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Which device for MAP sensor?
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jksav7 Offline
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Which device for MAP sensor?
Just wondering if anyone knows what the difference is (if any) in performance/tuning ability between the device outlined in "tuning for fuel economy" and the device that just uses a potentiometer to dial down the voltage? I know the former goes to the signal wire from the ECU to the MAP sensor and the latter taps into the wire that goes from the MAP sensor to the ECU. Obviously, the device in the "tuning" article is more complicated to build.
05-24-2008 10:49 PM
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colchiro Offline
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RE: Which device for MAP sensor?
I know a lot of people have posted that the resistor caused problems with their MAF sensor (I have that instead of a MAP). Even as low as 7 ohms caused surging with my Toyota.

My first impression of the voltage regulator (LM317) was that it replaced the sensor, rather than tweak it's output, which I do not want. I want that sensor operational so I need to look at that again. Maybe Mike knows about that. I got one as part of a package. They're also available on fleeBay.

OTOH, a EFIE there might work too. FWIW, I have one and a 5 ohm pot to try.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
(This post was last modified: 05-25-2008 05:50 AM by colchiro.)
05-25-2008 05:49 AM
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jksav7 Offline
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RE: Which device for MAP sensor?
I have the more primitive kind on my Saturn. I can dial down the voltage signal to the ECU, but it didn't help with my fuel economy any.
05-25-2008 07:38 AM
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HHOe Offline
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RE: Which device for MAP sensor?
jksav7 Wrote:I have the more primitive kind on my Saturn. I can dial down the voltage signal to the ECU, but it didn't help with my fuel economy any.

I installed the MAP enhancer with the trap door using a pot. tested it without an efie and it seemed my tank emptied pretty quick and had no gains. now i have an efie its getting better mileage. still tinkering. i just read about the more complicated one with the voltage regulator. i think the one i use works just fine

2001 Chevy S-10 2.2 5 speed
22-23 before
27-33 after
07-07-2008 09:19 PM
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Grisen Offline
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RE: Which device for MAP sensor?
I just installed the "tuning for mileage" MAP enhancer yesterday. It would not give me fine control over reference voltage (5 v circuit)-- I couldn't dial it high enough to get more than about 4.3 volts when hooked to the vehicle.

Initially this produced surging at idle and engine died a few times.

On the road ECU adapted by increasing long term fuel trim (read by scangauge) drastically. So, even though timing was advanced-- balancing the retard from what I've done with CAT and IAT resistors-- the results on use of fuel were disastrous. I think the VREF needs to be close to 5 volts than what I could do.

If I put a pot in the cabin that I can tweak as driving, what size does it need to be. And I guess this goes on the output wire back to the ECU(?)
07-17-2008 12:03 AM
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