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Post by Deleted on Nov 23, 2019 14:44:53 GMT 1
We towed the car in from National tyres yesterday, the car had a discharged battery and would not start when we got there. I fitted a new fully charged battery and cranked the engine over and it immediately started and then stopped. I repeated the starter cranking several times and each time the engine started and immediately stopped. We towed the car back to our garage and today I have had a look over it. I found nothing obvious. I advised the boss to put his scanner on and see if any codes were present and what live data was showing. The boss said no codes are present and live data is not showing anything wrong.
I advised the boss to contact the customer and ask if a spare key was available. The customer arrived with the key and I tried it and it made no difference. The boss advised the lambda sensor could be causing the problem, I advised that I didn't think it would. I was then advised that the timing chain would cause this problem and I said now you really are clutching at straws. I rang the local auto-electrician we use and advised him of the car problems and he said normally those cars are bullet proof and don't give up easily. He was not aware of anything obvious. I asked him if it were possible for something like the coolant temperature sensor to malfunction and stop this engine from starting and he said no. Later I decided to try and unplug the sensor and see if it made any difference, and what I experienced was that the engine would not start at all when the coolant sensor was unplugged, and when plugged in the engine would start and stop, therefore I think I can rule out the coolant sensor circuit as the fault there.
The customer said to me that National Tyres did a service on it and drove away but very soon after the car stopped running and this is now the end result. I have had a good look over the engine and can't see that National tyres have done anything wrong, so back to the drawing board.
I have checked the ignition spark during cranking and running and the spark only stops when the engine stops. I did a fuel volume test and there is plenty fuel supply to the engine. I removed the spark plugs and they are dark and damp, and they don't look like they were a service replacement item in this last service. The spark plugs fitted are NGK BKR5EYA, which look like a standard spark plug to me but would need to check manufacturer data if say platinum etc.
Anyone any ideas?
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Post by rhyds on Nov 23, 2019 15:05:23 GMT 1
Off the top of my head I'd check the following:
1: Is the ignition switch working correctly i.e. when it springs back from "starter" position it isn't going to "engine stop" position?
2: Engine to battery/body earth in good condition?
3: Call a priest
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Post by wheelnut on Nov 23, 2019 16:09:41 GMT 1
Something like that used to happen in the days of the old Lucas starters. I can't remember exactly how it happened but the effect was that there was no live feed to the coil. When the starter was operated the coil got a live through a back-feed at the solinoid, so the engine fired up when the key was turned and then died when the key was released. Maybe you should start by checking all the wiring at the starter.
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Post by rhyds on Nov 23, 2019 16:15:38 GMT 1
Something like that used to happen in the days of the old Lucas starters. I can't remember exactly how it happened but the effect was that there was no live feed to the coil. When the starter was operated the coil got a live through a back-feed at the solinoid, so the engine fired up when the key was turned and then died when the key was released. Maybe you should start by checking all the wiring at the starter. That would be a ballast resistor fault. Back in the day you'd have a resistor that meant the coil only usually got 6v-9v in normal running, but when you turned the ignition switch to "start" the resistor was bypassed and the coil got a full 12v feed while cranking to assist starting. The problem was the resistor would fail open circuit, so then the coil only got power while the starter was turning and the second you let the key go the coil would lose its feed. |
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Post by Deleted on Nov 23, 2019 17:56:07 GMT 1
Something like that used to happen in the days of the old Lucas starters. I can't remember exactly how it happened but the effect was that there was no live feed to the coil. When the starter was operated the coil got a live through a back-feed at the solinoid, so the engine fired up when the key was turned and then died when the key was released. Maybe you should start by checking all the wiring at the starter. That would be a ballast resistor fault. Back in the day you'd have a resistor that meant the coil only usually got 6v-9v in normal running, but when you turned the ignition switch to "start" the resistor was bypassed and the coil got a full 12v feed while cranking to assist starting. The problem was the resistor would fail open circuit, so then the coil only got power while the starter was turning and the second you let the key go the coil would lose its feed. What we have here is the modern day version of that fault. I have not yet been afforded the time to dig in deeper but I suspect something along the lines of the ignition supply failing and possibly a electrical supply through a relay/fuse, although in saying that I still had a spark while cranking, and fuel supply. A test plan is what I'll need to create for it I think. |
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Post by trickydicky on Nov 23, 2019 18:13:53 GMT 1
With the ignition switch in the run position do you have an EML light?
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Post by Deleted on Nov 23, 2019 18:43:46 GMT 1
Yes
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Post by trickydicky on Nov 23, 2019 19:04:05 GMT 1
I dont get why the boss is doing the scan and live data and taking pot shots at the diag whilst your checking fuel and spark and disconnecting the coolant sensor?
Too many cooks in that kitchen!!
Scan tool: did he scan all modules or
just EMS,what pointed to o2
sensor?
Live data: coolant temp?
RPM signal?
Cam/Crank synch?
