[Phdv61]

So a fast update today... i am still getting a hesitation at 2000rpms
Dan

If that "hesitation' disappear when you stop pressing the pedal and then press it again, it might just be a high tension on MAF compared to Revs ( Limp Mode) which drives the ECU to cut fuel to protect your motor. This sometimes happen when you block your EGR.

What you can do is get a voltmeter connected to the MAF signal at its input on the ECU.
If the tension exceeds by just a little, 3.55V below 2OOORPM, you get a limp. It is not a faulty MAF, but more probably an excess of air coming through.

To suppress : screw the adjustable screw behind the actuator, which limits the closure of the VNT, and set the turbo spool-up OR, add a diode or two in serie on that MAF signal to decrease its tension.

 

[dan ahern]

Ok today was a bad day with this 2007 Patrol and yet again Nissan's DI crappy poor self diagnostics isn't been any help at all.... in my 15 years driving Patrols i have never had this annoyance!!!
It will not go past 2000rpm's but otherwise it starts fine BUT NOT COLD.... cold starts are terrible...

This is my new pump i just fitted...drove fine for a long time before it cut back on the road and wouldn't go past 2000Rpm's .... i really don't know how about diagnosing this one because no lights are present or no codes. I have changed TPS as mentioned and checked every possible thing. I unplugged CAS and it threw an engine light so i know that is fine. The MAF should throw a code and when i unlplug it it does not drive any differnt.

I am going to drive it to Nissan in the morning just to plug it in to see what they think and it may shed some light on the issue but i have a feeling i am wasting my time...my pump is under warranty so i may have to send it back for repair but i don't mind that aslong as i know what the hell the problem is...
The Patrol again is prooving to me it's impossible to diagnose in these situations. Timing is 100percent as i say it drove fine for a good while and i had been using it everyday since the pump change. I think it could be wiring..god knows what the last clowns were playing at because my glow wasn't working no more off the key as i previously mentioned nor the engine heat button (Two things i really miss right now in winter weather here!!!) i get the feeling this is an electrical/ wiring fault...i pulled a few connectors and used contact cleaner as they looked very bad.

How can a perfectly working IP from my other patrol now be suddenly bad?? And the Grey Patrol is currently flying with the older pump i just put in that!!!

Patrols can be a pain in the rear end i have so much work done here and now this....

I will update hopefully very soon with a solution but i have a feeling it's going to be a tough one!!
it seems to rev ok when cold but once up to temps it starts to kick back at 2000rpms!
Yes i have changed both coolant temp sensors one above the IP and the other on timing case both to no avail.

Dan

 

[dan ahern]

Quick small update.

It's 8:30 PM here now and -1 degrees ice. I went out to Black 07 Patrol and started it and it ran perfect until it got up to temps and back to cutting at 2000Rpms again. This can't be a MAF problem.

On another note the Grey Patrol is going it's best and like lightening with the old VP44 Pump...i can't believe how well it's going. Really flying...not even a full turn of the starter it's litterly a touch and it's running.I am been honest when i say it is going as good with this old pump as it was with the new rebuilt pump!!

 

[Phdv61]

the only time when I get this kind of symptom, is after a cold night in winter when in the mountains, with the fuel filter being 'clogged' with 'parafine' in the morning, due to water mist getting mixed and frozen with fuel. Only way out is to change the fuel filter for a brand new one. And the result is that you can't go beyond 2000RPM as enough fuel does not get through the filter.

If not already done, try the replacement.

Long term solution is to replace the fuel filter every year by the end of October in cold regions...

 

[dan ahern]

Hi
I just changed the fuel filter and no joy! I blocked EGR today and no joy...i have tried everything inc changing TPS and checked everything.....the turbo actuator arm position makes no differnce. It seems to be fine and working as it should. However you know what i am going to do in the morning is take off that throttle body...i wouldn't be surprised if something was sticking in that!!! Worth a shot..

 

[dan ahern]

Ok it's almost my bed time here but i'm still playing with the Patrol...so i checked the throttle body and all is well...nothing is sticking and no vacuum error was made on my part but it was still worth checking.
I might pop off IC in the morning and check glowplugs for tightness even though i know they are tight it's worth a peep.

Then it's off to Nissan for the proper scantool reading.Hopefully it will show something because i am out of ideas...if that fails it's wiring and needs a good autoelectrican!

 

[Phdv61]

One idea : Did you check your idle swich ? If blocked, and indicating gearbox in neutral position even when a gear is on, ECU prevents REVS from going up when driving. But from the top of my head, it is above 2000RPM than fuel is cut. Worth a check.
Easy : In idle mode, press the HEAT button on the dash. Revs should go to 1200RPM. If you put the first gear on, the REVS should go down as normal. If they don't, you've got it.

 

[dan ahern]

PHD61,

Thanks so much for that...i think you could be on to something my friend. How do i check this?? Now as you mention it my heat button does not work any more!! How ever the revs rise normally for a while once cold but once getting up to opperating temps the revs no longer go up past 2000rpms...but like i say you could be on to something how do i check this sensor or what ever it is?

