Switching two cylinder running

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Re: Switching two cylinder running

Postby Terry Ferguson » Thu Mar 03, 2016 9:30 pm

Thanks , I'll give it a go, To the pattern for TDC on cam & crank, Can I tell which is TDC, The larger gaps in the pattern? How do they fit in & the peaks in the up & down wave on cam sensor? what I mean is , is the cam in the correct place relating to crank? thanks terry
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Re: Switching two cylinder running

Postby Terry Ferguson » Thu Mar 03, 2016 9:31 pm

sorry meant up & down waves on crank
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Re: Switching two cylinder running

Postby KimAndersen » Fri Mar 04, 2016 10:56 am

Hi

What common rail system are this Ford S-Max 1.8 tdci equipped with !!!

If its a Delphi system, I might be able to help you in determining the TDC reference mark in your waveform.

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Kim
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Re: Switching two cylinder running

Postby Terry Ferguson » Fri Mar 04, 2016 11:24 am

The injectors Are siemens, ECU is Continental, So not sure, My condern is that non of the injector pulse or cam sensor signals seem to line up with each other or in a prominant place in the wave form overall ? In the Blue Crank pattern there are obvious Gaps in the wave form, 2 of these are eaqual the the measurment of the Cam sensor signal, So obviously TDC is someware? Either this gap in the blue pattern Or the Peak of the wave on blue pattern, On the square wave of Cam (red) is the 2nd line TDC ? if so why is it not lined up with a promenant part of the Blue waveform ? I hope you can see what I am trying to get accross, Saying that if they are out of sync, this still does not explaine why it is alternating across 2 lots of 2 cylinders, I am greatfull for any help, as you can see I am new to the scope, I hope I am getting there? I'll keep trying, Thanks for your help, Terry
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Re: Switching two cylinder running

Postby KimAndersen » Sat Mar 05, 2016 5:35 pm

Hi Terry

How do I determine the top dead center (TDC) is an easy task with Picoscope if you have the right information from the vehicle manufacturers.

After have done some internet research I found that this particular engine uses a reference mark at the flywheel at 90 degrees before top dead center (BTDC). And here comes the easy part !!!. Down at the bottom of your picoscope screen are there a " ruler settings" icon - try to play with those settings.

To help you a little, try my way first.

What I did was to place the two degree ruler over two revolution (2 RPM) or 720 degree - measured at crank position sensor (CRK) as shown in this picture. Next thing you should do is to change the "Rotation Partition" to 8 which changes the interval to 90 degree and you should see the result right away.

It is quite fun to play with the ruler settings and now that you know where your TDC are at this engine you can begin measure the injection point in regards to TDC. I measured the first two injection points and the first takes place at 3 degree before top dead center (BTDC) and the second at 1.831 degrees after top dead center (ATDC).

FORD 1.8 TDCI CAM CRANK RELATION.jpg
FORD 1.8 TDCI CAM CRANK RELATION


With degree ruler fixed at the crank position sensor waveform is it a matter of how to use the "time ruler" together with the "degree ruler".

Do not change the position of the "degree ruler" at first, but use the "Time ruler" as you wish. It can be placed anywhere and will show the degree difference between the two ruler right away.

I don't know whether or not this will help you diagnosing your problem - it may be related to other issues such as calibration of the injectors - just a thought.

Is there any history or record on this car - I´m thinking about trouble codes !!! :wink:

Regards
Kim
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Re: Switching two cylinder running

Postby Terry Ferguson » Sun Mar 06, 2016 1:28 am

I have read that , But not fully understood it, Yet! But I will get it & it is a big help, There are no trouble codes, Also the thing I don't get, if it was an injector ?? Why do they runn ok then not, Never more than 2 at once? Never 3 or never 1 always runs on 2 cylinders & can be any 2?? at least by your calcs it fires at 3 degres which sounds ok, the other 2 cylinders only have a very faint fir event? what do you know about the cam sensor? is it in the correct position in relation to the crank? Thanks for your help, I lookforward to getting to grips with the rules< Thanks again Terry
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Re: Switching two cylinder running

Postby KimAndersen » Sun Mar 06, 2016 12:29 pm

Hi Terry

I hope that I didn't confuse you, but I wasn't precise with the placement of the degree rulers which is crucial for a correct measurement.
With the new settings the first injection happens 4.246 degrees after top dead center (ATDC) as compared with old measurement at 3.0 degrees before top dead center (BTDC) which creates a difference at 7.246 degrees.

I know that I should have uploaded the source file, but I cant put arrows in this file showing where TDC are and the 90 degree reference mark are located. About your concern for the the camshaft/Crank position sensor correlation would I say that there are between 2 and 3 degrees difference compared with a "known good" file from the waveform reference library as "Volrem" has mentioned in his reply.

I have uploaded the source file to you as it's much easier to see how I have used the degree ruler.

Ford_S-Max_2007_Diesel_TEST.psdata
FORD S-MAX 2007 1.8 TDCI
(2.55 MiB) Downloaded 25 times


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Kim
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Re: Switching two cylinder running

Postby Terry Ferguson » Sun Mar 06, 2016 6:29 pm

Thanks, I will study all this tomorrow, so you would say the Cam & crank relation is out by 3 degrees, This is not good, But I still don't think this would cause my 2 cylinder switching miss fire? what do you think? Thanks again for your help? Terry
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Re: Switching two cylinder running

Postby Terry Ferguson » Mon Mar 07, 2016 10:58 am

Hi I am assuming the cam / Crank relation is with in limits as No code comes up? Have you any thoughts on why 2 injectors go are off, The injectors appear to draw no current, when the 20 amp clamps are on, the running ones show the good trace? The ecu has been exchanged on a trial & a new ecu fitted was exactly the same? should I be suspecting the injectors? I am waiting for my original ECU to be returned (today I hope) then I will run it again & put up a couple of wave form files, as requested in earlier posts, Thanks Terry
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Re: Switching two cylinder running

Postby KimAndersen » Mon Mar 07, 2016 12:10 pm

Hi Terry

Yes - I would say it's within the specifications regarding the correlation between the cam/crank position.

After that I have reread some of your post again I saw that you have made resistance test of the injectors you wasn't happy about.

Try to make this resistance test again and set your DMM on auto setting.

Siemens piezo injector have a resistance around 200 kohm as they piezoelectric and in principle work as capacitor.

If there are to high readings could it mean something in terms how many amps your injectors consumes.

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