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Pico Newsletter Jan 2015 (Read 6,618 times)
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LSD Guide
Picogroup
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Bentleigh, Victoria, Australia
Bentleigh
Victoria
Australia

Pico Newsletter Jan 2015
Jan 30th, 2015 at 12:27pm
 
I bring your attention to this article in the Pico Newsletter.



  1. Case Study: Celica brings Scope and Scan Tool together
  =========================================================
  This month Steve Smith demonstrates how PicoScope fits within
  the diagnostic jigsaw when resolving seemingly complex issues.
 
  The analogy of a jigsaw fits well if we look at the essential
  pieces required for a successful diagnosis.
 
  ~ The relevant Scan Tool
  ~ Accurate technical information
  ~ Experience gained as a direct result of training
  ~ PicoScope
 
  The vehicle in question is a 2001 Toyota Celica 1.8 190 PS
  utilising variable valve timing and lift. The complaint from
  the customer was poor idling, heavy fuel consumption, lack of
  power, periodic cutting out on over run and the all-important
  engine warning light was illuminated.
 
  As always the customer interview is vital, and in this case
  revealed that extensive engine work had been carried out
  including a cylinder head replacement due to severe
  overheating.
 
  At this point it is very easy to jump to conclusions and
  assume "doom and gloom" when a customer arrives having
  experienced numerous attempted repairs after a major engine
  overhaul. However, by maintaining a methodical approach
  throughout the diagnostic procedure we can present our customer
  with not just a bill, but a working vehicle and the evidence
  and data trail that supports the necessary rectification.
 
  A basic inspection revealed the tell-tale signs of intrusion
  about the engine to include, a new cylinder head, VVT oil
  control valve, coolant temperature sensor, catalyst,
  pre-catalyst O2 sensor accompanied with a punctured and
  misrouted wiring harness that resembled a pincushion! A brief
  road test confirmed the customer's complaint but also revealed
  the engine to sound fine with no knocks or rattles, or smoke
  from the exhaust and both coolant temperature and pressure to
  be correct. Note: The exhaust fumes did emit the sulphur odor
  associated with over fuelling or a catalyst working overtime!
 
  It is essential to establish the engine condition before
  spending the customer's money...
 
  You can continue reading the Toyota Celica case study online:
  http://www.picoauto.com/tutorials/celica-faulty-maf.html
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WWW WWW iancrane01  
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Robski
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Yorkshire, Great Britain
Yorkshire
Great Britain

Gender: male
Re: Pico Newsletter Jan 2015
Reply #1 - Jan 30th, 2015 at 1:05pm
 
I don't understand towards the end he mentions 'doner car' is this how he fixed the faulty one ?   Undecided

"Below we have the waveforms from our donor Celica"
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Cheers

Rob.
 
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autosparky
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Porirua, New Zealand
Porirua
New Zealand

Gender: male
Re: Pico Newsletter Jan 2015
Reply #2 - Jan 30th, 2015 at 6:32pm
 
he also takes about theoretical MAF math channel, while this sounds very clever, how accurate can this be??
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can't see, can't hear, can't remember
 
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JOHNNY5
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Diesel and automotive
diagnostic tech

Posts: 4

Gender: male
Re: Pico Newsletter Jan 2015
Reply #3 - Feb 13th, 2015 at 8:09am
 
I believe there are two critical miscalculations in his MAF formula calculation. Please Correct me if I'm wrong.

MAF miscalculation
I believe there may be 2 miscalculations in the MAF formula. ---First, the weight of air is 1.286 grams per liter as nitrogen alone weighs 1 gram per liter almost exactly and the remaining oxygen weighs .286 grams (air is 80% N and 20% O)
Almost 30% more.
-Second is where we calculate 25 intake strokes by 1.8 liters. The entire 4 cylinder engine is 1.8 resulting in each cylinder and therefore each intake stroke to be only .450 liters.
25x.450 = 11.25 liters
11.25 liters x 1.286 = 14.47 grams
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