Upgraded hpfp

[ch1z64]

I recently fitted a stock hpfp with Autotech internals to my S3 Cdla engine and now car stutters and slows down as if engine is getting starved off fuel and on vcds it shows low fuel pressure .
So have others suffered the same problem when they changed theres out to go St2 and how did they sort it .
I still oy have stock fprv in not the RS4 one , now could this be the problem . Cheers Ears

 

[nluk100]

Who fitted the internals? Did you replace the cam follower at the same time? If you have vcds then I would log both actual and requested rail pressure to see what you are requesting (especially if you are mapped). I would also replace the fprv as it is a known weak point when you replace the hpfp (use the rs4 one).

 

[ch1z64]

Who fitted the internals? Did you replace the cam follower at the same time? If you have vcds then I would log both actual and requested rail pressure to see what you are requesting (especially if you are mapped). I would also replace the fprv as it is a known weak point when you replace the hpfp (use the rs4 one).

Have resorted to putting back in the old one until i get someone who is a bit mire experienced that me to fit pump and rs4 vavle as i think there lies the problem .
What i have noticed and camt explain is why unplugging both sensors on pump causes my battery to drop below 11.3 volts , but once batteey is jumped is all good again any idea why changing pump would cause this

 

[prt57]

What can happen when you disconnect and reconnect the rubber fuel hose is that bits of rubber break off and get into the inlet of the pump causing fuel starvation.

 

[ch1z64]

What can happen when you disconnect and reconnect the rubber fuel hose is that bits of rubber break off and get into the inlet of the pump causing fuel starvation.

Reconnected old pump back on and all seems to run ok so i am.leaning to the stock Fprv which is not strong enough for the upgraded pump , so will have to wait until i can get some1 to fit both and see what happens then .
The battery problem i haven't been able to solve yet and spoke to an Rac guy who says pump shouldn't have any impact on battery when sensors are disconnected so totally baffled to why that would happen unless when priming pump that impacts on battery .

 

[prt57]

Your car should run fine with the upgraded fuel pump and stock fuel valve. I was running APR stage 2+ with the standard valve for a while with none of the problems you are describing.
I’d be wanting to check the inlet fitting on the replacement pump as I said before. It should be drilled out to 5mm anyway to help the lpfp. Take care removing the brass fitting as there is a little washer in there that is easily lost. The pump will leak petrol without it. While you’re at it I would replace the little rubber pipe as pushing it back onto the fitting if the pipe is old can cause little bits to break off clogging of partially clogging the inlet causing a low fuel pressure fault.

 

[prt57]

Your car should run fine with the upgraded fuel pump and stock fuel valve. I was running APR stage 2+ with the standard valve for a while with none of the problems you are describing.
I’d be wanting to check the inlet fitting on the replacement pump as I said before. It should be drilled out to 5mm anyway to help the lpfp. Take care removing the brass fitting as there is a little washer in there that is easily lost. The pump will leak petrol without it. While you’re at it I would replace the little rubber pipe as pushing it back onto the fitting if the pipe is old can cause little bits to break off clogging of partially clogging the inlet causing a low fuel pressure fault.

 

[ch1z64]

Your car should run fine with the upgraded fuel pump and stock fuel valve. I was running APR stage 2+ with the standard valve for a while with none of the problems you are describing.
I’d be wanting to check the inlet fitting on the replacement pump as I said before. It should be drilled out to 5mm anyway to help the lpfp. Take care removing the brass fitting as there is a little washer in there that is easily lost. The pump will leak petrol without it. While you’re at it I would replace the little rubber pipe as pushing it back onto the fitting if the pipe is old can cause little bits to break off clogging of partially clogging the inlet causing a low fuel pressure fault.

Now i was wondering if there should be a little brass ring inside the part that the fuel rail attaches to but no one has ever been able to give me a definte answer to that only reason why i say this is the first time i removed my hpfp i couldnt get it out so unscrewed the brass fitting u speak about am i am sure i heard something drop , spoke to R-tech then and have to say i am not 100% sure if they said it should have a little brass compression ring in it as they had never took 1 apart .
So are you saying there should be a brass ring in there cause other pump too never came with 1 .
After fitting old pump bk in i am able to go over 60 mph without any probs and revs seem to be ok . Anything else u can think off would be appreciated .
On another subject but related to pump would the sensor on top whdn disconnected be draining battery

 

[ch1z64]

Couple off pics 1 showing inside off inlet other showing autotech internal i hope . Any advice or anything you nitice different pls advise as appreciated

 

[prt57]

I have never taken a pump apart myself but have read about this happening on other forums after doing the 5mm drill modification.
I can see no logical reason why removing the sensor would cause a flat battery.

