Fuel System Problem ?

[4hirpm]

hey people

just had a new fuel system installed into my skyline and i seem to be having an issue with it. Im running a 040 as a lift pump to my surge tank then an o44 to the rail that then returns back to surge tank then return to tank etc

after awile the main pump becomes pretty noisy and after few drift runs on the weekend the car would start to cut out\lose power but not stall the pumps are wired up with relays and getting good volts but it just seem's like its running out of fuel or something.

was thinking the fuel my be getting to hot as its flowing from the engine back to tank and then back again rather fast and when i put an extra 20 ltrs in the car it seem to take longer for the problem to start but its just guess

any ideas would be great

Edited May 14, 2009 by 4hirpm

[Craved]

fuel cooler, especially since your running the return to the surge tank from the rail - have a look for a thread by Guilt-toy regarding his findings.

[SirRacer]

I added a cooler onto my car and whilst it helped, it didnt completely fix the problem. It cut out the other day whilst in rain with the fuel cooler.

Ive got another pump here that i know whos which im going to swap, however i think there maybe a dodgy batch of imitation 044's on the market as it seems to happen too often.

[The Dan]

Do you have one relay for each pump and how good are the earths/power wires to each one? are you running a self resetting circuit breaker in line?

It sounds like the lift pump is having issues. It's a bad idea to use an EFI pump for a lift pump, although many people do it, best practice is to get a low pressure lift pump to do the job so you don't get cavitation.

[Guilt-Toy]

the issue is because the fuel is getting too hot. if you do a search you can see I have had this issue before after installing a 044 pump. best way to check is once it starts to get noisy and you have a quarter of a tank of fuel go to a servo and fill the tank up with fuel.

within 1 minute the noise will stop and it will go back to normal. i put a fuel cooler on my return line and it did not completly fix the issue but it did delay it for quite a while longer.

just put your hand over the 044 pump and feel how warm it is when its making the noise and when its not you can feel the difference.

[SirRacer]

the issue is because the fuel is getting too hot. if you do a search you can see I have had this issue before after installing a 044 pump. best way to check is once it starts to get noisy and you have a quarter of a tank of fuel go to a servo and fill the tank up with fuel.

within 1 minute the noise will stop and it will go back to normal. i put a fuel cooler on my return line and it did not completly fix the issue but it did delay it for quite a while longer.

just put your hand over the 044 pump and feel how warm it is when its making the noise and when its not you can feel the difference.

Hi GT,

Its definitley part of the problem, however im not sure its the whole problem. In New Zealand here its half as hot an Aussie and I had a fuel cutout the other day whilst driving in rain with a fuel cooler. When i pulled over my surge tank was reasonably cold as was my pump. Ive got 2 seperate relays running each pump.

Other friends who have exactly the same setup - the fuel coolers have no problems.

Ive got another pump here that i know works so im going to do a few tests and post my findings in a few weeks. Id like to be able to remove the fuel cooler due to perhaps having an accident and having it shatter in the impact.

My setup as below

http://farm2.static.flickr.com/1062/317023..._b16d645bc6.jpg

http://farm4.static.flickr.com/3127/316940..._f35841970d.jpg

Ive since changed the relay on the second pic to a bosch one.

[PSI Parts]

Why are people insisting on using a 040 for a lift pump? The stock pump is fine and will help reduce heat by reducing the pressure the fuel is under from the time it begins it's journey from the main tank.

[rob82]

What horsepower are you making beacuse an 044 will flow enough for 350rwkw at 5bar of pressure.

[shotter]

I have found in the past when i used a high flow pump as a lift pump it would just run flatout and get really hot, I think it's because there isn't really any restriction going in to the surge tank. So any fuel thats pumped in and not needed just flows back to the tank. So the pump just runs at max flow constantly. I would say if you dont have much luck with anything else try a smaller lift pump.

[SirRacer]

i have a nissan laurel turbo lift pump and i still get massive cut outs.

the local guy at petroject has also told me that the lift pump may be the problem. im not too sure about that, but heat doesnt seem to be 100% the problem in my case.

here is his email

-a bosch 044 can draw 15 amps continuous so your factory relay won't cope. Replace it with a 30 amp (=15 amp continuos) Bosch or Hella relay (best quality).

-run each pump off a separate relay, again both pumps together will be too much draw for just one relay.

-makes sure all your connectors are soldered and terminated correctly and not just crimped = asking for trouble.

-are you using the factory EFI pump as a lift pump?

