Thread: 3.5L running on 5cylinders! please explain??

Originally Posted by p38arover

i spotted that this morning, damm eyes!
thanks ron.

As said, the first thing is to eliminate spark as the suspect. Check that there is spark to each cylinder, if so, pull the plug and check that the plug will fire (not fouled).
Then check the carbs - is there oil in the carb slides? Are the diaphragms intact? Disconnect the linkagages which connect each carb and rev the motor independantly by hand on each carb - the result should be similar - it should rev but not cleanly.

As Frank suggests, I'd check that the leads are on the dissy in the correct firing order.

I'd check that the leads are on the dissy in the correct firing order.

checked that twice on the first dizzy and twice on the second dizzy.

there is deffinatly spark at all the plugs and at the leads.
the plugs are new and not fouled and ive changed out the ones that arnt firing with ones that are.

one thing that may point to langys theroy is that it runs really rich!like fills the shed in 3min with a black fog. ive not done alot with SU's/strommies but ive completed the simple things that the book suggests in the tuning section. these are the cd's that require a special tool the adjust the mixture ( i think) there is no adjustment on the bowl of the carb's.

langy i may call on a favor soon

cheers phil

The cyls that arnt firing may have sticky exhaust valves

Originally Posted by langy

For Mr Tank: I used to own a 83 2Door - and I've done fair amount of work on it.
One carby does 1,4,6, and 7. The other carby does 2,3,5,8. Its a dual plane manifold. It seems coincidental that 1,4,6 ( well not 7 but close enough) aren't igniting. Given that the ignition system has been changed, the next thing to look at is fuel/air/vacuum

6 is firing though, 1,4,7 aren't, Regards Frank.

Originally Posted by discowhite

checked that twice on the first dizzy and twice on the second dizzy.

there is deffinatly spark at all the plugs and at the leads.
the plugs are new and not fouled and ive changed out the ones that arnt firing with ones that are.

one thing that may point to langys theroy is that it runs really rich!like fills the shed in 3min with a black fog. ive not done alot with SU's/strommies but ive completed the simple things that the book suggests in the tuning section. these are the cd's that require a special tool the adjust the mixture ( i think) there is no adjustment on the bowl of the carb's.

langy i may call on a favor soon

cheers phil

You said you set the points, so I assume it is a Points Dissy, did you replace the Condensor, it can cause similar problems.
When the engine is running and the 3 cylinders aren't firing have you pulled the plug leads and checked to see if there is spark.
The fact that you are getting clouds of black smoke indicates either no spark at some cylinders (as you described) or you are getting too much fuel (flooding).
Question: How did you install (time) the distributor when you replaced it, you can call me if you wish, Regards Frank.

Originally Posted by Tank

6 is firing though, 1,4,7 aren't, Regards Frank.

Is 6 firing or is it that the corresponding cylinder on the other carby is very weak and therefore it appears that 6 must be firing.

To check the diaphragms, remove the cap from both carbies with the engine idling and use a small screwdriver or something to push the piston down. If the diaphragm is gone in 1 then the piston wont be lifted at all and pushing will not affect idle revs. However the black smoke does not suggest a diaphragm problem.