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Exhaust temp above 550dec (update)

Posted: Sun Jun 14, 2009 6:03 pm
by mr-hilux
Hi all
New to this forum someone one another forum pointed out the way.

Just have a question regarding my hilux.
it's an 89 dual cab with 2.8d (3l) . The motor was replaced 15000kms ago with a full rebuilt one with forged pistons to handel a turbo set up. it runs 10psi with a top mount intercoler .
pump and timing was adjusted to suite the turbo earlier in the year on a dyno. It has ran like a dream with out any dramas until last sunday when i noticed that the exhaust temp was going up quick a rising above 550 dec. On monday when i drove it, it went up to 500 dec just driving it normaly with out pushing it. The engine has a strange noking sound like it has air in the fuel system. The fuel consumption has jumped from 10.5 to 15 liters per hundred. it dosnt lack any power when driven hard just exhaust temp goes up.
Any thoughts would be greatly appriciated .

Regards

Mr-hilux
p.s thanks

Posted: Sun Jun 14, 2009 6:51 pm
by howesy
The overfuelling would be enough to drive up the EGT. i would be investigating the knocking And maybe get the pump checked by a specialist. Could be any number of things bu remember overfueling can lead to failure.

Posted: Sun Jun 14, 2009 7:33 pm
by Z()LTAN
leaking injectors
or
Inj pump mounting bolts have come loose and has moved, adjusting the timing.

The knock u are hearing is called 'diesel knock' it is created by advanced injection timing.

Posted: Mon Jun 15, 2009 9:20 am
by mr-hilux
thank you for the info
now the question is how do i fix the problem??
with out costing the earth

Posted: Mon Jun 15, 2009 3:28 pm
by KiwiBacon
Have you checked first for mechanical drag?
Anything which causes higher load on the engine will give you higher EGT's and worse fuel consumption.

Posted: Mon Jun 15, 2009 4:01 pm
by gotta_b_a_lux
mr-hilux wrote:thank you for the info
now the question is how do i fix the problem??
with out costing the earth
i had my injection re calibrated by diesel austraila for 75 bucks, it used to have a horrible fuel knock an blew heaps of smoke. now you wouldnt believe its the same engine

Posted: Mon Jun 15, 2009 5:42 pm
by hilux79
Whats your air cleaner like? I would start there. Especially if it was really dusty where you were playing.

Posted: Mon Jun 15, 2009 6:30 pm
by Beefcake
could be a boost leak too. Have you got a gauge fitted?

Posted: Tue Jun 16, 2009 9:46 pm
by mr-hilux
okay guys
thank you for your help in this matter.
Now thing that have been done.
air filter was replaced the day before the trip and rechecked day after still clean.
no leaks in turbo boost.
After speaking to the gent that tune the pump up about the issue he suggested that i try to find the source of the knock as this will be most likely the cause of the problem as the fuel will still be burning when leaving the chambers.
I found that their is air in the fuel lines when the engine is revving at high rpms.
Have replaced prime pump and water sensor, hoses and still no luck .
Will be doing some more tommorrow so if anyone has any more info please post it by.
Once again thank you for your help.

Posted: Tue Jun 16, 2009 10:39 pm
by Punchy
After speaking to the gent that tune the pump up about the issue he suggested that i try to find the source of the knock as this will be most likely the cause of the problem as the fuel will still be burning when leaving the chambers.
In English please? Did i read that right ?????
This is the way i understand your top statement.....
"The guy that tuned ya pump wants you to find the problem ?
But then says the problem will be because the engine is so overfuelled thats its causing it to knock as the exhaust valve is opening????.."""
Is that what you mean ?> Is that what you said ????? cause the tuner should be telling you what the problem is..not the other way around...

I found that their is air in the fuel lines when the engine is revving at high rpms.
How did you come to this conclusion?

Posted: Wed Jun 17, 2009 9:41 am
by mickbeny
Hi all...What about your Intercooler?Is there somthing stoping it from working properly like blocked with leaves or mud ect.Or the bonet is not sealing on the IC to force air thru ect?

Posted: Wed Jun 17, 2009 10:13 am
by mr-hilux
sorry guys for the bad reply
wife was on my case last night to get off.
I rang the turbo place up to have the car booked in to find out what was going on. I explained to him what was happening and he said that i could do a few checks before i take the truck down to him for inspection .
He just said that on past expericences that the cause of the engine knock is air in the fuel lines. He pointed out as to how i could go about finding out if that was the problem.
In order to find out if you have air in the lines is by replacing the fuel hoses with clear ones before and after the filter to see if air passes through and to rev the engine at around 3000rpm as this will show any air that maybe sucked in from a leaking part or joint.
First i could only see air after the filter.
Replaced filter still the same.
Replaced prime pump got better then replaced water sensor still the same so it means that some were in the line it has a leak just have to get under it and start replacing all the hoses and clips with new ones and if i have to will have to take fuel tank out to see if the pick up has any holes in it.
Now if only this rain went way it would be good.
So thats the story so far.

With my good luck my other car just had half it's back end taken out this morning and now i'm i dont have a car to get the kids around.Just got the thing fixed and couple of months ago after having the front end taken out as well. What a year it has been.

Posted: Thu Jun 25, 2009 10:46 am
by mr-hilux
okay guys
problem solved
problem with injectors. had them serviced
waste gave on turbo was playing up had it repaired and all works well.
So once again thank you to everyone for their input.
:D :D :D