GU patrol replaced MAF sensor, now have power loss

Hi Jon,

It's a mob over at Essendon.

By the way, my names not Ta :)
Cheers.

Thanks Steve,

You're probably on the money, the pump is just about the only thing I haven't replaced so far....not having much luck with this thing and I cant even sell it right now.

Do you have any info about the pump fault? What I mean is, does it need a reco or can a specific component be replaced?

I'll wait and see what the Dealer tells me as well.

Cheers,
Enzo

Sorry to say going on past posts over this subject I reckon the dealer will tell you its about $5,000 for a new pump.

we just did a change over pump on a 3ltr
total cost fitted ect was around $3500
cheers

If you want to speak to me, e-mail me on, rencol@bigpond.net.au and i will send you my number.

I am 99% sure you have the same problem.

I can only agree, as I watched "on patrol" go greyer and balder as this problem was sending him crazy.....well crazier than normal. And it really was as simple as the hoses being on the wrong way too bloody simple sometimes!!!

If you haven't already I suggest you do e-mail him and have a chat

Cheers Stefan

It does sound like a typical overboost situation. Would be worth checking the hoses aren't mixed up.

!MPG:55!
These are the hoses I refer to.

go back to the turbo control and a third goes back into MAF area.(dont touch the third one) sawp the other two IF the rear one has no valve body on it, the valve should be on the middle one as shown in picture.

Crikey!! I don't own a Nissan, But I do have an NP Pajero that is doing exactly the same thing. The dealer has no idea what it is and I'm starting to lose it! After reading this I dashed out to the carport and had a look. While the components don't look exactly the same, the same principle is clearly on show!

I've rung the dealer and booked mine in for tomorrow. It's still under warranty so they can deal with it. Thankyou, thankyou, thankyou!

Good on Ya Im.Away

If i knew I was helping an Itsibitsi owner i would never have posted that reply. LOL.
Good luck tomorrow mate. Hope it works for you.
Colin.

Wow! this input is really appreciated, thanks to everyone.

This reply drags on a bit so a warning to you all.

Before I read the latest responses (last night) I had the urge to test the original MAF (as I knew it wasn't happening with this one), well I was right, no power loss.
This other MAF however caused the truck to drive like a slug (as it used to) with little or no boost. I might be completely wrong on this but I can only assume that the problem wasn't obvious back then due to the overall poor engine output and now with the new sensor installed its raised the boost levels enough for it to cause an issue.

In reference to 'OnPatrol's' suggestion, I wish it was as simple as reversing the hoses, I had a look at my vacuum layout and found that all was ok.
I too had a snorkel fitted some time ago and have seen some shocking work done by 'so called mechanics /fitters'.

I've also checked the factory manual and confirmed that these hoses were ok, I'll check the whole vacuum system soon.

Another stab in the dark is that with the old MAF, the fuel pump didn't need to deliver high amounts of fuel so it didn't 'struggle' to keep up with load. Since the new MAF it may have caused an increase in flow rate causing it to fail. This theory isn't very strong as one would think that this would also occur during hard acceleration and not during cruising, also when throttle is backed off and re-applied the pump has no issue with supplying required fuel.

I called about 10 different dealers and a few private mechanics and the best I could get was 'you'll need to bring it in and that it would be caused from:
Turbo system
Fuel pump
Accelerator potentiometer (fly by wire system).

Cheers.

Dingo,

This might be worth a try.

Go to your Nissan dealer, ask them to plug in their testing equipment to the ECU and go for a drive (insist that the car is driven until the problem arises). If the issue is related to the injector pump a diagnostic fault will register. This is the only way mine could be detected as faulty. If it's not the pump then some other fault may come up on the diagnostic tool.

Good luck.

Steve.

Yeah no worries Batman,

Good plan, I have to wait till next week to do it as their diagnostics unit is out of action.

Cheers.

Hi Chaz,

Not sure what you mean by 'meter' but according the the the factory manual the name of the solenoid valve is a variable nozzle turbocharger control (VNTC) solenoid valve, and the name of the actuator (mounted on the turbo) is a (VNTC) control actuator. I assume this refers to the turbo having the variable part to it.

The test for the the actuator involves comparing vacuum/rod stroke amount.
-46.9 KPa /0.2mm, to
-9.09 KPa /5.0mm

Seeing that the stroke of the actuator is governed by pressure I can only assume that the pressure changes originate from the vacuum pump, which would be governed by engine speed, can anyone confirm this?

