Blanco

iTrader: (8)

Reminds me of a problem I had long ago with a Ford Mustang SVO I used to own. The condensed version of the whole story goes something like this. I drove home from work one night in a baaad rain storm(minor flash flooding). At a particular stop light with high water, the motor backfired once. No mechanical problems before this night. After about 6 turbos, an engine rebuild, and THOUSANDS of $$$, the root of the WHOLE problem was the MAF. On that rainy night when the engine backfired, it fired hard enough to bend the flap/door/etc. inside the MAF. That bend totally threw off all fuel management and eventually led to an engine rebuild. Of course they didn't catch it until I had already spent all that money. Doh!! Bottom line: check the MAF CAREFULLY. Maybe you could get them to try and swap it out for a new one.

Hope my story can be of some assistance.

Good Luck,
Blanco

GSquicksilver

banana,

so what is your take on the MAF? could it really be the culprit for our problem? hot air, cold air, humid air, dry air, it all goes through that sucker first.

check out this link of toyota MAF's

http://www.autoshop101.com/forms/h34.pdf


found another link on cleaning the MAF
http://www.therangerstation.com/CleanMAF.html

ooh..this one has pictures. scroll down to the MAF pics
http://www.glue.umd.edu/~singletn/web/pages/ping.html

nice thread on MAF info
http://www.wellsmfgcorp.com/counterp...erpoint3_2.pdf

step by step MAF cleaning with pics
http://www.spydermagazine.com/2002/M.../maf_clean.htm

GSquicksilver

UPDATE:

i popped open my MAF to inspect it and it was kinda hard seeing into the grill that covered it (kinda a cross grill). but the two filaments look clean to me so i dunno. don't want to be spraying stuff in there if it already looks clean.

BananaGS

quicksilver, I had my eyes on the MAF for a while. Aftermarket intake created more carbon deposit in the throttle body, I bet it gives a lot of deposit on that sensor or mess up its charisteristic quicker (washing it is not a bad idea, but if the sensor just totally not in-specs any more, then we just have to replace it, don't )

That is the only other sensor on the intake path, and the only one that Lexus had not changed out.

Synergy is taking the car in next week, I told him to ask Lexus to replace the MAF. If that work, then, we all gonna replace that hee hee. I had funny idle on one of my car, and it turn out to be the MAF also, but the ECu actually log en error for this. On our car, there is no error logged. This MAF must still work intermittently.

Good call guys.

///MDex

You can wash the MAS?!

I thought that thing wasn ever to see any saturated moisture.

Synergy

Want to know how to fix your low idle issues? Turn on your parking lights the next time your car starts shaking....

The parking lights increase your RPM where it SHOULD be....now why can't Lexus fix this!!??

GSquicksilver

yup synergy, you're right.

if you want the roughness to "temporarily" go away, either turn on ur AC or your headlights. turning on your headlights draws more current so your engine revs higher in order for your alternator to output more juice.

NYC Max

Add me to the list. This is now the only thing that bothers me about this car. My simple fix is not running AC, or parking lights, but running the headlights/fogs and I dont mind as it makes the car stand out more anyway. Makes it run perfect. I would however like to get this fixed as well, I was all set on doing the TPS sensor, but I guess it isnt even worth it according to you guys.

BananaGS

I may have fix the problem, not a real fix, I still need more time to test it out. But so far, I raised the idle rpm by 150rpm, maybe I need to low it down a bit.

What to know how I did it?





I tighten the throttle cable a bit, forcing the throttle cable to pull the throttle plate all the time. Surpisingly, the shifting from P to D is still smooth even with the added rpm.

I still need to test this out for another week, unless Lexus come up with something good, I guess I have to stay with this fix.

GSquicksilver

banana, you are the man!

play around with it for a bit and let us know how it goes. will this screw up our emissions tho if we get our cars smogged?

what is the rpm when it is fully warmed up and in P?

BananaGS

I will test it out some more and let you know, it should not effect smog test in anyway.
I will test it out for a few days. So far, idle rpm in P and D are increased by about 150rpm more.

i think 150 is a bit to much, I will decrease the tension of the cable a bit, (increase 100rpm probably good enough.

my current idle in D is 680 or someting, a bit too high, since the low idle is intermittent, i will test it out a few day just to be sure. will low it down to 600 (instead of the 400 crap)


Anh

GSquicksilver

synergy,

any news on the MAF? did the dealership try to change it out?

Synergy

Nope - not yet. I plan to have them do this at my 45K service coming up...I will let ya know if it helps.

bitkahuna

iTrader: (20)

Another data point...

This past weekend the weather was fabulous, dry, sunny, about 70. I was out driving with a friend and for once I decided to open the roof and roll down the windows (something I do about once a year). Of course I then turned off the AC since there wasn't much point in leaving it on. I did notice that at a stop with my foot on the brake in D that the idle was SLIGHTLY lower in rpms and slightly rougher, but not uneven, and certainly not a problem. I engaged the AC and sure enough, the rpms moved back up a little making the idle its normal glassy smoothness.

BananaGS

yesterday with old throttle cable setting, D is 680 close the 4th mark

changed my throttle cable tension again this morning:
Engine is fully warm up: idle speed measure, AC off.
In park (P) : 970 rpm (close to 1K mark)
In Drive (D): 610 rpm (a bit over 3rd mark)

Engine is perfectly smooth. If Synegy replaces the MAF and still does not help, I will keep this set up. Will update in a few more day. We can really fix this problem now. hee hee. I still need more time to test this out.

Bit, we NEVER have this problem when we have the AC ON. only when the AC is off. and yeah, the idle feel a bit funny on my car when it hit the low, but not too bad, but for a couple time, for some unknown reason, it went REALLY low and died, if you have your a/c on all the time, you will never see it, even with my AC is off, it only died on me 3 times for the whole year, last year, and 1 time this year. I normally don't drive with AC off, but now, I do, I want to see what the heck is going on with my car. We are in the 60-70 in texas lately, perfect time for me to turn that AC off.