Smoke testing Procedure help needed

[nonickatall]

It is direkt behind the fuel tank, between axle and tank. You can reach it laying unter the car. 5 Minutes to disassemble. Cost 20$.

But i am not sure that this is your problem, because the so called EVAP system which is the vent valve, a purge valve direct on the intake, and a pressure sensor, plus the charcoal tank throws errors when one of this valves or sensor fail.

And if the vent valve stuck open, you have a leak, but so small that it should not lead into P0171 and P0174 if not something else is not ok.

I would check for intake leaks with smoke test, then check MAF sensor, and o2 sensors. Have you swapped the airfilter? And check for the correct fuel pressure. What is about coolant temperature? Is the coolant temperature normal when warm?

Something makes that you mixture is to lean, to lean to be adjusted by the ecm.

Because its on both banks i would suspect 1. air intake leak, 2. Fuel pressure, 3. MAF Sensor, 4. Two defekt O2 sensors.

 

[rod7515]

The reason I want to do a mole test at the intake is to see if the intake has any leaks. Does the vent valve need to be blocked off to do this? I. Not trying to check for EVAP leak. I am suspecting an intake leak.
Rod

 

[strutaeng]

The reason I want to do a mole test at the intake is to see if the intake has any leaks. Does the vent valve need to be blocked off to do this? I. Not trying to check for EVAP leak. I am suspecting an intake leak.
Rod

The EVAP vent valve under the truck? The smoke shouldn't make it that far...

The purge solenoid valve is normally closed, but if you want, unplug the line to see it leaks smoke out. There's a diaphragm inside the purge valve that can tear. However, in this case, the system will run rich because it's always sucking in fuel vapors.

Edit: lean on both banks (with fuel trims on both banks being the same, and percentage lean through the RPM range) is almost always a fuel delivery problem. If smoke test looks okay, hook up a fuel pressure gauge.

 

[nonickatall]

Thats true, that takes time, but I would not test the vent valve with a smoke tester.

Just start the car and blow pressure in the hose, which should be airtight while engine running.

And additionally as I wrote. Its not necessary to test the EVAP system with a smoke tester, because it should throw an error with a malfunction.

Just try this. Open your fuel cap and let the engine run. You should receive a Message: "Error: fuel cap open" or similar in the instrument cluster.

But attention. The EVAP self test only runs on certain conditions. I don't remember exactly, but something like: "fuel tank filled up to 3/4", or something.

The smoke test is more for intake, between MAF and trottle housing, intake itself, attached hoses, purge vent, throttle body, dipstick, oil cap and so on.

 

[Fless]

It will help your smoke test to have the system as closed as possible. You can apply 12v to the connector on it to close it, polarity doesn't matter as long as it's out of circuit. Here's a pic with the evap vent valve shown and circled in red (spare tire and fuel tank removed for clarity):