Fuel starvation problem - help!

[jess]

Hi Steve,

sounds like its a supply problem to your 044 pump, if there are rubber lines used at or as a pickup they could have cracked and are sucking air also

remove surge tank could be backfeeding into tank use pri and sec pumps straight line from reg to tank lastly check fuel cap could be creating a vacum in the tank although unlikely

cheers
jess

[NASSTY]

Hi Steve,

Another issue may be that your low pressure line to your 044 may not have enough volume in it. The line from my surge pot to the 044 is the largest line in the fuel system. That said, unless you have a stepper on your line to the 044 then you would already have the right sized line.

[sideshow]

just wondering does the return line from engine if u have one return to the
swirl pot or to the tank

if u have the return goin to the swirl pot it acts as a filler for the swirl pot
aswell as filling it with the prime pump

we always run things this way

some people say this way te\nds to heat the fuel up abit more but we never had probs this way

my prefference is the mod the tan k and get an internal swirl pot and efi pump
all inside the tank so there is less connnections

[stephen low]

Thanks guys once again.

Seemed to have repeated issue in my other thread but have tried several setups.

Started with scavenge pump to swirl to Bosch and return to swirl and overflow to tank.

Then tried scavenge direct to bosch with swirl acting as remote bypass back to tank.

Then tried bosch direct to engine no scavenge or swirl and return direct to tank. By this attempt I think the pump was fried but would pump 300kPa at start and run engine at high revs. but within minutes it would die from overheating and rapidly loose pressure.

Interestingly I remounted the initial bosch that was put in the car and it failed in the same way although it was developing slightly less pressure initially.

I've a stock GForce tank that came with the kit so it is a bit limiting to modify but what intank options are suggested?

Is it better to go a standard car's in tank pump system or use an intank bosch or similar. If I go this route I will want the pump capable of feeding the 5L when I stroke it to 347 down the track.

Any ideas would be appreciated.

Cheers

[sideshow]

if uhave tried afew diff ways then u might have a problem elsewhere

to know if u r running out of fuel is get a passenger to hold the return line
into large container

drive the car carefully and see if u run out of fuel coming out of return line

best way to do this is on the dyno but u can do it on street but its not the right way and its dangerous so im not saying to do it this way hehehee

maybe your carby is not right

maybe a dyno is the way to go

much safer when your diagnosing fuel problems

another thing would be to connect a fuel press gauge and go for drive

see what happens

if press drops then u have fuel feed problem

if press is ok and car still plays up then u have carby problem

[stephen low]

Thanks sideshow but have rear jacked up on blocks and ran car with gauge attached so loss of fuel is via main pump. And with pump connected direct to fuel tank it has to be an issue within this line. Car is EFI too not carby.

Will reinspect fuel filter that I had only recently cleaned.

Cheers

[NASSTY]

Hmmm, interesting problem Steve

The line from my surge pot to the 044 is 1/2" ID from memory and about 50-60cm long as it goes behind the seat belt bracket to the 044 on the other side. WHen designing the system I was advised to use 1/2" b/c the issue was volume of fuel getting to the 044. What size line are you using on the low pressure side of the 044?

Cheers

[Philm]

Slowly,
I run the exact same system, carter black lift pump and 044 I have the surge pot as in the pick below.

The bottom line is the feed to the 044 which is about 100mm from the end of the filter.



I have had no problems with this and it feeds the 48 pound injectors and maintains the fuel presure at the rails with out a problem.

All hard lines are 1/2 inch and all braid is AN 8.

I am not sure if some one has mentioned this but is your tank vented?

Phil

[stephen low]

Maybe some poor early advice isn't helping as I think all my fuel lines are only 5/16 tube and that's inlets and outlets. But would this make too much of an issue?

However am seriously thinking of one of the VK/VL/VN series pumps in tank. I believe the pumps were in 6cylinder VL and 6 or 8 cyl VN versions and I have no idea which of the VK models.

Can any one set me straight and do all these mount on the side wall of the tank or is there a top mounted version?

Also I'm running Don's fuel filler neck system which I believe allows venting via the filling return flap. Or am I wrong on this?

Cheers

[Philm]

Slowly,
I think the filler neck is not a breather!!!!!!

Try driving with the petrol cap loosened, it could be as simple as that.

I run Don's neck but also have a 1/2inch breather line further down that runs into a charcole canister

[alffie]

Slowy
I dont think your 5/16 line will feed a strong 347!!. The early VN V8 run a internal lift pump and a bosch external 047 i think. Post 91 use the 023 internal pump. Try a cool can they will at least give you some more power. How have you set up the charcol canister? Your breather should go through it, late model fuel caps dont breath because of the charcol set up.

[stephen low]

Sorry guys forgot about a late set up change made were I had Marty Govett add a breathing point to my charcoal cannister just beneath the fueling point, so have no breathing issues there.

Recognise now that the fuel lines are small, probably ok for the 5L as the stroker idea only came later after doing all this work. I'll be happy to change this to suit down the track.

I'm aware some of the early commodores ran the two pump arrangement but I thought there was reversion to a single large in tank pump later on. Is this wrong or does anyone know what model Commodores this was done in?

When I was buying the Bosch I asked about in tank options and I can't recall which model the fellow was talking about but he indicated there was an aftermaket pump, presumably a good deal more potent than the standard pump, that could be substituted into the standard in tank carrier.

This would be an ideal option to eliminate all the external crap hanging around the car. I'll ask more tomorrow when I front them with the dudded pump.

Failing that if I have to buy another pump, perhaps the Bosch in tank variant, but is there a standard carrier kit it can be mated to or does this all have to be fabricated.

Cheers

[Rebel1]

Stephen, here is an aftermarket in-tank bracket you can use with any pump.

http://www.breezeautomotive.com/deta...=402&cat_id=27

Maybe an option for you.

Cheers

[alffie]

Slowy
The VN SERIES 2 POST 91 ON run the single in tank pumps. The bosch 023 pump is the intank 044 equvilent. They replace the std bosch commodore pump.
Sounds like you have vapour lock issues

[Outwest34au]

My 2 bobs worth.
5/16" sounds a bit small, volume and pressure are what every fuel driven car need.
I've always used 3/8" standard dayco braided line on everything I've built, even my LPG powered pulsejet, (pulled about 42 hp too )

They were all small engines, most of the guys that had thier speedway cars at home on methanol ran 1/2" line minimum. I know it's a different fuel, but they were only 250 crossflow Falcons. 5/16" line is for mums car.

Other obvious suspects, vapourlock, but on a fuel injected engine a fuel return/ bleed to tank (however small) would eliminate this?
And, any chance your inlet outlets on the surge tank could be arse about face? I've only ever made that type of turnout for carby engines before.

There are some cluey ford lads at the fordmod forum site too, some of them are nearly as fanatical as cobraists.

Good luck