-if you are, its actually pointless running a surge tank and inline EFI pump, the purpose of which is to eliminate surge and prevent the EFI pump from running dry. Your factory pump is still susceptible to surge if if it does run dry (and in race situations it will), it will starve your main pump in not much time at all = 2 dead pumps.

-capable lift pumps are $150 + gst, Pierburg (Germany) brand and designed for the job.

-the inlet to the 044 should be a minimum of 12mm internal diameter, -6 is too small. You need big volume at low pressure to the pump so you need a big diameter hose.

-the rest of your setup looks fine, you could add in a $25 pre-filter between the surge outlet and the inlet of the 044 as a last resort protection as well, but so long as your fuel system is clean (was the o.e fuel tank inspected/cleaned/stripped?) its not 100% necessary. (it is if there are no other filters on the inlet side, i.e if there is not one on the lift pump)

The only other minor thing I would add is that with your 044 outlet fitting you have no non-return valve in the system. That means after engine switch off, your fuel line will drain back through the pump, this can in the worse case cause vapour lock in a hot engine bay and make difficult starting = can cause engine damage and even an engine bay fire.

The intermittent noises can be related to low voltage = high current = excessive heat and swelling of the pump armature which will not cause the pump to fail all together but limit its output, (causes shorts in the armature and lowers the pumps terminal rpm)

and/or

starving of fuel pump under surge conditions = wear in the gear set = terminal pump damage and will eventually stop altogether.

Edited May 17, 2009 by SirRacer

[SirRacer]

Do you have one relay for each pump and how good are the earths/power wires to each one? are you running a self resetting circuit breaker in line?

It sounds like the lift pump is having issues. It's a bad idea to use an EFI pump for a lift pump, although many people do it, best practice is to get a low pressure lift pump to do the job so you don't get cavitation.

hi mate,

care to elaborate on why this may be the issue?

ive heard that piersberg do a great lift pump

[The Dan]

hi mate,

care to elaborate on why this may be the issue?

ive heard that piersberg do a great lift pump

Usually when the pump becomes noisy it is because of the cavitation. When using an EFI pump for a lift pump the fuel is pumped in at such a high speed that it cavitates the fuel. The air is then sucked in by the main pump which causes it to be loud.

I usually use Carter for the lift pump. They pump 100gallons per hour at low pressure.

[hypergear]

No. This is due to a shit design of the fuel pump of how they added a very fine micro filter on the bottom of it. when dirt blocks up the filter, the pump can't suck in fuel so it drains all the power trying to suck harder and makes a very loud noise.

I've had the same problem which I had to clean the pump and tank once a year. I ended up removing that filter and it never played up again.. Hoo just make sure you run a good fuel filter.

[Beer Baron]

i have a nissan laurel turbo lift pump and i still get massive cut outs.

the local guy at petroject has also told me that the lift pump may be the problem. im not too sure about that, but heat doesnt seem to be 100% the problem in my case.

here is his email

-a bosch 044 can draw 15 amps continuous so your factory relay won't cope. Replace it with a 30 amp (=15 amp continuos) Bosch or Hella relay (best quality).

-run each pump off a separate relay, again both pumps together will be too much draw for just one relay.

-makes sure all your connectors are soldered and terminated correctly and not just crimped = asking for trouble.

-are you using the factory EFI pump as a lift pump?

-if you are, its actually pointless running a surge tank and inline EFI pump, the purpose of which is to eliminate surge and prevent the EFI pump from running dry. Your factory pump is still susceptible to surge if if it does run dry (and in race situations it will), it will starve your main pump in not much time at all = 2 dead pumps.

-capable lift pumps are $150 + gst, Pierburg (Germany) brand and designed for the job.

-the inlet to the 044 should be a minimum of 12mm internal diameter, -6 is too small. You need big volume at low pressure to the pump so you need a big diameter hose.

-the rest of your setup looks fine, you could add in a $25 pre-filter between the surge outlet and the inlet of the 044 as a last resort protection as well, but so long as your fuel system is clean (was the o.e fuel tank inspected/cleaned/stripped?) its not 100% necessary. (it is if there are no other filters on the inlet side, i.e if there is not one on the lift pump)

The only other minor thing I would add is that with your 044 outlet fitting you have no non-return valve in the system. That means after engine switch off, your fuel line will drain back through the pump, this can in the worse case cause vapour lock in a hot engine bay and make difficult starting = can cause engine damage and even an engine bay fire.

