Towing. Is this normal

[mktriton]

Good afternoon.
Have just returned from a weekend away. Kinglake to Horsham and return
Car is new 2020 NX.
Have fitted Auto mate Scangauge and catch can recently
Caravan. Jayco off-road. Dual axle. Fully loaded around 2.2 t. Towball weight 240 kg

Friday car towed beautifully automate tended to keep car in 4th gear mostly. Cruised at 95 -100. Fuel consumption about 18-19 lt per 100.
Very happy

Today returned. As far as I know I made no changes to automate
Car would not cruise at 95. Struggled to get to speed. Gearbox constantly shifting between 3 & 4 Gear. Fuel con 23-24 lt per 100
Eventually I shifted it into manual mode and it seemed to get better
When I hit the big hill heading up to Kinglake I ended up having to shift back to 1st gear to continue momentum. We weren’t travelling at speed by than
Car seemed to have trouble revving above 2000-2500 revs

When I got home. Disconnected van and took car for a drive
It revved freely. Accelerated easily and would in both std mode and with automate

Sorry if this is getting a bit long but question time
Does today’s towing seem normal and I am expecting too much
Have I inadvertently changed the Automate setting
Does the car change its acceleration profile when towing to protect the drivetrain

I will be giving my mech and mm auto mate a call regarding this but just wanted to see if these are common issues
Thanks

[2bad4u]

Basically - no it is not normal.

Eliminate simple things first like:
*Were there strong head winds
*Was the hand brake left on

Even then, these things would be obvious.

[mktriton]

Wind was virtually nil for most of trip.
Yep checked handbrake on car
Checked brakes on van
Checked handbrake on van
Did a hand touch test. no wheel felt excessively warm let alone hot

My auto temps did not exceed 85 deg and my coolant temp sat around 86
Auto mostly sat around 70- 75

[Ian H]

Likewise, it's not normal.

I had a van about the same weight (2.2T) and would get around 15-16L/100klm regularly and often less, down to 13-14. But it would depend on head wind and terrain of course, those were on a mostly straight road.

First thing I'd suggest is to tow again on a flat road and leave Auto Mate off. Then check the fuel consumption which should be as above. Then turn AM back on again and do the same trip and compare the fuel. With AM on, you should be using less and it should be in 5th if it's a flat road. You will find AM does tend to hunt a lot between 4th and 5th if it's hilly so in those areas I shift to sport mode and leave it in 4th.

[Keithyv]

That consumption seems awfully heavy. Did you have the transmission temperature up on the scangauge at any time?
Whoops edit sorry can’t read. Those temps do seem fine.

[Phree_ed]

Not normal from here either.

I just went through a spreadsheet I have for a 12,500km trip towing a 2550kg van.
Using only the data where I did 98 to 100 percent towing stages between refills I averaged 18.45 lt/100. That was over 5711km at a reasonably steady 90kph.

Best consumption was an incredible 12.71 and the worst (into STRONG headwind) was 20.91.

I do not have an automate, I simply tow in sport mode 4th gear so I too would be trying a trip with the AM off and 4th gear.

Oh and constant 4WD as well as the card in the sun visor pocket advises.

[mktriton]

Yes I had the transfer case in 4H

[nj swb]

Strange. I can't see how it could be auto-mate, but that's a question for Marshall.

What about ambient temps? What was your weather like over the weekend (I was in the Flinders Ranges ).

Did you drive to Horsham on Friday night, return mid afternoon today? I guess I'm wondering if things are working OK when cool / light load, but something got a little too hot towing in the afternoon and that's what created the problem?

You have fitted a catch can. Just speculating, but if there's an issue somewhere in that install the engine could be sucking air in through the catch can system that is bypassing the air filter / MAF. If the MAF isn't seeing all the air that's being sucked in by the engine perhaps it isn't supplying enough fuel? I would've thought inlet temp and manifold pressure would be able to compensate, but it's somewhere to start looking?

[aussieintas]

Could a caravan brake have been dragging a bit

[Ian H]

Doubt it, there'd be smoke coming out of the wheels after a while, I know from experience !

[mktriton]

Yes checked brakes.
All 4 caravan brakes were warm to touch but were not hot. All felt about same temp to me so figured it wasn’t one dragging
Vehicle hand brake was off
Weather was cool both days.
Vehicle temps seeemed ok. Both trans and coolant reading from scangauge
No codes were coming up either

[Caggs]

Did you refuel before you returned?? If so, could it be a lesser quality fuel. I have noticed my NX is very sensitive to using non premium diesel, especially from remote towns. In my last trip up the Darling River it meant a difference between 17.5l/100km to 19.5l/100km and i was towing a similar load to you.

[mktriton]

Yes I did refuel in Horsham
BP premium diesel
I did think it may be dirty fuel but not sure

I will be taking it to mechanic today to run a scan over it
Ideally I hope it is a fuel problem ie dirty
I can’t understand why Friday it pulled like a steam train coming out of Bacchus Marsh
And Monday I had to drop the gear box back to 2nd in manual mode and struggled to maintain momentum

[NTBenny]

If your car is making the expected boost pressure (18psi) than I feel you may have a fuel restriction issue. That potentially being a partially blocked fuel filter.

Benny.

[cruisn06]

Not normal from here either.

I just went through a spreadsheet I have for a 12,500km trip towing a 2550kg van.
Using only the data where I did 98 to 100 percent towing stages between refills I averaged 18.45 lt/100. That was over 5711km at a reasonably steady 90kph.

Best consumption was an incredible 12.71 and the worst (into STRONG headwind) was 20.91.

I do not have an automate, I simply tow in sport mode 4th gear so I too would be trying a trip with the AM off and 4th gear.

Oh and constant 4WD as well as the card in the sun visor pocket advises.

can you take a photo of this card that states to tow in 4H?