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Discussion Starter · #1 ·
Guys I am going to search myself in a minute .. but I'm hoping one of you will know the answer. I'm giving you the short version

- Our sept 2002 built 325ci (I think late 2002 were sold as model year 2003 ) runs gret most of the time , But can't get emissions done because EVAP and cat won't finish. O2 Sensors and MAF are DEFINATELY working pretty well. I'm getting the dreaded "Lean" P0171" & P0174 whatever it is for bank 1 and bank 2. It goes for 2 days then ... on again. I clear it and we continue ..the circle of BMW life ad-nausea

I've smoked the SH#$ out of it with a serious smoker. I've smoke thru oil cap, I've smoked via Air Duct at the MAF. I've SMOKED both directions. of the power brake. I've smoked so much I need to get my own lungs checked. There are no external leaks. I can find.

But recently I saw a few models of 325 have this "leak detect pump" behind the engine and on those the little 1/8 tube on the Sec Air Pump valve goes to that pump

On a whim I pulled the 1/8 inch tube from the SA pump valve (it heads back along the Head and disapears somewhere) .
blew into it. It is wide open. with a cold engine. Is that right? did I find my air leak? What does that little tube do?

When I blow into the same size tube from the the post MAF "F" connector it is completely shut. I believe that one goes to the fuel pump purge housing.


I'm just sitting here .. hoping MrMcar , NA, Or NZ will see this ...

txs
 

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Discussion Starter · #2 · (Edited)
When I blow into the 1/8" tube that connects to the SAP valve (cold engine) the air goes right in.
Is that correct for a 2002 325ci coupe? Where does the other end of that tube go? To that little block of barbs on the back of the engine up towards the top Dside?
Can I plug that hose a few days without consequence?

For those who don't know me .. I have smoked the heck out of the car with an ass kicking smoker .. no leaks found
 

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Discussion Starter · #4 · (Edited)
Just look up that valve and vacuum hose on realoem.com and see the diagram. Also, search on here and use google images.
You help a lot of newbies by looking things up for them which is quite kind.

Some days I just seek a one sentence response.

Experience like MrMCar, NZ, Effduration give the answer in 5 words

You taught be about your search engine and realOEM. Exepct that I use those resources first most of the time.

I appreciate all you do Scott .. its al lot. Many of the fantics here already know I am not a lazy man.
 

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On a whim I pulled the 1/8 inch tube from the SA pump valve (it heads back along the Head and disapears somewhere) .
blew into it. It is wide open. with a cold engine. Is that right? did I find my air leak? What does that little tube do?
My 10/2002 325iT M54 doesn't have the vacuum tube to the SA valve, but my 2000 M52TU had. This vacuum tube is to activate the valve to close/open the air path from pump to the exhaust.
 

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You should not be able to blow air through that tube: one end to the valve diaphragm chamber (unless a torn diaphragm) and the other end connected to the DME controlled solenoid valve which connected to the intake manifold. The valve normally closed and only opened when the SAC pump running a minute with cold engine to heat up the cats faster.
 

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Discussion Starter · #8 ·
OK .. didn't find it this AM .. but I was really upset. I'll look again.
You should not be able to blow air through that tube: one end to the valve diaphragm chamber (unless a torn diaphragm) and the other end connected to the DME controlled solenoid valve which connected to the intake manifold. The valve normally closed and only opened when the SAC pump running a minute with cold engine to heat up the cats faster.
Hope you are still here my friend. I found my nver ending leak leak for sure .. that sac line had a little cut way back at the "Pump" of is it a solenoid?
I Know that was the leak .. so I put all new silicon on it blind.. I had enough markers I'm pretty sure I got it the same .. but did the precious owner have the one way valve in correctly?

So here's my question. (what's confusing me is that it looks like a solenoid .. not a motor ..
To me it looks straight forward ... The SAP valve opens when a suction appears at the 1/8 inch hose. The suction would appear because DME opens solenoid. so if that's the case
This diagram would be correct and its simple.
RealOEM.com - Online BMW Parts Catalog

But Sapote I see sites that know better calling it a "motor". But is just looks like a simple vacuum "on/off" solenoid to me. I can't see it or remove it .. but I can feel it blind

Also there is a 3rd vacuum barb there next to 7 and 9 in the sketch. On my sedan (I removed the intake manifold) there were 3 barbs .. one large, 2 small just like this coupe
I had cap 1 or 2 of them.

