TOPIC: 2000 Mitsubishi Montero Endeavor 2.5L V6

Hi Ron and everyone in Gadgetman Land! This is a fairly long post excerpt (edited to remove names a numbers) from previous E-mails to share my experience and questions:

Thank you for the follow-up reply!

I have downloaded and read the following pdf's from the Gadgetmangroove site:
ECU conditioning 2011 PDF
Event planning Groove Tour 2012 PDF
Gadgetman MAPster info PDF
The Gadgetman Groove White Paper 12-01-12 PDF
Vacuum and the Gadgetman groove PDF
Vacuum Systems and tweaks feb 2012 PDF


I have read many of the posts and probably not ALL. I have also subscribed to your YouTube channel and watched many clips.

Grooved TB was installed.

I noticed the increase in power but no mileage gain. I disconnected the PCV hose from the manifold and put a small conical filter on the PCV itself. I plugged the dynamic PCV intake port on the manifold. All other hoses were replaced as the vehicle is 13 years old with 158,000 miles on it.. The ECU was cleared by disconnecting the battery and touching the wires together with the ignition ON.

I followed the ECU conditioning procedure at idle warm-up, then off and ON with 5 mins run time, repeated three times, then moving at least 10 ft in drive, then Park and ignition off. i then drove steady at 35, 45, repeating the stop, P and ignition OFF cycle in-between, then 65 on highway, stop and wide open on way back (well sort-of: 100 is all I could get for the stretch I drove on with the traffic and "officials" watching .

I took the vehicle and MAPster to a mod shop in Raleigh, NC. I had purchased the DIY Chilton online for my car but it did not give the wiring diagram. I eventually put my hands on one but the ECU pin numbering which showed on paper did not exist on the actual connector, nor did the wire colors on the harness match. Mayhem understood wat I was trying to do, although they were skeptical of the results. Their sole interest is usually to modify engines for pure HP and they care little about mpg increase. They deal mainly with LS1 and LS3's. They tinker with cosmetic stuff and install turbos, intercoolers, Nitrous Oxyde tanks, and the like as well as install MSD's, etc. They specialize in corvettes and hot rod mods. The mechanic who helped me, pulled the Mitsubishi wiring diagram, isolated where the MAP connects to the ECU and spliced the appropriate wires IAW the info page and diagram you provided with the MAPster (MAPster info PDF). They have a dyno, but I was reluctant to have them put it on the dyno as they were not sure what to do with it and wanted $600 to do three pulls.

I did the ECU conditioning, again.

I purchased a wifi OBDII module (PLXwifi), which I plugged into my Mitsubishi diagnostic connector and it interfaces with my iPhone on which I purchased and installed Dashcomnd. It returns no error codes and although some sensors do not have PID's and show NA, I have the following information available:
Speed [mph]
RPM
BST/VAC [PSI]
Load [%]
MAP [In Hg]
MAF [Ib/Min]
Inst MPG
Avg MPG
LTFT [%] (-15 to + 15 scale)
STFT [%] (-15 to + 15 scale)
Timing [degrees]
O2 Sensor [V] (0 to 1V scale)
Coolant TEMP,[F]
Intake TEMP [F]
Power [HP]
Torque [Ft/Ib]
Fuel Flow [GAL/H]
(HP and Torque must be "computed" values I guess, as they are intermittent and inconsistent with the driving conditions)
There is no value displayed for LAMBDA
There is no value displayed for AFR
There is no TPS value, either.


I started with the 5V according to what the mechanic told me, then IAW with the instructions, I decreased the voltage by rotating the pot counter-clockwise and monitoring the OBDII information. Because the values dance around quite a bit based on load due to terrain, I was not sure what adjustment did what, so I familiarized myself with the various values: which ones change and which don't. The O2 sensor reading bounces around from full scale left to full scale right, back and forth (0 to 1V scale on the OBDII), which tells me it is in closed loop and therefore takes O2 sensor into consideration (good, I take it). I backed the pot in quarter turns, looking for the LTFT/STFT to show a lower value. It did not seem to make a difference on the MAP or VAC. I reached a point going counterclockwise where I still did not see any fuel trim changes, but the power increase (from the groove) was no longer there and it got actually worse. Beyond that point, the power started increasing, again but LTFT went nearly full scale + (adding fuel), so I went in the opposite direction (clockwise) a quarter pot turn each time, until LTFT was at a minimum without loosing power. That is where I am at, now. I understand that LTFT will not settle immediately as it is the learning function, hence I made sure I stopped numerous times, went to Park and turned the ignition off.

I forgot to mention that I borrowed a vacuum gauge and plugged it in the (previously plugged dynamic PCV port on the intake manifold) and registered a 20" at idle and 20.5" at 2500 and 4000 RPM. There was no fluctuation. I disconnected the gauge after turning the engine off and plugged the port back up.

