Vac line to no where...what do you think?

[carboncow]

OK. Trying to solve another issue as well as pull the throttle body for a cleaning and noted there is a vac line that originates at solenoid/sensor "thingy" under the TB and heads towards the firewall (under the intake) and then heads toward the passenger side. It's cut right about where the brake master cylinder meets the shock tower...cannot find anything it should connect to.

Any theories or help?

Who knows their vac lines in a superman and unholy way?

[bkats]

http://blog.bavauto.com/8393/bmw-m30...i-635csi-735i/

The M30 doesn't have too many vacuum lines, the image in the link above should be more than enough to find it.

[mauryc]

Do the pre 88's have the purge valve under the throttle body (Can't remember from my e23's but don't think they do as the 88-89's have an electrical plug on them) either way, if memory serves on my 88' the line from the purge valve hooks to a large diameter nipple under the plenum body (I think). Can check when I get home.....

[carboncow]

Do the pre 88's have the purge valve under the throttle body (Can't remember from my e23's but don't think they do as the 88-89's have an electrical plug on them) either way, if memory serves on my 88' the line from the purge valve hooks to a large diameter nipple under the plenum body (I think). Can check when I get home.....

Thanks guys...should have noted that I do have a 1988 too.

The hand written diagram is gold for sure and will come in handy as I start to replace all the old lines.

Maury, are you saying this may be the Evap Purge valve as shown in the diagram bkat supplied? If so you could you guys point me to the Act. Carbon Filter in the engine bay then as well as the Purge Valve Vaccum temp switch...since one of those is the missing path to my loney hose.

[bkats]

The carbon canister is the big black cylinder ironically located at the other side (passenger's) of the engine bay. It's right on top. You can see all the hoses that go in and out.

[carboncow]

Thanks...I have been educated with this great link.

For other newbies who start asking silly questions like me....

http://home.insightbb.com/~todd.kenyon/bomb.htm

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OK...going to need some more input and maybe someone to look at that engine bay!

Bkats...if the carbon canister is the cylinder on the pass. fender then i've found it. If you look at the photos of mine there is one line coming in, one line with nothing on it and a hose going off toward the front of the car down into the engine and it connects to nothing...WTF is going on here?

I see from Gary K's drawing a mention of the expansion valve can be bypassed...has someone disconnected something on mine?

I'm not a great at understanding emissions but have chased my share of lines in the80s and 90s. Yes this system is silly easy but just not sure what I'm all looking at.

Is the part in my first post in fact the Evap Purge valve show in the diagram? Thus it should route to the Act. Carbon Filter that vents to atmosphere hence why I prob don't have any noted typical symptoms of leaking emissions/vac systems?

[bkats]

http://www.realoem.com/bmw/showparts...20&hg=16&fg=10

Another helpful diagram.

I actually didn't drive my 6 today, so I can't run out and check for you, but I know that image 1 ain't right, just by the fact that there's a nipple on that line.

Unless there's a major coincidence, we are definitely looking at the red line in the vacuum diagram. Seeing as your plenum hose ended up on the other side of the engine bay, I think someone intentionally disconnected/bypassed the evap. purge system. I'm sure there's a half-decent reason why, but I think it's not good enough to justify "modifying" a system full of $10 rubber hoses.

Anyways, image 2 may be a normal atmosphere vent, but I punt on that one without seeing my own car.

Next is to figure out which hose on that canister is the missing one. Hopefully it's the evap purge system and not the line going to the rear of the car and fuel vapor expansion tank. If it's the purge line, your problem is sort of contained and you can work from both ends to the middle and determine what's missing, and hopefully, why someone disconnected it.

Don't worry about asking these questions. Unlike the rest of BF, most here won't give you the "search" lecture. These are rare-ish cars of a classic age. They are now being passed on/bought by another generation, and as such, the info needs to be re-documented and re-condensed periodically. Otherwise, in 10 years, using the search function will lead to someone like you or I having to pour through 1135412341251 threads of 90% applicable info, without ever getting a direct answer. Then, you end up starting this thread anyways.

And as far as the car goes: it was top-notch tech at the time. There's so many goddamn systems, it's hard for anyone to be an expert at all of them. And if the 6 teaches you anything it's that simple don't mean easy, and complicated don't mean hard.

Edit:

By the way, the diagrams were excellent. A big "help me help you" thing. Thanks.

[mauryc]

the diagram is for a pre 88' where the valve is the little rubber thing on the side of the intake boot. your setup is different. forgot to look last night let the sun come up and I'll verify.

Maury

[WWW89E24]

Don't worry about asking these questions. Unlike the rest of BF, most here won't give you the "search" lecture. These are rare-ish cars of a classic age. They are now being passed on/bought by another generation, and as such, the info needs to be re-documented and re-condensed periodically. Otherwise, in 10 years, using the search function will lead to someone like you or I having to pour through 1135412341251 threads of 90% applicable info, without ever getting a direct answer. Then, you end up starting this thread anyways.