So my "never ending lean signal" may all have been coming from 2 worn out caps. .. and a few jelled 3 inch tube. I replaced them with silicon after I got the barbs cleaned up.
I'll proceed now (because you also called it a solenoid) and check for your replay in about 15 min.
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Item A (1), is the air pump valve. It requires vacuum from the inlet manifold to open the valve and let the secondary air pump air flow into the exhaust. The exhaust gases are isolated from the vacuum supply. If you are getting an air pulse out of the vacuum port with the engine running, then the Valve has failed.
Item B (5), is a solenoid. It's an open/close device. Normally closed, opens when energised. Some non technical people call it a motor, but it's not a motor, nothing turns.
Item C (6), is a one way valve. Remember that you're working with vacuum not positive air pressure, so air flows are backwards. It should be installed so that you can blow air through it from the SAP end and not from the inlet manifold end.

The 3 ports at the firewall end of the inlet manifold are for:
  • 3.5mm for SAP control for the MS43 DME, your car. It is capped off for the MS45 DME cars.
  • 3.5mm for vacuum controlled exhaust flap. Otherwise it is a capped off spare
  • 7mm capped off spare.
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Discussion Starter · #10 ·
OK Sapote .. .I tested the tube all the way from Valve to solenoid. no leaks ..I also have the other barb from the solenoid plugged .. but the solenoid is somehow letting gas escape.
Maybe there is a little diaphragm in there that's ruptured.
 

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Discussion Starter · #11 ·
Item A (1), is the air pump valve. It requires vacuum from the inlet manifold to open the valve and let the secondary air pump air flow into the exhaust. The exhaust gases are isolated from the vacuum supply. If you are getting an air pulse out of the vacuum port with the engine running, then the Valve has failed.
Item B (5), is a solenoid. It's an open/close device. Normally closed, opens when energised. Some non technical people call it a motor, but it's not a motor, nothing turns.
Item C (6), is a one way valve. Remember that you're working with vacuum not positive air pressure, so air flows are backwards. It should be installed so that you can blow air through it from the SAP end and not from the inlet manifold end.

The 3 ports at the firewall end of the inlet manifold are for:
  • 3.5mm for SAP control for the MS43 DME, your car. It is capped off for the MS45 DME cars.
  • 3.5mm for vacuum controlled exhaust flap. Otherwise it is a capped off spare
  • 7mm capped off spare.
View attachment 954944
thank you NZ & Sapote as well. I couldn't actually see it so I did everything blind. I should have known that was a solenoid.. I assumed is was what I read .. and I didn't understand why a motor was in there. A solenoid I do. That rotation you drew in turned out to be the last issue because when I understood I hooked up my line to one end of the solenoid no power and still could blow thru the tube on the other end. so then I started thinking about vented solenoids which I've used zillions of times for my conveyance systems for industry. They are "one way". I had put it back together the way the diagram showed. I had just flipped it around and tested again. Now all works perfectly. I think.. I'm about to take a test run. I was getting 15 LTerm and 10 ST on that run .. so I knew I screwed something up. The the "arrow of NZ" confirms that I've got is right now.

As rfar as the leaks go ... the answer appeared mid day when I started thinking about how much time I've poured into this 1 hour (should have been) issue and how broke I would be if I were "in the business". On my way in I stopped and looked at the 1/8 inch tube (couple of mms) going into that SAC Pump. I wondered if something could be wrong with that & when I blew into it air passed freely. and I heard air coming frm elsewhere. I chased it (not knowing if it was ok ... but suspecting it was not). I ended up with my hand touching brittle 8mm pieces of spaghetti and goo from gelled port caps. I knew that place behind the manifold because I pulled the manifold off the sedan when we bought it to freshen the rubber etc.
So that was it. I was able to peel the goo and brittle stuff off the nipples blind (except the big one which you can see from the side). * put new ones on. That would be tube 7 and cap 9
There is a 3rd unused port not shown in the diagram but ... I knew about that one. its "Cap was Crap".
I tested and siliconed the Non return too.

NZ I'll report back asap. Thanks a million.!
 

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Discussion Starter · #12 · (Edited)
Well ... I didn't get out of the driveway. I worked all day .. to get my trim to 15% lt and 11% st. I have to take the car out of service.

This is terrible. I rolled out this AM about 5 to smoke the heck out of this car. I have pictures of my massive smokeing ...but no smoke ever came out of the car. Smoking is not viable in my opinion.

I made a special fitting. I smoked thru the brake line, the oil hole, and the MAF. Not a drop of smoke anywhere.
The last thing I checked was the MAF so I doubt I tore the IAC. It has been a 12 hour day ..just for this.
The last thing I did .. was I went back to the non return feeder and stuck a drill in there to removed all that jazz .. and I'm still getting 11 and 15 Why would LT fuel trim instantly jump for any reason those were at 11 before.

