Air mass meter repair

Has any one ever replaced the broken platinum sensor wire in a air mass meter? I have a Bosch AMM with a broken sensor wire and would like to attempt to repair it. The problem is in sourcing a few inches of 0.0025" ( 0.05mm) of platinum sensor wire. Any suggestions?

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs

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Ontario

Reply to
Boris Mohar
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Maybe you could harvest one from a junk yard car.

Reply to
E. Meyer

The wire isn't platinum. A guy on thirdgen .org tried to do the same thing and when he replaced the wire, it worked but the specs were way off..

-Bruce

Reply to
Bruce Chang

Yeah Boris,

BITE THE BULLET! Just replace the unit for Pete's sake! Granted, the danged thing is gonna run you close to between $100 or $500 for a replacement. But, the fact is, without proper facilities (ie, correct type of solder and 'halfways' clean room) facilities you'll never do it correctly.

That is why there are re-manned units, and in particular why they exist as only re- manned units and still seem to cost as much as the original! It costs damned near as much to remanufacture it asx it does to produce it.

Stop and think about this for a few minutes:

  • The reason that Platinum is used is because it has such a free flow of electrons. But it must be VERY pure to obtain this.
  • Have you ever thought about why Platinum is used in sparkplugs? See The previous point...
  • Look at the periodic table of elements (Once again we encounter 9th grade science) and you'll notice that properties of elements increase as you go up and to the right, or down and to the left. Going down the column of Copper (Cu) we find Ag (Silver) then Au (Gold) and then to the left we find Platinum (Pl). Copper has a very easy flow of electrons and therefore it is used in wiring. Silver is better, but not as good as Gold! Gold is what Champion and Marantz, et al. have decided to use as a conductor in there wiring and connections. Why7? Because it is easy to electroplate and damned cheap to electroplate to a metal! It's About the best thing a person can use except for _PLATINUM_! Platinum has better electron flow, and therefore less resistance, than Au and being that it's more precious (less easily found) than Au it costs more.
  • Now add PbSn (Lead-Tin) solder into the equation... You've just de- stroyed any attempt you've gained in speed by adding a stop light. The best way to imagine this is to see the platinum wire as a garden hose. The PbSn is a visegrip placed on it and clamped down. The elec- tricity will still flow, but nowhere near as quickly, easly or well. Keeping in mind that temperature and resistance are directly related (hence, the reason that MAF sensors even work at all!) ((Once again, 9th grade science)) and we will also find that "Lead Tin solder" has a __M_U_C_H__ Higher resistance than Platinum...
  • Are you seeing the trend yet?
  • It would be fairly impossible for you in your garage to repair a MAF sensor. Everytime a person heats a metal to liquid form you allow impurities to enter the substance. Hence, even though it doesn't _REALLY_ exist, AuO (Gold Oxide) does impede the flow of electrons in wiring just the way that PlO,or PbSn-PlO would impede the flow of electrons through a Platinum wire.

I'm sorry to tell you, but it's basically not possible for a shade-tree or even shop type mechanic to repair or rebuild a MAF sensor. It requires material, pro- cedures, and facilities which the average man can't imagine. That's why they are always rmanned in a 'facility' with ISO 9K+ certification.

This is the time to shell out the $150 at O'reily or NAPA and just keep the re- ceipt for when it goes bad.

Hope this helps.

Reply to
Drew Hill

replacement.

resistance,

shade-tree or

material, pro-

Hmmm..., why is it that you're unaware that neither gold nor platinum are better electrical conductors than silver, nor have you correctly related the logic for the use of those metals in a circuit.

Reply to
Hoonoze

And why is it that you never answered this question?

Other than the anti-theft system let's see you name just one ..... ponder that for a while and then piss off. Bob Once again I'd say PISS OFF

Reply to
Bob

I'd say it's about time you went back to 9th grade science.

Also, the platinum wires aren't soldered, they're crimped. Everytime the MAF burnoff relay shut, it'd melt the solder off. If you only got one burn off for each MAF, they'd have to be really cheap or designed to never need but one burn off cycle.

-Bruce

Reply to
Bruce Chang

You don't need a clean room to make hot wire probes. One of the first things they tought the fluid mechanics grad students to do when I was getting my masters was to how to make em. I've seen hotwire probes made in a rather unclean lab with a vise to hold the body and simple soldering iron.

Now making the hotwire the same way as the manufacturer with the right 'range' (for a lack of a better term and foggy memory on hotwires) would be a significant challenge beyond just making a hotwire probe... Getting the right stuff shouldn't me too difficult. A scientific supply house should have the stuff.

How to make a hotwire probe? I dunno, I know the fluids guys bitched about it everytime they broke their wire, so it had to be a P.I.T.A.

