# Emissions problems



## TheBrownRobert (Aug 28, 2007)

I've been battling the stupid emissions system on my car for a while now. I disabled the EGR valve by disconnecting the hose between the EGR valve and the BPT valve, and the car ran better than since I bought it. All was well until...

I noticed that my highway mileage has been severely impacted. It used to get 45 to 55 MPG, but now it barely gets 35 MPG. I didn't care about this loss before, but I'm going to start commuting 60+ miles to school each way in less than a month so now that difference in fuel economy is much more meaningful.

I've removed the EGR and BPT valves and hosed them down in throttle body cleaner. I tested the diaphragms on both of them and they both appear to work. I noticed this plug that was dangling from the back of the engine, I hypothesize it goes to the EGR temperature sensor (the wire leads up to a device bolted into the back of the engine less than three inches away from the EGR).* The previous owner must have unplugged it for some unknown reason and I cannot find a female plug to insert it into for the life of me. I've consulted my Chilton manual, but it was useless.

So after cleaning all of the stuff, I reattached the EGR-to-BPT hose and it did exactly what it did before. It hiccuped and misfired while in overdrive, and intermittently did so while accelerating in certain gears.

Has anyone else had problems with the emissions system?

*


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## tlhingan (Jun 8, 2009)

Don't you have to block the EGR hose after disconnecting it to prevent the engine from sucking in fresh air through it?


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## TheBrownRobert (Aug 28, 2007)

Negetive. The hose that I removed carries exhaust to the BPT valve, one of the mechanisms that engage the EGR. Leaving it open simply allows a little bit of exhaust to come out.


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## zacward (Aug 23, 2009)

That plug may go to the throttle body. Your mileage is bad because you have no egr.


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## kizer24 (Mar 23, 2008)

The harness has some plugs that are not used. As for his mileage being bad because he has no EGR well thats just a bad statement. Some people have seen a slight drop in MPG after removing the EGR, def not 10-15 mpg. What engine also year is your car. Clean your IACV, replace your fuel pump if its been a while. Check to see if you have any ECU codes being thrown. When was the last time you did a tune up? Have you checked the air pressure in your tires? What mods have you done?


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## TheBrownRobert (Aug 28, 2007)

It's a 1993 Sentra with a 1.6L engine, automatic. I already cleaned the IACV. I've never had a tune up and I haven't modded anything. I check my tire pressure twice a month and it's fine.


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