The intermittent noises can be related to low voltage = high current = excessive heat and swelling of the pump armature which will not cause the pump to fail all together but limit its output, (causes shorts in the armature and lowers the pumps terminal rpm)

and/or

starving of fuel pump under surge conditions = wear in the gear set = terminal pump damage and will eventually stop altogether.

all of what the petroject bloke has told you sounds reasonable to me. and yes using high flow, high pressure EFI pumps as a low pressure lift pump can cause problems. you are far better off with a high flow low pressure type pump that is designed for that application. some high performance carby type pumps are suitable and not expensive.

[SirRacer]

Usually when the pump becomes noisy it is because of the cavitation. When using an EFI pump for a lift pump the fuel is pumped in at such a high speed that it cavitates the fuel. The air is then sucked in by the main pump which causes it to be loud.

I usually use Carter for the lift pump. They pump 100gallons per hour at low pressure.

i would have thought there wouldnt have been any problem with fuel being pumped in at such a high speed considering that it will effectively be splashing the side of the surge tank and then making its way to the bottom?

what prices are a carter lift pump, and have you had 044 cut out issues before and had them solved with a change of lift pump?

and hypergear, do you mean the filter in the 044?

[The Dan]

i would have thought there wouldnt have been any problem with fuel being pumped in at such a high speed considering that it will effectively be splashing the side of the surge tank and then making its way to the bottom?

what prices are a carter lift pump, and have you had 044 cut out issues before and had them solved with a change of lift pump?

and hypergear, do you mean the filter in the 044?

When you fill your car up at the petrol station. Ever notice when the pump clicks and the fuel stops? Same thing. Let it settle for 10-15 seconds and you can start pumping again.

That's what happens when you jet the fuel in at high speed. It cavitates.

[rob82]

When you fill your car up at the petrol station. Ever notice when the pump clicks and the fuel stops? Same thing. Let it settle for 10-15 seconds and you can start pumping again.

That's what happens when you jet the fuel in at high speed. It cavitates.

An 040 will pump like 6-7 L/min not under load - so I can almost garuntee that your swirlpot will be full to the brim the entire time - cant see thats going to cause cavitation with 300mm of head above the pump.

Like I said how much horsepower are you making. An 044 will flow 3.3L/min at 5bar and 12Votls so its preobaly more like 3.8L/min at 5bar and 13.8volts. So at 3bar and 13.8Volts you may be flowing 6-6.5 L/min at low load - THATS GOING TO HEAT THE FUEL VERY QUICKLY.

[The Dan]

An 040 will pump like 6-7 L/min not under load - so I can almost garuntee that your swirlpot will be full to the brim the entire time - cant see thats going to cause cavitation with 300mm of head above the pump.

Like I said how much horsepower are you making. An 044 will flow 3.3L/min at 5bar and 12Votls so its preobaly more like 3.8L/min at 5bar and 13.8volts. So at 3bar and 13.8Volts you may be flowing 6-6.5 L/min at low load - THATS GOING TO HEAT THE FUEL VERY QUICKLY.

I understand what you are saying but I don't make the rules, it is a known fact that it will cause cavitation.

And the pumps flow 4-4.5L min under no load.

I seriously doubt his problem has anything whatsoever to do with hot fuel. It could do but I have never experienced a 'hot fuel' issue in any of the 044 setups I have done. Even with two of them going in our 600+ hp track car, the fuel does not get hot to the extent it will cause this problem or any problem for that matter.

Have you done a fuel pressure test while under load? And noted the results when the problem is occurring?

That would be a place to start I would think.

[s13_Skyline_inside]

how about using one of the walbro pumps i think they'd 180lph and would you run the return back to the surge tank or run it back to the fuel tank with a Y peice in there for the surge tank to overflow back to the fuel tank as well

Edited May 19, 2009 by s13_Skyline_inside

[4hirpm]

cheers for the info guys

i use an 040 for the lift pump because i had already installed it but it wasn't flowing enough so i had to go 044 so i just left it as i thought why replace a pump thats not very old

i think i still have stock pump laying so i will try and use that see how it go's as by the sounds of what your saying that should fix the heat and cavitation issue's if that dosent fix it i'l try a fuel cooler

i'v been told a transmisson cooler will do the same thing i have one but its a plate one and was unsure how it would flow

as for power it makes im unsure as i havent had the car on the dyno we do all the tuning on road (got to love tassie )

Edited May 19, 2009 by 4hirpm