That said, the conclusion is probably the same, just buy one. Because my guess is any home repaired probe will become a regular maintaince item to do and redo....

Reply to
Brent P

Apparently, in addition to your inability to render competent analysis, also beyond your assessment skills (or lack thereof), is the slightest modicum of potential for the realization of when you are being duly ignored.

Notwithstanding your eventual yet trammeled recognition of the facts of the discussion (replete with requisite, albeit contemptible, change of argument maneuver), and although I have no doubts in my abilities to educate even you, I've neither obligation nor any desire whatsoever to continue a dialog with such a loutish, boorish ignoramus such as yourself.

You may also rest assured in the certain knowledge that I will respond whether, when and in the manner I should so choose.

In closing, suffice it to say (and in a vernacular that will hopefully not escape your comprehension) that "you may stop humping my leg now".

Reply to
Hoonoze

In other words, you were wrong. You bring to mind the old phrase "If you can't dazzle 'em with brilliance baffle 'em with bullshit". Bob

Reply to
Bob

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I think your on a goose chase, but have fun trying. The wire will not solder. But maybe with the right crimp connectors you could re attach your broken wire?

BOB

Reply to
BOB URZ

I wrote this:

  • Look at the periodic table of elements (Once again we encounter
9th grade science) and you'll notice that properties of elements increase as you go up and to the right, or down and to the left. Going down the column of Copper (Cu) we find Ag (Silver) then Au (Gold) and then to the left we find Platinum (Pl). Copper has a very easy flow of electrons and therefore it is used in wiring. Silver is better, but not as good as Gold! Gold is what Champion and Marantz, et al. have decided to use as a conductor in there wiring and connections. Why7? Because it is easy to electroplate and damned cheap to electroplate to a metal! It's About the best thing a person can use except for _PLATINUM_! Platinum has better electron flow, and therefore less resistance, than Au and being that it's more precious (less easily found) than Au it costs more.

Um, did you actually read the post? Because I did mention exactly what you said that I hadn't.

Concerning the other posts:

And no, I never said a clean room was needed for a MAF sensor, only a 'halfways' clean room. You're not gonna do this on your work bench that's covered with grease and wood shavings.

And no, I don't recall saying that the wire is soldered (at least I didn't MEAN to), only that to use solder to repair it would be counter productive.

This is a job that doesn't get done at home by a shade tree mechanic, I've never heard of any mechanic at a shop anywhere ever successfully re- pairing one. It gets sent in as a core for the next guy's part.

-andy

Reply to
Drew Hill

Look at the CRC handbook. It will tell you that silver is the best conductor, followed by copper, gold and aluminum, in that order.

Reply to
Clifton T. Sharp Jr.

To clarify on my previous post:

The wire is not pure platinum. It's some kind of platinum alloy.

-Bruce

Reply to
Bruce Chang

Hmm.. "... Silver is better but not as good as Gold!..." This was in reference to "...easy flow of electrons." Which leads most everyone with a basic grasp of the english language that you have stated that Gold is a better conductor than silver. The reason people use gold is because it doesn't oxidize. If silver didn't oxidize, people would use it instead because it's a better conductor.

As a side note:

You've confused rare and precious. An object being rare is a fact, an object that is precious is subjective. Diamonds are not as rare as some other precious gems (I think the sapphire is one of them) but people have deemed the diamond more precious and therefore they cost more.

Reply to
Bruce Chang

electrons

Apparently logic isn't a strong suit for you either. Perhaps you'd prefer a spoon feeding. Consider these statements from your post: "Platinum has better electron flow, and therefore less resistance than Au..." - WRONG! and, "Silver is better, but not as good as Gold" - WRONG, again! Silver is the BEST conductor, not gold, not platinum! Also, gold is much less chemically reactive, and platinum a much higher melting point, than silver; it is due to these advantageous properties that these elements are chosen for use in circuits. As stated in my reply, neither point is addressed in your silly and pretentious primer. Encountering such fundamental errors, and so early in the post (not to mention your follow-up gaffe), provides at least this reader precious little incentive for a further continuance of such nonsense.

Reply to
Hoonoze

Silver is a better conductor at normal temperatures than either gold or platinum - see

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). Silverdoes have problems when it comes to use as a contact material - it willtarnish, which increases contact resistance and there is a tendency forsilver to form whiskers. These whiskers are not much of a problem inhigh power applications, but they can really screw up low current flowapplication. Therefore it is very common to see silver used as a contactmaterial in high current circuit breakers and switches, but never in lowvoltage / low current switching applications. Regards,

Ed White

Drew Hill wrote:

Reply to
C. E. White

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