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E34 (1989 - 1995)

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  #1  
Old 02-19-2014, 05:00 PM
twise twise is offline
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Mein Auto: 525, 540 M-Sport 740,
Angry California Smog Woes

After three years of planned non-operation (storage) we decided to wake up our 92 525i (automatic) for my son. With a new battery, she started right up, so we activated the registration and were instructed to have the car smog checked at a Star Station. We changed the oil, oil filter and air filter, took it for enough of a run to heat up the cats and took it to be tested. Not surprisingly, it failed, but just barely for HC. NOX was high, but within passing.

2nd try: after new plugs, valve cover gasket, and running a tank of fuel with fuel injector cleaner, I refilled with regular unleaded fuel, took it for another good run, and it failed again--worse. Higher on HC and higher, but still barely passing on NOX.

3rd try: I had my cats inspected by the shop who installed them just a couple years before we quit driving it. They cut inspection holes on both ends of both cats and said that visually, they look to be in perfect condition, and although that did not definitively mean they hadn't failed, they believed they were most likely good. I then tested my 02 sensor, which put out voltage within the specified range, but did not fluctuate as it should. Believing this to be the problem, I changed the sensor, ran the car, and returned to the test station. It failed again!! Now it failed miserably on HC and was over the limit on NOX as well.

Now what?

No fault codes, no Check Engine light

Also, the MAF fails the diagnostic test where it should read 5v and the hot wire glow red for about 1 sec, five seconds after revving the engine past 2500 rpm and then turning off--There is a click at the right time, and about .4 volts, but not enough to heat the wire. A send unit from the junkyard performed exactly the same way...Where does the 5v come from? Could this and the rock solid reading I got from my 02 sensor indicate a failed DME module?

If these results suggest anything meaningful to you, please share your thoughts.

Tim

92 525i
95 540i M-Sport
2001 740iL
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  #2  
Old 02-20-2014, 07:13 AM
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Doktor Bert Doktor Bert is offline
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Tim,

High HC is the presence of unburned fuel. NOX is generally influenced by ignition timing and/or the EGR valve, which I do not think our cars have. Cats should be tested by reading their skin temperature. The outlets of the cat should be 400°F t0 600°F with the engine at high rpm at operating temperatures. This is hard to do on an engine at rest (no load) but you can get a close approximation with an infra-red heat gun and a quick check right after a drive.

MAF can cause you some problems and the easiest thing to do is swap it out with a used unit for testing. However, a very common cause of elevated HC levels are vacuum leaks.

I think your problem is simple, but it may take a while to locate...
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  #3  
Old 02-22-2014, 09:08 AM
imae34driver imae34driver is offline
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Mein Auto: 1995 540i SPORT /6 spd
My s10 for what ever reason would pass after a new caytlist only, after a few weeks id go bad... About 110$ to replace i just threw a new one on an smogged it...


I feel if the catalysts really are "newish" and the car runs ok, you should get a pass once at least!
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1995 540i /6 speed.Black on black. C.A.I/JBR LWFW/ Dinan tune/hi flow exhuast /545 SSK /3.15 with LSD / rev-shift racing motor mounts/stage 4, 6 puck clutch/ K Sport coil overs / 19" BBS LM's / suede sparco 368 steering wheel, Recaro bucket seats, sparco 4 point harnesses, NX wet kit, M/T drag slicks
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  #4  
Old 02-24-2014, 09:37 AM
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Updates????
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  #5  
Old 02-24-2014, 11:43 PM
twise twise is offline
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So far, not much progress. Unfortunately I don't have much time to invest in the issue right now, but I'm slowly working through it on the weekends.

I checked the skin temp at the back of he cats. I suspect they are not performing adequately, since they are only in the mid 300* range, even after a 30 run on the freeway. They seem to only get about as hot as the exhaust manifold does. Conclusion: no magic left in the cats.

I also replaced two rotted vacuum lines, one from the fuel pressure regulator and one from the crank case ventilation port at the front of the valve cover.

Next, I sucked a bit of sea foam through the vacuum lines and sprayed some into the intake, finally dumping the remaining 3/4 can or so into the crank case. I drove it hard for about 30 miles, and then did an oil and filter change. (This sea foam prescription came from another post on this forum from a couple years ago.). After the oil change, I drove it another 70 miles--my daily commute. I ended the 35 mile (freeway) trip home at the smog shop. The owner has a third party program that will check a gar a idle before you put it on the dyno, which commits to reporting to the DMV. It won't check NOX, but he says the HCsseem to be pretty accurate.