OBDII VAC is in the -11.2 range at idle and will rise toward 0 or even +1.2 during accelerations uphill before settling back down. MAP shows around 7-9 at idle and will vary with load up to 31-33 in accelerations under load. The timing goes as far as +30 degrees based on driving conditions.

Please, note that the CAT is new (1 year old and less than 15,000 miles) and so are the O2 sensors (2 upstream and 2 downstream) / it is a California Emission CAT.

I followed your suggestion and put a rubber sleeve on the temp sensor of the MAF (tried three thickness sleeves) and it threw a "service" light. I did not have the OBDII, then so I do no know what the code is. This is something I did while I was awaiting the MAPster.

In the mpg log (below), the first three readings are the stock engine. The next three are with the groove on but no MAPster and the last three readings are with the groove and MAPster installed and being tweaked.

I increased the pot another quarter turn from last position (enriching) and it seems like it lost a bit of the HP increase but the LTFT and STFT for the first time hover around "0"! What I noticed is that when I accelerate, LT goes to 0 or + 0.2 while ST will show -5 to - 7 temporarily and both ST and LT will oscillate around 0 while holding speed. As soon as I decelerate, LT shoots up to +6.7 (not as high as before) and ST shoots down to -5.2 or so before they both return to 0. At idle, car not moving, the LT hovers around + 5.7 and ST hovers around + 2.1.

Next post will be an update and questions on same vehicle and progress report and getting this Mitsubishi ECU to give-up the mileage. It is a matter of time as I know the groove works and am very grateful for Ron's discovery and support!

Hello Everyone!

Update and question:

Following Ron's recommendation, I checked the valves by sticking a piece of paper behind the exhaust pipe. The exhaust was strong without any suction back toward the pipe. The paper did "flutter" slightly and rythmicaly but I could not tell whether it simply was the paper springing back or a slight "sticking" of the valves.

Anyhow, I added a quart of Castrol "high mileage" ATF into the crankcase and ran the truck with 1 quart of same ATF in a full gas tank (24 US GAL of 87 Octane). I ran two full tanks and am in the process of running the third one that way, too.
First impression: the vehicle runs much quieter and much smoother.

The last three tanks I ran before the O2 sensor heater P0141 showed up (see below) were respectively 19.6 mpg, 17.6 mpg and 18.1 mpg. All three were 80% highway miles and the last two with 1 quart of ATF in the gas tank.

I kept tweaking the MAPster and got a "Service Engine" light. Fortunately the OBDII was hooked up and I noticed the O2 sensor reading was still fluctuating lean-rich, back and forth but would stick on 0V for a few seconds here and there (which told me it was likely on and off in "open loop"). The DTC was P0141 O2 Sensor Heater Performance Bank 1 Sensor 2

Looking up P0141 revealed the following:

That code isn't for the sensor directly. It is for the "heated oxygen sensor heater" circuit. The current supplying the heater in the O2 sensor is below target.
"TROUBLESHOOTING HINTS (The most likely causes for this code to be set are
Open or shorted right bank heated oxygen sensor (rear) heater circuit, or harness damage.
Open circuit in right bank heated oxygen sensor (rear) heater.
Connector damage.
PCM failed."

I was able to clear the code with the OBDII but the light comes back on. Suspecting the tweaking of the MAPster had caused it, I cleared the code and enriched the MAPster but the light came back on and the LTFT/STFT pegs on the rich side with the O2 sensor voltage showing 0 (Must be open loop) when it happens.

What do I do? Is the heater circuit part of the O2 sensor? Is it separate? It is apparently a 4-wire sensor. By the way, if I had not mentioned it. this vehicle is a "California Emission."

I was planning on adding a resistor (again) to prevent the ECU/PCM from adding a bunch of fuel to heat-up the CAT (See Groove diagnostic). What am I to do, now?

Thank you ladies and gents, in advance for your constructive input!

Hi EJDP. The O2 in question has the heater integral w/ it. Think I'd check the wire plug connection to it. Is it an aftermarket O2 or a dealer part? It's been pointed out to me by a guy who knows that OEM O2's are the way to go, that aftermarket ones often die sooner and give bad readings.

I'm fuzzy on the OBD lingo bank/sensor # stuff--so is this an upstream or downstream O2 in question? MY understanding of downstream O2 is monitoring of cat. function thru temps. The more un-burned HC's in exhaust, the more fuel to feed the cat., so the hotter it gets. ECM is looking for a certain temp range thru downstream O2 readings to give an air/fuel ratio feedback. I'm not expert here; but I think cooler temps at downstream O2 sensor--are from more complete combustion (or lean A/F ratio).

