Removing EVAP System??

[MrZ71man]

I did a search, and I can't find any info. Is there a way to remove some of the EVAP controls of the PCM? After I did the motor swap, I couldn't take a lot of the EVAP system components on the fuel tank, and it's throwing codes and my motor is acting crazy...Please help!!

[2002_z28_six_speed]

Evap system problem ---> Vacumn leak.

[97K15004WD]

What year is your vehicle? OBDII requires different responses from the monitoring sensors, depending on the year. PCM is looking for .040 size leak in one year, .020 size leak in others, in some, doesn't care. EVAP system holds tank vent gases and if not done properly, can vaccuum your tank flat. Be aware that the solenoids allow engine vac to draw vapors into the engine after an off cycle and a certain outside temp is met. PCM goes into test mode to check for leaks by creating small vac and then times how long it takes to reach atmospheric pressure (uses MAP and pressure sensor in the tank to compare).

Thats why he said "vaccuum leak".....

[mr.prick]

What year is your vehicle? OBDII requires different responses from the monitoring sensors, depending on the year. PCM is looking for .040 size leak in one year, .020 size leak in others, in some, doesn't care. EVAP system holds tank vent gases and if not done properly, can vaccuum your tank flat. Be aware that the solenoids allow engine vac to draw vapors into the engine after an off cycle and a certain outside temp is met. PCM goes into test mode to check for leaks by creating small vac and then times how long it takes to reach atmospheric pressure (uses MAP and pressure sensor in the tank to compare).

Thats why he said "vaccuum leak".....

nice first post.

[MrZ71man]

The engine is from a 2004 Silverado, but my truck is a 1995. I kept my original fuel tank but put a new fuel pump in it (for the increased PSI). The donor truck had sensors in the gas tank to monitor the pressure and fuel level. I kept the purge canister from the tank and installed it on mine during the swap, but didn't take the other sensors. I was wondering if there is a way to delete the necessity for this system, or if I just need to swap in the whole fuel tank assembly/system?

[2002_z28_six_speed]

So is the Evap canister hooked up or not? I was thinking that maybe you have the Evap canister still on the engine and the PCM is turning it on without the evap line hooked to anything ---> big vacumn leak.

Try diabling the Evap in the PCM first:

LABELS Purge Canister Open Loop
Parameters Value
{B0501} Purge Canister Min Temp 30.000000 °C
{B0502} Purge Canister Min Speed 16.093445 KMH
{B0503} Purge Canister Min Air Flow 12.000000 Grams/Second
{B0504} Purge Canister Min Run Time 100.000000 Seconds
{B0505} Purge Canister Open Loop Disable

You shouldn't have to swap everything over unless you really want a good smelling car.

[MrZ71man]

So is the Evap canister hooked up or not? I was thinking that maybe you have the Evap canister still on the engine and the PCM is turning it on without the evap line hooked to anything ---> big vacumn leak.

Try diabling the Evap in the PCM first:

LABELS Purge Canister Open Loop
Parameters Value
{B0501} Purge Canister Min Temp 30.000000 °C
{B0502} Purge Canister Min Speed 16.093445 KMH
{B0503} Purge Canister Min Air Flow 12.000000 Grams/Second
{B0504} Purge Canister Min Run Time 100.000000 Seconds
{B0505} Purge Canister Open Loop Disable

You shouldn't have to swap everything over unless you really want a good smelling car.

I'm trying to understand this a little more...those are currently all of my stock values, but are you saying all of those need to be changed? If so, what would you recommend changing the values to?

[2002_z28_six_speed]

These conditions will not allow the purge canister to open:


LABELS Purge Canister Open Loop
Parameters Value
{B0501} Purge Canister Min Temp 139.960938 °C
{B0502} Purge Canister Min Speed 411.979618 KMH
{B0503} Purge Canister Min Air Flow 511.992000 Grams/Second
{B0504} Purge Canister Min Run Time 13421772.793750 Seconds
{B0505} Purge Canister Open Loop Disable

[97K15004WD]

nice first post.

Thanks. This is a great site, and I hope I can contribute.

[MrZ71man]

I figured that's what you meant - just set the parameters so high that there is no possible way for the requirements to be met. It seemed to work out. I'll eventually have to swap the tank assembly over, as I live in Cali and have to get this smogged in a year