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Discussion Starter · #1 · (Edited)
This had me scratching my head...

Took it in for CA smog. No CELs, running fine.


  • Failed for Hydrocarbons. 78ppm at 15mph (limit 47) and 57ppm at 25mph(limit 31) (Yes, was hot for test)

Hmmm.

No CEL. Checked codes with peak, No codes


  • OBD scanner. Long term fuel trims elevated, 3% on bank 1, 6-7% on bank 2.


  • Cleaned MAFs, changed pre AND post cat O2 sensors, new air filters, Oil change, what they heck, eh?


  • Drive 300 miles, retest

Fail. Pretty much the same numbers.


  • Pull the plenum, check all hoses for leaks. Replace a few. Smoke test. Nothing seen.

  • MAF test gives 138.x at redline in 3rd

  • Thermostat and T sensor replaced at 13k miles ago, temp readings all good.

Still fails. CATs again good and hot for test.

138k miles on the ODO



Time for better computers. Took it to a shop for further tests.


  • Autologic report, looking at O2s and adaptation shows rich... ran the VANOS test:

  • Bank 2 shows "Deviation, Leak Test, Exhaust (ocr)" = 9.3 Fail (limit 7)

  • Bank 1 showed 6.7, 6.8 and pass.

So, surprised that I have a vanos issue that is causing no codes, no issues, just running a bit rich.

My plan- replacing:


  1. All 4 CPS,

  1. All solenoid o-rings (both banks).
Will check solenoid screens for debris/damage.

Thoughts?

A

PS Anyone replace solenoid assemblies recently? What are those puppies running ($$)? I'd usually buy parts prophylactic, but these are not hard failures, and the price for two is a bit surprising....
 

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depending on where you get them anywhere from 350-500. Yes they do throw codes/run funny without CEL. Happened to me for a while.
 

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Looks like the price for the solenoids went up... WAY UP! Tischer BMW is selling them for $1,100 a pop. I remember when they were around 300-400. If you're just replacing the solenoid o-rings, it will cost a couple of bucks if you're doing it yourself.

CPS sensors are still around $90 each.
 

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Discussion Starter · #4 ·
Looks like the price for the solenoids went up... WAY UP! Tischer BMW is selling them for $1,100 a pop. I remember when they were around 300-400. If you're just replacing the solenoid o-rings, it will cost a couple of bucks if you're doing it yourself.

CPS sensors are still around $90 each.

Indeed. I just ordered CPSs and orings from tischer and had heart failure on the solenoids...my recollection was 400-500 ish!

Soldering iron for sure if they fail.:eek:h:
 

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Discussion Starter · #6 ·
Yep,solenoids got recently very expensive....


Did you check for cracks around the O2 sensors,btw?
Just my luck.

Yes, I'd checked for cracks following up on Alan's (Vector57) fine input.

Thanks-
 

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So, surprised that I have a vanos issue that is causing no codes, no issues, just running a bit rich.

My plan- replacing:


  1. All 4 CPS,
  1. All solenoid o-rings (both banks).
Will check solenoid screens for debris/damage.

Thoughts?

A

PS Anyone replace solenoid assemblies recently? What are those puppies running ($$)? I'd usually buy parts prophylactic, but these are not hard failures, and the price for two is a bit surprising....

Yeah, sounds like you are on the right track.

I just ordered the o-rings myself ..... my car is running rich too. I was going to replace the cps sensors after replacing the rings, but I think I might just do the same and replace all 4 now. Again, no codes, 137-141, new thermostat, plugs, filters, 02, +3/5, never took it to a better computer to test the vanos, yet I couldnt think of anything else. I also hear a slightly increased vanos noise on startup on bank one that, looking back on it, started right before it got a bit rich. I hope it isnt the solenoid assembly, It was just as recent as Jan. that you could pick them up for 400. good luck..
 

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Discussion Starter · #10 ·
Quick Question:

Grubb screws that pretension the solenoids are impossibly tight. TIS says remove these first...by hand says I will strip it first.

Thread says: http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/150762-vanos-grub-screws-tight.html

Can I leave these 'as is'? Reusing the same solenoid, just changing oring and gasket. Should maintain proper preload? Or should I remove cover first, then boil or heat to remove grubbs?

Thoughts?

(Quickly... ;) )

A
 

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Quick Question:

Grubb screws that pretension the solenoids are impossibly tight. TIS says remove these first...by hand says I will strip it first.

Thread says: http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/150762-vanos-grub-screws-tight.html

Can I leave these 'as is'? Reusing the same solenoid, just changing oring and gasket. Should maintain proper preload? Or should I remove cover first, then boil or heat to remove grubbs?

Thoughts?