I had him test the car with this program while it was good and hot from my drive, and the HCs were close to 200, this is with a used MAF I picked up at the junk. Yard, so I swapped back to my original and tried again. Now the HCs read well over 300!! Everything I touch makes the car test worse!!

This weekend I hope to pull the intake manifold and check the entire vacuum system, IACV, intake manifold gaskets, etc. I also want to do a compression check to rule out leaking valves.

I tend to think the cats have failed, but there is an underlying cause that is sending oil or unburned fuel through fast enough to destroy the catalyst. The cats are six years old, and the car wasn't driven at all for three.

If you have other thoughts, I'm all ears (eyes, actually).

Last edited by twise; 02-24-2014 at 11:44 PM.
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  #6  
Old 02-24-2014, 11:48 PM
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When's the last time the injectors were cleaned off the car?
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Last edited by Radian; 02-24-2014 at 11:51 PM.
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  #7  
Old 02-25-2014, 07:29 AM
twise twise is offline
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Never that I know of. I've had the car for nine years now. It seems like clogged/dirty injectors would cause a lack of power, but I'm not so sure about causing unburned fuel to pass through the cylinders... For what it's worth, I've listened to the injectors with a stethoscope, and mechanically they all sound the same.
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  #8  
Old 02-25-2014, 07:30 AM
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Doktor Bert Doktor Bert is offline
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I concur with your diagnosis...bad catalysts. The lack of temperature change is an important clue. On a OBD1 car, you should be able to legally put any cat on there...
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  #9  
Old 02-25-2014, 10:17 AM
Larrick Larrick is offline
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Mein Auto: 1994 525it
I have 1994 525i.
I had a thread which may interest you.
Go to "search" Help with failed smog. Larrick.
It states how I passed smog but it also shows the results of several tests
and how the numbers change seemingly at random with every test.
The ambient air temp, humidity and tire pressure can make a difference.
Go to a smog station where they will give you free retests and work with you.
Mine failed and then passed a few minutes later.
You know that all vehicles 1996 and newer no longer have to do the tile pipe test!
They need only pass the physical inspection and a check of the computer codes.
My neighbors just came back from a smog detected because they failed.
I asked the year of the van. It was a 1998 but the tested had done a tail pipe test.
I told them to call him and he said he made a mistake because he thought it was a 1994.
That in itself sounded strange but he said to bring it back and it will probably pass.
I will ask today how thy faired and repost.
The fact is that the law is now unfair. Only car form 1976 thru 1995 are subject to the
tail pipe portion of the test.
If the van passed without the tailpipe that would be proof enough for me.
Look at my smog number results and you will see that it is a crap shoot.
Good Luck.
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  #10  
Old 02-25-2014, 10:46 AM
imae34driver imae34driver is offline
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Drive like a pissed off teenager with his crotch on fire... Get them Catalysts HOT!!!!


Take it to the "hole in the wall" type place, aired up tires, a/c off fresh gas..

pull it up to the dyno with it fresh from a good session of WOT runs....


Let the man work, don't watch ( if he were to wanna let something get by, he is less likely if he's being watched like hawk..)

One pinched off a evap hose or something i noticed and then it passed! (Said nothing)no clue if that "allowed" lol

Just thank you...


. I always get a pass.
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1995 540i /6 speed.Black on black. C.A.I/JBR LWFW/ Dinan tune/hi flow exhuast /545 SSK /3.15 with LSD / rev-shift racing motor mounts/stage 4, 6 puck clutch/ K Sport coil overs / 19" BBS LM's / suede sparco 368 steering wheel, Recaro bucket seats, sparco 4 point harnesses, NX wet kit, M/T drag slicks
"Skill can only get you so far, then comes money!"
R . I . P Paul Walker - 1973 - 2013

