Purge Solenoid
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Purge Solenoid
Purge Solenoid is bad. From what I've read it seems to be a pain to replace. Is it mandatory that this be replaced? What effect does this have on the engine? Thanks.
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vrg3
- Vikash
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It's part of the evaporative emissions control system. Before EVAP existed, gas tanks were just vented to the atmosphere. Gasoline is highly volatile, of course, so it would evaporate from the tank and the raw hydrocarbons would escape through the vent into the atmosphere.
Such a system polluted needlessly and also hurt fuel efficiency because the system was always losing fuel even when the car was parked and not running.
Modern cars have an EVAP emissions system that doesn't vent to atmosphere; instead, gasoline vapors are collected in the charcoal canister behind the passenger side headlight and when the ECU wants to it uses the purge control solenoid to allow the engine to ingest the fumes.
Without this periodic purging, I'm not sure what would happen. I would guess the canister would become saturated and then begin to vent the fumes through its own vent hose. If your area doesn't have emissions inspections, you could probably get away with it.
If you want to make the Check Engine light go away without actually replacing the solenoid, you would need to wire in a resistor between the ECU's "canister purge control" pin and a switched +12v source. I'm not sure what exact resistor you'd want, but I'd say to start with a 400-ohm 1-watt resistor and mount it somewhere where it'll be okay for it to get a little warm.
The ECU's pinouts are here: http://www.graphics.cornell.edu/~v/ecupins/
Such a system polluted needlessly and also hurt fuel efficiency because the system was always losing fuel even when the car was parked and not running.
Modern cars have an EVAP emissions system that doesn't vent to atmosphere; instead, gasoline vapors are collected in the charcoal canister behind the passenger side headlight and when the ECU wants to it uses the purge control solenoid to allow the engine to ingest the fumes.
Without this periodic purging, I'm not sure what would happen. I would guess the canister would become saturated and then begin to vent the fumes through its own vent hose. If your area doesn't have emissions inspections, you could probably get away with it.
If you want to make the Check Engine light go away without actually replacing the solenoid, you would need to wire in a resistor between the ECU's "canister purge control" pin and a switched +12v source. I'm not sure what exact resistor you'd want, but I'd say to start with a 400-ohm 1-watt resistor and mount it somewhere where it'll be okay for it to get a little warm.
The ECU's pinouts are here: http://www.graphics.cornell.edu/~v/ecupins/
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
Thanks vgr3. I guess that would explain the 2-stroke smell when I first fire it up. The car is a bit tired. It has 173,00. I picked it up for $300 from the original owner who did regular maintenance. It does smoke occasionally when I fire it up,(light blue) I was told that it is probably the valve guide seals. It has been a great commuter car. It passed DEQ with less than 2PPM so I think I will not bother to replace the solenoid just yet. I have noticed that when going uphill sometimes it will start to act as though it is running on 3 cylinders. It is as if I am gunning the motor and it's pinging. This occurs at around 3000 rpm, and it slowly fades then comes back to full power after I get out of the throttle(usually). Quite odd. Would you happen to have any ideas on that? TIA
Could you lead me to some info on how to diagnose the brake lights they do not come on. Bulbs and fuse look good. I lost the link in the forum that described how the Brake light Switch should operate and how to adjust/diagnose it.
Could you lead me to some info on how to diagnose the brake lights they do not come on. Bulbs and fuse look good. I lost the link in the forum that described how the Brake light Switch should operate and how to adjust/diagnose it.
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vrg3
- Vikash
- Posts: 12517
- Joined: Sun Nov 03, 2002 2:13 am
- Location: USA, OH, Cleveland (sometimes visiting DC though)
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Well, the purge control solenoid won't affect exhaust emissions. But from what I understand some states do test evaporative emissions...
Your intermittent rough running problem could be anything, but I'd start by changing the spark plugs, ignition leads, fuel filter, and air filter. Couldn't hurt to pour some Techron cleaner or Sea Foam into the fuel tank, either.
Your intermittent rough running problem could be anything, but I'd start by changing the spark plugs, ignition leads, fuel filter, and air filter. Couldn't hurt to pour some Techron cleaner or Sea Foam into the fuel tank, either.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212