evap disabled and near perfect maf ltft's

[SgtMarshal]

I just loaded my last adjustment and drove for about an hour to get another scan. over the last couple weeks of tuning I've noticed if I make adjustments from scans taken too soon after an adjustment it leans the fueling. I went on grand prix forums this morning and discussed the lean situation and they suggested I unplug my evap and then turn the evap code off. I did so when I loaded this last adjustment. looking at my maf ltft's after this scan was done and they are damn near perfect in every cell recorded. think I have an evap problem?

[Scottydoggs]

it may have a leaky line. f it, leave it that way if things are tuning better. i took mine off a while back and noticed a difference as well.

[SgtMarshal]

I was thinking that too, curious how my gas mileage will change

[Scottydoggs]

i bet it dont at all. all it does is suck up fumes.

[91parkave]

You guys iirc don't have a cess to purge reduction tables like us but the evap will always skew your fuel it's just the nature of the beast.

[SgtMarshal]

learn something new everyday. do you leave your evap hook up?

[91parkave]

Yup but I reduced my value 25% seems like best compromise

[SgtMarshal]

I dont think my 2001 has the option to do anything to the evap other than turn it off. Which tab was it under that you adjusted it by 25%?

[91parkave]

You don't if you haven't seen it already like I mentioned earlier it's probably just a LS motor thing

[bandook]

it may have a leaky line. f it, leave it that way if things are tuning better. i took mine off a while back and noticed a difference as well.

How did you take it off? Like which parts were removed, which left?

[SgtMarshal]

I just unplugged the evap purge solenoid. left everything there. I also unchecked the P0440 code and set it to no reporting because I'm not sure how the car will react to a known evap fault.

[bandook]

I had it disconnected for a little. But I just want it out of my engine. Because of top swap it still sits right in front of the blower, not behind it because I didn't lengthen the wires. But if I lengthen the wires and put it back there there is a crap ton of extra hose and it bends it all weird. Wish I could confidently rip it all out. Just don't know where is safe for the gases to vent. At least E85 wouldn't be as bad to smell.

[SgtMarshal]

I think there is a how to on removing the evap system. I also had to disable engine code P0443.

[Scottydoggs]

theres a good 10 codes in there to delete the evap. hp tuners shows you all the code # and what its for like it will say evap next to it. at least thats what bill has told me. where dhp is just the codes.

just delete everything that says evap.

[EHB]

If the computer does not know that the EGR is not functioning, it may be commanding more ignition timing (as it usually does when it commands the EGR system ON) which can result in hotter combustion temps and even detonation. If you remove or disable your EGR system, you should have the computer reprogrammed to disable the EGR spark advance parameters or significant engine damage could result. Shown below are some of the EGR adjusting tables from a 1987 Fiero 2.8L stock chip program that show the adjustments the ECM makes to fuel and spark when it thinks the EGR is operating...
http://www.gmtuners.com/tech/EGR_EVAP.htm

[91parkave]

We're talking evap not egr

[EHB]

We're talking evap not egr

oops ...

[SgtMarshal]

that was good info about the egr, I didn't realize the car did that.

[bandook]

Since were on the topic, kinda, all I did after removing it was set the temp that egr is enabled to max, 255 or something. Will that keep it off and prevent timing changes or is there something else I need to change?

[SgtMarshal]

I think that is sufficient, but you can scan for egr operation and see if its turning on or off. that will tell you for sure, I think