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Discussion Starter #21
I will think of a way to move the bloody thing into the cabin, with a flick of a switch to adjust the voltage

a) 1.85-1.95 - general purpose, easy driving
b) 2.2V - basically i will cancel the resistor for offroading

So far, replaced the resistor with something new, same values, different shape. But this time i made sure the wires are fitted just perfect. I discovered that the initial instalation was ****ty (to say the least).

Anyway, i set the voltage to a value of 1.95V, a value wich does not cut from performance at low RPM so much, and yet, it keeps the engine idle without that "terrible" smell (though a friend of mine says that smell indicates the presence of a REAL CAR :) ).

Watch the video below, and notice the voltage read by ECU at 4.000rpm and idle, and at some point i tried to get on the camera the rear of my troll, to show you ....NO SMOKE :) For me this is a sign of a (still) healthy engine....wouldn't you say ? (No smoke was even without the MAF mod).

BigUrsu - Nissan Patrol 3.0 Di MAF mod - YouTube
 

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Discussion Starter #22
Updates:
This morning i started the car, there were 11oC. The ECU read a value of 2.04V. I didnt get angry, as i had my suspicion that the readings are influenced by outside temp. When i arrived at destination, after 20km, even the outside temp was still 11oC, when idle the MAF reported 1.95, just like yesterday.

In the afternoon, i started again, but this time, the temperature was 19oC. MAF reported 1.95. So far....so good. The only thing i dont really like is the "struggle" to go from 1500 to 2000 rpm (from 3rd to 4th gear and from 4th to 5th gear). To shorten that period, you have to change gears at 3000, i guess, because at 2.500 the rpm falls to a value 1.500.

But when it hits 2000 you see the thing is alive :). No limp mode so far, even if i tried a few times to put the troll in such a position.

Cannot tell you anything about fuel consumption though, as the driving style was quite aggressive, very different from daily driving style. That is mainly because i wanted to see where limp comes into equation. I would estimate somewhere around 11l/100km-12l/100km (13l/100km was without altered MAF signal).
 

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Ursu,
Thanks for this – very helpful information. I noticed that my MAF voltages were also slightly higher in the mornings, so I wonder if the MAF itself gets warmer after a while and influences its own output.
 

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Discussion Starter #24
Ursu,
...so I wonder if the MAF itself gets warmer after a while and influences its own output.
I guess that one would be quite a challenge to proove, but if somehow an temp probe could be fitted near the MAF sensor, to measure intake air temp, then it will be easy to establish if intake air temp influences MAF readingds. It will also be a challenge to see how this mod performs in the cold mornings that are to come here. In Romania, the winter is aproaching fast, the specialists predict a cooler and longer winter than the one we had last year (-30oC at night, -21oc in the morning).

I will keep you updated, maybe sometimes next week i will measure up and see the aproximative value of the resistor, maybe somebody would be interested. I am fully aware that this improvisation i did cannot be compared to what Chaz and others developed for their Patrols, i guess it could be called an cheap and easy fix. And to be honest, the original ideea belongs to Chaz, so he deserves all the credits.

PS. I know you guys in Australia dont have such harsh winter, but maybe some of you could help me with my next mod i am thinking....a cheap and eficient way to warm the fuel filter.
 

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Discussion Starter #25
Well guys, i came back with news regarding fuel economy. I usually put 16 litres of diesel in my tank when driving around home, for economical reasons. Since i blocked the EGR, the best fuel consumption was something like 12%, but using stock tyres. After changing the tyres with bigger ones (255/85/16 BFGoodrich KM1), the consumption increased a little, to a value of 13 litres/100km. To be more precise, with those 16 litres, i used to made 120km.

Today though, the "tradition" broke. Earlier today, i stated that since yesterday i drove quite aggressive, in order to "invoke" the limp mode. Even so, i managed to do an AMAZING 151km with 16 litres of diesel. Calculations show around 10 litres/100km. I said AMAZING because it exceeded my expectations. Around 30km of those 151 were made in urban regime, so that's even better.
 

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Cold air enters the intake air box and flows over the MAF sensor wire that measures only a % of the intake air in the upstream pipe from the air filter. We all know this !

Due to cold morning air flowing over the MAF. The wire is cooled so the ECM adjusts the voltage to maintain the heat of the wire. This works in connection with the ECM barometer, coolant temp. ICTV.

For the fuel filter you can buy a truck fuel filter heater from Fleet Guard. It comes in 12 or 24 volt system and is a built in type version.
 

