10 seconds to Diagnose ??

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10 seconds to Diagnose ??

Postby tangoman » Sun Aug 28, 2016 12:58 pm

You all might be thinking about this case study I have subject I put up 10 seconds to Diagnose ?? . well this is all the time I had to get a positive answer for this car .

OK the car 2010 2.4 petrol Captiva this car only played up when it was cold less then 10 c ? and where I live Brisbane Australia this does not happened to often but we had about 2 weeks off cold morning .
so this workshop give me the job tried to fix this car with no scope just a Scan tool
the car when was seating for more the 6 hours would a long time to start so it had a new in tank fuel pump module , 4 new injectors , new cam and crank sensors so now I get the car .

so I will share with you how I went about testing this system and how I had to use a few tools to come up with 100 % positive answer

like we all should know when a cars is hard to start we must always start at the battery if we skip this test we should just close the bonnet and go home its very important test ( you can see the test results I post up in the photos ) I used the picoscope for this test and it pass battery ok

ok next test set up a fuel pressure gauge and see if there is any fuel leaks in the system had gauge on for a few hours and no leaks was 56 PSI when I set it up and drop to 49 PSI after a few hours so was happy with this test .

so now I did a few easy tests it was time to get a few test ready for when I came in the morning to see why this car was so hard to start ?

so first I needed o set up something to make sure the ECU was getting the command from the immobilizer this was not that easy I use the Bosch Tech 2 scan tool this works great on this car but no PIDS on the scan tool to see id the ECU was getting the command ? ok I have to know or I will not get positive answer why this car hard to start ? ok next scan tool I have OPP COMM scan tool I got form the UK great on Opel cars and this cars is a Opel rebadge Holden in Australia
this time this Scan tool had the PID I was looking for very happy when you put the ignition on the scan tool said standby and when you crank the car it said released ok we getting there

Next set up a spark tested open it up so I can see there is good spark that was easy

Next set up Picoscope and have look at injector volts and amps

Next find the power relay and make sure that the ECU Grounds it when we crank the car

next set up the scope to make sure we have good cam and crank sensors I know there was new but I need to test then too .

was hoping I had more channels' on my scope but I only had 4

ok next go home and hope it a nice cold night of this car will start if it does not go under 10 deg c
next morning vey luck 5 deg c happy

open up work shop wake up my PC so I have two screens coming from the one PC one for the OPP.COOM scan tool and one for the picoscope but I have only two eyes to see why this car does not go and I can only do this once when the car goes it when then go and start ok for more then 6 hour !

ok the crank the car and see why this car does not go when cold ??

my eyes does not need to look at the picoscope the scope has a good buffer I can look at his later so my eyes had to look at the scan tool screen to make sure it said that the Immobilizer had to say release ?

its said release ok that was ok .

so then looked at the spark wow great spark ok

also I was looking at the fuel pressures 56 psi ok

my eyes also looks at the meter that I had on the power relay control by the ECU this was good too

my 10 sec was up the car did not go and I had all the results to analyze ?

I stop the picoscope so I can see the injectors pulse ?

so now it was time to have some coffee and lets see what I come up with ?

The test I know you all what to know what I came up with ?

battery and starter test pass
fuel test pass 56 psi did not lose pressures pass
spark test great spark pass
power relays test pass
cam and crank pass
Immobilizes test pass

so you might be all thinking so why did this car not start ?

ok one test did not pass and you will all see why this car does not start when get down to 5 deg and start when hot or when its summer ?

when I looked at the picoscope injectors pulse the very first time the engine went round did not have time to do a 720 cycle we got 42 mil second but we only had this once then when I was cranking I kept cranking we had nothing just a bit of noise but when I turn the key off and did it again the ECU fire up the injectors ok !

so we know now when the out side air was say 20 deg c it get to about 24 in Brisbane in winter the 42 mil seconds was ok to start the car

so how did I fix this car ?
I put in a new ECU and the car was fixed

all up it was about 2 hours to fix the car most of the time was seting up and doing a few test before
holden captiva 2007 does not go when motor below 15 c..gif
This is cranking the car we can see why its does not start this was not a pass test
making sure the car was not Immobilized pass
Testing injectors and using scan tool at the same time
Testing for spark pass
Testing the power relay
now no injectors control
Injectors look at the very first pule 42 mil sec
Engine speed pass
Battery test pass
The car I work on
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Re: 10 seconds to Diagnose ??

Postby STC » Sun Aug 28, 2016 9:08 pm

Although it took me 10 minutes to read the post, looking at the evidence I had that nailed in 9.8 seconds. (Wishfull thinking) 12,000 miles away from the car :D

Well done, another good catch. A testament to the Bosch Training Regime ?

Wiring had to be good (42ms injection Event) then just noise.

ECU Power & Grounds intact, ECT Temp, I would have called the ECU too. Hybrid ECU - Ultrasonic Bonded Alloy Connections internally ?
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Re: 10 seconds to Diagnose ??

Postby tangoman » Mon Aug 29, 2016 11:56 am

Yes I bit of reading STC but I was just showing everyone how we should go about looking at evidence before we put a
$1400 part in someone car that's how much the ECU was in Australia !
and to tell the truth I had a good idea the ECU was going to be bad but I seen the same thing very hard to start when cold on Alfa Romeo cars with almost the same ( Bosch ) ECU some BMW .
but I have learnt on working for almost 40 years not to use my experience to fix cars !

you all might be thinking why !

we should always analyze the job we do and DONT memorize .

if I had the same model car in to my workshop tomorrow I would do the same tests again

I would NOT just put in a new ECU .

but there are some jobs that's using are experience is the only why to fix the car and is we did not have this it would be very hard to fix the car .
one example this happened today just a few hours ago
2009 TK Barina with ZX 14 motor in it this work shop rings me up and said to me can I help him ? this car has a p0300
and he put in new coil pack new leads removed the injectors and got them flow tested and clean and was lost to what to do next he was thinking maybe it might be the head Valve's not sealing ? but he was not sure ?

so asked him do you know has this car had a new battery or a very low battery on crank and can he feel this miss fire ?
so he tell me he can not feel any missing fire and yes this car had a new battery last week ?

ok now this were my experience comes in now on this car and a few Opel car and a few late past 2010 GM car when the ECU loses battery is sometimes ( not all the time ) needs to have a Crankshaft Position Variation Learn ! but not sure why the only codes it comes up with is a P0300 ( misfire code ) and most scan tools that's I have will not do the Crankshaft Position Variation Learn the only two that work for me is the Bosch Tech 2 and the OPP.COM .

so he brings be the car I do the Crankshaft Position Variation Learn with the Tech 2 scan tool and this car P0300 code is fixed . so this is one example when we do have to use our experience
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Re: 10 seconds to Diagnose ??

Postby STC » Tue Aug 30, 2016 12:35 pm

this car P0300 code is fixed . so this is one example when we do have to use our experience

I agree, experience is everything and cannot be bought. Has to be lived, mainly in early mornings and late nights cold and hungry.
As you will know from the training we did, half the stuff you do is not going to fix that car, but you need to know it - if that makes sense ? I.e. Knowing how and why we use EGR to reduce NOx is not going to find the broken wire to the EGR Valve valve. But we need to know.

so he brings be the car I do the Crankshaft Position Variation Learn with the Tech 2 scan tool and

And Yes! Dont be afraid to press buttons :shock: Some of my customers, have a reasonable scantool yet never venture further than reading the code. They would not know that Actual Values & Adaptations Exist, Yet they are masters at EGR/DPF/DTC Deletion - Funny that ?
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