[65' I6] Black ash/smoke from exhaust, no power on cold start, bad mileage
Recently I posted a topic regarding my engine's lack of power on a cold start, and got some replies that perhaps the choke butterfly is too open, letting too much air in. This may be the case, however, I did not mention that the exhaust also lets out A LOT of black gunk during cold start, and when stepping on the gas pedal, more black smoke comes out.
Is it possible that the carb fuel float is not working properly? It's an automatic choke autolite 1100.. carb tag is not there so I'm not sure which exactly. Also, lately it's burning more gas than usual, which is causing me to speculate that too much fuel is entering the engine from a bad float.
I'd like to get some help to diagnose the issue before I start taking anything apart. Thanks in advance.
I'm no mechanic, so I'm hoping a more experienced VMFer will correct me if I am wrong, but it sounds like you may have a few worn rings. That would allow oil into the chambers where it would foul the plugs (oil on the plugs from the inside) diminish your MPG and be rougher than normal to start, when the engine is cold and lack normal acceleration when at operating tempurature. It would also explain the black smoke - burning oil!
If possible, take a picture of your plugs so others can see them and better diagnose what's wrong.
I believe a compression test would validate/invalidate this. You can get one at any auto store or tool store. Fairly easy instructions.
1965 200ci I6 Hard-top,
Black & Wimbeldon-White and Awesome Car All-Over!
Last edited by Dogface GI; 12-26-2012 at 06:09 PM.
Reason: Added info about burning oil.
Thanks for the reply! I'm not sure if this is the problem, as my acceleration goes back to normal as soon as the engine heats up in about 10-15 minutes. I will go get a compression test to check out the cylinders.
If you haven't done a full tune up on it lately, new plugs, wires, cap, rotor, points, coil, etc. do it now. Even if that isn't your problem, more then likely it is needed anyway if you have never done it since you got it or can't remember when it was done.
That would rule that out entirely and it is just not needlessly throwing money out the window as it should be done anyway as it is a preventative maintenance thing.
'99 GT automatic
CDC Shaker scoop, K&N Filter
MAC cat back
Max Speed 1 ½” Lowering springs
KYB GR2 shocks and struts
Cobra front brakes
I recently changed the plugs, which ended up working horribly so I put the old ones back in. I ordered an electronic ignition which I will put in when it arrives.
For the oil on my plug threads, it might be because I've got a leaky valve cover gasket. I'm changing that today or tomorrow so I'll see if it helps.
Originally Posted by bartl
+1 on carburetion problem, most likely a malfunctioning choke mechanism, although a weak spark/bad points can also do this.
How do I regulate the choke mechanism? The butterfly seems to open during cold start. If I close it with my finger, the idle speed decreases. If I rotate the thermostat that would just change the rate at which the flap opens, correct?
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