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Y2KGUII ZD Wgn
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Well guys, i came back with news regarding fuel economy. I usually put 16 litres of diesel in my tank when driving around home, for economical reasons. Since i blocked the EGR, the best fuel consumption was something like 12%, but using stock tyres. After changing the tyres with bigger ones (255/85/16 BFGoodrich KM1), the consumption increased a little, to a value of 13 litres/100km. To be more precise, with those 16 litres, i used to made 120km.

Today though, the "tradition" broke. Earlier today, i stated that since yesterday i drove quite aggressive, in order to "invoke" the limp mode. Even so, i managed to do an AMAZING 151km with 16 litres of diesel. Calculations show around 10 litres/100km. I said AMAZING because it exceeded my expectations. Around 30km of those 151 were made in urban regime, so that's even better.
Not an uncommon issue my friend, I learned early that each time I have worked on a Patrol "project" the fuel eco during "testing" is an absolute shocker, but when you stop driving like you stole it, the eco comes back and often improved.

Cold air enters the intake air box and flows over the MAF sensor wire that measures only a % of the intake air in the upstream pipe from the air filter. We all know this !

Due to cold morning air flowing over the MAF. The wire is cooled so the ECM adjusts the voltage to maintain the heat of the wire. This works in connection with the ECM barometer, coolant temp. ICTV.

For the fuel filter you can buy a truck fuel filter heater from Fleet Guard. It comes in 12 or 24 volt system and is a built in type version.
Funny, maybe the climates I have driven in are not severe enough to see changes in MAF voltage between hot and cold , because I have never noticed a difference.
 

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Discussion Starter #28
Funny, maybe the climates I have driven in are not severe enough to see changes in MAF voltage between hot and cold , because I have never noticed a difference.
Last winter i didnt have the EcuTalk thing, but now i guess it will worth some monitoring when the temps drop significantly.
 

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Today while driving in 36c temps I noticed my MAF was 1.8v at idle where it’s normally around 1.85v and 1.90v when cold, so it seems that temperature does make a difference. I wonder if that’s why the 05 and later models incorporate an intake air temp sensor in the MAF. I always thought that it wasn’t used on the diesels, but it seems that some other models use them too.
 

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Y2KGUII ZD Wgn
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OK I'm going to have to start taking more notice!!!!! but, the Queensland Sunshine Coast climate may not impact that much, definitely will be more aware now though.
 

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Discussion Starter #31
I wonder if that’s why the 05 and later models incorporate an intake air temp sensor in the MAF. I always thought that it wasn’t used on the diesels, but it seems that some other models use them too.
On my 2.2 CRDi Hyundai Santa Fe 2007 there is a sensor that monitors the intake air temperature.


This morning i started the car (15oC) - 2.02V. After warming up and driving 5km, water temp went to 86oC and MAF reported....1.95V. So, coolant temp definately influences what MAF reports. So @V856PTRL was right about that.

Kind of offtopic now: what ICV means ? I have it on my EcuTalk display, but dont know what it means.
 

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On my 2.2 CRDi Hyundai Santa Fe 2007 there is a sensor that monitors the intake air temperature.


This morning i started the car (15oC) - 2.02V. After warming up and driving 5km, water temp went to 86oC and MAF reported....1.95V. So, coolant temp definately influences what MAF reports. So @V856PTRL was right about that.

Kind of offtopic now: what ICV means ? I have it on my EcuTalk display, but dont know what it means.
It should be the Injection Timing Control Valve and it reads a percentage of operation or duty cycle. Not sure how much value there is in this information, but could help to diagnose a problem with the fuel pump.
 

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Discussion Starter #33
Went today for a short picnic, with a little bit offroading....soft, a few small mud holes, nothing fancy, but for sure the lack of power is there in the low RPM (1500-2000). And when i arrived home, i measured the resistor.....550Ohms. That is for a value of 1.95-1.97V reported by MAF to ECU. Hope that helps somebody.

Some Q's:
a) the tyres i use right now are 8% bigger than the stock ones. The distance on the odometer is also 8% bigger ?
b) i dont remember how the Patrol works with the EGR unblocked. If i unblock it right now, and the MAF voltage would show something like 1.95 - 2.00V, would it behave the way it does right now ? (I mean the lack of power and the fact that you have to step a bit on it to make it "fly").
 

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with a KN you see it go to 2.47 @ 34 deg ambient. I sucking in to much air and cooling the heat wire so the ECU ups the voltage. Now were borderline limp mode and other issues so you unplug the speed sensor, coolant sensor at cold. On the auto box 5sp on 4.8 it hold the gear's a little longer but will do no harm. see what happens its worth a go.
 

