Cold weather effects on starting

[NC Tom]

Per @89 MJ I'm starting a new thread about sluggish turnover and no start when cold weather hits.

 

I charged my battery overnight and this morning cranking my 88 Auto is VERY sluggish. It ran well just two weeks ago.

Cold hit and now crank with no start.

 

It's been suggested that I test some sensors, MAP and the coolant temp sensor. However, Neither one of those would be responsible for slow cranking, would they?

[eaglescout526]

MAT and CTS. It uses those temps to determine if a cold start is needed. 

[NC Tom]

1 hour ago, eaglescout526 said:

MAT and CTS. It uses those temps to determine if a cold start is needed. 

That means more fuel? How does that cranking speed?

[eaglescout526]

Typically it would be more fuel yes. 
They have no relation to cranking speed. But you mentioned the MAP sensor which just measures the pressure not the air temp.
 

Like Carter said in your other thread, battery, battery cables having resistance and starter would contribute to such. Hell starter relay could if it’s not fully engaging to throw the bendix out to engage the starter. 
 

I would suspect starter last since the cold weather has brought on this issue. 

[89 MJ]

The other thing that might be worth looking at is the engine to chassis ground. 
I’d start by cleaning the grounds and measuring the resistance of your battery cables. It should be near 0 ohms. If you need new battery cables, you could build new ones or get the big 7 battery cable kit from Jeepcables. I don’t think I’d trust parts store off the shelf ones. 

If you don’t need battery cables, get the battery load tested. It may be fully charged, but it might’ve died enough that it lost some capacity. 

[Eagle_SX4]

Cold weather really tests the battery. It may be dead even if it was charged over night. If you have a multimeter you can check the battery voltage before and while cranking. I have had batteries that checked good with no load and drop from 12 volts down to 1-2 volts when cranking. Definitely worth a quick check. You will need someone to help you with this and hold the test leads on the battery when trying to start the engine and watching the multimeter.

[75sv1]

How old is the battery? Check to see if the sides are bulged. How many miles on the OD? Thus, how old is the starter? Also, what oil are you using?  To heavy of an oil can cause sluggish starting. 

[GonzoTheGreat]

A slow crank will typically only be caused by the battery, starter, or connections. 

 

starters typically either work or don’t work. Slow cranking is a possible symptom, but not likely. 

 

If the battery is around 4 years old or more, I wouldn’t trust it. Yes, many batteries last longer than 4 years, but parts-store quality batteries are not expected to. There should be a sticker on it somewhere with a build year/month. You can load test it to confirm, but if it’s over 4 years old, replacement is a safe bet. As @Eagle_SX4 said, metering it during cranking is a good idea. If it dips below 10v on a cold start that’s not a good sign. 
 

if the battery is good, check the condition of the cables, and the connections. The engine-chassis ground is a common failure point, like @89 MJ said. But all the cables can be suspect after 30+ years on the road. 

[NC Tom]

7 minutes ago, GonzoTheGreat said:

A slow crank will typically only be caused by the battery, starter, or connections. 

 

starters typically either work or don’t work. Slow cranking is a possible symptom, but not likely. 

 

If the battery is around 4 years old or more, I wouldn’t trust it. Yes, many batteries last longer than 4 years, but parts-store quality batteries are not expected to. There should be a sticker on it somewhere with a build year/month. You can load test it to confirm, but if it’s over 4 years old, replacement is a safe bet. As @Eagle_SX4 said, metering it during cranking is a good idea. If it dips below 10v on a cold start that’s not a good sign. 
 

if the battery is good, check the condition of the cables, and the connections. The engine-chassis ground is a common failure point, like @89 MJ said. But all the cables can be suspect after 30+ years on the road. 

Sure. The battery is dated 4/23. Need to thoroughly check the cables. They look good up top.

Over a month ago, it wouldn't start. I cleaned out the C101 and the Ballist Resistor. It cranked strong and started right up. Keep in mind that it was sitting for almost a year. I thought it something mechanical, not electrical. 

I drove it for several days without issue.

The weather turned cold and that's it. No more starting. Just long cranking. 

It does need an oil change. I currently run 10/40.

 

I have much testing to do based on previous comments. I'm just throwing out a little background. 

[GonzoTheGreat]

3 hours ago, NC Tom said:

No more starting. Just long cranking.

Ok, just to clarify: Is the motor slow to turn over? Does it feel like it turns very slow and heavily? Almost doesn’t want to crank at all?

Or

 

does it crank and turn over, but it keeps cranking for too long before ignition kicks in?

 

if it’s the latter, it’s more likely a sensor or connection issue. It sounds like you might already be off to a good start tracking that down. 

[NC Tom]

34 minutes ago, GonzoTheGreat said:

Ok, just to clarify: Is the motor slow to turn over? Does it feel like it turns very slow and heavily? Almost doesn’t want to crank at all?

Or

 

does it crank and turn over, but it keeps cranking for too long before ignition kicks in?

 

if it’s the latter, it’s more likely a sensor or connection issue. It sounds like you might already be off to a good start tracking that down. 

Just turns over indefinitely. But not not quick enough to start. Before the cold start in, it turned over much faster. 

[Eagle_SX4]

33 minutes ago, NC Tom said:

Just turns over indefinitely. But not not quick enough to start. Before the cold start in, it turned over much faster. 

If it turns over slow the battery is probably dead. If it is low enough none of the sensors will get the proper voltage to give a good reading. Causing all of the issues you have listed. Test your battery and report your findings. You could even jump start it with jumpers cables to a running car and see if that helps.

