Truck stalls, black smoke from exhaust

[68longhorn]

My 86 with a 305 with a q-jet (all stock) started acting up. It started idling low then cut off. It was hard to restart and when I give it gas it smokes black smoke from the exhaust. Any ideas? I had previously bypassed the faulty timing module but it ran fine for a year prior to this.

[85gmcguy]

Black smoke is usually an indication of over-rich (too much fuel). Make sure nothing is "hung up" in the carb linkage/choke/throttle butterfly department.

[bmchevy1979]

Definitely check your choke my Blazer did this to me after changing the distributor cap and rotor I started it up and it just started choked itself to death I shut it off and the choke was closed tight I adjusted it and made sure all of the linkage was free and clean and never had another problem

[1LowToy]

I'd check the vacuum diaphragm for the choke pull off.

[68longhorn]

How do i check the diaphram? It does it randomly. Mostly seems to happen when I let off the gas to slow down

[mooseknuckles]

x2 on the choke.

[68longhorn]

update: Its still randomly acting up, I did get it to happen in the driveway with the air cleaner off and didn't see any thing change or move with the linkage or throttle plates. Does this mean those are ok?

[cr34t3d_by_d4rkd3n]

Originally Posted by 68longhorn

My 86 with a 305 with a q-jet (all stock) started acting up. It started idling low then cut off. It was hard to restart and when I give it gas it smokes black smoke from the exhaust. Any ideas? I had previously bypassed the faulty timing module but it ran fine for a year prior to this.

re check those connections.....

sounds like a valve went to me, read ur plugs and go from there.... its hard to say what it may b when u cant hear it run.....

[68longhorn]

I did recheck that connection because it was acting similar to that but different. when it happens I'm normally off the gas slowing down and you just stop hearing the truck because the idle drops real low and she tries to stall so i put it in nuetral and rev it up and she struggles to rev up at first but once the rpms come up its ok till i let of and let it return to idle. If it happens when driving i down shift to keep the rpms up and it seems fine.

[Hottrucks]

sounds like the float in the carb might be hanging up??? heres a cheater thing that might work ...put a clamp on the fuel line ( down where it feeds the fuel pump the rubber line) start the truck and let it run till it dies...this will burn all the fuel out of the bowl....take the clamp off and fire it up again...SOMETIMES..if theres a small spot of dirt in the needle valve or jet the rush of new fuel will wash it though since the float is so low it will allow the needle vavle to be wide open....like I said this is a SOMETIMES..quick fix...