(Quickly... ;) )

A
I have yet to do it, but I did read the referenced thread and it seems like its better to just leave them as is if they are using red LT on them. IMO I would remove them without removing the grub screws, and then once removed, if I looked at the cover and decided it was a good idea to boil/ heat and get them out of there. If you already have tried to remove a few, I would say remove it and boil the rest loose. If they are all still in there locked, I don't see much advantage from removing them.

let me know how this goes, I'll be doing it next weekend
 

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I guess I should have read the TIS I just removed the covers. I loosened the center bolt first then snugged it back up. I removed the outside bolts then removed the center one. Things will be different when you reassemble. The tension on the grubbs will screw up the torque of the retaining bolts. You may just have to tighten them to a higher torque. I think the grubbs are there to just stop them moving. Should not make a huge difference. The gasket is just a dust shield. Reuse the old one if it does not break, that way the distance is unchanged.

How were your co2 levels? Did the NOX value change with the change in O2s?
 

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Discussion Starter · #13 ·
I guess I should have read the TIS I just removed the covers. I loosened the center bolt first then snugged it back up. I removed the outside bolts then removed the center one. Things will be different when you reassemble. The tension on the grubbs will screw up the torque of the retaining bolts. You may just have to tighten them to a higher torque. I think the grubbs are there to just stop them moving. Should not make a huge difference. The gasket is just a dust shield. Reuse the old one if it does not break, that way the distance is unchanged.

How were your co2 levels? Did the NOX value change with the change in O2s?
Removed the outer bolts and removed the cover. Then heated the grubbs and reused, using a hot air gun (for shrink wrap)

Personally I don't think it is that critical.

So, did it work? Dunno. Car feels strong- placebo effect at work.

I've driven it a bit, LT fuel trims are moving around, but I have no way to reset VANOS adaptations.... so we will see. And no way to check emissions.




Initially my failure was HCs only. CO% was at 0.07, 0.08% and NO(ppm) was 0 and 1. After replacing pre and post cat O2 sensors (posts were original, pre had 60k on them) there was no change at all.
 

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Removed the outer bolts and removed the cover. Then heated the grubbs and reused, using a hot air gun (for shrink wrap)

Personally I don't think it is that critical.

So, did it work? Dunno. Car feels strong- placebo effect at work.

I've driven it a bit, LT fuel trims are moving around, but I have no way to reset VANOS adaptations.... so we will see. And no way to check emissions.




Initially my failure was HCs only. CO% was at 0.07, 0.08% and NO(ppm) was 0 and 1. After replacing pre and post cat O2 sensors (posts were original, pre had 60k on them) there was no change at all.
You needed to that work anyway but I doubt that will have any effect on your e test. Here is my test results when I bought the car with all the things wrong with it. 1 hard open solenoid, 3 slow solenoids, hard orings, 2 code throwing cps, 2 weak exhaust cps. The exhaust cps were masked by the 4 bad exhaust solenoids, which were probably caused by the 2 bad post cat O2 sensors. Fortunately we only have a gas test not a OBD check because my SES was as bright as the high beams. I should mention you would pass up here with your readings.My results:
first number is high RPM second is idle. HC =34 and 29 CO was .02 and .09 last NO was 0 and N/A.

The only real work I did prior to the test was injector cleaner at double dose and then I put a an intake cleaner through the brake vacuum line and cleaned the inside. Next I put a 1/4 tank of low octane fuel in 89 and to that I added a liter of methyl hydrate.

When you went for your test what octane gas did you have in? Any ethanol in your gas? Are your injectors clean? Do you do a lot of stop and go low RPM driving? What is your oil consumption? When you had the plenum apart how much oil was present?

Here is a list of things that could cause high hc and nothing else high. Unburned gas or oil. Not to big a list. The list that can cause that is much longer but not that long and fairly easy to trouble shoot. First thing that comes to mind is poor atomization of fuel. Even with that you could pass as long as your octane is low. High octane resists fuel igniting due to heat. So if it is sitting on a carbonized surface or if the droplet size is to large it may not burn completely, then when it gets to the cat it does not want to convert. The fuel is not to blame but high octane only does you good in a good clean engine. The use of methyl or ethanol is good because the particle size of the gas is further reduced and I am told has fewer measurable HC per volume.
The dirty injector problem is compounded when there is unburned fuel because the pre o2 see more o2 than it should so it turns the trim up which usually makes things worse.
First thing I would do for a no code fault is check electrical system and fuel supply then fuel delivery. It is almost certain that the electrical system is not at fault so just rule it out. Next thing would be to do would be to make sure the system has good pressure and volume. I think we can rule that out because you have no codes. Can't forget about it just not a good place to start. I would want to see the injectors but I am very lazy so I am going to cheat and look at them without seeing them.