Last edited by imae34driver; 02-25-2014 at 10:52 AM.
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  #11  
Old 02-25-2014, 05:56 PM
Larrick Larrick is offline
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Mein Auto: 1994 525it
The mechanic who passed my 1994 525i said that the catalytic converters are
further back in the exhaust system than most and need to get really hot
before you bring the car in for test.
Oil change, inflated tires, high octane gas etc.
Like imae34driver said, give the man space.
My numbers changed from fail to pass within a few minutes on different tests.
He was rooting for me and may have manipulated something to help.
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  #12  
Old 02-25-2014, 06:12 PM
imae34driver imae34driver is offline
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Ya, i can tell you... The fines for "tampering" with test results where massive! And they have only gotten worse.!!! Way over 10k-100k and loss of licence

So much so i decided not get the extended training for a smog cert, witch is one of the most valueble cerfications you can have!
Im far too nice and wanna help all my friends who could never pass, but the EPA will try and set you up..!

So if he wanted to squeeze the juice a bit, maybe slightly bend a rule.. He would rather even you not know.!

What ever you do, don't try to make it verbal. (Ive tried bribes ect myself.. No go mostly)
And i was clearly the young dumb street racer anything but a cop. Haha there more affaid of word getting out..

Sure i tell a buddy, he tells one.. Then one to many find out ect.. Not so cool
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1995 540i /6 speed.Black on black. C.A.I/JBR LWFW/ Dinan tune/hi flow exhuast /545 SSK /3.15 with LSD / rev-shift racing motor mounts/stage 4, 6 puck clutch/ K Sport coil overs / 19" BBS LM's / suede sparco 368 steering wheel, Recaro bucket seats, sparco 4 point harnesses, NX wet kit, M/T drag slicks
"Skill can only get you so far, then comes money!"
R . I . P Paul Walker - 1973 - 2013

Last edited by imae34driver; 02-25-2014 at 06:16 PM.
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  #13  
Old 02-25-2014, 08:07 PM
twise twise is offline
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Thanks all. To each his own, I suppose. But I would prefer to find real answers to what is most likely a real underlying problem that is keeping the car from passing. If there is a valve issue spewing unburned fuel out the exhaust, that robs me of power and fuel economy. If a timing issue is affecting NOX, that could lead to overheating or burned valves. I know individual motivations will vary, but I'm trying to make sure the car runs well and will be reliable for my son, who will be on his own with it 300 miles away, with no real mechanical experience. Other advice toward that end is greatly appreciated.
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  #14  
Old 02-25-2014, 08:17 PM
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E34ZombieHunter E34ZombieHunter is offline
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Don't take this the wrong way but....
It is a 22year old car, it is not going to run like new, or if it tries emissions are much stricter now than when these cars were made it will be hard to pass. There are many threads like said before that after many tries even same day they finally pass. The car runs fine, but the emissions standard is almost too much for these old beasts. Just keep trying, it may not be any issue that can be fixed, just people making laws that most can barely scrape by on.
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  #15  
Old 02-25-2014, 11:20 PM
twise twise is offline
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I get that, but in my case, the exhaust doesn't even pass my own sniff test--it's so rich, you can smell the unburned fuel like crazy. This tells me that the CA required long-life cats did their job, using the catalyst to burn the unburned fuel leads until the cats are no longer effective. I get the whole over regulated, over stringent thing, but I think signs point to a correctable condition in this car.

Now I don't mean to come off sounding like such a purist. My resources are limited, and the reality is once it passes, I'll probably stop worrying about it, but if I can make some meaningful improvements in the process, all the better.
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  #16  
Old 02-26-2014, 08:00 AM
Larrick Larrick is offline
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When there is a problem with one of the many sensors
which regulate the engine fuel consumption, the engine
will default to a too rich condition.
This is to protect the engine.
Do you have any other problems, rough idle, hard start when cold or warm,
lack of power, etc, etc.
It may be crank position sensor or a coolant temp sensor or….….….….….
If you can smell raw gas then that is a fixable problem.
Zombiehunter is correct, The test gets tougher each year.
There is a concerted effort to get older cars off the road.
The only cars which are subject to the tailpipe test are 1976 to 1995.
I have not seen the folk with the van which failed but should
not have had the tailpipe test (see my previous post on this thread)
They brought it back for a retest.
I am curious to see if it passed.
Talk about vehicle inequality.
I'll post when I find out.
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Old 02-26-2014, 10:30 AM
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FYI, with new cats, you can start my 525i and it will go to almost zero exhaust emissions after idling for a few minutes. The further back the cats are from the motor, the more degradation will affect them. My wife has sever allergies/asthma that is aggravated by older car emissions, you know, like sitting behind a 1960-something car in traffic, so I run new cats on everything...
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Old 02-26-2014, 10:32 AM
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Quote:
Originally Posted by Larrick View Post
You know that all vehicles 1996 and newer no longer have to do the tile pipe test! They need only pass the physical inspection and a check of the computer codes...
That's only in certain areas we are being told, based on population and number of registered vehicles per capita...