Today was a dead loss again and i'm under pressure now because my insurance won't transfer the insurance back to the Grey Patrol because it's yearly test is just out!! So i have to keep this on the road now...it's painful to tow a trailer without passing 2000rpm's LOL!!

Today i have swapped out MAF for a replacment, ECU, Keyreader and key magnet....no joy....same thing happening AS I GUESSED IT WOULD!!

So tomorrow i am changing a few relays mainly the ECM one and that's about all i can do apart from changing pump out again which i am not about to do without a proper diagnosis! It's booked in at 4PM with Nissan monday for a proper diagnostic check!

Dan

 

[Phdv61]

as written above my friend :

Start your COLD patrol :

• don't touch the throttle.
• In idle mode, press the HEAT button on the dash. Revs should go up to 1200RPM.
• If you now put the first gear on, the REVS should go down as normal (750 RPM)

If they don't, the neutral switch is dead. and the ECU believes you are always in Neutral.

 

[Phdv61]

and for the heat switch, note that when the coolant temperature is above 105°C (221°F), the engine speed does not change. So test has to be done when COLD.

No

I believe all these docs are available in the DI Archive.

 

[dan ahern]

Hello
Phdv61

Firstly, thanks for the input. Don't forget this one is a manual transmission too!
I am not sure if it would cause this limp problem, if so why is it revving fine once cold?
I am getting nervous now that this could be a sticky valve in the head because it seems to me that once the Patrol comes up to opperating temp it won't rev up... now i could be jumping the gun and again this is just a theory going on in my head.

I am going to check that sensor now Phdv61 and i have a spare so it's sure is worth a shot...i can't see why it would stop the engine revving up though. Yes i have no heat button working at all and as you mentioned this that recently just stopped...but it was driving fine without it for a week or so....plus if the ECU always thought i was in neutral due to a faulty sensor then the Patrol should rev up when parked and in neutral. This won't rev up anytime.

 

[Phdv61]

Dan, to my knowledge, limp at 2000RPM is normally linked to the MAF tension being seen by the ECU exceeding 3.55V for RMP below 2000.

Be aware that if the MAF grounding reference is not correct ( ie ECU ground used to determine the tension of this sensor, is bad) then the tension read by the ECU can be anything, and most probably in excess of 3.55V.
So you straight have a limp mode, and REVs won"t exceed much more than 2000RPM.

I had this once when setting my own electronics to work, with an improper grounding of my MAF_out signal on my PCB due to a dry soldering point, and the ECU was reading an excess of 4.5V. No need to say I was in permanent limp.

Check your MAF output tension vs chassis ground is ok, and then the ECU grounding.
An improper grounding of the MAF ( connector ?) itself could well be the cause.

 

[dan ahern]

Thanks very much for your help! ... Anyway the plan is to take it to Nissan tomorrow evening so i am hoping they can diagnose this. Maybe it might need to be left to them.

If that fails i am taking it to a very renowned autoelectrican locally in limerick city he is very very good and has got cars back running that had no hope for people lol!

Btw i sold the Grey Patrol today!! I will miss it and it was driving awesome, new engine and it's gone off with the old VP44 which seemed to be flying and driving like new! The new owner is delighted with it. Looks like the end of an era for me.I have had the old girl for 9years!! Nine trouble free years until a mechanic broke my radiator and she boiled (Then they fitted a new engine from Nissan) and i done the injector pump and all on it but like i have said here i have taken that out and fitted it to my 2007 current driver because it has a warranty till next may! So the old beast is gone and she had almost 600000Ks onboard with the first engine and IP. A great service indeed i think and hard towing everyday....2004 Patrol ZD30 sure is bulletproof and it was bog standard! I think the harder they are worked it helps the EGR and stuff that way to keep things cleaner.

So back on topic, here is hoping i will get this 2007 one sorted...my first thing is to diagnose it now.I don't mind if it's the pump because i have warranty and i will just take it out myself and drop it to the diesel specialists but i am not convinced it's the IP because it's driving away and runs fine once cold....NOT an IP issue because they generally just STOP! To contradict myself i would be upset too if it was the Injector pump because certain amount of faith would be lost in my diesel specialist because the thing is just newly rebuilt!! To confuse things further an air leak could kill the pump too but i don't think there is any air in the system because after fitting a clear line recently it looks great and air free.... it is showing air like symtoms though been sluggish to start in the mornings hence why i suspected air in the first place!
I doubt it's injectors either...
I think with the absense of my Heat button i think user PHDV61 here could be on the money!! Tomorrow i plan to get to my 2001 parts Patrol and remove the neutral switch from the gearbox...will be handy to have it off anyway to get the heat button back working!

 

[Phdv61]

Dan,
Are you sure the MAF tension seen by your ECU is correct ( grounding check) as suggested above ?
Simpler : unplug the MAF and tell us what you get. If the MAF value is really out of range, your PATROL will not work as it should, but should REV above 2000RPM if the MAF tension is the culprit.

 

[dan ahern]

Don't worry i am listening to all your advice and so far thanks very much you are very helpfull!!

I have tested the MAF when the problem first happened as the first thing that popped to mind was the MAF so i simply unplugged it and it still didn't rev up.

