[Nick Gibson]

Hi guys. I was wondering what normal EGT's for the Pajero are. I fitted a probe a month ago and have seem some high readings when pushing my van when over taking up a hill, as in above 730 deg for very short periods less than 5 seconds.
My probe sits in the down pipe of the exhaust manifold just before the turbo, so it reads an aggregate temp of all of the cylinders.
Normal cruising at 120kph is about 520deg C. I shut down when EGT reaches below 200 deg C.

Now I see CATS posted he rarely sees above 600 degrees C on his van, but his probe only reads on the one cylinder nearest to the EGR port. Could it be that I am picking up a higher heat load where the gasses collect, than just reading off one cylinder?


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[CATS]

Nick

Firstly the probe that I am currently using has been moved from the one pipe towards the EGR system where it was previously located, to a new spot just where the manifold converge towards the turbo IIRC. Will check tonight.

Since it was moved, and the engine rebuild was done, temp readings has been a lot less than previously. Which worries me a bit, but currently I have bigger fish to fry on the overheating side.

I think normal temps on a 3.2 Did should be between 300 and 450 around town and up to 650 when pushing it and loaded. I have only once or twice experienced around 680 on a bad uphill when towing. BUT, Like Dyno readings, I think a lot of this is very subjective regarding make, position etc. So don't read too much into it.

CATS
PS - after my engine failure on 300000kms after nursing EGT and 5000km oil services I believe it is the luck of the draw. No matter what you do it will go when it's time come up. Not much one can do about it, so maybe my pessimistic opinion is not a sound one to go by. Or maybe I just had a dud engine and a dud rebuild.

[RoelfleRoux]

C'mon Cats, 300k hassle free km isn't a dud engine. Snoopy was n star for a VERY long time. The 160k failure just reported is a different story. That one is almost in the 3.0 Disco failure class - unacceptable.

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[Nick Gibson]

CATS I am with Roelf here, I think your van has done you proud. I am certain the over heating gremlin will resolved, lot of good ideas and advice being shared on the forum. My money is on the radiator... But Back to topic.

My EGts are a lot higher than that, I have a madman EMS2 and a probe supplied by madman too. Probe position is also similar. Think there is something very wrong with the high readings I am getting.

I think my intake manifold might be gunked up with the unblanked EGR combined with PCV gasses. As I understand the fueling of the motor is controlled by the ECU, which determines how much fuel to inject from a couple of parameters, one of which is the MAP sensor. This in combination with the known engine Rpm allows the engine to calculate the volume of air being drawn though the motor.

If the intake manifold is obstructed/constricted with deposits of gunk this will reduce the volume of air (even at the right Manifold Absolute Pressure) into the cylinders, causing an over fuelling condition. And Thus higher EGT's. I think I need to pull the manifold and give it a good clean.

It is a bit of a PITA I believe...

If that fails I will have to pull the injectors to be tested for pop pressure and spray pattern. Injector pump was done a few months ago so I am sure that us fine.

Another though is the pump timing, not sure if that can have an effect on EGts?

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[larry007]

I hear what you guys are say about the location of the probe and different equipment, but the temps should still be respected and trusted to some degree. If your probe detects high temps, your temps are high imho. Having researched this topic to the n-th degree due to the 2.8TDi reputation, the general consensus is that over 600'C, the motor is working hard, 700'C is bad for your motor, and over 800'C, you will almost certainly pick up damage. From the readings you quoted, my gut feel is that they are a bit too high.

To my knowledge, High EGT temps are 98%+ due to overfueling by the diesel pump, that part is easy, the why and the resolve, that could be tricky. Your EGT's aren't terribly high, so it might not be too obvious. What is your observation in terms of 1) consumption, and 2) smoking under acceleration? These should assist in assessing the above fact that the motor is being overfueled. Alternatively, go to a reputable dyno guy or someone who is familiar with the 3.2Did to have the pump checked over and set again - PS these pumps are expensive!! They may very well find that it is overfueling and set it correctly, or may find a seeping seal. If that is sorted, then have the injectors serviced if not done recently - spray patterns can influence temps.

My own experience on my 2.8TDi I had normal highway temps of 350-450 at 110-115kph, and when under load/uphil, would rise to 550-600, and severe load up to 650-ish, at which point I would nurture it. From my experience compared to yours, I would have been slightly concerned to get this addressed...

[Nick Gibson]

I hear what you guys are say about the location of the probe and different equipment, but the temps should still be respected and trusted to some degree. If your probe detects high temps, your temps are high imho. Having researched this topic to the n-th degree due to the 2.8TDi reputation, the general consensus is that over 600'C, the motor is working hard, 700'C is bad for your motor, and over 800'C, you will almost certainly pick up damage. From the readings you quoted, my gut feel is that they are a bit too high.