[75sv1]

I did have issues with my '81 MB 240D starting in the colder months. I switched from Rotella T4 15W-45 to Rotella T4 10W-30. It helped a lot. I also use the block heater. I am not using Rotella T6 

[NC Tom]

Lots of good feedback. It's supposed to be pushing 60 degrees here Sunday, so I'll do some investigatin' and update.

[gogmorgo]

How cold is cold?

 

Take a voltmeter and measure voltage between both battery posts, should be around 12.7 if you’re fully charged, but that’s not a great test of battery condition on its own. It might be  Get a helper to hit the starter and watch the voltage dropping. If it goes below 10ish that’s not good. Either your battery isn’t charged or it’s toast. Heat and sitting discharged are the biggest killers of batteries, the cold reduces their output but as long as they’re not discharged it won’t damage them. A good battery should still crank your engine over enough to start it down to -40.

If you do suspect your battery, most places that sell them should be able to test it for you if you bring it in. 

 

Ohm tests for battery cables are basically useless. They’re designed to carry hundreds of amps, but if a single strand of wire is connected you’ll still see zero ohms. You need a voltage drop test to confirm they’re good. If you test the voltage between the positive terminal on the starter and a good ground on the engine while it’s, cranking it shouldn’t be more than 1.5V below what you saw at the battery. If it is different, it tells you there’s a problem in the cables or connections somewhere. You can use your voltmeter again to test on either end of the cables or on either side of a connection while you’re cranking, and if you see much voltage difference between the two points that’s a bad point. Either clean up the connection or replace your cable. 
Just be careful not to overheat your starter. Don’t crank for more than 30 seconds, and give it a minute or two between cranking. 

 

Starters often get weak as they get old. The windings can internally short (especially if it’s been overheated) and it’ll still work but will turn slowly. If your battery and the cables check out, there’s a good chance it’s the starter itself. Any time I replace a starter the new one cranks over tons quicker than I’m used to. 

[NC Tom]

5 minutes ago, gogmorgo said:

How cold is cold?

15+. Nothing sub-zero. In case it's the starter, do you have any suggested brands for a replacement?

[gogmorgo]

16 hours ago, NC Tom said:

15+. Nothing sub-zero. In case it's the starter, do you have any suggested brands for a replacement?

I don’t have a specific recommendation on brands, no. I’ve never had bad luck with whatever the closest parts store carried.

Probably your best quality for dollar value would be to take it to a local automotive electrical shop that repairs and rebuilds starters and alternators, but those shops are getting few and far between anymore. 

[TurboedMJ]

On 12/6/2024 at 2:48 PM, NC Tom said:

15+. Nothing sub-zero. In case it's the starter, do you have any suggested brands for a replacement?

If it was me I'd buy a power Master gear reduction starter from summit. They have a good reputation and are made in the USA. 

 

https://www.summitracing.com/search/part-type/starters/year/1989/make/jeep/model/cherokee

 

[NC Tom]

@89 MJ @gogmorgo @Eagle_SX4 @GonzoTheGreat @eaglescout526

and anyone else.

 

53 degrees and she started on the 2nd try. Go figure. About 5 min in, stumbled and shut off. Started back up with a little hesitation. 

 

does this change anyone's theories?

Or things I should check?

[Eagle_SX4]

3 minutes ago, NC Tom said:

does this change anyone's theories?

Or things I should check?

I still think it is the battery. If you can drive it to your nearest parts store they should be able to test the battery, alternator and starter to help you diagnose the problem.

[89 MJ]

Stumbling and shutting off after 5 minutes sounds weird. Very possibly could be a connection issue, like grounds, or a bad battery issue. Like Eagle_SX4 said, get the battery, starter, and alternator tested at a parts store. Could also be a fuel issue, but that would be a problem when it’s warm too. 

[eaglescout526]

I’m literally not gonna be a lot of help cause I live on the surface of the sun and haven’t had many cold start issues. Though when I lived at my parents, my MJ was outside and during the winter it was pretty damn cold at 7am and would notice slight sluggish start and just would attribute such to being cold out on everything. 
There’s a reason why batteries have cold cranking amps posted on them and it’s to tell you how many amps it will still make during the cold weather. So say you have a G 34 batter with 750CCA. Now it’s super sluggish and not starting. It could be putting out 500CCA or less. Amperage is the driving force of electrical currents. AC or DC. If it’s not sending enough Amps to the starter to really crank over that massive chunk of iron, it’s not gonna go anywhere. 
 

Now to it stumbling and failing and then restarting with no issue could be a whole new issue of its own. But you can’t know for certain while fighting this cold start issue. 

[NC Tom]

20 minutes ago, eaglescout526 said:

 

Thanks. Here is where I am now. Battery check cold read 12.97. Battery while running read 14.5. After the stumble, I noticed an active leak at the fuel rail. I replaced the rings, etc. Fuel pressure now at 33. It's running nicely at the moment. Going to let it idle a bit to see what happens.

[89 MJ]

9 minutes ago, NC Tom said:

Thanks. Here is where I am now. Battery check cold read 12.97. Battery while running read 14.5. After the stumble, I noticed an active leak at the fuel rail. I replaced the rings, etc. Fuel pressure now at 33. It's running nicely at the moment. Going to let it idle a bit to see what happens.

Did you check the voltage while cranking?

[NC Tom]

30 minutes ago, 89 MJ said:

Did you check the voltage while cranking?

Didn't have a helper. Let it idle for about 15 mins. No stumbling or shutoff. Assuming she starts in the morning, I'll try to get by parts store tomorrow.