We are trying to burn more fuel IN engine less in cat. If we do that then logic says downstream O2's will see cooler temps. Or possibly your downstream O2 or it's wiring or plug connector are on the fritz.

I just recommended to another poster to wrap his cat. w/ some HD tinfoil w/ baling wire to hold it. Put shiny side foil inside dull side out. This will reflect heat back into cat. helping to give a hotter reading to downstream O2. Don't go overboard here w/ the foil, don't want to overheat the bugger!

An infrared thermometer available even at Harbor freight w/ a range up to 1000 deg F. or higher would be a great diagnostic tool for checking the cat/ O2 temps. Check cat. temp after driving awhile and record. Then you could foil wrap say 2-3 layers and re-check.

And an OBD11 scantool that can give real time data stream is also necessary to eliminate "in the dark" guesswork, ya really need to see what's going on as it's running or record data then playback.

All $$ of course! But once ya have tools ya HAVE 'em! Makes us better tech's. Sucks about OEM Dealer prices for O2's but that's from the horse's mouth!

So check the O2 wireplug(S) If ya get the infrared thermometer they arent too much$$. TONS of scantools on Ebay, I prefer an actual scantool not something going thru a smartphone and program, but that's just me!

ATF in gas-that's interesting, dunno if I'd use that much that close together, could that foul cat/ O2's??

your idle vac. guage readings 20 inches Hg is excellent what altitude are you at?

Lastly I always at least increase the plug gap by 20%, currently I run Torquemaster's from ExtremeSpark.com in my Subaru. They gave an improvement in power/driveability, and you don't gap 'em. I bang the Ignition drum Loud and Hard!

Ok enuf babble from me for now, let us know how it goes, would be cool of you to use your real name...

Tracy G

Thanks much for the reply, Tracy! Eric Du Pont, here in NC.

I did see your post regarding the cat and wrapping it to conserve heat. I am currently on a trip, away from town and my vehicle so when I get back I will address your suggestions and report back with the results on this forum.

One answer I can give right away is that the sensors are OEM. The Cat was replaced last year (the original cat went bad after 12 years and 140,000 miles). The O2 sensor has a 4-wire plug.

DTC isP0141 "O2 Sensor Heater Circuit Bank 1 Sensor 2" It shows as "Stored Codes" and "Pending Codes" as well. I can clear the Stored Code and the light extinguishes but the Pending Code remains per the OBDII. Under "Permanent Codes," it says none were found (good). My preliminary research shows that it must be a Post Cat sensor (Bank 1 Sensor 2) responsible for added fuel consumption thank to the ECU "just for CAT warming."

My thought right now is to get that heater circuit replaced first ... Check to make sure the code clears from Pending Codes memory as well as stored memory and then. Add a resistor in the circuit (As Ron suggests in the Gadgetman pdf's) in order to fool the ECU to read a 200 degree difference and stop injecting additional fuel needlessly. I would like to find out how to best do that as well as see what kind of resistor/value could be added without causing another DTC. It seems like the heater circuit is used mainly during engine start before the cat comes up to scheduled operating temperature. This seems to confirm my OBDII real time reading of the O2 voltage. At idle it shows 0, which indicates the system is in open loop and throws the LTFT full scale rich as well as illuminate the service engine light.. When temp is up while driving and I cleared the service engine light, it does not come back on unless I let the engine cool and I start it back up; then, the code comes back on. Once the engine is at operating temperature, the LTFT/STFT fluctuates according to demand/terrain as set through the ECU, based on the MAPster setting.

With regard to plugs, thank you for the advice. It has been my desire to implement the plasma ignition from Aaron Murakami, but one thing at a time ... I would love to maximize the huge benefit of the groove, first before I vary one more parameter.
I saw another post on the Energetics Forum re: successful plasma ignition on a Subaru. I have looked for zero resistor wires and plugs. Granatelli (SP?) does not appear to make those non-resistor plugs that fit my 2000 Mitsubishi Endeavor 2.5 V6. I will look up those Torquemaster plugs. I went to extremesparks.com but did not research it in depth as I was not working on the plugs at the time. Plazmofor as depicted in A. Murakami's book look mean. I checked them out online but they are manufactured in the Ukraine it seems. In the interim and after I get this heater circuit taken care of, I will re-gap the spark plugs and Le the ECU reconfigure the timing, while adjusting the MAPster for best power/mpg based on LTFT/STFT. The real proof ends up being at the pump when I fill-up and figure mpg based on odometer reading vs fuel used.

One last thing, elevation is 480' msl.

Thanks, again Tracy and I will post back with new results.

Cheers,
Eric Du Pont