The problem is i have no way of testing any of these elecs myself so i will wait to get to nissan tomorrow!

Any easy fast way to check them?

 

[dan ahern]

Ok a little update here! So i went to my local autoelectrican's to try to diagnose this very annoying problem and no nothing!! No codes showing up so it's really a case of what i am at myself,swapping and changing crap around trial and error!

So i bite the bullet and went to Nissan down in Cork and me and Nicola had to wait 4 hours just to be told that (No codes or faults showing) they may have to dig deeper in to this but they suspect it's the 'pump'.

I suspect personally it's an injector and i have a spare set for it but i am not going to go against Nissans advice just yet so i bite the bullet again and yesterday i removed my newly rebuilt IP and we drove the 150Kmh one way trip and dropped the Injector pump back to my diesel specialist to have bench tested (Under warranty) i am not going to take any chances because after all like i say i have the warranty and when the pumps can't be diagnosed easy this was the best option for now!

Did i mention how annoying i find this in the Patrols that the engine light don't always come on and they are a pain to be diagnosed!!!

So i think i made the best choice, i have plenty of new tools got every week now so the jobs are getting easier too and the IP removal now is easy but a little time consuming for me.

So my plan for now is to await hearing back about my pump. To be honest i am hoping it's a pump problem now because we can't diagnose this thing!! When i hear back and in the chance they say the pump tested perfect then i am pulling the injectors. After that if the problem still persists it's straight up an electrical mess which needs to be sorted out with a good autoelectrican.

Some very dull pics at Nissan as it was such a bad wet dreary day & BTW they charged 50euros only which wasn't bad considering we were waiting 4hours but they didn't spend that time at it as we were in a que for ages waiting.I guess they just plugged it in. We had plenty of tea and biscuits though there LOL Also some last shots of my Grey Patrol before leaving with it's new owner which he loves BTW and it's going so well... we will keep in touch as he is a spot on guy actually and knows a lot about Patrols too!

Sorry i meant to say too that we did get one code at Nissan 0208 cooling problem and they said the patrol wasn't overheating...i can explain that code though.When i got the Patrol running this fan was running the whole time so i just unplugged it and unplugged the A/C too as i don't need it here anyway in Ireland. I then though the AC pulley might be seezed but it was fine to turn over and nice and smooth.That fan as far as i'm aware if just for the AC anyway so it would have nothing to do with this problem.Ok there is a chance i could be wrong about this but i doubt it.
On the VP44 pump too i think it has it's own temp sensor so maybe this could be playing up & also it has as far as i know the corisponding TPS sensor on the IP to take input from the throttle pedal. Maybe it's something electrical in the pump. Let's see...Ohh and BTW i bridged the terminals on the connector plug myself too 1& 8 and got the same code 0208... no engine light came on ever for this code but it looks like it as i say just stored it after i unplugged the AC Fan.

 

[Phdv61]

Hello Dan,
as far as I now yes there is a fuel temperature sensor in the IP (and a barometer too), but no TPS input. The injection values are computed by the ECU and passed on to the IP for adjustments. At least, it is the way it works on earlier 3.0s.
Hope you will find out what's wrong. For the VP44, it is known to need more lubricant than what modern diesel fuel can bring, and I add therefore 1/2L of 2-stroke-oil for each fuel full filing to help out .
One transistor on the electronics is subject to failure too. Mine is still the original as bought 19 years ago. You need to make sure the IP connector is fully and well connected with its security mechanism.
To clean the injectors, which have to be replaced regularly - 100 000km advisable - to avoid making holes in the pistons, I use injector cleaning every two fill. That said, my injectors have 180 000km and re still fine, but I will replace them early next year.

 

[dan ahern]

Hi PHD,

My last Patrol had over 570000K's onboard, first day pump and injectors. I used change my diesel filter every 10000k and used a diesel additive/cleaner called Dipetane (Which i stopped using in the end and don't plan to continue) who can say if they do anything for the pump.A lot of people i have talked to about the diesel pumps (Specialists) say that diesel is the only best lube for the pump and never to run it out of fuel. I think too much cleaners/injector cleaners etc are bad and only wash the lube from the pump too much.
I do agree with two stroke oil though especially with the low grade diesel on the market sometimes today.

 

[Phdv61]

Hi Dan,
I did not know about Dipetane, but sure we'll have a look at it. I don't know anybody around here in France who did not get holes in his pistons with more than 250 000km on original injectors, so that product might really help to keep them clean. Our "gourou" (yes, we have one too!) is a retired diesel motor designer owning his 2001 Patrol since new, and knowing evry bit of it by heart. I don"t know anybody with such a deep and detailed knowledge.
Personnaly I am happy to learn from anybody around the planet, and happy to share the little things I have learnt.

 

[dan ahern]

PHD,
Getting back to the Gearbox neutral switch do you really think this could cause no revs above 2000rpms? Would it not throw an engine check light though? This is strange because like i mentioned previously my heat button lights up but does nothing anymore for engine revs when pressed. It stopped working completly..
Would Nissan not have diagnosed this too?? I did mention it to the guy at Nissan at the desk..now weather or not he said it to the mechanic is another story....