Engine details- A15. Bought it fully rebuit and never run. Apparently has a cam. E15 elec dizzy(all new ign parts). Has approx 130miles(not thousand, just 130) on the motor.

So what its doing. Occasionally the car will die in the ass. Only occasionally tho. What it does is start running like #### and trying to stall under 3000rpm. Also makes a kind of cracking noise thru the exhaust... not really a backfire though. Then it just gets worse and worse all over the RPM range so i pull over and it will die. I try to keep it alive by just feathering the throttle. You can hear the carby sucking but it just dies. Then when i try to start it it starts backfiring thru the carby! Ive tried moving the timing to no avail. Then after leaving it for a few mins it will be driveable again(still running like ####) then clear and run beautiful! It have only really driven the car 3 times and its done it 2ce. usualy about 5mins into the drive. First with a standard carby, then today with a 32/36.
Or it will try to do it(try to die under 3k) after i do a bit of a burnout(not sit brake or anything, just drop the clutch)... but then clear.




Any ideas guys and gals?

I might dig around and try to make a standard dizzy back up and try it.

Carby ice?? It happens when there,s high airspeed through the venturies it wrings the moisture out of the air and the airspeed factor makes it cold!! It happened to me..When my carb was too small for the motor, Next time it dies feel around the base of the carb if it,s cold could be the reason.. maybe..... Just check the simple things man before you start pulling s@#t to pieces.

I'm thinking that it sounds like the engine is running out of fuel. Perhaps you should check out the whole fuel delivery system, starting with the filter.

EDIT
With carby ice, what happens is that the air passages in the caeb freeze up & becoome blocked. This results in a rich mixture & lots of black smoke, so this is something to look for.
Backfiring through the carb is a sign of a lean mixture, while backfiring through the exhaust coule be a result of an excessively rich mix.

All efficiently operating carby's will feel cold around the base, but frozen ones will frequently have some frost or ice around the throttle area. The better the state of tune, the more efficient the engine, & the lighter the throttle setting at cruise, the more chance there is for ice, but usually only in cold & humid condidions, ........ usually.

It has a new filter and elec pump on it, with all new rubber hoses. Maybe the metal hose got some #### in it. Ill blow it out with a air gun tomorro. I might re-loacte the pump too. It says in the manual the optimum position is neer the bottom of the fuel tank but must be within 1 foot of the bottom of it. I have it in the engine bay and from my rough measuring it should be within a foot (on the top horn mount).

How does a lean mixture make it backfire thru the carb? I havnt seen it spit any flames out, just raw fuel.

I have no idea why very lean mixtures spit flame through the carb, but I have seen it many times.

i'll agree with dodge on the leaning out bit if not nearly running out of fuel completly ...

cant help on the spiting flames and backfiring bit either but i had this same sort of problem with my old maverick ...
everything was spot on - had the dizzy rebuilt, new leads, coil etc ... had the carby rebuilt and she ran like a dream till i'd give it a bit and everynow and then cough cough groan ... pump accelerator ... back fire crackle groan ... pull over ... engine die sit and crank and nothing but fire and run briefly then die ... get out look at everything in the engine bay, wiggle wires and the likes get back in crank and pump accelerator nothing ... 5min later crank it over and off we go like nothing happened ...
had everythin checked and checked had carby removed and checked .... no idea ?? finally worked out waht i needed to do to get it to happen, took the mechanic for a drive in it and then they solved it ... the carb had been rebuilt to suit a standard engine and the thing was just running out of fuel at WOT then heating up and causing the little fuel that was getting in to the carb to evapourate to quickly to be of any use .... leaning out something feirce to the point of stopping ....

but if you've got this happening with 2 diferent carbs i'd start looking at the fuel pump or a blockage somewhere ...

Yep, sounds like a fuel delivery prob to me too. What shape is the gas tank in? The pickup screen in the tank may be getting plugged, and the sit time gives allows the vacuum in the suction side of the pump to drop.

Try inserting a fuel presure/vacuum gage on the intake side of the fuel pump and see if you are developing vacuum in the pickup line. Also you can use the same gage on the outlet of the fuel pump to verify the fuel pressure delivered to the carby.

I had something like that happen on my E16 b11, it made me insane for a long time, what i finally discovered was the dizzy had fallen apart inside from vibration, and for some reason it would run 5 min maybe 10 then get odd and die, then after sitting a few minutes, maybe an hour run again, repeat.

try swapping dizzys.

yes it looks like a fuel problem but that's not it ;) which is why it took me so long.

the electric fuel pumps like to push not pull and sounds like a dizzy problem maybe.

Ok, update!

First off i relocated the fuel pump next to the fuel tank under the floor.
Then i checked cam and ignition timing. I found that the advance weights on the E15 dizzy were sticking and 1 of the springs wasnt doing anything. so i raided a spring off a old a series dizzy and lubed it up and it works beautifully.
But it still wouldnt start! Thats right it wont even start now! I have fuel and i have spark. But it seemed a very weak spark. So i made up a A series points dizzy (new cap/rotor/points/condenser) and it seemed to beef the spark up. It tried to start once but chugged and died. Now it wont even try to start/backfire... NOTHING! Then i ran out of battery so thats why im here typing my findings.

I had it idling away for ages yesterday and free revving well, but as soon as i decided to drive it, it packed the ####s and yeh now wont even start!

And theres no oil in water/water in oil incase your thinking head gasket