To my knowledge, High EGT temps are 98%+ due to overfueling by the diesel pump, that part is easy, the why and the resolve, that could be tricky. Your EGT's aren't terribly high, so it might not be too obvious. What is your observation in terms of 1) consumption, and 2) smoking under acceleration? These should assist in assessing the above fact that the motor is being overfueled. Alternatively, go to a reputable dyno guy or someone who is familiar with the 3.2Did to have the pump checked over and set again - PS these pumps are expensive!! They may very well find that it is overfueling and set it correctly, or may find a seeping seal. If that is sorted, then have the injectors serviced if not done recently - spray patterns can influence temps.

My own experience on my 2.8TDi I had normal highway temps of 350-450 at 110-115kph, and when under load/uphil, would rise to 550-600, and severe load up to 650-ish, at which point I would nurture it. From my experience compared to yours, I would have been slightly concerned to get this addressed...

Hi Larry

My Consumption is spot on for my vehicle, bearing in mind I have one profile size up tyres on 265/75r16 and carry a lot of extra weight in my ARB front Bumber, Lynx Rocksliders, 4mm belly plate & steel rear bumper and a long range fuel tank (generally kept full) and roof load bars permanently fixed on roof with a 50mm suspension lift. I am getting 12lt/100km town driving and about 11-10lt/100km open road, very average.

I have absolutely no smoke on startup or acceleration, and motor runs smoothly.

We had a Dup-diesel techie on site one day and I asked him to look at my Pajero. He said to start it and then rev it to 3000Rpm quickly 3 times in succession while he was looking at the exhaust. While it is not a conclusive test, he said if there is a injector problem he would generally be able to pick it up while doing that simple test by looking at the smoke coming out of the exhaust under startup and revving. He said it look very good, nothing untoward...

You are right by saying you would be concerned by the EGTS's and I am too. The pump was completely overhauled by the previous owner at Randburg Diesel in joburg, so I am sure that is fine - but was installed in the Pajero by Mitspro. I should check the pump timing though as that could also be a culprit. It could also probably explain why I have trouble starting the engine when hot on 50ppm Diesel, but fine on 500ppm??

THere is a method of setting the pump timing in the workshop manual, I think that should be my second port of call after cleaning my inlet manifold up, and lastly have the injectors tested.

[larry007]

It sounds like there ain't anything obvious, which I suspected would be the case. I concur that cleaning of inlet manifold is worth doing. Whilst at it, clean the intercooler as well, and verify that it receives sufficient airflow with that bumper!

Next I would have the injectors tested, ditto on that. It is a long service part and can't do any harm to have it done.

And lastly have the pump settings checked over, maybe even dyno tuned. Please keep in mind these pumps are $$$$'s, only allow trusted pro's touch it!!!

If all the above is done, take the temps on face value and live with it. Gain and gauge more opinions as you carry on, but I would warn against going over 700'C - I mean, that is the whole purpose of having the monitoring installed

[Nick Gibson]

OK.
So I spent most of yesterday stripping the intake manifold off to see what it look like inside. Not bad at all, only about 1mm of gunk on the walls, deposited just after the EGR inlet port where the hot exhaust gasses combine the oily PCV gasses.
I cleaned up the manifold as best I could with the 1 bottle prepsol I had and a bit of petrol.

While I had the rocker cover off I pulled the injectors to see what they look like, they were quite gunked up, so I cleaned them as best I could with some carburettor cleaner and a soft cloth. See before and after pictures. The injectors have been worked on in their lifetime, there is a serial number engraved on the body and the orifices on the tip look pretty good.

I also looked at the upper timing chain guide, also good condition. Cam lobes also look good.

Took a car for a test drive and still getting over 700deg C under heavy acceleration with no trailer, so back to drawing board...

So with all of that checking out it leaves 4 possibilities.
1. Faulty injectors pop pressure.
2. Faulty injector pump timing.
3. Faulty MAP sensor.
4. Faulty EGT probe (unlikely though).

I think I an going to try a bottle of injector cleaner as well, no harm in doing that.


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[andrew.ashton]

Hi Nick,

Did all the injectors look like that?

The deposit looks oily in the pic. Was it?
I think that it could be time to have those injectors refurbished and maybe a compression and leakdown test while you are at it.

[Nick Gibson]

Hi Andrew. Yes, the injectors looks more or less like that. I really struggled to get them out of the head, I thought some of the residual oil had seeped down from the cam shafts area and oiled up the tips as I wiggled them to and fro to release them out of their recesses...

Yes I think it is imperative to have the injectors tested asap.

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