However, on a OBD2 equipped vehicle, with pre & post calayst monitoring, it won't make much of a difference - you will fail the smog check if the cats are not operating efficiently because catalyst efficiency is monitored by the OBD2 system, regardless of actual tailpipe emissions...The new BAR regulations will not allow an inspection to take place after the MIL codes have been cleared, so you still have to wait for the monitors to reset...FWIW
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Last edited by Doktor Bert; 02-26-2014 at 10:53 AM.
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  #19  
Old 02-26-2014, 10:49 AM
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Quote:
Originally Posted by Larrick View Post
The only cars which are subject to the tailpipe test are 1976 to 1995...

Functional test changes from BAR flyer sent to smog inspection stations:

1. Fuel cap test limited to 1995 & older

2. Timing test limited to 1995 & older

New Regulations:

1. No tailpipe test on 2000 & newer (all inspection areas)

2. Proposed - No tailpipe test on 1996 & newer (not yet implemented in all areas)
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Old 02-26-2014, 11:11 PM
twise twise is offline
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Thank you Doktor Bert, and Larrick. You have helped confirm that if an e34 525 is running correctly, it is capable of running very cleanly as well. In response to Larrick's question, there are no blaring problems. The car starts easily and runs well. Although the idle does seem to float continuously up and down a little--maybe 50 rpms or so (IACV dirty?). Also, I would say it seems to lack a little power, but nothing dramatic.
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  #21  
Old 02-27-2014, 08:19 AM
Larrick Larrick is offline
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an erratic idle is a symptom of something wrong. Even a small problem
may be causing a fail on the smog.
An intake vacuum leak, (even the dipstick O ring)
A dirty Idle control valve
leaky injector, faulty temp sensor, dirty maf etc.
Try to have the engine running perfectly before you try again.
Others on this forum are much, much better than I at diagnosing problems.
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Old 02-27-2014, 12:08 PM
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Fluctuating idle, hmmmm.
I do believe that could cause a fail in theory.
The car is in park, and the TPS says the throttle is closed. So the ECM knows to idle.
It designates so much fuel for idle along with the o2's.
The IAC is giving too much or too little air throwing the mixture off and causing a failed test.

This is just a thought that went through my head when i read the last two posts. I am not an expert so i may be wrong, but why don't you give a cleaning to the IAC.
Do you smoke? Try this test.
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If you want to get junkyard parts remember one thing, if it was wrecked you know it was running/driving. You may not know how well, but it was.

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  #23  
Old 02-28-2014, 06:55 AM
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Doktor Bert Doktor Bert is offline
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Could you find vacuum leaks with a blunt????
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Old 02-28-2014, 07:03 AM
imae34driver imae34driver is offline
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Quote:
Originally Posted by Doktor Bert View Post
Could you find vacuum leaks with a blunt????
LOLz, of coarse. The smoke is even heavier actually so it will stay in the bay easier...

Though the it may make the car seem kinda lazy and start chewing threw fuel
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1995 540i /6 speed.Black on black. C.A.I/JBR LWFW/ Dinan tune/hi flow exhuast /545 SSK /3.15 with LSD / rev-shift racing motor mounts/stage 4, 6 puck clutch/ K Sport coil overs / 19" BBS LM's / suede sparco 368 steering wheel, Recaro bucket seats, sparco 4 point harnesses, NX wet kit, M/T drag slicks
"Skill can only get you so far, then comes money!"
R . I . P Paul Walker - 1973 - 2013
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  #25  
Old 02-28-2014, 07:11 AM
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Doktor Bert Doktor Bert is offline
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Quote:
Originally Posted by imae34driver View Post
LOLz, of coarse. The smoke is even heavier actually so it will stay in the bay easier...

Though the it may make the car seem kinda lazy and start chewing threw fuel
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