Just for fun...

[84Toyota4x4]

Well, I dont feel like a complete ass, but I feel I should know more. What I know has just been picked up from working in a shop as a shop bitch swapping parts, and started out as just sweeping floors and ****. Ive never taken any classes or anything, and everything Ive learned so far has been mostly "over shoulder" asking the whats whys and wheres.

Thanks for the fun!

~T.J.

 

[skrause]

How do you expect people to answer the code # questions /w no outside resources? I don't even have 'em all memorized :flipoff:

Ya, since when did codes have letters in them!?!? I swear, once math started this crap it all started going down the shitter. :haha:

 

[84Toyota4x4]

By the way, I didnt list the MAF and O2 sensor and crap on the crank/no start because in my experience, the motor WILL start with these malfunctioning, however usually die shortly after and or run bad... I would call that poor running, not a no-start problem. Am I wrong?

I know with my car and my girls Runner, it will start up and somewhat idle (usually die) with no MAF plugged in, and with my car, it runs fine without the O2 plugged in until it gets warm, then it goes down the tube a little (closed loop vs open loop I assume?)

~T.J.

EDIT: D'oh! I'm such an idiot sometimes. That was the whole question! Obviously, I just said they WOULDN'T cause a crank/no start issue, therefor should have been listed. Jeeze, such a moron :looser:

 

[CrustyJeep]

still missing 1.

OK narrowing to 4 is kinda tough, but I suspect you don't like the mental compression check one. So, if it were me, after all the other stuff, I'd try a squirt of starting fluid, and if that didn't get a rise, I'd go after the ignition timing.

But alas, all that trouble code stuff is out of my leaque so I guess I can't have a job anyway :booo: :flipoff:

 

[4xjunkie]

Ive never taken any classes or anything, and everything Ive learned so far has been mostly "over shoulder" asking the whats whys and wheres.
~T.J.

That is some of the best schooling.

 

[TreeClimber]

still missing 1.

Dang it GaryTJ, you didn't grade my test! OH well, I've been putting my knowledge to good use with my SB Chevy into a TJ (with a little help from a Jeep Tech)

 

[KarlVP]

Let's see, I used to be a parts bitch at Autozone.

1. What does an E.G.R. valve do? Why is it necessary on today’s vehicles?
The EGR sends the exhaust gasses into the combustion chamber so it doesn't have to heat up the air and fuel mixutre thus the vehicle runs more efficently.

2. Explain the reason for the A.I.R. system on modern vehicles, describe what it does, and what components make up that system.
Not a clue in the world.



3. What is an OBD readiness monitor?
It's the thingy that runs all the diagnostics while the vehicle is being driven. It checks things after the car has been run for a while, because it can't check them at initial startup.

4. What does the EVAP system do and how can you test for a problem with that system?
It takes the evpaorated emissions and filters them through that little box under the hood in my TJ (Learned that from GaryTJ of all people)



5. Which of the following can NOT cause a cranks/no start condition on a fuel injected engine?
May be more than 1 correct answer. Circle all possible causes.

Starter Motor
CKP Sensor



6. What is voltage drop? Explain how to test for it.
How much voltage is used by the conductor that carries it. "Waste energy" essentially.

7. A car comes into the shop and has a p0301 code. Circle all the possible causes.
No clue, but I could look it up in the book or use the code reader thingy.

Spark Plug Timing Belt MAF Sensor Ignition Coil
Starter Motor EGR Valve Fuel Pump Oxygen Sensor CMP Sensor


8. What is the most likely cause of a p0440 code?
No clue, again I don't know my codes.

9. A car is towed in for a no start. A technician checks it out and says it cranks ok but will not start. What should be the first 4 things checked to narrow down the possible causes of the no start condition?
Does it have gas? Does it have spark? Is the battery Good? Are the tires inflated?


