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Any tips for better cold weather starting - 258?

4626 Views 9 Replies 3 Participants Last post by  jerry
Does anyone have any tips that would help out with cold weather starting. It seems that the colder it gets, the more and more cranking it takes to get my 258 in my 88 YJ to run. Would a better coil help, or perhaps a new battery, or am I just doomed until I get rid of the BBD Carb? any thoughs are greatly appreciated.

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I have the same problem. 85 CJ7 Stock 258 with Carter 2 BBL. Any suggestions?

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A couple of things to look at first before you blame it on the carb. First, is there gas in the carb when you first pump on the accelerator? And does the choke close? If both are true then look elsewhere.

If your engine turns over too slow it causes two things. First, the voltage to the coil is lower than desired thus causing a smaller spark. That is one of the reasons they install resistor wires on coils with a bypass for starting. When starting you want a full 12vdc going to the coil. Second, if it cranks too slow then the velocity that air is pulled into the chambers is too slow to atomize the air/fuel mixture. Side Note: they change the formula for gas in the winter to allow it to atomize at lower temps to help with cold starting. Also note that cold weather is hell on batteries.

If we get this far then start looking at plugs. Additionally, there is a heater under the carb in the intake manifold. It does the same job that the heat riser on V8's does....A relay on the firewall feeds 12vdc to it to help heat up the fuel when its cold. However, a failure here is usually noticed once your started...i.e., it takes a long time to warm up.

Before you start replacing stuff, follow the above and see who the real culprit is. In many cases its a combination of 2 or more problems.

Good Luck and let us know what you find..........

John......southern CA
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Hi,i dont have a Jeep,I have a 86 eagle with a 258 and carter BBD,It had same starting problems when i got it,now after 2 winters of use
it is still starting almost on first crank hot or cold,everytime.All i have done is the nutter bypass(this wasnt for starting tho)rebuilt the BBD
New plugs and 8mm wires.I replaced tin can coil with one from a 86 Ford Tempo,one of those square laminated type,they are a lot hotter
than original.I have the large hose on from air cleaner to grill,I have a good working heat stove pipe and air cleaner snorkel flapper door
.(biggest thing on a 258 for good cold weather starting)My electric choke is set to just close and no more..Wants to flood out cold if choke is to tight.
I do NOT have a working electric fuel heater in intake bottom,never bothered to hook it up and dont seem to need it.Our winters can reach below 0 temps
and have and it started fine as long as you have a good battery.Now i am talking a good 258 with no blowby,and only 60,000 on it.I still think
99% of all 258 cold start problems lay with no heat pipe and non working snorkel flapper door and choke .I have (before fix) noticed mine would even ice up
the carb in damp moist days at temps 30 to 40 degrees.And worse in colder temps.Did anyone ever notice some foreign cars and trucks
had a manual leaver on air cleaner marked Winter/Summer ??? it shut snorkel off all together in favor of all air coming in thru manifold heat
pipe.Ill tell ya,little things means a lot,on a 258/bbd

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I had trouble starting in the cold until I started plugging in the "engine heater".
Mine is a 84 CJ7 w/ 258 and it came stock with a 3 prong plug on one of the
lines to the heater core that I hook up and it warms up the oil in the block.
On the CJ you can probably find one of these in a junk yard but I don't know
about the YJ. Someone else can probably explain this better than I have.

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LoneEagle.......I agree that the heat stove pipe is a great feature of the modern day engine ...... but it doesn't help one bit for starting ........just for "stallling" provides 70-80 degree air after the motor is already running for 30sec. I was going to ask if this was a starting or stalling problem......and in reviewing the original post appears to be a starting problem. Since there doesn't seem to be a "warm weather" starting problem sounds like an air/fuel carb problem. could, however, be compensated for with a better spark out of an HEI which may ignite poorly atomized fuel.

Does this motor start OK in warm weather?........or is it just more tollerable/less of a pain in warm weather?


Had a Carter in an AMC 232, have two BBD's in two CJ's....Most of the cold start problems I've had have been directly related to the choke not working as it should. Even installed a manual choke on one of the BBD's and it started flawlessly even to -30,-40. Eventually went back to auto choke when I replaced the carb; got tired of explaining to others who drove it how a manual choke works. I spray the choke linkage about once/month with carb cleaner to keep the linkage from binding.
The above comment about the gasoline "type" is right on. The first few times it gets real cold here everyone has a hard time starting, until the gas station gets a more volatile fuel which is better in colder weather. Of course, you can't use the more volatile fuel when it's warmer because the more volatile components evaporate quickly to leave a "gummy" fuel. So try switching gasoline stations and you may find a blend that starts easier. Just a thought.

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I run dual 800c.c.a. atteries and that sucker is running faster than you can release the key. And my choke is broken.

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One thing to keep in mind, When it was new it probably started fine in cold weather. So... if you repair,re-build or replace everything mentioned in previous posts ie. choke, intake stove, manifold heater, BBD carb then it will probably perform as new. However, I'll also add that I have an MSD ignition on a small block Mopar (notorious for poor cold weather starts) and along with a well adjusted electric choke that sucker starts the first time every time and stays running.

When I got my 90 YJ (with 123,000 miles on it) I put Mobil 1 synthetic oil in it so it would start better in the winter. It alway started right up last winter. Since then, I added Jacob's plug wires and coil (the $60 one) and it starts even better. When it's cold out your supposed to press the gas down once to set the choke and not give it any gas while starting (according to owners manual and my experience).

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