Buzz and contribution tests

[hheynow]

What equipment is needed to do these tests? A specific scanner? How are these tests administered? Are the results reliable? How many hours should a shop charge me for both tests?

 

[Ford_Forgotton]

my AutoEnginuity scanner will do those tests.

Takes about 15 mins to boot the computer, hook it to the truck, launch the software, scan the sensors, then run the tests.

 

[95_stroker]

Daryl,

Can you explain the test and what the results mean for the rest of us?

 

[Ford_Forgotton]

buzz test is a "key on, Engine off" test (KOEO).

Sequentially fires all the injectors and then all 8 at the same time. Hence the "buzzing" they make. If an injector doesnt buzz the same as all the rest, you may have a problem.

Cylinder contribution test turns injectors on and off, and somehow the computer decides that each injector is squirting the right about of fuel. Im guessing it looks at RPM or something and if it sees a drop during a certain injector event then it tags it as bad.

 

[94f450sd]

buzz test:when it initiates it opens all 8 injectors at once.then it goes through all 8 one at a time in sequence,1,2,3,4,5,6,7,8.during this test you will hear an audible"buzz"from the injectors.this test checks the electrical circuitsof the IDM and injector solenoids.it will then give you a code for any cylinders that are buzzing correctly and why.or it will say system pass.

the contribution test"this test will shut down cylinders,over fuel cylinders,under fuel cylinders.each cylinder must drop a certain amount of RPMs and recover in a certain amount of time and raise RPMs and recover in a certain amount of time and .while this test is in progress the enginewill run real ruf and sound seriously wierd.idle will go up and down all on its own.in order for this test to initiate the engine must be warmed up enough to warm the oil to a certain degree.this test will either say system pass or give you cylinder#? contribution balance fault.this means that either you have abad injector/s or cylinders.its usually a good idea to do a compression test on said bad cylinder/s before yanking an injector as its not always an injector causing the fault but its more than likely a bad injector

 

[95_stroker]

Cylinder contribution test turns injectors on and off, and somehow the computer decides that each injector is squirting the right about of fuel. Im guessing it looks at RPM or something and if it sees a drop during a certain injector event then it tags it as bad.

So the CCT is done KOER then?

Good info so far.

 

[94f450sd]

yes KOER

 

[95_stroker]

Ahh, Rich added while I was posting, more good info Rich.

 

[94f450sd]

im full of it

 

[95_stroker]

Any other "off the shelf" type of scan equip that will perform these tests?