth (the engine itself). At one point I shorted it on the engine by accident and realised what the problem was. I then put it back together.
Since that time it requires about a good 10-15 seconds of cranking before the engine starts.
I have since then done alot of work on the engine and ignition system, but it didn't seem to help much.
Does anyone have any ideas at what I could try next? I still have to check the ignition timing but apart from that I have replaced all the most obvious things.
Cheers,
Niek
Starting Bx 1.4i 1992
Moderator: RichardW
Niek
Is the question you are asking 'Have I damaged the engine management computer by the sparking?'
If so try disconnecting the battery for some time (minimum 1/2 hour - overnight ideal) and see if it makes any difference.
Where did the starter contact the engine block - was it anywhere near a sensor? - if so check that sensor.
jeremy
Is the question you are asking 'Have I damaged the engine management computer by the sparking?'
If so try disconnecting the battery for some time (minimum 1/2 hour - overnight ideal) and see if it makes any difference.
Where did the starter contact the engine block - was it anywhere near a sensor? - if so check that sensor.
jeremy
Hi,
I've reset the computer and checked it for error codes, nothing there.
I shorted it on the inlet manifold, the sensors closest to that are the ones in the bottom half of throttle house which I replaced becasue of (another) problem with the throttle sensor.
Futhermore I've measured every sensor and valve and they all but the air-temp sensor give correct readings, I've replaced the air-temp sensor (I've been almost living at the breakers!!)
Niek
I've reset the computer and checked it for error codes, nothing there.
I shorted it on the inlet manifold, the sensors closest to that are the ones in the bottom half of throttle house which I replaced becasue of (another) problem with the throttle sensor.
Futhermore I've measured every sensor and valve and they all but the air-temp sensor give correct readings, I've replaced the air-temp sensor (I've been almost living at the breakers!!)
Niek
Niek
sounds as though you've been very thorough.
Its not starting as you release the key is it? By this I mean you turn it over, think its not going to start and as you let go of the key it springs into life?
Have you metered the high tension cables? If so were they all 20K ohm or less? I'm sure the distributor cap and rotor arm clean and the centre brush is in position and free.
Are there any vent hoses which could have come loose and be leaking air? In particular the nearer the throttle itself the more suspect they are.
jeremy
sounds as though you've been very thorough.
Its not starting as you release the key is it? By this I mean you turn it over, think its not going to start and as you let go of the key it springs into life?
Have you metered the high tension cables? If so were they all 20K ohm or less? I'm sure the distributor cap and rotor arm clean and the centre brush is in position and free.
Are there any vent hoses which could have come loose and be leaking air? In particular the nearer the throttle itself the more suspect they are.
jeremy
Hi Jeremy,
Thanks for thinking with me on this one.
The HT leads, rotor, cap and spark plugs are new.
I'll check the hoses tonight again. (quite sure none are loose though)
The only thing I can think of is the spark being either too weak or too late. It's definetly getting petrol (you can hear the pump as you turn the key) and the stepper motor works (you can feel it moving when you turn the key)
So I'll have to check the advance (how???) and maybe the timing.
Cheers,
Niek
Thanks for thinking with me on this one.
The HT leads, rotor, cap and spark plugs are new.
I'll check the hoses tonight again. (quite sure none are loose though)
The only thing I can think of is the spark being either too weak or too late. It's definetly getting petrol (you can hear the pump as you turn the key) and the stepper motor works (you can feel it moving when you turn the key)
So I'll have to check the advance (how???) and maybe the timing.
Cheers,
Niek
I was actually wondering about a bad earth or poor power connection to the ignition circuit, causing a weak spark while the starter was operating but clearing when it was not. Quickly checkable with a meter or a jump lead.
Can I take it you don't have a catalyst? - (some correspondence recently about cold start faults being compensated for by Lambda sensors)
I don't think the timing is adjustable, the trigger being a sensor bolted into the flywheel housing. fine running adjustments are made by the management system. It could be worth pulling the sensor out and making sure its clean and no metal filings have accumulated on its end.
jeremy
Can I take it you don't have a catalyst? - (some correspondence recently about cold start faults being compensated for by Lambda sensors)
I don't think the timing is adjustable, the trigger being a sensor bolted into the flywheel housing. fine running adjustments are made by the management system. It could be worth pulling the sensor out and making sure its clean and no metal filings have accumulated on its end.
jeremy
No it doesn't start on letting go of the key.
This type of engine doesn't have a sensor on the flywheel that determines the ignition timing. How would I go about checking for weak spark with a meter?
It does have a catalyst, and thus a lamda sensor. Does the engine management use input from the lamda at cold start?? (I thought the sensor only starts working when reaching operating temperature ie around 300 degs??)
Niek.
This type of engine doesn't have a sensor on the flywheel that determines the ignition timing. How would I go about checking for weak spark with a meter?
It does have a catalyst, and thus a lamda sensor. Does the engine management use input from the lamda at cold start?? (I thought the sensor only starts working when reaching operating temperature ie around 300 degs??)
Niek.
Sorry for not making myself clear. I wonder is there is a voltage drop between the battery and the engine caused by a poor connection. So connect a meter set to measure voltage between the battery earth terminal and the engine block and operate the starter. Should be no reading but there will be some. If its more than a volt or so you may have a poor earth connection. The other way is simply to put a jump lead between the battery terminal and the engine block and see if there is an improvement.
Much the same is true for the power supply - find the ignition feed wire and put a wire from the battery on there - thus eliminating everything in between. on my BX (TD) there is what looks like a heavy duty plug and socket below the battery tray in the (positive I think) lead.
i cannot find any details in haynes for a fuel injected 14 but if you have a distributor the suggestion is that the timing is adjusted by turning the ditributor body. There doesn't seem to be any reference to timing marks on the K1G engine but you may know where they are. I'd make a quick check with a strobe lamp if I could find a mark. There is some reference to a mark on the head adjacent to the distributor but I presume this a starting point for assembly before fine tuning using a strobe.
I think the cold start/lambda interaction affects hot starting and goes like this: Cold start failed - causes rich mixture. lambda sensor reads rich mixture - weakens it - car runs ok. Stop when hot - management system thinks cold and provides rich mixture - car won't start - but if it does lambda sensor weakens off and car runs ok.
it was explained poperly in the threads - so have a look there.
jeremy
Much the same is true for the power supply - find the ignition feed wire and put a wire from the battery on there - thus eliminating everything in between. on my BX (TD) there is what looks like a heavy duty plug and socket below the battery tray in the (positive I think) lead.
i cannot find any details in haynes for a fuel injected 14 but if you have a distributor the suggestion is that the timing is adjusted by turning the ditributor body. There doesn't seem to be any reference to timing marks on the K1G engine but you may know where they are. I'd make a quick check with a strobe lamp if I could find a mark. There is some reference to a mark on the head adjacent to the distributor but I presume this a starting point for assembly before fine tuning using a strobe.
I think the cold start/lambda interaction affects hot starting and goes like this: Cold start failed - causes rich mixture. lambda sensor reads rich mixture - weakens it - car runs ok. Stop when hot - management system thinks cold and provides rich mixture - car won't start - but if it does lambda sensor weakens off and car runs ok.
it was explained poperly in the threads - so have a look there.
jeremy
Hi guys,
No progress yet, I measured the voltage drop over the negative pole of the battery and the engine when starting. Not much there.
I then cleaned all the connections I could find that are related to grounding (including the heavy duty black conn. under the battery) and replaced the negative battery pole and lead by a better one. All of this didn't help. Yesterday evening when it was starting badly again I undid the main plug lead directly of the coil and tested for sparks. They were ther about 1-1.5 cm long but they were yellow instead of blue (I read that somewhere) could this be connected? I also measured the voltage drop over the two battery poles when cranking (engine was hot so no starting probs) and measured a 2 volt drop, is this too much, if so could the battery be causing it the troubles?
One more thing I noticed is that it hold back when accelerating with a cold engine, related???
I intend to try fitting another ignition module tonight, and if this doesn't change anything I'll the the battery from the Xm in there tomorrow night.
Any ideas, tips, hints or whatever are very welcome...
Cheers,
Niek
No progress yet, I measured the voltage drop over the negative pole of the battery and the engine when starting. Not much there.
I then cleaned all the connections I could find that are related to grounding (including the heavy duty black conn. under the battery) and replaced the negative battery pole and lead by a better one. All of this didn't help. Yesterday evening when it was starting badly again I undid the main plug lead directly of the coil and tested for sparks. They were ther about 1-1.5 cm long but they were yellow instead of blue (I read that somewhere) could this be connected? I also measured the voltage drop over the two battery poles when cranking (engine was hot so no starting probs) and measured a 2 volt drop, is this too much, if so could the battery be causing it the troubles?
