Sometimes, it is good to sit on a school bench. VVT refresher course.

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#1
Along side the two day refresher, we saw and will see scope related diagnostics, and with transducers and volume yield in relation to how to calculate that in 14.1 to 7 ideal versus when short term trims shut down for WOT.

Transducer here is key. Great course to day loved it. Tomorrow, get cool cars to practices live road WOT scanning and graphing. Fun also today, the newer version coming out, no cam cars, solenoid driven valve actuators.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#2
Especially hard for me today was the translation as most if not all the guys where french canadian and the terminolgy had me confused, but as the math and graphing went on I got the gist of the volumetric reading we were seeing in relation to amps and vac and psi reading the transducer could give us in a 3 minute hook up.

That I saw a great time saver potential compared to my conventional methods of relative compression readings, versus direct and static.

Most impressive, using static to help determine time and volume to ease a better diagnostic approach IN conjuctiontion with a scope.:eek:

I will up date this thread tomorrow, and if any have questions, I am obligated to say by copyright, I can up load course but at my risk as it is paid for by my employer and has associated student ID #.

But I will try, if some want to ask me anything related to this, I will sure try to lend a hand.

In the mean time, for a 2019 active tech, this is a must course to get IMHO. ;):bat:
 
Last edited:

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#4
So here is a scope seeing retard, but no short fuel trim loss or gain in a substantial way, lean toward a mechanical issue.

When attacking these sorts of problems, a dvim is simply not enough. But if the info gets out there, a guy with a elm 327 chipped phone can do 3 1/4rs of the diagnostic hood closed by just checking mode six hex data and freeze, or make his own, clear all and just clean the whack out of an engine and do simple math.

Key is to know how to read the data. That is where these courses shine. Refresh rate of the human mind is not like a hdd drive compared to todays standards.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#7
Second day today went like this, class was split in two, each given scanners and scopes and transducer kits. Oh And cars and truck to WOT on under LOAD!!. The test doesn't work in a bay/stall WOT.

Lets say the tacoma 5.7l had less rubber in the rear cuz the trac control screwed the test a few times. We deactivated, did recommended 5000rpm test, spinning tires in from of a subway sandwich store cuz traffic was light. :eek:;) MORE than once. Those tacomas are tuff, this one had 459,000km's on it.

A "VE" of 82%. Theoretical was 79ish%. Pretty good. After maf and intake cleaning, brought the VE up to 84. Damn near close to pass for this type of engine which needs at least 85 to pass calif law.
 
Last edited:

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#9
Of note, trims are not essential to the VE transducer test. Just need the transducer when theoretical WOT test is done properyly in thee or four rpms ranges, as long as you smash the gas and maf follows rpms, that is where you take snapshot of all data and take it back to shop and analyze waves forms,.

If VE is out, you pull the transducer and then start really having fun with a laptop and scanner, scope 4 channel full automotive based.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#10
We tested the pico and the maxi scope from autel.

Sorry for myself and other autel scanner lovers, but the pico won HANDS DOWN!!! in every scope based dept, apart from the fact that pico is not made for android or iOS.

Both tranducors were pico, but with the tacoma, my team, so to speak, we were able to modify BNC conector to fit the maxi scope and the pico, but autel software sucks large in the scope. The actual scope and hardware itself seems rugged and well thought out, probably a few more updates on the software and the autel could do better, but it is chinese built and not rugged laws really do good there.
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,383
Likes
78
Points
48
#11
Where do the pressure transducers install? I assume somewhere with the spark-plug, do they space the plug out slightly from its normal depth in the head?

What do the traces indicate? 13.8 bar (peak) suggests it is compression pressure, but I would expect you would also want to be looking at combustion pressure too, getting all four strokes.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,523
Likes
172
Points
63
Location
St-Hyacinthe, Quebec, Canada
#12
Two transducers are great, but hardly anyone has the budget for that. These kits are 5grand + a piece.

But graphing in vac on one on booster, the other on cyl #1 like a basic compression gauge, we were able to know the cat was the problem without even opening modes 5 and 6.
 
Last edited: