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Discussion Starter · #1 · (Edited)
How to make/borrow/buy lean-condition-misfire test tools (smoke, vacuum, & pressure)?

Lean-codes diagnosis DIY-priced test tools only!

Q: What are some cost efficient tools we can borrow, make, or buy (at DIY prices) to effectively test for lean-misfire conditions?

Specifically:

  • Can we make/borrow or buy a DIY-priced effective smoke machine?
  • How can we make/borrow or buy DIY-priced manifold vacuum test equipment?
  • Where can we make/borrow or buy DIY-priced fuel-pressure test equipment?
  • Can we make a simple propane source tester (combined with a DIY exhaust analyzer)?
This thread today, where an OP lamented spending over a thousand dollars (apparently throwing parts) on a lean condition misfire, got me thinking we need to point users to a comprehensive lean-codes DIY-test-tools-only thread:
- E39 (1997 - 2003) > $1,000 later, SES still on dont know what to do..

Specifically, this response, kindly supplied by Manybrews, hit the diagnostic nail on the head:
Why keep tossing parts at it? Diagnose it ... Use a smoke machine to check for vacuum leaks. Check crankcase vacuum ... and fuel pressure ... You can get a lot of diagnosis for 1000 bucks...
In summary, the purpose of this thread is to provide functional links to DIY-priced lean-condition misfire test equipment.

PS: I'm battling lean codes myself, and, to that end, here is a fuel-pressure tester I borrowed (for free, for 90 days with $160 deposit) from Autozone. But, I really should run a smoke test and manifold vacuum test first - so I need the results from this thread as much as anyone will.

Unfortunately, Autozone didn't have a smoke machine or manifold vacuum tester available.
  • Actron CP9920A, price = free


Please focus the discussion on lean-codes DIY-priced test tools only!
The lean codes needing diagnosis may be, for example, any of these:

  • P0171, BMW 227, System Too Lean (Bank 1)
  • P0174, BMW 228, System Too Lean (Bank 2)
  • P1083, BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
  • P1085, BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
  • P0300, BMW 62, Random/Multiple Cylinder Misfire Detected
  • P0313, BMW 238 to BMW 243 inclusive, Misfire Detected with Low Fuel
  • (any others?)
 

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Unfortunately, professional smoke machines are expensive. It does kinda place that out of the range of the average diy'er.
I don't know where one could be rented, either.
However, a manometer is cheap.
http://www.google.com/search?q=mano....,cf.osb&fp=cb377f2b52d83e5f&biw=1024&bih=672

All you need is one of those, then another oil cap with a nipple attached. You can easily test crankcase vacuum then, and find out exactly what it is?
Fuel pressure testers are also pretty cheap, depending on how wide you want to go with it (all cars? Bmw only? Etc).
http://www.google.com/search?q=fuel....,cf.osb&fp=11a11842428d597f&biw=1024&bih=672
 

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I have a Mity-Vac hand-operated vacuum pump that can be used as a vacuum gauge. I think they cost about $50 now, but it looks like Autozone lists a similar pump as one of their loaner tools. Also, some fuel pressure test kits will read vacuum.
 

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Discussion Starter · #6 · (Edited)
BB: Try using brake or choke spray to locate vacuum leaks. It actually works.
Yeah. I've done it. Personally, I think spraying stinks as a method (for details, see post #21 here).
- How to diagnose a BMW E39 misfire (1)

First off, there is a huge variation of the volatility of the sprays, secondly, I can't hear a thing change when I do it, even though I practically soaked the engine, thirdly you have to know all the places first before you can spray them and some are inaccessible and most people don't even know where they are (least of all me), and fourthly, the bounced spray makes a streaky mess of your windshield (especially when the washers aren't working).

I could go on - but, IMHO, the carb spray method isn't workable (at least by me, maybe because my misfire is hardly noticeable).

BTW, maybe I'm using the wrong stuff. What do you guys use?

 

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You could try attaching a tube to a propane torch after covering the air inlet holes in the tip. Turn on the torch valve, and put the end of the tube where you think the leak is.

Granted, if the engine is not running rough as a result of the leak / misfire, this will have limited diagnostic effect. Some sort of monitor would be needed to detect any changes to fuel trim as a result of using this method.
 

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Discussion Starter · #8 · (Edited)
You could try attaching a tube to a propane torch after covering the air inlet holes in the tip.
While I inherently prefer the inside-out method of building or buying a (workable) smoke machine:
- How to build a $30 smoke machine to test for vacuum leaks (1)

a buddy that has a import repair shop is using this 30 buck smoke-machine gadget and he told me he had been using it for years--does the job and works just great. I'm headed to Spencers
what a great idea.
I should take your advice and exhaust the outside-in methods first.

I'll take my blue propane tank to the hardware store to see if I can fit a clear flexible tube over the end. How large of a "tip" would you fit onto the working end of the tubing (the end that touches the vacuum hoses)?

BTW, they seem to use propane in combination with an exhaust analyzer ... so I guess we have to add an exhaust analyzer to the mix of tools to look for:
- Random Misfire Page
- Engine Vacuum Leaks

Note: Some use kerosene or alcohol.
 

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How large of a "tip" would you fit onto the working end of the tubing (the end that touches the vacuum hoses)?

BTW, they seem to use propane in combination with an exhaust analyzer ... so I guess we have to add an exhaust analyzer to the mix of tools to look for:
The 'tip' size is up to you - I would probably get one of the air blow guns from harbor freight with the 2 foot rigid aluminum extension (item number 68257, price $4.99) and attach that to the end of the tube. Now you have a 'wand' to probe into the engine compartment while you stand back and observe.

As for the exhaust analyzer, that's only for checking the operation of your O2 sensors and is not necessary for this test. For vacuum leaks, one only needs to monitor the idle RPM. Once the propane is pulled into the vacuum leak, the rpm will rise as the fuel / air mixture changes.
 

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Discussion Starter · #10 · (Edited)
a 'wand' to probe into the engine compartment while you stand back and observe.
The wand seems useful, especially for the harder-to-reach areas in the back of the M54 engine where the vacuum endcaps and SAS electrical valve hoses tie to the intake manifold.

Most seem to use a simple glycol in water, at anywhere from 10% to 75% concentration ... which they then heat up with a heating element ... to make smoke (at least based on this site):
- MAKE YOUR OWN SMOKE FLUID

It looks like 'most' smoke machines use a simple 'glycol' as the smoke fluid:

  • glycerol (aka glycerine)
  • triethylene glycol (aka TEG)
  • Propylene glycol (aka PEG)
  • etc.
One problem (according to that site) is that some glycol-based smoke-machine fluids will leave a sticky residue, which I would think would be a 'bad thing' in the engine intake system - so we would need to choose well.

This Chevy thread shows how to make a $35 smoke machine from an aerosol spray can using a seven dollar AC Delco # 60G Diesel Glow plug as the heating element:
- Made a homemade Smoke Machine for Vacuum leaks

They create the 3 psi to 4psi pressure just by blowing into the tube (or using a 12 volt air pump).

Interestingly, the Chevy guys used 'baby oil' which is a simple 'mineral oil', which can be almost any light mixture of alkanes (the point being it is not a glycol).

Googling a bit, I find they're not the only ones using mineral oils:

And, no, baby oil is not made out of babies.
 

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Discussion Starter · #11 · (Edited)
I've googled smoke machines and realized the similarities & differences - and I came up with my own idea for a smoke machine that is the simplest of them all (if it works).

There are three and two hole designs; but I have an idea for a one hole design.

These are the typical three holes for a smoke machine:
#1: You need an exit for the smoke to be piped to your manifold (usually connected after the MAF to the air intake)
#2: All seem to have a mechanism to generate pressure (about 2psi to 4psi)
#3: Many have a heating mechanism to generate smoke (the cleaner, the better, for the sake of your components)

The typical 3-hole smoke machine:

  • Is a metal container (typically a $1 paint can)
  • Which is filled with smoke fluid (typically a glycol)
  • Which is heated by a heating element (typically a $10 glow plug)
  • Which is forced out by air pressure (typically from a compressor or fan)
The typical 2-hole smoke machine:

  • Does away with the heating element (typically using a diesel soaked rag, burned and capped)
  • Some use dry ice for the smoke instead of the smothered soaked rag
My idea for the world's simplest single-hole smoke machine:

  • Creates both its smoke & pressure from the same action!
  • All it needs is a hole for the smoke to exit the container
I bought some of the parts already - and will attempt to create one or more of the smoke machines above to diagnose a persistent vacuum leak.

BTW, this article has a good description of smoke-machine fluids:
- Smoke Machine Chemistry
15%-35% food grade glycerine to 1 quart distilled water
125 ml glycerine to 1 liter distilled water
(glycerine creates a 'haze' at concentrations of 15% or less and more of a fog or smoke at concentrations higher than 15%)
Unscented mineral oil (baby oil), with or without water
10% distilled water: 90% propylene glycol (dense fog)
40% distilled water: 60% propylene glycol (quick dissipating)
60% water: 40% propylene glycol (very quick dissipation)
30% distilled water: 35% dipropylene glycol: 35% triethylene glycol (long-lasting fog)
30% distilled water: 70% dipropylene glycol (dense fog)
 

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Discussion Starter · #13 ·

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Discussion Starter · #14 ·
What would you suggest for the snorkel fitting & to power the glow plug?

Specifically:

  • Can we make/borrow or buy a DIY-priced effective smoke machine?
While I had designed (on paper) a single hose smoke machine (using 20 psi CO2 vapor pressure for movement & dry ice for smoke) ...

I ended up buying the parts at ACE Hardware for
the 3-hole home smoke machine.

  • One empty quart paint can, ACE PN 16067, $1
  • One Autolite glow plug, PN 1111, $10
  • One hose barb, ACE PN 42776, 1/4 x 1/8 inch MPT, $4
  • One brass tank valve, ACE PN 11138 (38-900), $3
  • Four brass nut pipe-lock-nuts, 1/8 inch, ACE PN 4183174, $3 each
  • One 1/4" clear tubing, 3 feet, $1
  • TOTAL ~= $28
Any suggestions for the fitting to the snorkel & what to use for connecting power to the glow plug?
 

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IIRC, photos I've seen of similar devices show a plastic lid on the end of the intake boot. I'd probably remove the air box and MAF. Then find an appropriately sized lid for the upper intake boot and use duct tape to make an air tight seal. You could put a hole in the lid, push the tubing through that and seal it with duct tape, too.

For power, I'd find a couple of alligator clips large enough the attach to the charging posts in the engine compartment. I'd fuse the positive wire going to the glow plug, but I'm not sure how much power those glow plugs take
 

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Discussion Starter · #16 ·
For power, I'd find a couple of alligator clips large enough the attach to the charging posts in the engine compartment.
I picked up the alligator clips ... so now I should have all that I need to build the thing. I see our friend 540indiana is in need of a similar test - so - maybe that will be the impetus for me to find that round tuit and built it this weekend to see how well/badly it works out in action!
- E39 (1997 - 2003) > Anymore suggestions before I spend money on smoke test?
 

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My turn for misfires due to air/vacuum leaks.

I'm in the shop right now (Ray's Ultimate BMW in Santa Clara, CA) for the $150 smoke diagnostic test.
They removed all the rubber & plastic housings from the engine air filter back to the windshield, including the cabin air filter.
They left only the large rubber boot connected to the ICV, which they put a latex glove over the 6 inch opening.
Then they removed the endcap on the back of the M54 where they hooked up the smoke machine.

Looking from under the car, smoke immediately was coming out of the lower CCV hose (which had a half-inch crack in it).
[ I wonder why/how it passed my CCV test - I probably didn't look hard enough! ]

They quickly replaced the lower CCV hose ($100) and running the smoke test again.
[ I thought the CCV was hard to get to but they said they didn't have to remove anything. ]

They said they visually saw a crack in the small bent finger in the rubber boot connected to the ICV.
They were going to charge me over $200 to replace that $20 boot when I put a stop to this nonsense.
[ In hindsight, I should not have paid them $100 to replace the lower CCV hose! ]

I picked up the $20 ICV rubber boot at the stealer instead of paying the $200 for someone else to do it for me.
[ I'll need three cold-start drive cycles to erase the MIL. ]

By the way, with a smoke machine, they make this look so simple to debug!
[ In double hindsight, I should have just bought a smoke machine if I could have gotten it for less than around $400. ]

Do these home made smoke machines actually work?
 

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Discussion Starter · #19 · (Edited)
I solved this a while ago but I realize I was remiss in not updating this thread so here's a quick update from start to finish on my various lean condition misfire codes ...

Specifically:
a) I first replaced all the rubber tubes/hoses/pipes/plugs I could easily get to in the engine bay ... which immediately helped somewhat lessen the frequency of the lean-condition misfire codes ...
- Where in the USA to get new vacuum tubing & vacuum caps (1) & what SAE sizes to get for all the metric M54 engine vacuum tubes, hoses, pipes, and caps (1) & correcting the F-connector errors in the realoem diagrams (1) & finding the ends of hard-to-locate vacuum tubes (1) & sorely needed clarification on how the M54 CCV vacuum port works on the M52 CCV valve connection to the fuel pressure regulator connection (1)


b) I then ran a smoke test ...
- How to make your own smoke machine (1)


c) Which pinpointed a lower CCV vent hose leak ...
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)


d) I also unclogged the dipstick guide tube which was clogged solid (and perhaps was a reason for the CCV vent hose leak) ...
- How to test, clean, & redesign the original BMW dipstick guide tube to prevent CCV vent clogs (1)


e) Lastly, I replaced the rubber boot which is connected to the ICV & TCV.


Those simple steps resolved my lean condition misfires!

BTW, while I rarely solve problems by replacing components without learning how to test them, I concur that one way to solve perplexing lean condition misfires, at this age of our bimmers, is to simply replace every vacuum-related rubber hose/tube/pipe/boot/cap/gasket in the engine bay.
 

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Discussion Starter · #20 · (Edited)
Here is a great cn90 vacuum leak testing diy:
> E39 (1997 - 2003) > Found this Ingenious VACUUM LEAK Testing Trick

EDIT: Another DIY smoke machine was posted today:
Hi all, here is my version of a M54 vacuum system smoke tester.
Built it today with stuff laying around. I could never have come
up with this if it were not for this forum. Thanks all to contributors!

Tools:
Glue gun.
Something to cut hose.
Something to make holes in plastic.
A source of compressed air.
Parts:
Plastic jar with screw on lid.
5/8 plastic elbow (i used a tee).
5/8 rubber hose.
1/4 rubber hose.
Cheap cigar.
3/8 drive socket that fits cigar.

Assembly instructions:
Drill hole in center of lid.
Drill hole in side of jar, at top.
Glue together. Lol

How to use:
First remove air filter box and put a rubber glove over MAF.
Remove hose from brake booster (be careful, the connector is plastic).
Put cigar in socket, light it, screw on jar, shoot air (low pressure)
into 1/4 hose at top of jar to get it really smoking good.

Insert smoking end into brake booster hose. Look for leaks.

And I got the famous CCV hose to dip stick leak.:yikes:

A video of using it.
http://youtu.be/u0HL3i_SYlQ
And another:
Or you can use a cigar!!

 
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