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Hi Daemonus,

OK I stand corrected, there is a change in MAFv between hot and cold even on a 2000 DI, started the old girl this morning with an ambient of 26c which was also the engine temp, MAF read 2.19-2.21v after a quick trip for milk I returned 20 minutes later with an engine temp of 84c (still 26c ambient) and 2.14-2.15v, so there was a difference of roughly 2%???????? not sure how much difference this will actually make though.

Mine originally had 1.85v before the EGR blocked itself and 2.2v after, this is roughly 15% differential so I can see that having a significant effect on fueling at idle. I can't remember my exact original flat out MAF voltage but I think it was in the order of 3.6v, now I get 4.27v and that continues the 15% trend noted at idle, now I wish I had taken notice of the mid range trend........

The other thing I am reminded of was when I was setting up my FCD2 for my under 3000rpm limp problem, I did all my testing in 4th gear, so I could keep the trials under 100k and therefore legal, limp occurred at 3.98v under 3 grand, so I clipped the voltage at 3.96v and all was cool. On the start of a long trip (5000k+, down to see Chaz, Dronus, Rumcajs and the other SA guy's) a short time later, I was in 5th and got limp several times in a row under load and it was happening at 3.94v so I adjusted it to 3.88v just to be sure and no further problem, so load has a significant effect (the TPS could be contributing to this???, I know it's not MAP) have since lowered my spoolup more and raised the FCD2 back to 3.94v and all is good.

Now there is another ongoing part of this story, if you care to read this http://www.patrol4x4.com/forum/nissan-patrol-gu-gr-10/turbosmart-fuel-cut-defender-fcd2-80424/ you will see I had significant issues with a low speed limp just below 2500rpm, which even though it is now much improved, still catches me out on occasions, I am a lot smarter now but I still don't fully understand what goes on with this, but haven't given up.
 

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Discussion Starter #36
Hey guys !

Like i said already, what i wanted to do was a cheap solution to my problems:
a) limp mode
b) annoying smell of diesel at idle

Both got me where i wanted, meaning that no matter how harder i tryied to invoke limp mode, did not show, and at idle everything is as it should be. The flip side of the coin is that in high gears (3-4-5), between 1500 to 2000 the car is lazy. Yet, it's a price i accept to pay, as fuel economy was a bonus to what i had in mind.

I say it again, you cannot compare a ****ty variable resistor with a tool like FCD2. They cannot be compared, more efficient and better control. But for a restricted budget, it will do the job. I went further and mounted a ON/OFF switch. When on-road, the resistor works. When off-road, with a flick of a switch, the resistor is canceled, and the car will have it's normal power between 1500 and 2000. Here it is:

Nissan Patrol Y61 3.0Di - MAF mod continued - YouTube
 

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Hi Daemonus,

I wasn't trying to draw any comparison between the two items, the intent was to add some of the interesting data I stumbled into while doing the project.
 

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Hey guys !

Like i said already, what i wanted to do was a cheap solution to my problems:

b) annoying smell of diesel at idle
Hi folks, does anyone have an explanation for this?

A few members have reported this before and have thought that it was the engine running rich at idle due to the higher MAF reading at idle however that should not be possible on a diesel, especially on one with the EGR inoperable?

:cheers:
 

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Hey guys !

Thank you for your input. Today will try out a brand new resistor too see what happens.
Why do i want this mod ? Main reason is to avoid limp mode as much as possible. Had a very bad period regarding finance and buying a FCD2 is out of the question. Taxes would double the price :(

Second reason would be fuel economy. When urban driving, i dont need much power, so a lower MAF voltage could help me save some fuel. If the new resistor holds up and does the job, i will think to a way to use it only when i am onroad and have no requirements for full power.

I'll keep you informed, any advise is apreciated.

PS. I regret i wasnt the son of a millionaire. :)
Thanks daemous,

I also have experienced significant increases in urban fuel consumption since moding which would be nice to see reduced. Its funny how highway driving hasn't changed as much. Nice work.

Geeyoutoo,

Nope i've missed previous threads on the MAF voltage changes.

As per Whities post does anyone have an explanation for this?

I've got my theory around more air getting pulled in at idle due to no exhaust gas recirculation, but this is only my speculation. In a stock engine, is the EGR recirculating constantly at idle. ?

But the running rich thing and unburnt diesel smell from the exhaust seems really strange. Surely if the ECU at idle is squirting in more fuel because it is getting a higher MAF reading, this should simply mean a faster idle. Isn't their oodles of air in an unthrottle diesel to combust all fuel injected at around idle.

Grogey
 

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Y2KGUII ZD Wgn
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Hi Grogey, Yes, EGR is open at idle, then at cruising when no/low load. Yes, theoretically all fuel should be burnt easily at idle but I did notice an increase black soot on the back of the vehicle after my EGR blocked itself and it is still the same years later after all this tuning????????
 
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