10. A Fuel injected vehicle is brought in and has a miss at idle on 1 cyl, but it runs fine over an idle. Power is fine and fuel economy is fine. Compression checks OK. What is the next thing to check and why?
IAC? I dunno. Probably causes that p0301 code or whatever.
:flipoff:

 

[skrause]

May be more than 1 correct answer. Circle all possible causes.

Thanks Gary, now I've got Sharpie marks all over my monitor... :haha:

 

[GaryTJ]

I'd go after the ignition timing.

But alas, all that trouble code stuff is out of my leaque so I guess I can't have a job anyway :booo: :flipoff:

You hit it there, but not just ignition. Cam timing too. Cam timing can be off and still run, or just a little farther and not run.

 

[GaryTJ]

Let's see, I used to be a parts bitch at Autozone.

Not even close..... funny though!

 

[GaryTJ]

Thanks Gary, now I've got Sharpie marks all over my monitor... :haha:

:haha: :haha: :haha: :haha: :haha:

 

[GaryTJ]

Dang it GaryTJ, you didn't grade my test! OH well, I've been putting my knowledge to good use with my SB Chevy into a TJ (with a little help from a Jeep Tech)

That is because everytime I read it, I am laughing too hard to answer...:clappy: :clappy: :clappy:

 

[79chevy39.5's]

my buddys toy 22re would actualy run with maf unpluged you could even drive it as long as you didnt give it more than 1/2 throttle

 

[GaryTJ]

These are the answers I was looking for. You would have had to have all 10 correct in order to even qualify for an interview.

1. What does an E.G.R. valve do? Why is it necessary on today’s vehicles?

__Exhaust gas recirculation, recycles used exhaust gases back into the combustion chamber to dilute the mixture. Because the gas has been burnt once already the gas is for the most part inert. This spreads the molecules which in turn cool’s the combustion and reduces emissions and allows higher timing numbers. The main emissions that are reduced are Nox
Although there is evidence proving NOx, in itself, is harmful to humans, the main reason NOx is considered an environmental problem is because it initiates reactions that result in the production of ozone (O3) and acid rain. Ozone is created when nitrogen oxides and volatile organic compounds (VOCs) combine in the presence of sunlight. Plenty of sunlight is needed to create smog, which is why we get more of it in summer than in the winter. In some major urban areas, more than 50% of the ozone forming nitrogen oxides come from vehicles.

2. Explain the reason for the A.I.R. system on modern vehicles, describe what it does, and what components make up that system.


Air Injection defines a system that introduces fresh air to the exhaust stream. This has been used in many ways, but the primary reason is to help raise the exhaust temperatures, promoting continued combustion of the exhaust gases as they leave the system. Air can be introduced either by way of a belt-driven air pump, or by the natural vacuum that occurs when hot, moving exhaust gases pass an open port. The latter style is usually called reed valve or Pulse Air Injection. In early cars, a thermactor system was used- This basically allowed the hot (partially unburned) gases leaving the exhaust valves a fresh shot of air, causing them to 're- burn' as they left the manifold. Heat was again a primary function in later cars using catalysts, as the catalyst needs to reach operating temperature before it an do its job (see Catalyst), and the fresh shot of oxygen also helps the chemical reaction inside the catalyst. Parts include the pump, routing hoses, solenoids, filters, and manifolds.


3. What is an OBD readiness monitor?

The monitors verify the OBD system has completed testing each system. When the vehicle's PCM's monitor completes testing , the readiness system status will be reported as "Ready" or "Complete." Once a monitor is set as "Ready" or "Complete" it will remain in this state unless diagnostic trouble codes (DTCs) are cleared by a scan tool or if the PCM's short term memory is erased by a power failure (i.e., disconnecting the battery). Since the three continuous monitors are constantly evaluating, they will be reported as "Ready" all of the time. If testing of a particular supported non-continuous monitor has not been completed, the monitor status will be reported as "Not Complete" or "Not Ready." You could fail an emission test by just having the codes cleared before you go in and not completing a complete drive cycle.


