black cap carb dizzy

[johnny27]

I know the spi and mpi dizzy with the orange cap are'nt very reliable, they sometimes go faulty and the car won't start or fire properly?

Does the carb type black cap dizzy ever develope any problems?

As i'm trying to source a fault in my nova, it is fine driving at low revs, but the engine dies when i get to about 3400rpm, i have to lift my foot off the throttle and use only half throttle to get the cat to drive, was thinking it was my weber carb the problem is with, but i would like to elimante any other possible cause. Thanks

[johnny27]

also i've changed the spark plugs and the plug leads are fine, the dizzy cap looks to be fine when examined

[Stuart]

which engine?

the 1400 carb REAL dizzy is great, no problems ever really

[Adam]

SPI's use both types of dizzy, they are both the same type of ignition system, but with a different cap.
Its the hall sensor that sometimes starts playing up.
Common in both types of dizzy tho.

On a carb dizzy, theres not really much to go wrong. Apart from the rotor breaking or something.

[mowgli]

if it is a black cap delco type, the timing advance retard vacuum unit can fail, causing the timing to be way out.
Dead simple way of testing it.
start the engine. pull the vacuum pipe off at the carb end & stick something over the hole on the carb end. then simply suck on the small pipe. if the engine note changes then it is ok. if not then the unit is broken. they are easy to swap.

[Adam]

I think the vacuum unit only makes minor timing adjustments, its the centrifugal system inside the dizzy that alters the timing mostly.