Fuel Pump / Injector / Coil Pack Issues

[Rufus007]

Found an Infinity technical bulletin on this one:

http://workshop-manuals.com/infiniti/g35x_sedan_awd/v6-3.5l_(vq35hr)/powertrain_management/prom_programmable_read_only_memory/component_information/technical_service_bulletins/customer_interest/07-045a/apr/09/engine_controls_cold_start_rough_idle/idle_fluctuates/

Edited April 6, 2016 by Rufus007

[colin.ssc]

So what was the fix they did on the ECM? I am unable to read it properly at the moment. Will try looking at it later.

Edit: nvm, it loaded. Looks like just a firmware update. Now the question is where do we get the firmware from

Edited April 6, 2016 by colin.ssc

[Rufus007]

Not sure whats updated software wise, but will be pretty hard to get the update in Oz. Still think a good way would be to get your tuner to delay the VCT operations for a few more minutes when engine is cold.

So what was the fix they did on the ECM? I am unable to read it properly at the moment. Will try looking at it later.

Edit: nvm, it loaded. Looks like just a firmware update. Now the question is where do we get the firmware from

[Rufus007]

Not sure if its the colder weather lately, or what, but mine has started to do this stutter occasionally again lately - maybe 1 in 4 cold starts.

So I started thinking of some solutions for this. I rang a tuning shop in Brisbane who said they don't have any software with the ability to delay the VCT operation.

I came up with another idea and want peoples thoughts about this as a possible solution:

Drill a small hole in the thermostat to slow down the coolant warmup speed. These cars really do heat up quickly in only a couple of minutes eg I'll leave home, make two turns and the coolant gauge will be at normal operating temp. As the VCT operation is based on coolant temp, this might delay the VCT operation long enough to heat the oil up a bit more. At most I'll be out of pocket one new thermostat and whatever time it takes if this doesn't work.

Opinions on this?

[colin.ssc]

I don't know enough to comment on that idea but just order the cover and change it and let me know if it works

[Rufus007]

Lol, so your opinion is 'just do it'

[Rufus007]

Okay I've got another little experiment to try first before I get out the drill. Can anyone else try this - turn the heater up to full blast as soon as engine is started even if this causes undesired side effects, eg sweating. This might help slow coolant warm up times. I'll report back but have been riding to work lately as weather is good

[mycarhasposessedme]

Personally I dont think drilling a hole in the thermostat will achieve what you want.

I have actual gauges fitted to my V36 that monitor all of the fluid temps (water, oil, transmission, diff.)

When the stock gauge indicates that its warmed up it really is only slightly warm (coolant that is).

Engine oil even less so & oil pressure has barely dropped to a drive-able level.

It really hasn't fully warmed up for 4-5 K's, so your hole could possibly become a problem.

Cheers.

[Rufus007]

Good info thanks, that's why I'm asking for thoughts like this before I do anything. I'll monitor coolant temp with my obdII and see if mine has a similar warmup pattern to yours

[Rufus007]

Ok I've just logged and graphed coolant vs oil warm up times at idle only. The graph does show how fast the coolant really does warm up in this car. My next step is to figure out at what coolant temp the VCT stutter starts and stops happening - this might take me a little while, obviously I need to drive around for a bit until I get some data.

X axis is time in seconds, Y axis red = coolant temp, blue = oil temp

After 2 mins of idle, coolant is about 53 celcius, after 3 mins about 60 celcius. Oil temp lags way behind...

Edited June 3, 2016 by Rufus007

[Rufus007]

@colin.ssc - before I go ahead messing around with the thermostat, I've tried one last thing on this otherwise lazy Sunday. Today I filled her up with some castrol edge 5w30 (the viscosity as per service manual, so far I have only used 40 weight oils). Will report back in a few weeks on this

[colin.ssc]

Lol, so your opinion is 'just do it'

Oh crap, just realised I never replied. Thought I did, maybe I closed the window before it posted. Anyway when I said just do it I meant changing the VTC revised cover that Nissan has. Some of the other forums have done this and seems to have fixed it. If you don't know what I'm talking about I'll find the posts. I thought we spoke about this before....can't remember now

[Rufus007]

No probs all good. I've seen several threads talking about the VTC covers, but I haven't seen any where they said "i've gone ahead and replaced them, and it worked". The only thing I've seen definitively fixing the problem was the elusive software update. Just for curiosity I dropped into Nissan today, about $900 each for the covers, or about $650 each delivered from the US. Faaark either way.

I've got three different recordings on the oil & water temps when I first noticed the stutter after cold start:

Water 82, Oil 49

Water 83, Oil 53

Water 81, Oil 47

So it appears the the VTC is probably kicking in at around the 80 degrees coolant temp. Ideally it would be dependent on the oil temp, at a guess over about 55-60 degrees to be safe. So this is maybe what the software update changes, but only a guess by me - no sure answer on this one.

I'm still thinking about this 3mm to 4mm thermostat hole drilling business to slow down the coolant warm up rate, and give the oil a chance to warm up a bit more before the coolant hits 80 degrees when the VTC kicks in. Just delaying by a couple of minutes would work I think (I don't want excessively long warm up times). Bought a thermostat gasket while I was there for $6.60 so I can think it over during the week, maybe do it on the weekend.