Not much I can add about the OP's problem, but I just wanted to say THANKS for your reply, bkats. It is very refreshing to see the folks here who just truly want to help.

[carboncow]

Maury: Thanks...I now see the diagram states thru 1987.
Bkat: I did chase (last night) the one hose on that canister and it runs low into the firewall on the pass. side so I'm going to guess it runs back to the and the expansion tank.

Q: What/where is the expansion tank? Is that the one under the speaker deck or is that just another carbon filter?

Thanks on the positive comments and the "search" comments that so many geniuses are quick to toss out there. I've been wrenching cars on the internet for close to 20 years and have helped moderate some auto tech forums...and I hate the grouchy old guys who's goal is to rush to every post to say "try the search" or "this has been covered ad nauseum". Yes we are all guilty from time to time of not digging too deep...but damn it...I like to start my own threads. I hope to be useful guy in a year as we hope to keep this car for a long time.

Lasty...I wonder why I don't get all update notifications. I got some yesterday and none from your both last response...nothing in my spam folder!

Bkats: Any chance when/if you guys get a look to tell me where the bottom line (missing on mine) to that canister runs too. Looking at that diagram it does show the top running to the exp. tank and that is what I"m guessing mine is. If I'm really lucky my "line to nowhere" in first post does in fact connect up to the open nipple on the canister and someone simply ran the line the wrong direction when they couldn't figure out what they did wrong. Again my missing line starts under the throttle body. I looked under the REALOEM website and looked under the section called FUEL PREP SYSTEM and just cannot figure out which one is the pressure/valve/solenoid thingy under the TB.

PS...I have no symptoms of an air leak although my idle feels "lumpy" as if I have a lumpy cam in a muscle car that makes the whole car shake a bit...smooth as butter when driving. If the "line to nowhere" does belong on the canister that would make sense cause it's just venting to outside and the canister just scrubs air, no?

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OK kids...I think the mystery has been solved since I studied the REALOEM.com scemtic some more.

The "hose to nowhere" does appear to go to the nipple with no friend. I noted on the link you supplied that the "bracket" is the same I show in the last photos although the valve doesn't 100% look correct it has to be it.

Anyone want to add in their agreement, or not?

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My guess is the hose broke and someone knew it just vented to atmosphere and wasn't to concerned that it needed to run through the charcoal canister. I have a vac line kit on order so that should solve that need.

[bkats]

Alright, so the line from the canister to the rear goes to the expansion /vapor tank in the rear shelf by the speakers. The other should be directly connected to the bottom of the throttle body area. So, there's nothing between your rogue line and the empty nipple.

The bottom of the canister vents to atmosphere, so no worries there.

The lumpy idle is an M30 thing. Probably has something to do with the AFM being such a primitive way to meter air.

[dwal95008]

Alright, so the line from the canister to the rear goes to the expansion /vapor tank in the rear shelf by the speakers. The other should be directly connected to the bottom of the throttle body area. So, there's nothing between your rogue line and the empty nipple.

The bottom of the canister vents to atmosphere, so no worries there.

The lumpy idle is an M30 thing. Probably has something to do with the AFM being such a primitive way to meter air.

It does smooth up with the Miller MAF but not quite perfect, yet...

[Sprocket]

It's not the temp sensor line? Your diagram shows it, and it goes through the firewall (obviously) to the driver kick panel. I am not sure exacly how it would be in an '88. Yes, your climate control uses engine vacuum to sense cabin temp..... (to pull small amount of air to temp sensor)

[bkats]

It's not the temp sensor line? Your diagram shows it, and it goes through the firewall (obviously) to the driver kick panel. I am not sure exacly how it would be in an '88. Yes, your climate control uses engine vacuum to sense cabin temp..... (to pull small amount of air to temp sensor)

The line you're referring to attaches at the bottom of the intake plenum and goes to a reducer and a nylon braided hose before going through the firewall. The OP's line is from the bottom of the throttle body.

[carboncow]

Glad the lumpy is common...it gives it a "bad ass" attitude. Doesn't really pass the wife test but she'll get used to it! Were they lumpy from day one or just as the MAF get's old? I'll research this Miller MAF...has me curious.

Thanks guys...that wraps it up! Thank you for the education and I hope to get a lot more info off this crew. This has been WAY more positive than the TDI, Vw and Audi forums. Nobody has told me I"m and idiot and don't deserve to own the car yet!

PS. Still not getting any email notifications anymore even knowing it's still checked "instant!". Very odd.

[wfwright2]

Lumpy idle can be reduced by slightly wider gap on silver OE plugs and valve clearance. This from older tuning guide from the big coupe group and Shark tuning chip.

[carboncow]

Looks like my hose kit came in from hiperformancestore.com. I've attached the diagram from them which may be of use to those who find my post in the future. I doubt they will mind me sharing this info since it mentions them in the copy. Let me know if this is violation in any way.