Intermittent Performance Issue

[leeroy12]

Hi Guys,
I have this strange issue over the last few months.
ML 3.2L Diesel / Manual GLX-R
When taking off from stand still once the revs get to around 1500-2000, boost around 3PSI it starts to struggle, and doesn’t accelerate. If I hold the accelerator were it is it gets through the issue and boosts/revs fine, until I hit second gear and it does it again.
It’s hard to explain, but it’s like I’ve got bad fuel or bad combustion or air in the system, and it's missing or chugging??
Now this might do it from when I start it in a morning on the way to work at every traffic light for say 30mins, and then not do it all the way home at the end of the day.
And then the next day nothing, but might do it a few times on the way home.
2 Weeks ago I thought I’d sussed it, I ran the tank for a while on empty (light on) and it did it every time I took off, stopped at the servo, filled up and it hasn’t done it since.
So I was thinking crap at the bottom of my fuel tank, so a full tank lasts me 2 weeks, so Thursday night that just passed I emptied the Fuel tank, had about 15L left.
Not a single bit of crap, now it hadn’t experienced the “issue” for this whole tank, so I thought it had gone.
But just to be safe I drove it to work and back the next day and really ran it nearly dry, and it didn’t have any issues.
Today, went to the servo on fumes  filled her up, drove home, all good.
1 hour later, headed to the Footy and the first 6-7 take offs, BAM it started doing it again F#$K was what came to mind.
So I’m stumped, oh and after the Crows Won  the Triton drove all the way home without an issue.

Things I’ve done
Oil and oil Filter Change
Air Filter change
Fuel filter change
Ran 2 bottles of Fuel cleaner through
Cleaned the MAF sensor
Empty the Fuel Tank
Check for Engine Codes (have an Ultra Gauge)
Monitored the Ultra Gauge, temp, boost etc to find anything strange, all I can see is issue happens between 1.5 – 3 PSI boost.
Disconnected the battery for 1 hour.

I have also noticed that the fuel economy has gone up, from 10.5 to 11.5ish.
Distance to empty, for the last 1.5 years always goes to around 570-580, now I’m luck to see it hit 520-540.

So if anyone has had a similar experience and resolved it, or has any ideas it would be great !

Cheers
Lee

[biggibbo]

Stinks of carbon build up to me. Have u checked the manifolds?

[leeroy12]

No, have not gone that far. I was hoping it would not be due to that.
I did actually check one of the posts on this site that talks about checking if you have a new manifold or an updated one or something like that.
It seemed that mine did, according to the pictures posted, not have the original manifold.
It has done 175K now though so who knows.
I have read through some of the Carbon build up threads but do not recall these types of symptoms.
However I guess i'll need to re-read them.
Cheers for the reply.

[Cowboy Dave]

Those boost levels sound low? Or are you not accelerating that hard?

Check that your hoses are a nice tight fit where they go onto the fuel filter housing. If they suck air that can cause some issues. If you hadn't already changed the fuel filter that was going to be my guess.

[biggibbo]

Like Dave said, check ya fuel hoses for leaks, and make sure the fuel filter is seated correctly.

Other than that I would be sussing out the manifolds. At 175 it's a fair bet they are checkers and it just can't suck in the air in needs

[leeroy12]

Boost gets stuck at that point, even if the accelerators flat to the floor, once it's clear it will go to 15-16PSI smoothly. I replaced the fuel filter and apart from the clips that hold the fuel lines on I also used some cable ties, cant move the hoses at all, so I don't think air is getting in at that point, but I haven't checked else where.
It's just strange that it can go such a long time with no issues and then it happens, always starts and idles perfectly.
If it was an air leak into the fuel lines I'd think it would happen more regularly.
Even with the Carbon, if she's blocked you'd think it would too happen more often, unless I'm at the stage of nearly blocked and soon this issue will occur more often.....
I'll go down the carbon path I guess and hopefully a manifold clean resolves the issue.
Cheers

[biggibbo]

TBH I would be taking it to someone to find the issue. Could be anything. Could be turbo, air, fuel and without all the info we are just guessing.

Maybe set the ultra gauge up with rail pressure and a few other inputs and see if anything seems unusual next time it does it.

[Lee-thal]

My money on a suction control valve,

[Tony]

Being an such intermittent issue pretty much rules things out such as Turbo and manifolds etc.

As Lee has mentioned, SCV would be my first port of call as possibly sticking. When they do this, most of the fuel gets bypassed around the high pressure pump.

SCV's are not expensive these days, or if your very careful, you can get more life from it by removing, cleaning then refit at a different angle.

[leeroy12]

Cheers guys, i'd rather replace the SVC than pull the manifold off
Guess that's what i'll be doing this weekend.
Cheers for all the responses, i'll update once done.

[Cowboy Dave]

Have a look at prices on eBay before buying one at a dealer, you may find you save quite a bit of money.

