Yes pressure reg is vaccum controlled.
Clamping down on fuel feed and return at idle increases pressure BUT engine goes to die as well. Which I think makes sense.
- Thread starter ukracer
- Start date
Clamping down on fuel feed and return at idle increases pressure BUT engine goes to die as well. Which I think makes sense.
Cobbler
Codger bodger
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Might be a silly idea, but the fuel regulator balances the fuel pressure to the manifold vacuum so it keeps a constant pressure above the manifold. When it goes onto boost the regulator is fed positive pressure not negative. Has the regulator been changed to one unable to cope with this? ...... As I said, maybe daft, but just throwing an idea into the pot!
bert
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The return feed needs to be clamped off after the FPR if you then have no issues with dropping pressure on boost its an issue with the FPR if it makes no difference then it's not a faulty FPR.
What pump do you have fitted? A walbro 255 or better should see no issues with fuelling on that.
What pump do you have fitted? A walbro 255 or better should see no issues with fuelling on that.
If pump is flowing correctly and it's not an issue with wiring to tank top and there is no in tank issue, no leaking in tank on connections etc, it would tend to point to the fpr
FPR1200
https://www.turbosmart.com/product/fpr1200-6an-black/
There is loads of info on fuel delivery on the link below.
https://fuelab.com/forums/forum/customer-support-2/
FPR1200
https://www.turbosmart.com/product/fpr1200-6an-black/
There is loads of info on fuel delivery on the link below.
https://fuelab.com/forums/forum/customer-support-2/
Actually this was what I struggled to get my head round as none of the you tube tells you they also have positive pressure.
@ukracer "I believe it runs fine at 450 brake but when the 550 map is used then the problem occurs."
Have you tried measuring the pressure in the fuel line before the pump. If it drops close to zero absolute pressure, when using the 550 map (presumably at full chat), then that would suggest an issue somewhere between the fuel in the tank, and the pump.
Why not leave it at 450 brake? Surely that's enough!!
Have you tried measuring the pressure in the fuel line before the pump. If it drops close to zero absolute pressure, when using the 550 map (presumably at full chat), then that would suggest an issue somewhere between the fuel in the tank, and the pump.
Why not leave it at 450 brake? Surely that's enough!!
The problem with that is it's an investment and any extra HP with documentation brings extra £££s.
If it was a build to keep and use on the road yes that would have been an option.
The other issue is we suspected a cracked oil cooler or cracked head or head gasket gone. And could obviously not sell it until that was confirmed one way or another.
Yes mate...
Ok latest up date. Typical son goes and does two alterations at once. So we don't know 100 % which one solved it.
First he rewired the pump to battery wiring as one spade connector had pulled off.
Also replaced stock fuel pipe that was not really long enough to create a nice slow uncrimped bend from pump to pickup with thick walled 8mm hose.
But sadly he also changed the GTR fuel pump.
Anyway one of those fixed the fuel pressure issue.....BUT it also confirmed our fears regarding the head or gasket. Oil cooler has now been discounted as it has already been bypassed and pipes are not oily.
There is definately a head issue.
But strangely enough he is actually over the moon with finally pinpointing the issue that was preventing fuel pressure staying with the boost.
Now to the major question I believe no matter how good the forum members are we will not be able to find this answer...
Apparently there is a mod that is done to the GTR Heads as they have a design flaw. But I can't find reference to it on YouTube or in writing on a forum.
It's allegedly a process of boring out two holes in the rear of the head and sleeving it. Allegedly the water and oil ways are very close in that part and are prone to cracking allowing oil into the water as oil pressure is higher than the water jacket pressure.
But it's my belief that as it costs £550 quid to have done what's actually done is kept secret.
First he rewired the pump to battery wiring as one spade connector had pulled off.
Also replaced stock fuel pipe that was not really long enough to create a nice slow uncrimped bend from pump to pickup with thick walled 8mm hose.
But sadly he also changed the GTR fuel pump.
Anyway one of those fixed the fuel pressure issue.....BUT it also confirmed our fears regarding the head or gasket. Oil cooler has now been discounted as it has already been bypassed and pipes are not oily.
There is definately a head issue.
But strangely enough he is actually over the moon with finally pinpointing the issue that was preventing fuel pressure staying with the boost.
Now to the major question I believe no matter how good the forum members are we will not be able to find this answer...
Apparently there is a mod that is done to the GTR Heads as they have a design flaw. But I can't find reference to it on YouTube or in writing on a forum.
It's allegedly a process of boring out two holes in the rear of the head and sleeving it. Allegedly the water and oil ways are very close in that part and are prone to cracking allowing oil into the water as oil pressure is higher than the water jacket pressure.
But it's my belief that as it costs £550 quid to have done what's actually done is kept secret.
Morrisman
Forum Supporter
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Tsk tsk, now you have learned nothing..... other than never change two things at once.....
It's allegedly a process of boring out two holes in the rear of the head and sleeving it. Allegedly the water and oil ways are very close in that part and are prone to cracking allowing oil into the water as oil pressure is higher than the water jacket pressure.
But it's my belief that as it costs £550 quid to have done what's actually done is kept secret.
That was the 'fix' needed on my old Rover 800, a common cause of an annoying incurable oil drip from the head gasket. I had the gasket changed once under warranty, but the garage who did it said it will leak again, the oily was too close to the edge of the gasket, a built in fault from the factory. I was told to simply open up the oil hole in the gasket and slip a short length of copper tube in twixt block and head. I never did it, just dropped oil everywhere unto I scrapped the car.....
... 6 years later.
I learnt years ago but when you have a son with ADHD you come to live with his impulsiveness.Tsk tsk, now you have learned nothing..... other than never change two things at once.....
That was the 'fix' needed on my old Rover 800, a common cause of an annoying incurable oil drip from the head gasket. I had the gasket changed once under warranty, but the garage who did it said it will leak again, the oily was too close to the edge of the gasket, a built in fault from the factory. I was told to simply open up the oil hole in the gasket and slip a short length of copper tube in twixt block and head. I never did it, just dropped oil everywhere unto I scrapped the car.....
... 6 years later.
But anyway I wrote the reply wrong and he did not change the GTR fuel PUMP he changed the standard GTR fuel FILTER.
It was not a stock hose. It was a rubber hose with a relatively thin wall that crimped down when fitted between the fuel pickup and pump. The replacement hose allowed a much smaller radius with no crimping or construction of the pipe.