The easy way is to hook up a fuel pressure tester in the fuel line. If you don't want to risk things you pick a spot before the fuel filter.
This is my rig for basic testing not accurate testing. It is made of some hoses a brass T and a cheap pressure gauge that goes to 100psi. None fuel rated except for the black line the gauge is for water pressure. The last critical part was salvaged from the end of a fuel filter. You can't se that part because it is clipped into the line from the tank.
fuel test2r.jpg

This is the close up of the hook up and one of the places you must clamp off to isolate the test to the injectors.
fuel test3R TXT.jpg

This pic shows the last place you must pinch off to isolate the injectors.
fuel test1rtxt.jpg

After you install fire up the car and look for leaks fix them first. Shut off the car and pinch off the two lines indicated. Now watch the gauge and see if or how fast the gauge reduces pressure. The faster the gauge drops the more attention your injectors need. If the pressure holds for ten minutes, your injectors are not very dirty and are sealing but that does not mean they are spraying correctly. If I got to there I would add to my fuel some Lucas upper cylinder lube at double to triple dose.I have added a whole bottle to a 1/2 tank and within ten minutes at idle an injector that was not working started working. That injector is still in that car the guy just uses this stuff in every tank. I think that was three or four years ago. Run two tanks then only add the recommended amount. That stuff works wonders on injectors. Think about it your injectors have been sitting in gas for 7 years and this stuff just makes thing slide better.
Hopefully this will give you some ideas, you are with the car so only you can decide the right path.
Best of luck
 

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Discussion Starter · #15 · (Edited)
You needed to that work anyway but I doubt that will have any effect on your e test. Here is my test results when I bought the car with all the things wrong with it. 1 hard open solenoid, 3 slow solenoids, hard orings, 2 code throwing cps, 2 weak exhaust cps. The exhaust cps were masked by the 4 bad exhaust solenoids, which were probably caused by the 2 bad post cat O2 sensors. Fortunately we only have a gas test not a OBD check because my SES was as bright as the high beams. I should mention you would pass up here with your readings.My results:
first number is high RPM second is idle. HC =34 and 29 CO was .02 and .09 last NO was 0 and N/A.

The only real work I did prior to the test was injector cleaner at double dose and then I put a an intake cleaner through the brake vacuum line and cleaned the inside. Next I put a 1/4 tank of low octane fuel in 89 and to that I added a liter of methyl hydrate.
Methyl hydrate? Need to google. ;)

When you went for your test what octane gas did you have in? Any ethanol in your gas? Are your injectors clean? Do you do a lot of stop and go low RPM driving? What is your oil consumption? When you had the plenum apart how much oil was present?
96 octane for first test. 91 for second. Ethanol yes, this is Kalifornia

Injectors unknown. Chevron fuel 66% of the time, occasional bottle of techron (every 15-20k)

Little stop and go driving. High speed highway 95% of the miles. Oil consumption is 1L per 2000 miles. Negligible oil in plenum. Oil separators clean, new hoses.

Here is a list of things that could cause high hc and nothing else high. Unburned gas or oil. Not to big a list. The list that can cause that is much longer but not that long and fairly easy to trouble shoot. First thing that comes to mind is poor atomization of fuel. Even with that you could pass as long as your octane is low. High octane resists fuel igniting due to heat. So if it is sitting on a carbonized surface or if the droplet size is to large it may not burn completely, then when it gets to the cat it does not want to convert. The fuel is not to blame but high octane only does you good in a good clean engine. The use of methyl or ethanol is good because the particle size of the gas is further reduced and I am told has fewer measurable HC per volume.
I know. Why I am still puzzzled.

I was under the impression that high octane simply resists spontaneous detonation, and not 'rate of burning' per se.

The dirty injector problem is compounded when there is unburned fuel because the pre o2 see more o2 than it should so it turns the trim up which usually makes things worse.
I still cannot understand why my long term fuel trims are running +5% if it is rich. How can the gas leaving the combustion chamber be rich, and not cause the O2s to dial back the trim???? I am not getting this.

First thing I would do for a no code fault is check electrical system and fuel supply then fuel delivery. It is almost certain that the electrical system is not at fault so just rule it out. Next thing would be to do would be to make sure the system has good pressure and volume. I think we can rule that out because you have no codes. Can't forget about it just not a good place to start. I would want to see the injectors but I am very lazy so I am going to cheat and look at them without seeing them.

The easy way is to hook up a fuel pressure tester in the fuel line. If you don't want to risk things you pick a spot before the fuel filter.
This is my rig for basic testing not accurate testing. It is made of some hoses a brass T and a cheap pressure gauge that goes to 100psi. None fuel rated except for the black line the gauge is for water pressure. The last critical part was salvaged from the end of a fuel filter. You can't se that part because it is clipped into the line from the tank.

This is the close up of the hook up and one of the places you must clamp off to isolate the test to the injectors.


This pic shows the last place you must pinch off to isolate the injectors.


After you install fire up the car and look for leaks fix them first. Shut off the car and pinch off the two lines indicated. Now watch the gauge and see if or how fast the gauge reduces pressure. The faster the gauge drops the more attention your injectors need. If the pressure holds for ten minutes, your injectors are not very dirty and are sealing but that does not mean they are spraying correctly. If I got to there I would add to my fuel some Lucas upper cylinder lube at double to triple dose.I have added a whole bottle to a 1/2 tank and within ten minutes at idle an injector that was not working started working. That injector is still in that car the guy just uses this stuff in every tank. I think that was three or four years ago. Run two tanks then only add the recommended amount. That stuff works wonders on injectors. Think about it your injectors have been sitting in gas for 7 years and this stuff just makes thing slide better.
Hopefully this will give you some ideas, you are with the car so only you can decide the right path.
Best of luck
Thanks for the thoughts. Given the fact that I m reliably hitting 138 L/H I am guessing the fuel delivery is good. Injectors, however, might be something to consider. I tend to be a "screw it, if I am taking it apart, just replace it" kind of guy... but we shall see.

A
 

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Methyl Hydrate = gas line anti freeze sometimes also marketed as "Guaranteed to pass" for emission tests.

I should watch what I say because my lack of experience with this engine, but in very simple terms it works this way. M engineers have surprised me before so take this with a grain of salt. The thought on why the trim is up. It is an O2 sensor and reads O2 not HC but other things can throw it off. MAF says air =X DME goes to data base says OK I open the injectors for this long based on that much air. DME checks with the O2 sensor to see how much O2 is present at the cat. Too much O2 and the DME puts more gas because it can and should because one of the biggest deals in the life of an OBD DME is to make the cats work properly. The DME does not want lean anywhere near the cat or it will burn up in no time, so again another great reason to add gas. We the guys with our foot to the floor want gas too. So adding gas is a win win.
Yes there are a ton of other things going on but.....

If it is poor atomization that is caused do to dirt or wear then the extra fuel will add more unburned for the same reason it is not burning in the first place.

Octane prevents fuel from pre ignition or resists spontaneous detonation do to heat. A property we like and want. When things are as they should be all of the gas will be a vapor and the spark makes it all go boom. What if it is not a vapor. What if it is a little bloob that hit the top of the carbon coated piston. It will become a vapor so it can ignite but that takes time if it is late for the spark, because it is high octane it may not go boom because it missed the spark so now all that is there is heat. If you have low octane the odds are it will ignite due to the left over heat. Don't forget gas only burns when in vapor. This is a border line issue and happens with other things that are wrong.

We are only talking about a very small amount of unburned fuel, but unfortunately they are calling us on the small amounts. I have had an experience where 94 made me fail and a wise dude at road fly posted to me what I posted to you. I did the methyl and the 89 and passed. That car had dirty injectors. I can't take credit it for this nor do I fully understand the science but it has worked for me. The octane problem only exists if things are dirty. If things are good it should have zero effect.
The one thing worth mentioning, fill the car up with 96 or 94 as soon as you are done because 89 sucks (for other less experienced readers).

With all things that you have said I don't see any likely cause. You should have passed. Highway driving with good rpm+1, Low oil consumption+1 ethanol+1. You don't have conditions that would give you carbon or even dirty injectors. The octane only fits on a dirty engine. What else could it be? Check your last test, if you keep that stuff, maybe there is an indication.
 

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Discussion Starter · #17 ·
Report:

After 150 miles of driving, following solenoid o ring replacement, the LT trims are 1.4% and 2.9%.

Also, bank two had failed the Vanos test...and that set of solenoids was badly fouled. On close examination, you can see where the orings have failed and allowed oil to pass. On the left bank only the inner oring appeared to be leakys. But bank 2 showed leakage past the outer (large) oring on two actuators...not a 'leak', but seepage with 'congealing' oil residue. Not sure what this means or tells one, but interesting.


Still working on it, more to follow end of the week.

A
 

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Hey Adam,

I have a set of 4 new CPSes that haven't been installed yet. I know sometimes Tischer can take awhile to ship, if you need any loaners to get your smog done before the deadline, I'd be glad to help out.
 

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Discussion Starter · #19 ·
Hey Adam,

I have a set of 4 new CPSes that haven't been installed yet. I know sometimes Tischer can take awhile to ship, if you need any loaners to get your smog done before the deadline, I'd be glad to help out.
Thanks- They UPS redded them to me on Friday, got them Sat AM. I justified it by all the $$ I saved by DIYing. :)
 

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Sounds like the VANOs was a major part of it, based on the new fuel trims.
Maybe I missed it, but how do the plugs look?
Regards,
Jerry
 
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