colt start issues

[db2u]

88 festiva LX (carb) 225k miles.

On a cold start (less than 25 degrees F outside temp) the car starts fine. It runs for about 15 seconds perfectly fine, then starts misfiring on one cylinder. I can let it sit and idle for several minutes and it will continue to misfire. If I jab the throttle a few times, it goes away. If I let it go for more than a few seconds before I jab the gas, when I finally do it blows oil smoke out the exhaust (I assume just from one cylinder not igniting). I can't wrap my head around what causes this. No misfire at any other time. beyond this small annoyance, it runs perfectly except for some valve ticking (I havent mastered the art of valve adjustments yet).

I am thinking maybe a fuel pump or carb issue, but not sure why it would only happen on cold weather.

Any idea what might cause this? I dont want to throw money at things so I need some logic involved other than just "replace the spark plugs" Thanks all!

[koRnhead]

Sadly the solution is probably a basic tune up. Plugs, wires and a cap and rotor. As for a reason, old stuff will act like that.

[bravekozak]

Take a look at all of your plugs to see which cylinder is the problem.
If one plug is black check that spark plug wire and plug.

[db2u]

alright.. just didnt make sense to me that it would be an ignition issue, especially since the first 15 or so seconds it is fine. Would the plug show me anything if it only does this for a few seconds? I drive the car pretty aggressively so I would think it would burn off any carbon/oil.

[bravekozak]

Plugs never lie. Take a look. They come out real quick and easy.
Or, get a multimeter and check out the resistance of each wire, one at a time.

Good luck.

[db2u]

Have not checked the plugs yet, but now getting occasional knocking right at startup. Fun times. Like I needed an excuse for a swap...

[Bert]

I only have colt start problems when I run out of caps, balls or powder!

Stop using ethanol-blend fuel when it's cold outside and hang a tuneup on the motor soon as you can. There is nothing like cold weather to accentuate battery and ignition problems. As bravesays; get the plugs out to have a look, and scratch the the corrosion off the contacts inside the dizzie cap while you're at it.

[db2u]

I only have colt start problems when I run out of caps, balls or powder!

Stop using ethanol-blend fuel when it's cold outside and hang a tuneup on the motor soon as you can. There is nothing like cold weather to accentuate battery and ignition problems. As bravesays; get the plugs out to have a look, and scratch the the corrosion off the contacts inside the dizzie cap while you're at it.

Yeah I saw colt in the title after I posted, it, couldnt change it and didnt care enough to worry about it further.

Not using ethanol blend isnt an option out here. It is required in Denver area. You can get it at a couple of stores (like an hour drive away from where I live) but even those you cant fill into a car, have to fill into a gas can.

[Bert]

Not using ethanol blend isnt an option out here. It is required in Denver area. You can get it at a couple of stores (like an hour drive away from where I live) but even those you cant fill into a car, have to fill into a gas can.

Check with www.puregas.org. Up this way most Premium gas is still devoid of ethanol. Take my word for it; carb engines especially, and early EFI motors, really don't want to ignite that stuff when it gets bitter cold.

[db2u]

Check with www.puregas.org. Up this way most Premium gas is still devoid of ethanol. Take my word for it; carb engines especially, and early EFI motors, really don't want to ignite that stuff when it gets bitter cold.

Yeah already have, puregas.org is where I found the two stations in the area that have it. Trust me, I would run it if it were an option, but I am not going to make a huge trip out of it and have to deal with gas cans etc. Thanks for the tip though. I will just have to check the plugs/wires/cap/rotor. I know the coil looks like crap too (very rusted) so it may be a weak coil as well. I just figured since initial start was fine, and the issues started about 15 sec after firing that it would be a carb issue. More worried about the intermittent clatter now though.,

[koRnhead]

Your clatter, is most likely just lifters....nothing to worry about. Its common, especially when it gets cold.
Its -19 right now by me, I would happily trade you youre mid 20's any day.

[db2u]

It's a carby so it doesnt have hydro lifters, I definitely know what the lifter sound is from other vehicles I have owned, and it isnt that. it def is internal engine. Hoping just piston slap. Is the Mazda B engine prone to piston slap?

[WmWatt]

The first 15 seconds on a carburetted engine sounds like the automatic choke is putting a rich mixture into the cyclinders and that boost keeps it running. Once the choke kicks out the engine is starved and begins to coutgh and miss. I'd check the fuel line and filtre. also maybe bump up the idle speed if it's below 750 rpm. When I start my carb'd Festiva I follow the owners manaul and tap the gas pedal after 10 seconds to release the choke. The idle backs off.

Oh yeah, spray some carburettor cleaner into the carb and on the external linkages in case something is sticking. I do ttah at least once a year as part of the tuneup.

[Bert]

Yeah already have, puregas.org is where I found the two stations in the area that have it. Trust me, I would run it if it were an option, but I am not going to make a huge trip out of it and have to deal with gas cans etc. Thanks for the tip though. I will just have to check the plugs/wires/cap/rotor. I know the coil looks like crap too (very rusted) so it may be a weak coil as well. I just figured since initial start was fine, and the issues started about 15 sec after firing that it would be a carb issue. More worried about the intermittent clatter now though.,

Already 20 years ago my carbed 86 F150 required a zap of QuikStart to start whenever temperatures dipped below 0 F. A fellow from the Nat'l Research Council engine lab suggested switching from 5% ethanol gas (hey I was trying to be Green back then!) over to 'ordinary' unleaded gas and lo and behold my cold start problems entirely disappeared. Now that 'ordinary' gas even has up to 10% ethanol I fill up my Festy (it's slow to fire when it's cold too) and the truck with Premium during the cold months.
Sharp knife is handy for slicing the scale off dizzie cap contacts. Buys you a bit more time until a new cap and rotor comes in. My first Festy clattered like a diesel upon start up and for 1-2 minutes after but nothing ever changed noise-wise during the additional 125,000 km I put on it.

[jason_]

Am I lucky with mix matched plug wires from older vehicles, factory cap, coffee can spark plugs, 30 below zero, and 350,000+ miles?

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