5 GT Turbo Fuel pump setup

[oreille22]

Hi guys,
I would like to know what is the proper setup for the fuel pump.
Is it the
Fuel tank ->fuel filter->fuel pump ->fuel line to carb.
Or is it
Fuel tank-> fuel pump->fuel filter ->fuel line to carb
?

Got phII gtt and under the higher boost it starts to get rough as like there is not enough fuel. I have resealed the carb, doublechecked the vacuum hoses, put uprated fuel pump, but the issue persists. The aem lambda dia shows afr 14,5 o. Idle and almost 15 under the throttle. ( The mix ture screw is almost loose.

Any idea what could it be( have clio williams and r5 gte at home but these are efi engines, no carb so i am not yet very familliar with the carb setup etc.)
Thanks in advance ,

 

[oreille22]

@admin can you please move it to technical section? I added it to wrong section
Thank you.

 

[Brigsy]

Ph2 gtt is tank to pump, pump to filter, filter to reg, return from reg to tank, single line off reg to carb.

What are your afrs on full throttle/full boost.

 

[oreille22]

Ph2 gtt is tank to pump, pump to filter, filter to reg, return from reg to tank, single line off reg to carb.

What are your afrs on full throttle/full boost.

Hi,

they are not nice ( about 14.5 and above (do not know if the aem dial shows well)). when I floor it, it shows for some seconds 13.7 and then it raises up to 14,7 - 15,0 ( very lean to me ) and it also begins to drive roughly .

 

[Brigsy]

Hi,

they are not nice ( about 14.5 and above (do not know if the aem dial shows well)). when I floor it, it shows for some seconds 13.7 and then it raises up to 14,7 - 15,0 ( very lean to me ) and it also begins to drive roughly .

Sounds like the carb needs rejetting or poss rebuild, how much boost

 

[oreille22]

Sounds like the carb needs rejetting or poss rebuild, how much boost

0.7 -0.8 Bar, so almost stock...
I have rebuild carb twice, but can check if there is something I have forgot.... on stage 1 jet I had problems to remove it, so maybe this has to be checked.... idle is ok at 950 rpm,

 

[Brigsy]

Boost pressure at carb top i assume ?

Check the fuel pressure at the the carb, should be 4psi on idle, and always 4psi above boost pressure at carb top on boost. The fuel pressure regulators are old now and sometimes fail.

Check the vacuum pipe to the fuel pressure regulator has no splits.

Is the fuel filter new ? Also worth pulling the sender unit out of the tank to check for blockages.

Also is the carb vacuum piperowk set up correctly? Any pics of the engine?

 

[oreille22]

Filter new, sender unity is next on plan, I will make some photos as soon as I am in the garage.
Piper work is set lik the Renault 5 gt turbo coupe version, fuel pressure regulator I didnt checked yet, fuel pump is new - from cgb motorsport - uprated one which should be ok also for the

** another symptom is that once I step hard on the brake the engine stalls and goes off (looks like all the vacuum is taken by the brake servo, or something like that.
I need to start again then...

 

[oreille22]

Here some photos. Engine is like the old owner left it...

 

[oreille22]

I have checked the sender unit, it was clear, no blockages...
I have today removed carb from the manifold and it looked a bit loose. ( Is there som torque values for that nuts) Is it possible that this could be the reason for lean mixture?

 

[Brigsy]

If the carb was loose it would cause issues. Renew the gaskets and check the spacer between them is not cracked. The bolts simply need a nip down by hand with a spanner or small ratchet, dont go too mad.

Have you checked fuel pressure?

 

[oreille22]

Fuel pressure i havent tested yet. Have to buy the fuel pressure gauge first.
Should i use som loctite for the bolts so it will not go loose from the vibrations?

 

[Brigsy]

Fuel pressure i havent tested yet. Have to buy the fuel pressure gauge first.
Should i use som loctite for the bolts so it will not go loose from the vibrations?

No need for loctite, they don't come loose when tightened properly.