One more thing I noticed is that it hold back when accelerating with a cold engine, related???
I intend to try fitting another ignition module tonight, and if this doesn't change anything I'll the the battery from the Xm in there tomorrow night.
Any ideas, tips, hints or whatever are very welcome...
Cheers,
Niek
Niek -
When testing the sparking from the HT leads - it's more important to check the lenght of the spark in open air. The actual colour impression depends much on the daylight.
Also any fumes near the spark will instantly make the spark yellow/red in colour - simply because these fumes are burnt. Both oil & fuel fumes does this.
In open air the spark should be at least 12mm - which also seems what you have.
There is one single component that acts as a "choker" for cold start.
This is the engine temp sensor - which is used EXCLUSIVELY for the ECU. It's readily recognised by being the only 2pole sensor on engine - near the thermostat housing. Usually the sensor's moulded on plastic contact piece is either blue or green plastic.
The sensor is a temp dependant resistor - with high resistance on cold engine. When engine heats up - this sensor decreases in resistance.
Therefore if this sensor - or it's cabling - is shorted or have a faulty earth connection - the ECU will not detect a cold engine - and the engine will never get "choke" on cold starts.
When testing the sparking from the HT leads - it's more important to check the lenght of the spark in open air. The actual colour impression depends much on the daylight.
Also any fumes near the spark will instantly make the spark yellow/red in colour - simply because these fumes are burnt. Both oil & fuel fumes does this.
In open air the spark should be at least 12mm - which also seems what you have.
There is one single component that acts as a "choker" for cold start.
This is the engine temp sensor - which is used EXCLUSIVELY for the ECU. It's readily recognised by being the only 2pole sensor on engine - near the thermostat housing. Usually the sensor's moulded on plastic contact piece is either blue or green plastic.
The sensor is a temp dependant resistor - with high resistance on cold engine. When engine heats up - this sensor decreases in resistance.
Therefore if this sensor - or it's cabling - is shorted or have a faulty earth connection - the ECU will not detect a cold engine - and the engine will never get "choke" on cold starts.
Hi Anders and the rest,
I thought of the engine temp sensor but I realised that it was probably ok considering the ecu still compensates for the cold start by 'pressing' the accelerator (stepper motor), you can actually feel it doing this in this car because it really does pull on the accelerator cable causing the pedal to sink slightly, so with your foot just touching it you can feel it working. And as the temp sensor is the only input[?] for the temp. of the engine figured it was ok, could still be giving a false reading though.
Anyway I promised to post when I found the solution. Yesterday after work went to the scrappy's and picked up a complete ignition (with rotor and ignition module because I thought I might have damaged the inner coil of the ignition with the shorting of the starter). Came back home, waited for the car come home with the girlfriend [B)] and took out the ignition. The new one was different (should have known considering Citroen has 3 million different kinds of each part). Took my own ignition apart, measured the coil (it was good according to my book) and cleaned everything. I then used the ignition module of the non-fitting ignition ... et voila ... the beast works like a charm again [:D]
I must have burnt the module with the shorting I did.
Thanks for all the input everyone!
Niek
I thought of the engine temp sensor but I realised that it was probably ok considering the ecu still compensates for the cold start by 'pressing' the accelerator (stepper motor), you can actually feel it doing this in this car because it really does pull on the accelerator cable causing the pedal to sink slightly, so with your foot just touching it you can feel it working. And as the temp sensor is the only input[?] for the temp. of the engine figured it was ok, could still be giving a false reading though.
Anyway I promised to post when I found the solution. Yesterday after work went to the scrappy's and picked up a complete ignition (with rotor and ignition module because I thought I might have damaged the inner coil of the ignition with the shorting of the starter). Came back home, waited for the car come home with the girlfriend [B)] and took out the ignition. The new one was different (should have known considering Citroen has 3 million different kinds of each part). Took my own ignition apart, measured the coil (it was good according to my book) and cleaned everything. I then used the ignition module of the non-fitting ignition ... et voila ... the beast works like a charm again [:D]
I must have burnt the module with the shorting I did.
Thanks for all the input everyone!
Niek