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Adjusting EFIE while driving, throws CEL.
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romulus Offline
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Post: #1
Adjusting EFIE while driving, throws CEL.
Mike, I have my Duel EFIE set to .25v and things seem ok. I have noticed a small improvement in mileage (13 mpg before 16mpg after efie hookup) If I adjust the efie any higher while driving I almost always throw a CEL. Do you think I have reached my lean limit on my vehicle (04 Tahoe)? or is there a better way to adjust so I dont thorw a CEL? On a side note, do you think adding a MAP enhancer help improve the mileage gains at all?
(This post was last modified: 07-22-2008 05:27 PM by romulus.)
07-22-2008 05:25 PM
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colchiro Offline
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RE: Adjusting EFIE while driving, throws CEL.
Have the code read and let us know what it says. (Is it a lean code?) If so, you might work on other sensors.

I'd adjust it about 50 mv below where you throw codes and play other stuff for a while.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
07-22-2008 05:38 PM
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romulus Offline
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RE: Adjusting EFIE while driving, throws CEL.
colchiro Wrote:Have the code read and let us know what it says. (Is it a lean code?) If so, you might work on other sensors.

I'd adjust it about 50 mv below where you throw codes and play other stuff for a while.

I have gotten codes 1133 Oxygen sensor circuit heater slow response bank 1 sensor 1 and 1153 Oxygen circuit slow response banck 2 sensor 1.
(This post was last modified: 07-22-2008 05:47 PM by romulus.)
07-22-2008 05:44 PM
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colchiro Offline
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RE: Adjusting EFIE while driving, throws CEL.
Hmmm... I thought usually you have to crank your EFIE above 450mv to get that.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
(This post was last modified: 07-22-2008 06:27 PM by colchiro.)
07-22-2008 06:27 PM
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romulus Offline
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RE: Adjusting EFIE while driving, throws CEL.
colchiro Wrote:Hmmm... I thought usually you have to crank your EFIE above 450mv to get that.

I am going to resest light then change the setting on the efie while the car is off and see what happens. Do you think it would make a difference if I added an extender to the O2 sensor in conjunction with the efie?
07-23-2008 04:12 AM
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mike Offline
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RE: Adjusting EFIE while driving, throws CEL.
Hi romulus,

I've heard from a reliable source that the extenders don't work. But I used to recommend them to folks whose sensor's were incompatible with an EFIE. If you try them, please note what improvement (or lack thereof) in mpg you get with them, and let me know. If you do this, please PM me with the result so I don't miss it. My answer to your question is, "I don't know". I've never used them.

As to your question about the MAP enhancer. The answer is definitely yes. That will work great with an EFIE. You should be able to get better mileage it, plus you should then be able to crank up your EFIE voltage a bit more without setting a CEL. Make sure you correctly determine the type of MAP you have. There are 2 kinds, and they get different handlings. See Tuning For Mileage for more info on how to do it.

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07-23-2008 07:23 AM
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romulus Offline
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RE: Adjusting EFIE while driving, throws CEL.
mike Wrote:Hi romulus,

I've heard from a reliable source that the extenders don't work. But I used to recommend them to folks whose sensor's were incompatible with an EFIE. If you try them, please note what improvement (or lack thereof) in mpg you get with them, and let me know. If you do this, please PM me with the result so I don't miss it. My answer to your question is, "I don't know". I've never used them.

As to your question about the MAP enhancer. The answer is definitely yes. That will work great with an EFIE. You should be able to get better mileage it, plus you should then be able to crank up your EFIE voltage a bit more without setting a CEL. Make sure you correctly determine the type of MAP you have. There are 2 kinds, and they get different handlings. See Tuning For Mileage for more info on how to do it.
Thanks Mike. I tried the extenders before I got the EFIE and got worse mileage. I have a 5v MAP and installed a 50k pot with a 33k resistor as my enhancer. I can definately lean out my engine to the point of stalling. I marked that point and turned off the truck, turned the knob back to 25% of the stalling point and will try to drive like that for a while. Do you see anything wrong with that approach?
07-23-2008 01:38 PM
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colchiro Offline
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RE: Adjusting EFIE while driving, throws CEL.
I added my extender over the winter, when it's hard to get a good eval of it's performance. Removing it is on my to-do list for this week. My mileage should be a couple points higher than what I'm currently getting.

My MAF (sounds like same unit) is set to just below the point where I get a CEL with in-town driving.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
07-23-2008 02:46 PM
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romulus Offline
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RE: Adjusting EFIE while driving, throws CEL.
colchiro Wrote:I added my extender over the winter, when it's hard to get a good eval of it's performance. Removing it is on my to-do list for this week. My mileage should be a couple points higher than what I'm currently getting.

My MAF (sounds like same unit) is set to just below the point where I get a CEL with in-town driving.

You said you have the map set just below the point where you get a CEL in town does that mean when you are on the hwy with higher vacuum you have less of a chance to throw a light? I am trying to wrap my pea brain around the MAP sensor adjustment. By adding the resistor we are actually lowering the voltage which tells the engine that we really dont need that much fuel? Do you have any idea what value in terms of voltage you want to start adjusting the MAP enhnancer, kinda like the .2v we use on the Duel EFIE? The reason I ask is that I tested the MAP enhancer for continuity of current and when I turned the pot I got approx 26 OHM change from low to high. Dont know how much of an adjustment I should be trying to make at any given time turning the knob on the MAP enhancer to get any effect on the MAP sensor?
(This post was last modified: 07-23-2008 04:43 PM by romulus.)
07-23-2008 04:13 PM
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colchiro Offline
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RE: Adjusting EFIE while driving, throws CEL.
I have a MAF, not MAP sensor, but using the same mod as you to tweak it.

MAF is similar to an engine load sensor so probably most noticeable at slow speeds and that's why in town it CEL's on me.

A Scangauge works great for tweaking sensors. When I added a 10k resistor to my intake air temp and coolant temp I could immediately see the difference (10 deg warmer) on the SG.

I guess I'd set it to half-way between cell/stall/driveability-issue and normal for now and see how mileage is affected. Then I'd go half-way higher and lower and test again.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
07-23-2008 05:09 PM
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