 

[ch1z64]

Fully the same when it comes to battery spoke to Rac guy and he said the same, but anytime i have removed pump battery has dropped to under 11volts , now i am not sure if primming pump can drain battery so that will be something i need to look into in time as battery is running fine the now .
Will again speak to R-tech about washer inside pump but mine holds ok the now with no leaks and waiting on stainless fuel line coming with correct diameter

 

[ch1z64]

Another Question if you dont mind answering pls what is the purpose off upgarding to the RS4 Frpv once u puy the upgrade hpfp in , just i am confused with that if stock can handle it . Cheers

 

[samisnake]

Another Question if you dont mind answering pls what is the purpose off upgarding to the RS4 Frpv once u puy the upgrade hpfp in , just i am confused with that if stock can handle it . Cheers

"The fuel system for the 2.0 TFSI separated in two systems:
The low pressure system (3 to 5bar) is feeding the high pressure system (50 to 130bar).
2.0L TFSI engines that are running more than 300hp need to change the high pressure fuel pump together with this upgrade valve. Otherwise under full throttle the engine can run too lean. Too lean running may result in engine failure!

This valve is a "bridge" between the low and high pressure."

 

[prt57]

"The fuel system for the 2.0 TFSI separated in two systems:
The low pressure system (3 to 5bar) is feeding the high pressure system (50 to 130bar).
2.0L TFSI engines that are running more than 300hp need to change the high pressure fuel pump together with this upgrade valve. Otherwise under full throttle the engine can run too lean. Too lean running may result in engine failure!

This valve is a "bridge" between the low and high pressure."

Excellent post!
I had the APR stage 2+ software added to my S3 and did not know about the RS4 valve and my tuner did not mention it. I only learnt about it later on after reading on this forum and elsewhere. I contacted APR HQ at Awesome and they confirmed not totally essential but for peace of mind it should be fitted. However places like RTech say needed for stage 2+. I understand that having the 165 or 175 bar valves put more strain on the vulnerable cam follower. The latest tuning advice for stage 3 is to run the RS3 injectors or the latest special high flow K04 injectors with an RS4 valve rather than the original Injectors and the ultra high pressure fuel valve.
The modified standard injectors are a massive step forward as you do not need a modified wiring loom or the cylinder head modification to suit the RS3 injectors. Cheaper overall as well.

 

[ch1z64]

"The fuel system for the 2.0 TFSI separated in two systems:
The low pressure system (3 to 5bar) is feeding the high pressure system (50 to 130bar).
2.0L TFSI engines that are running more than 300hp need to change the high pressure fuel pump together with this upgrade valve. Otherwise under full throttle the engine can run too lean. Too lean running may result in engine failure!

This valve is a "bridge" between the low and high pressure."

Cheers for ur in depth explaination @samisnake , so can you tell me if i fitted the Rs4 Fprv would there be any problems qith the stock pump being used , just incase the other pump i have is faulty plus i can change the hpfp myself

 

[ch1z64]

Excellent post!
I had the APR stage 2+ software added to my S3 and did not know about the RS4 valve and my tuner did not mention it. I only learnt about it later on after reading on this forum and elsewhere. I contacted APR HQ at Awesome and they confirmed not totally essential but for peace of mind it should be fitted. However places like RTech say needed for stage 2+. I understand that having the 165 or 175 bar valves put more strain on the vulnerable cam follower. The latest tuning advice for stage 3 is to run the RS3 injectors or the latest special high flow K04 injectors with an RS4 valve rather than the original Injectors and the ultra high pressure fuel valve.
The modified standard injectors are a massive step forward as you do not need a modified wiring loom or the cylinder head modification to suit the RS3 injectors. Cheaper overall as well.

Cheers for all ur replies and knowledge

 

[nluk100]

The RS4 valve is fine even for a std tune. It increases the max rail pressure by a very small margin, but only if the map asks for it (I think it's less than 10Bar, which is less than 10% extra). Tuners like fitting them as they can push the rail pressure a little bit harder without maxing out the std valve. Also, they are known to fail - I had 2 go on my own car during my ownership, both genuine, one OEM S3 and a new RS4 valve.

 

[ch1z64]

The RS4 valve is fine even for a std tune. It increases the max rail pressure by a very small margin, but only if the map asks for it (I think it's less than 10Bar, which is less than 10% extra). Tuners like fitting them as they can push the rail pressure a little bit harder without maxing out the std valve. Also, they are known to fail - I had 2 go on my own car during my ownership, both genuine, one OEM S3 and a new RS4 valve.

Cheers for reply , would you happen to know if a washer should be in behing the brass screw that takes the union as thats something know one is able to confirm yet , now as old pump is bk in it didnt have a washer nither has new one but people have mentioned washer

 

[nluk100]

I can't answer that one as I fitted a Loba pump to mine.

 

[Charlie23]

HI mate,

I had to remove all the fittings when fitting my Upgraded Pump.

The Union that people mention drilling out has a small washer, the rest do not if that helps.