21 replies to this topic

[Udo]

Right bit of background first.Sorry for long winded explaniation although hopefully will answear questions before they get asked

 

Friends engine that he had built, spec as below:

 

1293 fresh bore pistons rings etc new bearings

New cam & followers timed in with dti on adjustable cam timing gear

Head work done by either MED or VmAX (i cant remmeber who mate said)

New roller rockers 1:1.5

Vmax Supercharger kit in general but with a slightly different intake to put the carb in top left hand corner of the engine bay

New electronic dizzy with vacumn

HIFF44 carb with spring in it from S/C kit

LCB manifold 1.75" system

New HT leads new resistive plugs etc

Fuel pressure regulator set to 3psi

 

Basically all new engine!

 

With another car on jump leads (so battery doesnt go flat) the car will turn over happily and make noises as if it wants to start but just wont catch.

 

Advancing/retarding the dizzy makes it sound more or less like it wants to catch (we know the dizy timing needs setting up properly once running)

 

Checks carried out so far

 

All plugs firing

Plug leads in correct order

Dizzy drive in the correct way

12 volt now going to the coil (mates wiring!)

Fuel is getting to the carb and to the plugs (however leads to problem below)

 

After cranking for a minute or so and then stopping fuel drips back out of the air filter (K&N type) (carb has been removed and checked nothing blocking anything and no debris in the carb, no wear etc)

 

 

Any help as too

 

A) Why fuel is leaking back out the carb

B) Why she wont fire up

 

Gratefully received

 

Cheers

 

 

[liirge]

1. Where is this fuel? do you mean back out of the filter or from a gasket/overflow outlet?

 

2. Have you tried cleaning the plugs, you may have just flooded them. I've had this stump me before causing her to nearly catch but then not.

[ChopperHarris]

If that's happening its obviously overfuelling....if you crank it without choke but with the throttle fully depressed will it catch?

[Udo]

1. Where is this fuel? do you mean back out of the filter or from a gasket/overflow outlet?

 

2. Have you tried cleaning the plugs, you may have just flooded them. I've had this stump me before causing her to nearly catch but then not.

 Fuel is out of the filter

 

Yes cleaning plugs although they are new. Fuel pressure is set to what mate was told to set it to, although yes can turn it down.

[Udo]

If that's happening its obviously overfuelling....if you crank it without choke but with the throttle fully depressed will it catch?

 

Not tried it fully open have tried part open, with with out choke etc

 

As above I will try to turn down the fuel pressure and try again

Edited by Udo, 11 August 2015 - 02:19 PM.

[ChopperHarris]

I would turn pressure right down, it should start on whats in float bowl anyway

[ChopperHarris]

Are you sure the cam timing is correct?

[liirge]

 

1. Where is this fuel? do you mean back out of the filter or from a gasket/overflow outlet?

 

2. Have you tried cleaning the plugs, you may have just flooded them. I've had this stump me before causing her to nearly catch but then not.

 Fuel is out of the filter

 

Yes cleaning plugs although they are new. Fuel pressure is set to what mate was told to set it to, although yes can turn it down.

 

Doesn't matter if they are new,

 

Oil in cylinder and fuel will foul the plugs quickly.

[liirge]

If you don't think it is over fuelling and you have spark try putting a cap of fresh fuel directly down the carb and try again. If that works you know it either needs more fuel or there is blockage somewhere,.

[jagman.2003]

How old is the fuel as well.

It can loose octane value quickly & high compression engines are fussy.

[Udo]

Are you sure the cam timing is correct?

 

Yes 100% sure its correct

 

If you don't think it is over fuelling and you have spark try putting a cap of fresh fuel directly down the carb and try again. If that works you know it either needs more fuel or there is blockage somewhere,.

 

No blockages in the fuel system - have checked already

 

How old is the fuel as well.

It can loose octane value quickly & high compression engines are fussy.

Good question - mates car so I'm not surre but will get him to get some fresh

 

Thanks all for help - will turn fuel pressure down, let plugs dry out/clean them anyway, put some fresh fuel in and try again

[liirge]

 

Are you sure the cam timing is correct?

 

Yes 100% sure its correct

 

If you don't think it is over fuelling and you have spark try putting a cap of fresh fuel directly down the carb and try again. If that works you know it either needs more fuel or there is blockage somewhere,.

 

No blockages in the fuel system - have checked already

 

How old is the fuel as well.

It can loose octane value quickly & high compression engines are fussy.

Good question - mates car so I'm not surre but will get him to get some fresh

 

Thanks all for help - will turn fuel pressure down, let plugs dry out/clean them anyway, put some fresh fuel in and try again

 

I still suggest you put a bit of fuel down the carb throat and see what happens.

[Udo]

Know the fuel is getting from the carb to the head though.

 

Thinking about it anyway from the car i.e. not frustrated with it I do think its over fuelling and so flooding it.

[blackbelt1990]

My mate's turbo was doing this recently, flooding the carb out of every hole. Fuel pressure was set too high and it was blowing the float open.

[Gr4h4m]

The suck through kits only need standard fuel pressure. I ran a 3 psi facet solid state pump she. I used a carb. I presume your using a SU. Just Checking you haven't blocked the vent pipe for the fuel bowl / chamber?