Sorry guys me again..
Little update, found a bad earth in the battery. Fixed that but still won’t start. There is now fuel getting to the injectors with good pressure. How ever the EGR is off and it’s blowing white smoke and still won’t start unless I spray easystart but then cuts out as soon as easy starts runs out
Little update, found a bad earth in the battery. Fixed that but still won’t start. There is now fuel getting to the injectors with good pressure. How ever the EGR is off and it’s blowing white smoke and still won’t start unless I spray easystart but then cuts out as soon as easy starts runs out
Do these fuel rails have an excess pressure relief valve? These can go and let the diesel run away. Although I say this not knowing if these rails have em. Just had that issue on a Reno van.
Also not being funny but if lack of fuel injection is the issue have you tried bypassing the entire delivery system from the tank to the pump by trying to run it straight off a can of diesel gravity fed? Or even from a can with an electric lift pump feeding the hp pump,
If that doesn't work is discounts everything up to the hp pump. If it does work your issue is between the tank and the hp pump.
It could even be an injector returning excessive fuel. Have you tried to clamp or block the return system to see if pressure builds up in the rail? Or if fitted with a excess pressure relief valve have you checked its line during cranking to see if diesel is flying down it?
Do you get any fuel pressure reading from the diagnostics at all?
Crank injector pipes then crank it to see if anything comes out.
Rossco
Also not being funny but if lack of fuel injection is the issue have you tried bypassing the entire delivery system from the tank to the pump by trying to run it straight off a can of diesel gravity fed? Or even from a can with an electric lift pump feeding the hp pump,
If that doesn't work is discounts everything up to the hp pump. If it does work your issue is between the tank and the hp pump.
It could even be an injector returning excessive fuel. Have you tried to clamp or block the return system to see if pressure builds up in the rail? Or if fitted with a excess pressure relief valve have you checked its line during cranking to see if diesel is flying down it?
Do you get any fuel pressure reading from the diagnostics at all?
Crank injector pipes then crank it to see if anything comes out.
Rossco
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Nodge68
Well-Known Member
Not on the TD4.
The EDC won't initiate fuel injection if it doesn't see over 200 Kpi on the low pressure fuel rail.
So trying to run it from an alternative supply won't work.
The HP pump is able to supply over 18,000 Psi of rail pressure. So blocking a spill pipe could be extremely dangerous as it would explode. Pulling the spill pipe off will give an indication of lost fuel, but blocking it is a bad idea.
Not being funny but quoting part of what I've said and responding to that isn't going to help.
I suggested gravity feed or electric lift pump, considering that hp pump is normally fed from an electric lift pump I don't see the issue with it not providing enough pressure. This is done in the trade commonly. It's a fast and effective way to check half the system in ten mins.
If you think I meant to just block the fuel pipe full stop and repeatedly try run the car you read my post wrong.
The purpose is to see if any difference at all is seen on the diagnostics pressure wise via the rail sensor. This would ideally be done momentarily for a short period of cranking just to see if it makes any difference at all so that you can discount the related issues.
Only carrying out these types of diagnostics in the correct order will get to the bottom of the problem. Discounting other people's ideas when you don't even understand them won't help anyone.
I suggested gravity feed or electric lift pump, considering that hp pump is normally fed from an electric lift pump I don't see the issue with it not providing enough pressure. This is done in the trade commonly. It's a fast and effective way to check half the system in ten mins.
If you think I meant to just block the fuel pipe full stop and repeatedly try run the car you read my post wrong.
The purpose is to see if any difference at all is seen on the diagnostics pressure wise via the rail sensor. This would ideally be done momentarily for a short period of cranking just to see if it makes any difference at all so that you can discount the related issues.
Only carrying out these types of diagnostics in the correct order will get to the bottom of the problem. Discounting other people's ideas when you don't even understand them won't help anyone.
guineafowl21
Well-Known Member
If you try to gravity feed the HP pump, the low pressure sensor will see no pressure, and the ECU will cut the HP pump output and injectors to preserve the pump. In other words, the rail pressure will be zero if you try to gravity feed the system.
An electric pump spliced in might just work and show you if the low pressure pump is part of the problem or not.
Nodge68
Well-Known Member
It was quoted because it wouldn't have helped it start.
You said block a return pipe to see if pressure builds up.
The problem comes because the minimum pressure sensed by the high pressure sensor, is well in excess of the pressure that would cause the spill pipes to explode, which is dangerous.
I don't know which trade your talking about, but I assume it's not connected with repairing common rail engines.
I don't know of many modern common rail engines that don't have a low real pressure sensor.
This means that no Jerry rigged gravity system will work when there's a low rail sensor. The low rail pressure sensor is there to stop HP pump damage, should there be insufficient fuel to lubricate it. So if the EDC doesn't see any low rail pressure, it simply doesn't run the engine, as I explained earlier.
Trying to gravity feed the HP pump would be counter productive and definitely won't help it start.
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guineafowl21
Well-Known Member
Where from?
I have the EGR disconnected
