Thread: 2003 TD5 Discovery running problem

Originally Posted by Disco Muppet

That sounds exactly like the boost modulator mate
Hope both of you get your issues sorted!

+ 1.
Exact issue I had. Modulator was stuck open causing the car to over boost and then the ecu tell the engine to retard performance.

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Originally Posted by PhilipA

Yes they sure do especially if the EGR is still connected. If never cleaned they can read no boost,so cut fuel accordingly.
Regards Philip A

How does the egr effect the maf? It feeds in well after the maf. Not saying your wrong, just curious as I don't understand.

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Originally Posted by singlecell

How does the egr effect the maf? It feeds in well after the maf. Not saying your wrong, just curious as I don't understand.

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MAP not MAF.

Rightio,
I have done some experimenting using a hawkeye and a few other bits.

Following on from comments I checked the boost regulator using the hawkeye and with another known unit. There were no other errors on the ECU apart from a injector trim data error which will not clear. MAF is ranging up from idle. MAP is measuring and changes with revs. Coolant temp ok. Air temp ok. EGR tested ok but didnt change with revs.

Firstly I took the fuel tank pump out and apart again to find that the internal filter was simply full of a black sludge. I didnt do ths before. I eventually cleaned this out (with petrol) and put it back together and rebled the system. No change

I then went and looked at the Fuel pressure regulator and cleaned the filter out and then discovered that someone had put the pipes back onto it the wrong way round. So the feed to the cooler was in the top hole rather than the bottom. I swapped this around.

I went for a spin and the fuel filter at the back by the wheel was stone cold.

I replaced the fuel pump with another known good unit as I was concerned with the amount of sludge I found after the filter. No change

I changed the FPR for another known unit and the vehicle is vastly improved but the problem is still there

The rear fuel filter is now hot after a short run (3-5 miles).

I also cleaned the air sensor in the airbox.

Can anyone shed any other insights?

Something someone has mentioned on another forum is is the High/low switch ok? I do remember seeing on the hawkeye that security didnt stay stable (High/low flickering). Has anyone else any thoughts on this and what it relates to?

Originally Posted by simonmelb

MAP not MAF.

Well that was embarrassing for me. . .

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With the dirt in both the pump filters and FPR gauze there seems
to be dirt getting into the fuel system.

Two possable causes dirty fuel supplies going into tank
or combustion gases passing the copper washers at the bottom
of the injectors if injector seals and washers have not been changed
in 150000 km's I'd be thinking about changing them.
Any dirt in the fuel system will cause wear to pump it will also have to
work harder if its srtrainer is cloged to pull fuel in and push fuel harder
to try and get enough fuel through FPR gauze to run at high load/speed.
Might be worth testing fuel pressure with a gauge to see if you have
enough (4bar) pressure at high load/speed, just because pump is running
does not mean it is delivering enough fuel for all engine loads/speeds.

Pete