Need Help with GU Servicing

[TiPatrol]

Hi guys,

As I've recently bought a GU '99 model 4.5L with LPG and 270K on the clock, can I get some pointers, help, suggestions, info... please?

- Running around town with LPG, it's using 33L/100km.
- Running around town with petrol, 20L/100km.

Are the above figures right? I know the engine has done a fair bit but I still thought it's excessive for a 4.5L 6 cylinder running 2WD. I thought it would be more fuel economical than my other fourby, which is a 340hp V8, AWD in high range, weighing 2400kg, but it's not. At least with the other one, when I put my foot down it bloody pulls like a race car, 15 sec on 1/4 mile, not bad for a 4WD but this thing, slow as a turtle and sucks as much.

Can someone give me their figures with their Patrol and also if you're running LPG?

I thought I might give it a major service overhaul. What do you guys recommend in terms of engine oil and spark plugs? I guess other things like filters, coolant, tranny fluid, diff fluids wouldn't play a role in terms of fuel economy, so I could just buy according to specs or bottle recommendations.

Should I replace any sensors (O2, MAP, AIT, PCV), if it has any, I'm not sure??? Didn't really look at those yet.

The Patrol is pretty standard, no lift, just AT's on and I added a set of Rhino racks. It has the Nissan bullbar, side steps and rear wheel cover.

Don't get me wrong, I'm happy with it, it's just that I didn't expect it to drink so much. I was more interested in a diesel in terms of fuel economy but the LPG sounded attractive. Oh, just came to mind, someone said I should install a valve saver kit because of LPG. I'm new to the LPG scene, what exactly is that and does anyone out there have it? Should I be worried?

I did have an issue with the LPG not being able to refill, I tried different servo's and still nothing. I carefully disconnected the hoses, drained what was remaining out of the tank, pulled out the valve and checked it (looked new), put everything back together, also took out the LPG computer (looked fine and new), went back to the servo and it filled up and worked flawlessly ever since. I thought there was too much back pressure that it didn't allow to fill. Is this a common thing with LPG's because I wouldn't wanna do that so often? The system is fairly new, it was installed in 2009.

Thanks for you patience and I hope someone can help me if possible. Regards.

[04OFF]

20L per 100 on petrol is very normal around town for a standard 4.5L bud :)

[BigRAWesty]

Yea sorry mate but you obviously didn't research this one. Well known fact that patrol, petrol and efficiency can not be used in the same sentence ever..
Even the 4.2's are high teens...
Sorry to break it to you but ain't nothing much you can do.. nature of the beast..

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[TiPatrol]

OK Thanks guys, that's fair enough if it's normal. Just got me worried that a 4.5L, 6 cyl would suck as much as a full time 4WD V8. So I assume that 33L of LPG is normal too.

What about oils and spark plugs, for when the time comes, is there better, best or worse?

[nissannewby]

You can get it better. I was hoping bob would drop by here as he has his running beautifully and using less fuel on both petrol and gas than you are. He has some really good advice :).

[Clunk]

Good strong motors but definitely not known for being frugal or quick. I have a gq 4.2 petrol, not on gas, again not fast and not frugal but plenty of grunt for what I bought it for and that's for off road, rocks and the odd occasion, mud n sand.
As has been said, with any luck Bob will see this and hopefully give some pointers on the gas..... that does seem quite excessive.

Don't slap it, tap it!!!!

[lhurley]

Petrol seems alright, i get about 21/100. But gas can be considerably better, get it checked by a gas tech, they are/should be good at that stuff. i had mine checked by a gas tech, i went from about 30-35/100 down to around 22/100. I also got way better power out of it too, something actually happens, not just loud noises and my fuel gauge going down

[paulyg]

What's your other V8 fourby?

[NP99]

30's a bit high for gas. Spark plug no 6 can be a challenge to change. Lube saver kits are easy to fit. Avoid BP LPG as it clogs filters with oil after a while. Mate, you have the best of worlds with LPG :)

[Alitis007]

My 4.5 is straight petrol, i get between 13 - 17l/100 13 being freeway. When i first got it, it was getting around 20 or more but first thing i did was adjust the TPS and the timing. I change the oil every 5k, air, fuel and spark plugs every 10 -15k also depending on the conditions i have been driving in. I think you could squeeze some more economy from the motor with a full exhaust extractors and high flow cat and sports mufflers with mandrel bends also a snorkel. I also only use 98 RON.

Your LPG sounds like its a bit rich, get the Co mixture check on a gas analyzer and ask the tuner to see if the gas is leaning off on cruise. You might have a clogged up converter or just a bad tune.

The valve saver is good because it lubricates the valve seats and keeps the motor moist, because LPG is a dry fuel it kills motor by drying it out, personally i don't like it lol.

The 4.5 is slow but it does its best work from 3,500 to 5,500rpm and it should surprise you!!

[danielhobby]

My duel fuel 4.5 gu is running 2o lpetrol and 22 gas,, (110 kmh)freeway and 18 l petrol and 20l gas(80/100kmh) windy rural roads

[TiPatrol]

I see some of you running really good figures on gas. I'll take mine in to get checked as suggested, when I get a chance. I'll also grab that valve saver kit off ebay: http://www.ebay.com.au/itm/VALVE-SAVER-KIT-V-Lube-Uses-same-oil-as-FLASH-lube-/251225921803?pt=AU_Car_Parts_Accessories&hash=item3a7e3b590b&_uhb=1.