[RHKTriton]

I'd give it shock treatment of fuel system cleaner and to stroke over a couple of tanks and see what happens.

[leeroy12]

Thanks Guys,
Found this on ebay.
http://www.ebay.com.au/itm/MITSUBISHI-T ... 2a38902be2

At least I know what I looks like now I'll see if I can pull it off for an inspection on the weekend.

RHKTriton, I've ran 4 bottle of Diesel Fuel System cleaner through, over the last 4 tanks, wasn't sure how much I could put into it to "Shock" it, so did 1 per tank.

[RHKTriton]

If you haven't been running with egr disabled, there is probably heaps of goop built up around the swirl flaps and shaft.

It would be so good if the lower manifold could be opened without a major exercise.

Have you taken the first piece of manifold off and checked for carbon at the bend?

G'luck with it L'12.

[pandakin86]

interesting thread.. I was about to post the exact same issues. taking the car for a service tomorrow so will see where that takes me.

[leeroy12]

Ok, haven't done anything yet, but it just happened all the way home.
I noticed that once it cleared and i was say in third, take my foot completely of the accelerator and put in on again and the issue was back.
I then noticed that heaps of black smoke is coming out when I'm trying to get past the issue.
I made it home with it still doing it (for the first time), left it idling, revving it still shows the issue, but no black smoke, rev it long enough trying to get through and i got a small amount of maybe white smoke?
When turning it off it seemed to overrun a bit...
Turned it back on and revving it still shows the issue, so i will wait until morning to see if it's magically gone again.
Taking Friday off, so will pull some stuff off to investigate and report back.

[pandakin86]

Have just picked my car up from service and it is running a lot better. No so much black smoke coming out now and have got most of my power back.. still lacking a bit in the lower revs. Was told by the mechanic to take it to a diesel engine specialist. They reckon its the SVC. Tempted to just buy it off ebay and replace it myself. Does anyone know where the SVC is located? I have a 06 ML Triton GLX-R.

Things that got done were
Oil and Oil Filter Change - They used a cleaner additive in the engine before flushing it all out
Fuel Filter Change
Air filter change - Decided to put a K&N air filter in. Has a nice sound to it

Im going to run the current fuel tank to empty and then see if all this has improved my fuel economy. Was about 11.5ish before the service was done.

[waterrat70]

my 07 had the same issue twice, had the manifold changed under wty no issue's since. Check the boost tube for a blockeage, a new manifold will be exspensive.

[leeroy12]

Just doing some early morning Forum reading in the "Surge Problem with MN Triton" thread,. And this has brought another thing to mind.
I've been running 2T in my fuel for a long time now and I've only recently started missing a few tanks here and there and then stopped putting it in.
Last tank I had the Fuel system cleaner in and had no issues, newest fill up has nothing added and issues started again.
Other thread mentions that the 2T helps lubricate the fuel pump and SCV.....
Just a thought, and a hope, that it's just a sticky SCV, and adding 2T might help relieve the issue..
200mls going in this morning !

[leeroy12]

Ok guys,
Here's the update.
Today, I Pulled the intake pipe off between the intercooler and intake manifold, shined a torch down past the butterfly and I can see a very slight build-up of carbon, barely 3-4mm only on the bottom around the bend.
Put it back, as I'm thinking this is not much for 175k.
Next step, I ripped the SVC out, had a look, didn't pull it apart, it did look very clean, which it should as it cover in diesel all the time.
Rotated it 180 degrees and put it back in.
While I was under the bonnet I thought I might as well make up a EGR blocking plate, so pulled the EGR pipe off between the manifolds and this was surprisingly clean too.
Actually all the bolts were very easy to undo, like it's been done before....
Anyway, made the plate and put it all back together, plan to get some resistors this week and do it properly.
Drives fine, as it does when the issue is not present.
The issues was heavily present on Friday and Saturday, and then clear magically after I topped the take up from a BP, it was just like gone, and Sunday did about 100kms and no issue.
On Saturday It was that bad, I could sit idle, rev it and it couldn't get past 3 - 3.5 PSI boost, it was streaming huge amounts of Unburnt diesel out, coughing clouds of White Worst it's been, and then after the fill up, poof, back to normal
Now to wait and see if rotating the SVC today has helped, as the issue is not currently present.

[leeroy12]

Update...
Over 2 weeks and the issue has not raised it's ugly head again.
Which is good.
I think I'm sold on a Faulty EGR valve, as I've been watching the Ultra Gauge data on when the EGR value is meant to be opening and when I'm idle at the lights the ECU wants it open 80%, as my issue was during take off, it's got my wondering if the value was opening and not closing off correctly.
Obviously I have the blanking plate in now, so it's blocked, but this is where I think my issue was.
However I did rotate the SCV at the same time
Wont update again unless the issue starts once again, cheers for everyone's suggestions!
Lee