CHECK ENGINE - PART II

[First of all, we're talking about a 1999 VW Jetta SR5 with less that 14000 miles.] Well, the "epoxy fix" ended one problem, but the check
engine light is back on after being cleared. The code was a P1128, which someone in this group translated to be "Long Term Fuel Trim B1 System Too Lean." I did some further internet digging and found that that error code could be caused by six different things (none of which I understand). As with medical problems, I sought a second opinion at Autozone today. The results on their Actron meter is: P-1128 "Manufacturer Control Fuel and Air Meter", or as the fellow that helped me said: "Tell them its the 'Mass Air Meter.'"
So -- after I tell my mechanic that, can I suggest something that will clear the problem without replacing the unit? After all, he was glad to hear about the epoxy fix for the ignition coil.
Mike
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http://autorepair.about.com/library/faqs/bl913b.htm http://forums.vwvortex.com/zerothread?id 45185
do all of the easy and cheap checks first..............look for vacuum leaks and then check the other components! You might need to purchase the tool/interface so you can read the codes better and check components on your Jetta yourself. It will pay for itself on just this repair! <g>

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and what is a "1999 VW Jetta SR5"?

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must be one of those toyota-made ones :)
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Then I guess it is no wonder why the check engine light is on! ;-)
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wrote:

I was going to suggest it was Toyetta. Matt beat me to it.
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Ok, all you smarty pants-es. My shrink tells me that when I say that, I display an intense longing for a time when I owned the best car in the world, and at the same time my utter contempt for the VW that I currently own.
Make that VR-6 !!
Thanks for the links, Dave, but my Win95 computer doesn't like them and tells me that "the program has committed a fatal error" and closes the browser when I try and link to those sites. Will probably have to wait until next Monday when I can try on a more modern computer.
Mike
Jim Behning wrote:

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On Wed, 16 May 2007 04:58:06 GMT, snipped-for-privacy@jetta.com wrote:

Is this an Mk3 or Mk4 body style?
Check all of your vacuum connections, and check them twice! That particular fault will pop up at the slightest of an intake leak, commonly on one of the smaller hoses around the intake manifold. Also, make sure your that your brake booster line(s) are free of cracks on your visual inspection.
N-80 valve could also be stuck open, allowing excess air into engine.
Not sure on your level of repair experience, but access to a scanner or vag-com software may help you in isolating a faulty MAF. Might as well clean it while you're in there.
-- deus
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deus wrote:

No idea of body style. Car purchased in July, 1999 -- made in Mexico, if that tells you anything.
As for repair experience == zero. If it needs fixin, I try and find an expert to do it (after discussing the problem(s) with the experts in this newsgroup).
mike
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You might not agree with my approach, but it works for me. I play the odds. An 1128 code is one that appears when the mass-airflow sensor goes bad. They are notorious for going bad, so... They're not super-expensive, the cheaper one of the two types that are used is around $75. They're extremely easy to replace by yourself, takes all of 15 minutes. I'd just do it, and not mess around with all the other possibilities. But then again, I'm kind of reckless that way -- but if your experience is like mine, the next step will be that the car will begin to stumble and buck, then will not run at all. You'll replace the MAF, and it'll run like a top again. All standard disclaimers apply. ;-)
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compared to the 2.0l engines the MAF on VR6's have a very, very, very low failure rate. That said the price on the VR6 MAF is way more. But they do go bad... The fault(P1128) indicates a possible vacuum leak and the best way to check is to look at the fuel trim data for idle and cruise mode. If idle is ok but cruise indicates lean then it's a good chance the MAF is faulty. But then again if idle and cruise both indicate a lean condition then I would look for a vacuum leak or sticky purge valve.

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