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1 UZ-FE performance upgrade w Temp Sensor replacement?

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Old 06-27-09, 12:26 AM   #31
sc-driver
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check out this thread: http://www.clublexus.com/forums/perf...er-signal.html

On the 18th post, I posted a portion of the repair manual that covered the maf and how to test to make sure its properly working.
http://www.clublexus.com/forums/4567139-post18.html
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Old 06-27-09, 02:08 AM   #32
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Mine was whistle clean all right but would only run if I had my AC going full blast. Turn it off & the car died immedietly.

Also took about 30 miles off of my total miles per tank. Purchased a used AFM, plugged it in and all went back to normal. Cause & effect was instantaneous and there were no other variables in my case.

Why do you think you have a AFM problem?

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Old 06-27-09, 09:24 AM   #33
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Thanks for the repost scdriver. I was bragging how good my car was running now after a couple of days of the new CTS, but this morning I get in to drive to work, go about 1/4 mile out of the subdivision up to the stop sign and wait to pull out. When I do I get a big double hesitation and then it goes on and runs perf. On the way back home I stopped 2 blocks from work and take off with the AC on and its fine. This morning I had the AC off. It seems like if I set and idle to long is usually when I get the hesitation from stop.
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Old 06-28-09, 11:35 AM   #34
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I did this a few months ago on my SC400 and there was no difference. Unless yours doesnt work or isnt giving the resistance based on the diagnostics using the service manual dont bother replacing it.
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Old 06-28-09, 12:33 PM   #35
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My car seems like its running better, but not all fixed, I dont really regret spending the $30.00 and hour of labor. I think Ill call Lexus monday and price a new MAF if its still avail.
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Old 06-28-09, 12:53 PM   #36
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New Karmen Vortex MAF from dealer is around $1000.
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Old 06-28-09, 04:38 PM   #37
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Holy over priced old car part Batman, other than a used one is there any other options
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Old 06-28-09, 06:01 PM   #38
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Used ones on eBay, work just fine. Just don't clean them with sprays meant for hot wire MAF sensor, I found out the hard way.
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Old 06-28-09, 06:15 PM   #39
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I swapped out the coolant sensor today, pretty easy job, just have to get the coil pack and spark plug wires out of the way. Original sensor had 194k miles and was clean, no corrosion at all, thanks to Dex-Cool (I know, a lot of complaints of this coolant, but working for me).

I did measure the resistance of the old and new sensor using a Fluke multimeter at 80F:

Old = 2050 ohms
New = 1650 ohms

Now that's quite a bit of difference. According to the services manual, the resistance of the sensor goes down as temperature goes up. So my old sensor was telling the ECU the coolant was cooler than it actually is causing the ECU to richen the mixture? That's the theory anyway. The chart in the service manual is not exact, has a wide zone of acceptable resistance range at a given temperature, and not the easiest to read the acceptable limits.

I'll report back after a couple of tank fulls, see if MPG goes up.
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Old 06-29-09, 03:33 AM   #40
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If you have a bit of patience, you can get rid of the maf all together with a MAFT pro. Changes everything to speed density.
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Old 06-29-09, 09:10 AM   #41
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Going to try it... car has been sluggish recently (basically when it got hot outside).
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Old 06-29-09, 11:19 AM   #42
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Just so you guys know most toyotas use this exact same sensor, including the 2jz.
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Old 06-29-09, 02:55 PM   #43
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Do you happen to have the Toyota OEM part #?
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Old 06-29-09, 04:06 PM   #44
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if you need a part number go to toyod|y.com, replace the | with a i
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Old 06-29-09, 05:51 PM   #45
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Its a little agreavating , one time it runs like new the next it has hesitation. And I have name brand gas with Lucas fuel injector cleaner.
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93 SC400
Carbing strut tower brace front.
Rear custom made strut tower brace.
Sunroof delete and A.C. delete.
http://img808.imageshack.us/img808/4913/dscf3750n.jpg
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Old 06-29-09, 05:51 PM
 
 
 
 
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1992, 1998, 400, coolant, duralast, ecu, lexus, location, ls, performance, plug, sc400, sensor, spark, temperature, wires

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