Also, the name given to the green 'filter' is a 'damper', I took mine off today and blew through it from both ends and in both cases air flow was present. Maybe the 'damper' controls the flow rate so as not to cause sudden changes to the actuator....not sure.

I did check the solenoid ports (as you suggested) and everything checks out ok. I'll look into this area further though, that link you sent was pretty full-on.

Off the topic for a minute -can anyone tell me where their temp gauge sits? mine had stayed just below 1/2 since I've owned it -even after changing the thermostat, replacing coolant and disabling the EGR (before the valve). The engine doesn't seem hot.

I'll keep at it (and even flip vacuum hoses around) and post something if I have any success.

Thanks!

Hi, Dingo77,
Sorry I didn’t explain myself well. By “Meter”, I meant that the valve controls vacuum flow. Some people say it’s on or off, by testing it with a meter or test lamp, but some say it’s controlled by “Pulse Width Modulation”, which would be from the ECU. I wonder if the voltage could be controlled by the ECU and the valve is in fact a needle valve that increases vacuum as the voltage increases. You may be correct by saying that the pump increases vacuum with engine rpm, but boost increases and decreases regardless of rpm.
You are correct, that little green thing is called a damper. My mistake, but I think it does more filtering than dampening.
If you swap the A & B port hoses around, you may find the VNC actuator won’t bleed down when the ECU want’s to decrease boost. Also if you have blocked the EGR, you need to lower your boost to compensate. Blocking the EGR will increase boost levels at times because there will be no boost lost through the EGR system. This is why they run such high boost levels (to overcome EGR) and why boost suddenly drops off (to allow for EGR).
My ZD30, like yours has always ran just under half way on the temp gauge.
Good luck with this and I hope you find the cause of the problem.
Chaz

Hi Chaz,

I dont want to start the EGR saga again but I read up on this topic (post# 36378) some time ago and from this (and due to finding a bucket of soot in my manifold) I decided to block mine off. The results were fantastic, no smoke and no flat spots, it was like driving a new car.
The forum didn't mention anything about increasing boost levels however (or compensating for it), but what you say does make sense.

From the post I know that you've blocked yours off, what have you done to compensate? from what I've been told, you cannot adjust boost on the turbo.

The last thing I want in my ZD30 is extra boost! I might remove the EGR plugs and see what happens.

By the way, I had a look at the turbo vacuum setup in a friends Series III and it is exactly the same as mine.

Cheers, Enz

Hi Enz,
Blocking the EGR system is probably the best thing you can do for your motor, but peak boost needs to be limited. There is a small grub screw just behind the VNC actuator rod on the turbo. Don’t adjust the length of the rod because that will change when you get boost, but by winding the grub screw down about half a turn you will limit how far the VNC lever comes up and opens the vanes. This LINK shows how, although it’s a bit hard to follow (it needs to be translated from French).
Making this adjustment should limit your maximum boost provided your exhaust is standard.
I spent a considerable amount of time tuning on a dyno and found that my Patrol didn’t make any more power over 16psi, so I limited mine to 18psi. It was going over 25.
I have since gone away from this method, because after other mods, my boost was too high again, so I now use a manual controller that allows me to adjust boost while driving.
This LINK shows the VTNC in operation.
Chaz

Chaz,

I'll give it a go on the weekend...cheers.

Problem solved!

Chaz was on the money with the peak boost (see above), thanks heaps!

The ECU would go into 'safety-mode' when boost levels got too high (all this with no engine warning lamp illuminated).
I made the adjustment to the actuator and have tested it thoroughly over the last three days and it runs like a dream....finally.

I missed the part about making adjustments to peak boost when I originally read the posts on EGR's. If you do decide to block your EGR's I strongly suggest make the changes to the turbo, it's too easy.
(by the way, I cant believe how clean my engine oil is since blocking the EGR)

Regarding the fuel pump, from what my dealer told me its water that kills them, he suggested to drain the water on a weekly basis (probably a bit of overkill but it would depend on where you buy your diesel from). I try to stick to busy truck stops, a bit hard when your in the middle of nowhere, I know.
Don't wait for the dash warning lamp to light up.

Thanks to all for the great help and good luck with those ZD30's.
Enz