4. What does the EVAP system do and how can you test for a problem with that system?

Purpose:
An evaporative control system is used to reduce emissions of fuel vapors into the atmosphere by evaporation and to reduce unburnt hydrocarbons emitted by the engine.
Construction:
The system consists of an EVAP Purge Solenoid, a Charcoal Canister, a Pressure Vacuum Filler Cap, and a Rollover and Pressure Relief Valve.
Operation:
The evaporative emission system prevents gasoline vapors in the fuel system from escaping into the atmosphere. When the vehicle is not running, fuel in the fuel tank evaporates. The vapors travel through vent hoses or tubes to be stored in the charcoal canister. Once the vehicle is running, these vapors are drawn into the engine and consumed with combustion gases.
Most common test is a smoke test to check for a leak. Beyond that, it would involve electronic component tests.


5. Which of the following can NOT cause a cranks/no start condition on a fuel injected engine?
May be more than 1 correct answer. Circle all possible causes.

Spark Plugs Timing belt MAF Sensor Ignition Coil

Starter Motor EGR Valve Fuel Pump Oxygen Sensor CKP Sensor

(with the exception of o2 heater failure causing the efi fuse to blow (like Toyota’s))


6. What is voltage drop? Explain how to test for it.


Voltage drop is the reduction in voltage in an electrical circuit between the source and utilitization device. It is measured by using a volt meter in parallel to the curcuit being tested. The most common failures are to the ground side.

7. A car comes into the shop and has a p0301 code. Circle all the possible causes.

Spark Plug Timing Belt MAF Sensor Ignition Coil
Starter Motor EGR Valve Fuel Pump Oxygen Sensor CMP Sensor


Could also be a vacuum leak or injector problem


8. What is the most likely cause of a p0440 code?
Gas cap 95% of the time. Never use aftermarket, only OEM


9. A car is towed in for a no start. A technician checks it out and says it cranks ok but will not start. What should be the first 4 things checked to narrow down the possible causes of the no start condition?

Always on a no start you are missing one of 4 things

• Spark, not just at the coil but all the way down to each individual plug
• Fuel, again not just at the pump, but all the way into the cylinder.
• Compression.
• Timing, not just spark timing, but cam timing also.

10. A Fuel injected vehicle is brought in and has a miss at idle on 1 cyl, but it runs fine over an idle. Power is fine and fuel economy is fine. Compression checks OK. What is the next thing to check and why?

Vacuum leak diluting the fuel charge, or erratic spray from an injector not allowing fuel dispersion.

If it runs OK off idle then spark and overall fuel dispersion is OK. If the power and fuel economy are OK, then compression and timing are OK. Just a small vacuum leak can cause a serious misfire at idle.

 

[426rider]

I learned something today. Mainly about 1,2,3,4,7,8,10

Now, Why only an OEM cap. I just replaced mine with an aftermarket one and what does a bad cap do to how your vehicle runs?

 

[GaryTJ]

OEM gas caps are gasketed exactly for the fill neck. the aftermarket gas gaps are more of a universal fit. They do not seal the same and at best, last 1/3 as long. It is worth the money to get OEM. Just from experience, time and time again. The first thing we look for on an evap leak is a universal gas cap.

 

[TreeClimber]

I learned something today. Mainly about 1,2,3,4,7,8,10

Now, Why only an OEM cap. I just replaced mine with an aftermarket one and what does a bad cap do to how your vehicle runs?

MOST of the problems we get with "Check Engine" lights on the dash are related to EVAP problems. The number one problem, which triggers this light is related to not properly tightening the cap (click-click-click). A miniscule amount of leakage in that cap will trigger it. ALMOST everyone who decides to put a non-factory cap (think aftermarket locking cap - as they're worried about gas theft due to the expense of gas nowadays) ends up in our shop with this complaint.