Lean Misfires at 2700-2800 rpm - Page 55 - 3000GT/Stealth International Message Center

badass3000 · 10-12-2007, 07:20 AM

Quote:

Originally Posted by ProwlerGT

Is the thought here that fuel vapor gives your engine "more combustible air"? Any odd affects to having it pre-MAF (MAS)? Whats the point in having the vapors go through the intake anyway? I know this is listed in the emissions section, but I still don't get it. Is this a safety precaution in case the gas tank get too hot or too pressurized?

I think its just to hide the smell of the gas tank ventings

DoctorDex · 10-12-2007, 08:26 AM

Quote:

Originally Posted by ProwlerGT

Is the thought here that fuel vapor gives your engine "more combustible air"? Any odd affects to having it pre-MAF (MAS)? Whats the point in having the vapors go through the intake anyway? I know this is listed in the emissions section, but I still don't get it. Is this a safety precaution in case the gas tank get too hot or too pressurized?

By hooking it up pre-maf & pre-turbo there is a relatively constant source of gentle vacuum (while the car is in vacuum) pulling the vapors from the tank. When the car is turned off the valve closes and no vapors are allowed to escape. From what I understand, this is generally for safety reasons. ie. if someone rear ends you, you don't want to have a pressurized tank of gas.

ProwlerGT · 10-12-2007, 03:22 PM

Quote:

Originally Posted by DoctorDex

By hooking it up pre-maf & pre-turbo there is a relatively constant source of gentle vacuum (while the car is in vacuum) pulling the vapors from the tank. When the car is turned off the valve closes and no vapors are allowed to escape. From what I understand, this is generally for safety reasons. ie. if someone rear ends you, you don't want to have a pressurized tank of gas.

So in actuality I should leave this vapor hose in use for safety reasons. Do you have it directly injected into the air filter or something or do you just have the vapor hose dangling right in front of the air filter?

brattesani · 10-12-2007, 03:52 PM

Quote:

Originally Posted by DoctorDex

I'll have disconnecting my SAFC-2. I take it temporarily cutting the power wire should work?

With regards to the "time & alarm" control box, I found out what it is. Its the ETACS unit. It seems to control the popup headlights as well the other functions listed here: http://www.3si.org/wiki/index.php/ETACS

I seriously doubt it is in any way related to our problem as I can't see any inputs to the ECU in the manual. However, with that being said, I'm going to pull the unit and revamp any old caps (if there are any).

mine was the same way though. it cant hurt to try. and you cant just cut the power line if its wired in because the MAS wire was cut and put through the SAFC, so if the SAFC isnt getting power then the signal from the MAS isnt getting past the safc to the ecu. i had mine wired in a boomslang harness so i could unplug it.

DoctorDex · 10-12-2007, 04:56 PM

Quote:

Originally Posted by ProwlerGT

So in actuality I should leave this vapor hose in use for safety reasons. Do you have it directly injected into the air filter or something or do you just have the vapor hose dangling right in front of the air filter?

I have it hooked up to the stock location (front pre-turbo pipe). Since I'm running blow through, my MAF isn't until after the turbos, so it doesn't matter how much air I pull out of the tank, it isn't going to affect my MAF readings.

brattesani · 10-13-2007, 05:05 PM

pull your safc yet?

DoctorDex · 10-13-2007, 05:48 PM

No, haven't had the time. Plus its so wet, cold and ugly out...

brattesani · 10-13-2007, 06:02 PM

sucks. its perfect where i live =P

wrighla · 10-22-2007, 06:43 AM

I'm pretty sure I have the same issue, although mine is not as bad. I get rough vibrations and slight loss of power through the 2500-3000 rpm band. I am completely stock. On very hot days and warm starts (although it has to be about 20 minutes sitting), I have rough idle until hot again. I do not get any sputters when I simply rev the engine in neutral through the 2500-3000 rpm range. Vibrations seem worse under light to medium load. Driving through a neighborhood at constant speed, in 2nd gear with very light to no load in that rpm range makes the vibration happen then not happen and cycles like that about once a second. I am not as familiar as most on this site with things like datalogging and tearing my engine apart, however I did do a full tune-up using the tune-up kit from Rockville Mitsubish (includes plugs, wires, pcv, fuel filter) and this made absolutely no difference to the vibration issue in the 2500 to 3000 rpm range. I don't know if this information can help or if there is something I can check to help, but I appreciate your efforts and will be following any progress that you all make.

DoctorDex · 10-22-2007, 06:54 PM

Welcome to the club.

Hopefully since enough of us have the problem, one of us will eventually stumble on to a fix.

Badass: Have you made any inroads into the problem at your end?

10-13-2007, 05:05 PM	#546 (permalink)
brattesani Verified Seller Join Date: Aug 2006 Location: davis, cali Drives: with 1g clears Trader Rating: (20)	Re: Lean Misfires at 2700-2800 rpm pull your safc yet?

10-13-2007, 05:48 PM	#547 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 Trader Rating: (13)	Re: Lean Misfires at 2700-2800 rpm No, haven't had the time. Plus its so wet, cold and ugly out...

10-13-2007, 06:02 PM	#548 (permalink)
brattesani Verified Seller Join Date: Aug 2006 Location: davis, cali Drives: with 1g clears Trader Rating: (20)	Re: Lean Misfires at 2700-2800 rpm sucks. its perfect where i live =P

10-22-2007, 06:43 AM	#549 (permalink)
wrighla Forum Member Join Date: Jun 2007 Location: Winchester, VA Drives: 92 Stealth TT FSRed Trader Rating: (2)	Re: Lean Misfires at 2700-2800 rpm I'm pretty sure I have the same issue, although mine is not as bad. I get rough vibrations and slight loss of power through the 2500-3000 rpm band. I am completely stock. On very hot days and warm starts (although it has to be about 20 minutes sitting), I have rough idle until hot again. I do not get any sputters when I simply rev the engine in neutral through the 2500-3000 rpm range. Vibrations seem worse under light to medium load. Driving through a neighborhood at constant speed, in 2nd gear with very light to no load in that rpm range makes the vibration happen then not happen and cycles like that about once a second. I am not as familiar as most on this site with things like datalogging and tearing my engine apart, however I did do a full tune-up using the tune-up kit from Rockville Mitsubish (includes plugs, wires, pcv, fuel filter) and this made absolutely no difference to the vibration issue in the 2500 to 3000 rpm range. I don't know if this information can help or if there is something I can check to help, but I appreciate your efforts and will be following any progress that you all make. __________________ Lloyd - '92 Stealth R/T TT ~78k miles Firestorm Red / Black Leather - K&N filter, Halo Palm III logging, mbc running 14psi, boost gauge in glovebox, GReddy type S BOV, Red painted brake calipers, 6K HID Xenons with Hella housing, fixed Active-Exhaust & antenna, 60k maintenance, Syncromesh in transax/fer, Royal purple in Diff

10-22-2007, 06:54 PM	#550 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 Trader Rating: (13)	Re: Lean Misfires at 2700-2800 rpm Welcome to the club. Hopefully since enough of us have the problem, one of us will eventually stumble on to a fix. Badass: Have you made any inroads into the problem at your end?

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