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Post by Deleted on Nov 23, 2019 19:24:50 GMT 1
I dont get why the boss is doing the scan and live data and taking pot shots at the diag whilst your checking fuel and spark and disconnecting the coolant sensor? Too many cooks in that kitchen!! Scan tool: did he scan all modules or just EMS,what pointed to o2 sensor? Live data: coolant temp? RPM signal? Cam/Crank synch? The boss is in control I can only do what he tells me. He advised there is nothing showing on his scanner. I had no diagnostic equipment of my own to hand so did basic checks. The auto-electrician said that the coolant sensor would not have an effect on the starting of the engine. Previous experiences for me have shown that coolant sensors have stopped engines running, so I decided to unplug it to see if it made a difference, and yes it will stop the engine starting. Cooks in the kitchen, yes to damn many and some guessing their way through or should I say want to decide what they want wrong with the engine starting on a personal basis rather than let the evidence prove what is at fault. The boss was on the scanner, based on things said to me over time I have to take it that he makes his own rules up and guesses his way through, so nothing reliable can become of whatever his scanner might of been showing or not! 02 from the boss was just his opinion without testing or proving anything. RPM signal not checked by me as I had no equipment to do it. The side track from that initially is the fact that the engine does start and stop. Cam/Crank is what I was just looking at on the wiring diagram. On another make of vehicle a while back we had an EML on and the engine took a long time to start. The auto electrician put his scanner on and said the crank sensor had failed and the engine was starting and running on the cam sensor. he cleared the code and the engine would not then start. I'm not convinced this is the same type of problem as the EML goes out while the engine runs and then returns after the engine has stopped. With reference to the wiring diagram and basic tests today I know the fuel supply is good even when the engine will not run. That tells me that the fuel pump/relay and fuses are all good to that circuit. The primary and secondary ignition relays are working OK. That then means the ignition supply to both the ignition coils and the injectors are also OK. It looks at the moment like the switching side of the ignition system is either failing because of a sensor input or something really basic like the plugs are past their sell by date, and it would not be the first time I've experienced four plugs failing at the same time. Monday is another day unless he ships it off to the electricians. |
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Post by trickydicky on Nov 23, 2019 20:08:55 GMT 1
Your wasting your life/career/skillset on this idiot and his "business"
Why wont he just let you use the scantool to do the diagnosis?
You shouldn't have to be second guessing what this f*cking control freak says and does
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Post by studabear on Nov 23, 2019 21:11:53 GMT 1
Our master tech is ex Toyota, I can pick his brains on Monday if it need be.
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Post by valhalla on Nov 23, 2019 23:24:15 GMT 1
I would want to see the Live Data for myself. What I would be looking-for is the engine status flag (if you can find it) but mainly any sign of the ECU switching-off through low voltage, etc.
It sounds like a power-supply or earthing problem - something has been left dangling after the service, and now whatever the engine was running through has packed-up from high currents.
Symptomatically, as soon as the battery voltage is kicked upwards by the alternator output, the engine switches-off, hence you are looking at putting the PicoScope leads on 1) battery +post, 2) alternator output post, 3) engine earth, 4) body earth - holding all four inputs relative to battery -ve post for a ground reference.
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Post by trickydicky on Nov 24, 2019 0:29:48 GMT 1
Theres something fishy about the job
Towed from a National Tyres fast fit centre who just serviced it??
Wont let you use the scanner but you have a pico for diag jobs?
Guessing at an o2 sensor or timing chain?
EML is on in the run position so it sounds like the ECU is powered up?
Its 100% got spark and fuel when it dies and no DTCs?
Are you sure the catalyst or exhaust isn't blocked?
Has it got the correct fuel in the tank?
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Post by Deleted on Nov 24, 2019 1:03:56 GMT 1
Our master tech is ex Toyota, I can pick his brains on Monday if it need be. That would be great, thanks studabearTheres something fishy about the job Towed from a National Tyres fast fit centre who just serviced it?? Wont let you use the scanner but you have a pico for diag jobs? Guessing at an o2 sensor or timing chain? EML is on in the run position so it sounds like the ECU is powered up? Its 100% got spark and fuel when it dies and no DTCs? Are you sure the catalyst or exhaust isn't blocked? Has it got the correct fuel in the tank? I'm not convinced there is anything wrong about the job, and I don't think National Tyres have done anything wrong. The boss does not like anyone's opinions except his own, and he most certainly does not like anyone using his tools. Yes I have a PicoScope but there are reasons why I have not got it involved in this job, and they are; 1/ My boss told me that my PicoScope setup is sh1t against his wall. Some members on here have seen the mobile platform I built to diagnose car electrical faults. 2/ Nothing the scope produces is anything other than sh1t diagnostics to him and it does not print on screen the exact cause of the fault in the english language so he can be told like spoon feeding a baby exactly the cause of the breakdown. Guessing is all he has ever done in customers cars regarding diagnostics. The ECM is powered up. You are correct yes it does have a spark and good fuel supply, and as far as the boss says, yes there are no fault codes. No I'm not sure the exhaust system/cat has not got a problem, and truthfully until talking to my dad this evening I'd not thought about the exhaust system having a blockage. Again I'd not thought about the fuel in the tank, but yes it smelt like petrol when I did the flow rate test at the common rail (petrol). |
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Post by trickydicky on Nov 24, 2019 1:42:16 GMT 1
What kind of scantool does the garage have?
Is nobody else allowed to use the scantool but the boss?
Do you have technical info at the garage?
Is there any access to regular tech training at this business?
How old are you and how long have you been a tech?
What area of the UK do you live in?
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