Ford smart charge

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Ford smart charge

Postby 3staar » Sat Dec 30, 2017 10:59 pm

Hi all,

relatively new to using the picoscope, the following was presented to me but i am a little stuck as to where to go now...

2005 ford fiesta 1.2 petrol engine, from what I've been able to piece together from the customer and previous garage it received a new genuine ford alternator and halfords calcium battery around this time last year, customer complaint now is dash lights go funny occasionally and blink.

no fault codes (i suspect the previous garage erased them, or it didn't log anything :?: )

I only had a few minutes with the car, will be spending more time with it tomorrow/in the new year hopefully.

I've attached files with the engine at idle no load but the cooling fan does kick in part way through and from what i can see is the ecu command signal does not change whereas the alternator feedback does. According to the picoscope guided tests the ecu command signal should be idle till a load is detected, duty cycle for the ecu command signal does not seem to change where as the alternator feedback does, varying from 50% to 90% when the fan kicks in.

i will be removing the multi plug and checking the battery voltage the next chance i get and putting the accessories on to further load the system,ill be closely inspecting the loom too.....but my question is whats going on with the ecu command signal?

files were too large so have uploaded here:

https://www.dropbox.com/s/hgnw6kz8m9nc0 ... sdata?dl=0

https://www.dropbox.com/s/1xtgk7zllo0st ... sdata?dl=0



fiesta no load fan kicks in.psdata
idle no other loads except cooling fan is running, it switches off on capture 15
(28.31 MiB) Downloaded 86 times




any help is greatly appreciated!
Attachments
fiesta 2.odt
capture 13 is when the fan kicks in
(172.55 KiB) Downloaded 26 times
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Re: Ford smart charge

Postby Steve Smith » Tue Jan 02, 2018 12:01 pm

Hello and thank you for the post, welcome to PicoScope

With regards to the dash light blinking, can you indicate which lights if possible?

Has our customer complained of battery/voltage related issues such as slow cranking, flat battery, flickering head lights etc?

At present looking at the file "fiesta no load fan kicks in. psdata file" I can see that the ALT feedback is consistent with load (buffer 15) and that the PCM command signal is active continually (No idle state as indicated in the Guided Test)

This suggests the PCM is requesting "Charge On" and the alternator is both responding and feeding back.

I hope this is of some help and please feedback when you can with any updates

Take care......Steve
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Re: Ford smart charge

Postby 3staar » Sat Jan 06, 2018 10:33 am

Thank you Steve

The customer reported the dash flickered namely the abs light flashed/came on....when scanned no codes were retrieved.

Unfortunately the car was scrapped as the customer did not want to spend any more money on it and has since picked up a nice little honda jazz, safe to say I won't be seeing them much!

I suspect the pcm was commanding charge all the time as the battery voltage was not as expected (~14v) thus the constant square wave regardless if loads were present or not (see earlier buffer, before fan kicked in with no loads and engine at idle). I also assume the pcm square waveform would return to idle once battery voltage came up and would only re-appear once loads were applied....anyone else agree?

Many thanks
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Re: Ford smart charge

Postby Steve Smith » Mon Jan 08, 2018 11:17 am

Hello and thank you for the feed back

I guess this is what we are up against as the cost of diagnosis and repair can exceed all economical sense

Interesting point about the PCM control reverting to an "idle" state when battery voltage has recovered and load has been removed.

Theoretically yes, but in the real world I think not!

I have no doubt the PCM idle state would return but from experience things are rarely as stated!

Using the scope reveals control strategies that are never included in workshop manuals and we need to be mindful of such.

It may have been the PCM was compensating for temperature or moving on through some form of battery "conditioning" that you can see with the scope but simply can't explain based on the technical information alone

I guess experience, training, sharing information and product knowledge all contribute to explaining what seems unexplainable at first glance

With all that said, I guess continued monitoring of the charging system (with a fully charged battery) over a typical driving cycle would be the next step.

I hope this helps, take care......Steve
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Re: Ford smart charge

Postby Technician » Sat Feb 03, 2018 12:25 am

Sorry for gate crashing the thread :idea:

A few months ago I had a Fiesta about 4 years old and the customer complained the car was unreliable because the battery was going flat every couple of weeks or so, she had a breakdown firm recover her a couple of times home and somebody put wiring across the battery so that a remote charger could top up the battery overnight for her to prevent flat batteries, however, when she moved home to her new home she was not afforded the opportunity to use the add on remote charger because she had nowhere to plug it in.

She was recommended to me to look at it, the first thing I did was look on here at Pico's test procedures for checking the Smart Charging Systems, a very good valid test procedure, however, maybe lack of experience I don't know, but the Smart Charging system when tested always worked fine, so I was stopped dead in my tracks each time I tested it, and the only clue that a problem was present is that the battery was discharged.

I checked the battery and found nothing wrong with it after charging it, but the battery was a standard lead acid type, and members on here advised that it should be a calcium type fitted, so because I had already read elsewhere that the Smart Charging System (single wire) from the alternator didn't require a calcium battery I decided to check with Ford Technical, they confirmed that this car did not require a calcium battery to be fitted.

Eventually the alternator was seen not to be charging so I took the alternator to the re conditioners and asked for the alternator to be tested, I was advised the alternator regulator was faulty and a new one fitted, I put the alternator back on the car and the alternator did not charge as expected, thus I too the alternator back and the re conditioner said the regulator was not fitted properly, quality service there then.

Two weeks later the customer was on the phone the battery was flat, I checked the charging system and had exactly the same problems, the battery was discharged and the alternator appeared to be charging, although on every occasion when tested, the volt drop on the earth line always appeared high to me, sorry can't remember specific values, but somebody on here advised me not to worry about that as he thought it was not a concern.

The alternator was taken back and another regulator was fitted, again two weeks later the same problem, I then went to the re conditioners and asked him outright are you putting inferior parts into this alternator, he replied no he does not use cheap parts. When I got the alternator back this time and reinstalled it on the car, as before the alternator was seen to be working, but this time the volt drop on the earth line was seen at 0V, an improvement. I do the servicing on this car now and she advises me since the last regulator change the battery has always remained charged and she has had no problems.

The moral of the story, buy genuine parts as pattern parts appear to work but are not reliable, will cause the diagnostic technician major headaches looking for invisible but very valid real faults, which can lead to the technician doing the job for the end user getting a bad name for poor parts suppliers who continue to make good profit out of cheap rubbish they sell.
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