Klondike Darol's EFIE'sWidebandNarrowband
Diesel EFIE • Air Fuel Ratio Fuel Savers Circuits

D & L Engineering • Darol Mason retired from selling his
EFIE's on ebay 4/17, Darol is 83+ years old. 60 years as a
automotive engineer. He picked Hydrogen Garage Store to
continue his great EFIE leaning circuits. 3/11/17
We thank him for being able to continue such
great gas saving & ARF control product!

TO SAVE FUEL 20% to 28%

Perfect for SUV and Trucks that guzzle fuel!

Save Fuel with WATER and a HHO Kit or Fuel Vaporising Kit
OR - by itself ( the circuit alone)

Which circuit works for what type of car? Check to see if you have Wideband O2 senors or Narrownband O2 sensors. Works on OBD II cars and trucks ( 1996 - 2017) GM created some freq. based O2 sensors and we have those as well.

updated 2/12/2018

NarrowBand T-101 Air Fuel Ratio Control
Most American made cars and trucks.

All Install Instructions are below.

All Install Instructions are below.

(805) 995-4809

Join us TeslaTech
Extraordinary Conference
July/August 2017
New Mexico

Do I have NarrowBand or WideBand O2 sensors
installed on my car/truck? Learn here.

WideBand T-101 Air Fuel Ratio Control

Japanese manufactured cars and trucks

NarrowBand MAF/MAP (2 in 1 combo)

NarrowBand Combo Install Instructions


GM V6 & V8 Frequency Based AFR Control


WideBand Combo MAF/MAP/EFIE • Air Fuel Ratio Control

WideBand Combo Install Instructions

EFIE = Electronic Fuel Injection Enhancer




Air Fuel Ratio Monitor /MAF/MAP/CT & AIT temp/ RPM/ MPG
ECM Monitor Gauge • A must for these EFIE adjustments

OR get the famous Scangauge E, II and D

Scangauge E
• AFR gauge monitor (Air/Fuel Ratio)

Scanguage II (clears engine codes)

Scangauge D (diesel, 6 & 9 round pin)


Download the manuals for
Darol's EFIE, MAP/MAF, IAT/CT Temp. circuits :

Please note : Darol's Install Instructions are updated once a year, so some of the install instructions are repeated. The latest ones are on top. It is good to read it all to gain more understanding and have the information sink in for all certified installers. As Darol says, If you can read and follow instructions step by step you can do this. Most installs are done under the hood near the ECM 50 pin connector. Find your wiring diagram for your year, make, model car or truck. Find the wire colors and pin number for each wire to the wiring schematic. If you have any further questions contract 805-995-4809 * (805) 235-3033 or info@hydrogengarage.com

NarrowBand AFR 2017 / Wideband AFR 2017

NarrowBand Combo / Wideband Combo

Modified Tuning 101 WB
/2016 Modified T-101

Tuning Tips 1 / Tuning Tips 2

Update NarrowBand
2.5v bias selection

Sensor Effect %'s / GM Freq. based / T-101 for GM Package

DIESEL EFIE / Locate O2 Sensor wire 

Automotive Terms Glossary

Darol's E-BOOKS

What HHO cells work, what do not perform so well.

Volo's are easier to install, just 4 wires and takes about 30 minutes to install.
Darol's Circuits take longer to install 2 to 8 hours, but more control and more MPG savings
You can monitor the inputs, as Volo FS2-HHO Edition does it for you.

About / Awareness / Education / HG store / Terms of HG / Contact / Links / Sponsor
Hydrogen Garage • California • USA • 805.995.4809

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