Is there anything else that could do that so quickly? Do you happen to have a photo of the back of the intake side so I can see what I might have messed up? I'll search around a little now.

I should mention those are all POSITIVE fuel trims. to its adding fuel both short and long term trims This means its adding fuel correct?
 

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#1 goes to vacuum canister for your exhaust flap. #2 is capped. Not labelled, but (nibble) above the white part of the one way valve is the connection to your SAP valve mounted to your exhaust manifold
 

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Discussion Starter · #15 ·
its running ok without the map
View attachment 954945

#1 goes to vacuum canister for your exhaust flap. #2 is capped. Not labelled, but (nibble) above the white part of the one way valve is the connection to your SAP valve mounted to your exhaust manifold
thank you sir. the 325ci 2002 has no flap .. so I capped #1. I'm getting there.
 

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Discussion Starter · #16 ·
I didn't make that photo/diagram, just stole if off Google images.

Hard to find vacuum leaks:
OK I think its good though because I smoked right thru it this am.

However I just pulled the MAF plug and the ST trims went to zero .. probably normal m
But I notice Mineral oil all over my MAF. I hate maf cleaning .. but that might have something to do with it.
 

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A MAF with oil on the elements will cause an under reporting MAF, which causes lean total fuel trims.

An over oiled mesh air filter is a bad thing for the MAF
 

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Discussion Starter · #18 ·
A MAF with oil on the elements will cause an under reporting MAF, which causes lean total fuel trims.

An over oiled mesh air filter is a bad thing for the MAF
Hey Hey ... The night ends on a finally happy note. I used my electronic cleaner for the MAF and that was it! No question about it.
I will chnge the paper filter tomorrow as I had the smoker sitting on it at one point during the day. Some oil probably got on it.

I'll spare the screen shots tonight ..

But Before the MAF clean I was getting +10% ST and +15% LT on both banks and CEL on. After clean I'm getting ST -3 LT +7 on both banks.

So ... I blew a day on it , but those 3" dried out hoses & cracked caps on the Barbs were in fact the leak we've been seeking. I just drove 25 miles and I'm certain.

I'm not sure smoking is a viable leak finder. You will laugh if I get around to sending you 2 photos I took today of my smoker gadget. But I didn't see a bit of smoke exiting anywhere ..including when I removed the gas cap and oil cap.

I enjoyed your latest BMW post. It sent me looking for the reason air doesn't behave strickly according to Boyle's law. The shortest way to describe my summary is ... Boyles law is for ideal gases, and air is not an ideal gas.

Ice changes size because of the bent tetrahedron shape. But (based upon my 1 hour of reading) mixed gases are a little different, apparenty it behaves more as a matrix (I can't say crystaline .. but similar) at colder temps & more a pin ball machine at higher temps.

I wish I had a 2nd life..there is so much to know.
 

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I'm not sure smoking is a viable leak finder. You will laugh if I get around to sending you 2 photos I took today of my smoker gadget. But I didn't see a bit of smoke exiting anywhere ..including when I removed the gas cap and oil cap.
1. if you don't see smoke coming out of the oil filler cap, then the smoker is too weak (it was damaged by Covid), let alone the smoke travels a long way to the gasoline filler cap (but the purge valve solenoid has to be energized to open the valve up).
 

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Discussion Starter · #20 ·
1. if you don't see smoke coming out of the oil filler cap, then the smoker is too weak (it was damaged by Covid), let alone the smoke travels a long way to the gasoline filler cap (but the purge valve solenoid has to be energized to open the valve up).
My smoker seems really strong ... not sure why it doesn't work well.

Thank you for the assist. I was frustrated watching myself turn a 1 hour job into a 12 hour ordeal. I couldn't fathom why a motor would be in that hose. On line I found it called "motor" & "valve". To me it made sense it was a solenoid. I couldn't see it so was unsure. I could only feel with hands.
(I moved the Non-return valve up to the open area at the top of firewall by adding longer tubing (silicon) so I can more easily troubleshoot in the future.

The problem I caused in the morning ..but affected me in the evening was my smoking saturated the MAF with mineral oil. +10 Strim & +15 Ltrim made NO sense. NZ said something that rang my bell. I cleaned and now its perfect.

Maybe that Covid has affected my brain. That or old age.

Kind Regards,

P.S. Here's something sad but true ... I had the VID; it was like the flu, with one bad side effect. It altered my smell a little. Now a lot of things smell like poop which should not.
Its funny for sure ... but unfortunately ... true
 
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