PS, second day on the 5w30 and the stutter happened. Felt no difference with engine characteristics etc.

Oh crap, just realised I never replied. Thought I did, maybe I closed the window before it posted. Anyway when I said just do it I meant changing the VTC revised cover that Nissan has. Some of the other forums have done this and seems to have fixed it. If you don't know what I'm talking about I'll find the posts. I thought we spoke about this before....can't remember now

Edited June 13, 2016 by Rufus007

[colin.ssc]

Wasn't the oil a 0w40? Was pretty sure that was what I was using.

As for the temps and when VTC kicks in, I'm not too sure how it all works, I should start reading up and see if I understand any of it haha...

[Rufus007]

Ive only used 0w40 until yesterday, I threw some 5w30 in just to see if that made any difference. The answer is nope, still the same stutter. VTC temps etc was all through my own obd2 monitoring, haven't seen anyone else recording and graphing etc.

Wasn't the oil a 0w40? Was pretty sure that was what I was using.

As for the temps and when VTC kicks in, I'm not too sure how it all works, I should start reading up and see if I understand any of it haha...

Edited June 13, 2016 by Rufus007

[Rufus007]

3mm hole drilled. I was just going to cut the jiggler valve off, but there are one-way screws holding the thermostat to the housing making that option difficult. So I used a long drill bit and went through the housing outlet. Some surface gunk on parts of thermostat as you can see - even though internal housing etc was 100% clean, not sure why. Anyway if this doesn't work it's about $80 for a new thermostat + housing.

I'll report back in a week on startup stutter, and also with a new warm-up graph. Wish me luck!

BTW oil does make a difference. Edge 0w40 was great and would only get stutter minor and occasionally. Edge 5w30 does it every single day and just about sends me through the windscreen as the stutter is much worse.

Edited June 25, 2016 by Rufus007

[Rufus007]

Hole vs no hole: oil warmup rate is almost identical which is great (didn't want to slow that down).

coolant warmup rate takes about 4.5min longer to reach 80 Celsius, which is approx when VTC kicks in.

with no hole oil temp is at 55 Celsius as coolant reaches 80

with hole oil temp is at 63 Celsius as coolant reaches 80

Both graphs are at idle only, so real road test to follow

[Rufus007]

Well tried and tested, and this doesn't work All that happens now is engine stutter starts when coolant is around 74 Celsius instead of the previous 80. Maybe the ecu was going off oil temp all along, and maybe the software update just raises the threshold oil temp a bit higher. All speculation of course. Oh well, now I get to install a shiny new thermostat.

[BTSV_Berni]

You can go and lower the temperature value which is sent from the sensor to the ECU.

For example: At 40 you have 280 Ohm.

At 60 you have 130 Ohm.

What you do now is: Put a 150 Ohm resistance in series to the sensor and at 60 degrees real temperature the ECU gets

a value of 40 degrees temperature.

Or, if you want to find out the best working resistance value put in a potentiometer 0-500 Ohm and have a play with it.

As soon as you've found the best resistance value replace it with a fixed one, bit heat shrink, neat and tidy. And you know

that the temperature shown on your gauge is behind the real oil temperature always "X" degrees.

But, you have to find out if the resistance changes linear or not. If not you might be better off with the 0-500 Ohm poti.

Cost only a few cents.

Regards, Berni

Edited June 29, 2016 by BTSV_Berni

[Rufus007]

On 6/29/2016 at 5:18 PM, BTSV_Berni said:

I agree this could work also, something I will try later on if needed.  And thanks also for including some technical detail, gives me a good starting point.  I went to pick up an extra oil temp sensor from Nissan to play with, but they are $108 so if going that route I'd probably just use the existing.   What I have done instead is order the consult 3 hardware clone (but original software).  Once this arrives I'm going to have a look at the VTC relearn procedure first, as I don't think the FSM procedure of just holding RPM's btwn 1800-2000 does anything.  There is also ECU updates etc but will have to be very careful with those - needs more investigation... 

Will report back once I have the consult 3.  I already have a windows XP virtual machine up and running with anticipation, since consult won't install on win10.

 

Quote

 

You can go and lower the temperature value which is sent from the sensor to the ECU.

 

For example: At 40 you have 280 Ohm.

                      At 60 you have 130 Ohm.

 

What you do now is: Put a 150 Ohm resistance in series to the sensor and at 60 degrees real temperature the ECU gets

a value of 40 degrees temperature.

Or, if you want to find out the best working resistance value put in a potentiometer 0-500 Ohm and have a play with it.

 

As soon as you've found the best resistance value replace it with a fixed one, bit heat shrink, neat and tidy. And you know

that the temperature shown on your gauge is behind the real oil temperature always "X" degrees.

 

But, you have to find out if the resistance changes linear or not. If not you might be better off with the 0-500 Ohm poti.

 

Cost only a few cents.

 

Regards, Berni

 

Edited July 3, 2016 by Rufus007