Strange Engine Cutout when on freeway??

[Big Gags]

Hey guys - first time back in the forum for a while......life is busy and time gets away!!!

I've got a 2010 manual GU Wagon with ZD30 and 126k on the clock. When i bought it it had 3" exhaust, extra fuel filter, and a Tuneit chip that can be set from 1 to 9 (I used to run it on 5 when I first got it but lately have been running it on 7 due to doing a fair bit of towing). I've recently upsized the boat and now it's about 1,500 kg or so on the trailer (and a big boat so catches a bit of wind). We regularly drive down Eastlink here in Melbourne to get to the Patterson River boat ramp (well at least it was regularly until lockdown last weekend!!!) and in the last month or so I have been having an issue. I can sit on 100 km/h no problem on the flats and it drops down a couple of km/h on the slight uphills but the big tester is coming back through the tunnel at Ringwood. It reduces to 80 km/h and then is downhill till halfway and uphill out the other side.

I get into 4th gear on the downhill and then usually leave it in 4th coming up the other side - the last few times it has seemed to struggle to keep the speed up and as the speed started getting down to about 65 km/h I changed down into 3rd gear and the motor just cut out!!! Put the hazard lights on shifted to neutral, back to fourth and tried to bump start it - tacho revved but no restart (so I assume no fuel getting delivered??). Back to neutral and as I am now getting down to about 50 km/h I switch the ignition off and restart and then all's good and we drive home without issue? I thought maybe I shifted down into 3rd too early and somehow hit a maximum rev limit and the engine went into some sort of protection mode and shut off the fuel?

Anyway, a couple of weeks later and exactly the same thing happened in exactly the same spot - this time I had waited until going even slower and the tacho didn't go above redline but it cut out and I had to go to neutral and switch ignition off and on again to restart.

Sunday was our last fishing trip before the current lockdown kicked in - did the same thing again. Then when I got a few more km down the road I exit at Bulleen road and had to stop at the lights there for a minute or so. Lights go green, I take off, half way around the corner I change into 2nd gear and it cuts out again (another quick restart in neutral and then I drove the remaining 15 min or so home without incident) and I haven't driven it since (we are now in lockdown).

I'm wondering if it has anything to do with the fact that I'm doing lots of towing now (probably 75% of all driving is with the boat on) or if it might be somehow related to me switching the Tuneit chip up to 7 (I haven't had a chance to try switching it back to 5 yet to see if that makes any difference)? Or maybe it's something totally different that you guys on here might be able to steer me in the right direction on?? Very keen for any advice on what this might be from those in the know!!

Cheers,

Gags

[mudski]

Have you ever cleaned the air flow meter? If not, get some MAF spray and clean it. Or it may need to be replaced. Reduce the chip setting and see what happens. Intercooler could be leaking. Is it the original cooler, if so check it for oily wet spots, especially the underside of the cooler. If it does have these, its leaking and need to be replaced. Sounds like limp mode you are seeing, which all of the above can trigger.

[Mickhead]

Only buy. a bigger boat if you get a JEEP. When is the last time you changed the fuel filter?

[Big Gags]

Thanks Mudski - I haven't ever cleaned the airflow meter but might have a look at doing it during the next 6-weeks of lockdown!! I will also check the intercooler (which is the original) - out of interest, if it does have a problem would you recommend going for another one of the same or going for an aftermarket unit??

[Big Gags]

Only buy. a bigger boat if you get a JEEP. When is the last time you changed the fuel filter?

I've never changed the factory filter but it has a pre-filter fitted and I changed it about 10,000 km ago. How often should the factory fuel filter be replaced?

[mudski]

Thanks Mudski - I haven't ever cleaned the airflow meter but might have a look at doing it during the next 6-weeks of lockdown!! I will also check the intercooler (which is the original) - out of interest, if it does have a problem would you recommend going for another one of the same or going for an aftermarket unit??

Well mate get some CRC MAF cleaner and go to town on it. Hopefully this will help. Sometimes its to little too late and the air flow meter needs to be replaced. As for the intercooler. Buy an aftermarket unit with welded end tanks. The OEM unit will have crimp on end tanks.

[Big Gags]

Well mate get some CRC MAF cleaner and go to town on it. Hopefully this will help. Sometimes its to little too late and the air flow meter needs to be replaced. As for the intercooler. Buy an aftermarket unit with welded end tanks. The OEM unit will have crimp on end tanks.

Thanks Mudski. Did the MAF sensor yesterday - got a bit of dirt off of it but it didn't look to be very dirty to me. I took the plastic cover off from around the intercooler and as per the photos - it's obviously not airtight anymore!! So it looks like I'm in the market for a new intercooler - I see that Patrolapart has a basic unit with welded end tanks for $675 or they have a HPD one with a thermo fan for $1275 - have you had any experience with either? Is it worth spending extra for the HPD version?

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[pollenface]

For everything regarding intercoolers check the ARE website
https://www.are.com.au/Inter/topMountIntercoolers.htm

[Hodge]

My money is on the rail pressure relief valve.


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[mudski]

Thanks Mudski. Did the MAF sensor yesterday - got a bit of dirt off of it but it didn't look to be very dirty to me. I took the plastic cover off from around the intercooler and as per the photos - it's obviously not airtight anymore!! So it looks like I'm in the market for a new intercooler - I see that Patrolapart has a basic unit with welded end tanks for $675 or they have a HPD one with a thermo fan for $1275 - have you had any experience with either? Is it worth spending extra for the HPD version?

Yeah a bit of oil dripping from the cooler there. Go the cheaper one mate. The nissan bonnet scoop is next to useless so a better IC you wont benefit much from.