Thanks for all your help and replies. I will post the outcome when I get to the bottom of it.

Anyone know of any good LPG guys in Sydney, that aren't rip-offs and that know these engines??? Preferably western Sydney.

[Bob]

Havnt tested mine on Petrol around Town but achieve 16L/100K's cruising on petrol and 18L/100K's on LPG and this drops to 22L/100K's towing my Camper Van
Mine is tuned for LPG by a LPG Specialist as most mechanics dont really know much about LPG
Plugs,Advance/Retard and Valve Clearance are really important for running on LPG.
Important to run a Tank of Petrol through regularly

BTW my 4.5 is stock standard with Road Tyres and no Roof Rack as Tyres,Lift & Roof Racks really affect Fuel consumption

[threedogs]

X 2 with Bob your electrics need to be spot on, plugs, leads etc.
Plus tyre size will make a big difference as well, say STD 265 as opposed to say 285
Plus convertors get dirty,Try to remove all air from system as well eg park on a hill nose up
with plastic coke bottle in radiator filler to raise fill point, gas likes it a touck advanced just off pinging.

[Chubba]

Havnt tested mine on Petrol around Town but achieve 16L/100K's cruising on petrol and 18L/100K's on LPG and this drops to 22L/100K's towing my Camper Van
Mine is tuned for LPG by a LPG Specialist as most mechanics dont really know much about LPG
Plugs,Advance/Retard and Valve Clearance are really important for running on LPG.


Hi Bob you wouldn't happen to know the spark plug gap for LPG. I have the tb45e on gas and have just bought everything for a service including a set of ngk gas plugs. Would they be preset or do I need to adjust them? Cheers mate.

[jay see]

https://www.ngk.de/en/products-technologies/spark-plugs/spark-plug-technologies/lpgcng-spark-plugs/

Here's a bit of information on plugs and lpg.

This is a job that I'm planning on doing soon, along with tappet adjustments. Then I get that gas service and tune and hopefully they can sort out why I lose power after 3000 rpm when under load.

[Bob]

Hi Bob you wouldn't happen to know the spark plug gap for LPG. I have the tb45e on gas and have just bought everything for a service including a set of ngk gas plugs. Would they be preset or do I need to adjust them? Cheers mate.

Sorry mate I dont know the Gap as this is done by my LPG Mechanic. I will try to find out tomorrow and get back to you.

BTW the Head on my Patrol had the inlet Ports enlarged which allows the Motor to breathe a lot better.
Expensive but if you have the head off for some reason get it done.

[Chubba]

Thanks jay see for the link you provided I see that I don't have the NGK LPG plugs (that's their iridium plug with a smaller gap and bigger price) but the standard plug but one grade cooler than what would be used for just petrol as the LPG runs hotter. The heat range for the tb45e plugs are 5 and on LPG 6, the higher the number the longer to heat up hence cooler plug. The site also suggest to close the gap from 1.1mm to 1mm to adjust for the higher voltage needed for LPG.
The service manual that is available on this forum states spark plug gap for the tb45e is 1mm to 1.1mm so allowing for the LPG I think I will go .9 and see what happens.

[JME_GU]

I have a 1998 GU 4.5, when I got it I was getting around 22l but I found the front hubs were permanently locked. I replaced the hubs with manual locking hubs, changed the plugs, oil, air filter, rotor button, dizzy cap, plug leads and increased tyre pressure to 40 psi. In the same conditions, I now get 18l

[Bigcol]

while I did not have the 4.5 in a GU, I had a 4.2 in a GQ
there are soo soo many Variables to set the gas up correctly
with Gas:-
I used to get around 28L/100 towing my Van
and around 19L/100 normal driving
with Petrol:-
I used to get around 26L/100 towing my Van
and around 22L/100 normal driving

Alitis007 is on the money with the mixer being out
replace the plugs and the leads
get it to a reputable Gas service place and get it tuned
if they know what they are doing they will tune it via the Lambda sensors
they DO change the mixture in the Gas for Summer and also for Winter - so getting it tuned twice a year is the best

[Chubba]

How often should the oxygen sensor be replaced.? Anybody.

[ed12371]

Jay See. where are you in Melbourne?

[ed12371]

Well, I have the 99 model Gu 4.5ltr. Dual Fuel. Not sure how to break down the figures but I have a 90 litre Gas tank and a 60 litre Petrol tank. I was getting 300klms out of the gas tank and 400klms out of the petrol. Just normal driving around the city, that's on 285/70/17 all terrain tyres. Since all of the extra accessories, she is a fat old girl now and I probably get 30klms less than before. I run 1 tank lpg then 1 tank petrol and so on...

[jay see]

Jay See. where are you in Melbourne?

Western suburbs.

[jff45]

How often should the oxygen sensor be replaced.? Anybody.

A bit late but I see nobody replied to this yet.
There's no particular timeframe for an O2 sensor. They only need changing when they no longer function correctly.
They can be tested with a voltmeter while running. Should fluctuate between 0v and 1v roughly. When they go bad they generally give a reading around 0.3v.