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Inside driver's frame rail is a black plastic box. Two circuit breaker type buttons, speedometer cable goes in and out.

And there's another white plastic plug, covered by a black vinyl boot.

What's it for, as the boot on mine is shot and two of the three wires into the plug are broken.

Thank you,

I believe, though I could be mistaken, that it's the count box for the 02 sensor light. After X number of miles, the idiot light on the dash comes on telling you to replace the 02 sensor. At least, I believe that's what you're looking at.

Reading Haynes it looks like a connection related to the EGR valve. Whatever that is. Exhaust Gas Regulation ?

Acronyms may as well be Chinese. But, I do know they save trillions in the time they save having to say words, or type them, or print them on paper that kill trees. Not counting the time wasted having to look them up, enough to finally remember them.

On 530's it was for EGR, and you're right on what it's an acronym for, and on 528i's it was for O2 sensor replacement. Might have also been for Thermo reactor check on 530's, I can't remember at the moment, but on either, there are two buttons and I've found the reset procedure to be push both of them twice. It seems like if you just do it once, it'll come back in a couple of thousand.

I always thought it was Exhaust Gas Recirculation.

swatterssr wrote:I always thought it was Exhaust Gas Recirculation.

Right you are. Shows what I get for scanning so quickly

Question is, as the plug on mine is junk, what's going to happen ?

Car ran fine as far as I could ever tell. When I saw the box was full of grease and dirt, that boot was torn almost in half and three of four wires were broken at the white plug.

The car will run fine. All it does is turn on a light, which I suspect won't even happen if the plug is off. It has no effect at all on the operation of the car.

Thanks for the heads up T.

I guess I don't really need to worry about mine. Car runs fine without those little sensor lights on to bug me.

I never hear of EGR on an E12 do know for sure it has that? Perhaps it's only in the USA for the tighter emission laws. Anyway if it's true, then you should block the EGR off it will cause a slight improvement in fuel consumption and your engine will remain cleaner.

If it's the O2 sensor then your car will use slightly more fuel cause it will run in an open loop mode.

Happy to do that if I knew how. Looking at the Haynes schematic: top view of engine compartment line drawing, looks like a fun exercise in translating the artist's idea of what a component looks like vs. real life.

Block off the EGR valve. With a sock ? Tape ? Cut a line ? To whatever the EGR valve is, looks like.

See how much stupid there is running around ?

DMS wrote:I never hear of EGR on an E12 do know for sure it has that? Perhaps it's only in the USA for the tighter emission laws. Anyway if it's true, then you should block the EGR off it will cause a slight improvement in fuel consumption and your engine will remain cleaner.

If it's the O2 sensor then your car will use slightly more fuel cause it will run in an open loop mode.

Yes, 75-78 US model 530i's had EGR, along with an air pump, air injection and a retard only distributor. 79-81 528is had an O2 sensor with a 3 way cat.

EGR is relatively harmless, especially compared to the air injection, but it would have to be removed and blocked off at both sides, both the intake manifold and where it comes off the thermo reactors. Or just block off the vacuum connections that accuate the valve.

My cars are '79 - '81 with cats.

As I wrote above, I can't point to the EGR valve using the line art schematics, thus I can't begin any process of disconnecting, bypassing.

Even thought the connection to the box is shot and as deemed only necessary to turn on the EGR light that doesn't matter, ...

Hey, am I voting for something in congress ?

Mike W. wrote:EGR is relatively harmless, especially compared to the air injection, but it would have to be removed and blocked off at both sides, both the intake manifold and where it comes off the thermo reactors. Or just block off the vacuum connections that accuate the valve.

Hmm I don't really agree depending on the amount of EGR. Because EGR will built soot up in the intake runners. This tightens the diameter there. My '97 VW golf TDI had almost half an inch less diameter because of soot built up in the intake runners. Ofcourse this concerned a diesel with more soot emissions but the principle is the same. Besides that your fuel consumption will be higher when you apply EGR.

Hanson:
Block it off at both sides with a plate or something if you want to remove it all. If you don't just block it off at one side and leave the rest.

I've no idea what it looks like so I can't help you there but it should be easy to find. Concerning the EGR valve it should be external EGR so there should an pipe running from you exhaust manifold to your intake manifold with some kinda valve somewhere in between.

Good luck.