Car cranking excessively when cold?

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1,322
Location
Central Oklahoma
My 2008 Impala SS is a bit of a drama queen lately. Keep her in the garage and she is happy, park her outside in the cold... she throws a fit. It only has issues on cold starts, and only when it's cold outside (the colder it is, the worse the condition). A normal start takes <1.5 seconds to fire. Lately, a cold start on a cold day could take 6-7 seconds to fire. This car is tuned (to disable AFM - Superchips 91 octane tune), but it's had the same tune for over 5 years. Never changed or messed with, never any issues. Here's the evidence I know/see: *The starter spins fairly well, I'd say on average 5-25% slower than a warm crank. The colder it is, the slower it seems to crank. I can't rule it out, but I doubt it's weak or bad (although it is the original at 133k). Nonetheless, it does audibly sound slightly slower than a warm crank. When it's warm it does crank in it's usual time/speed/sound. *The battery was replaced in the last ~12 months. No issues there, it cranks excessively, so I know it's not a power issue. *Plugs are Delco iridiums and were changed at 80k, wires done at the same time. Runs perfect once started, cold or hot, cruising or racing. Ruling out spark. *That also makes me believe it's not a fuel issue either, but I'm not too confident saying that. I always use Top Tier 91 E-0 (NO ethanol), and run Techron religiously (at least once per 4k mile OCI). *Air filter is factory paper and was changed about 15k miles ago. Looks good, doubt it's an air issue. *Oil is the spec'd 5W-30 (Valvoline Synpower). It's not thick/old/low oil. *Remote starting the car doesn't make any difference versus manually starting. The only interesting info I can offer is when it's cranking, if you press the gas pedal very lightly while it's struggling, it seems to help it fire. But this car doesn't have a throttle cable, it's electronic. So maybe the gas pedal is a placebo? shrug I was hoping it would give me some sort of hint, perhaps a code/light, but no. Nothing other than these observations. Common sense says it's air, fuel or spark. None make sense. It runs perfectly once it's started. My best guess is it's either starving a bit for fuel on startup, or it's a starter on the way out. But both just don't make sense. Any ideas? Thanks in advance!
 
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Somewhere
Originally Posted by tony1679
The only interesting info I can offer is when it's cranking, if you press the gas pedal very lightly while it's struggling, it seems to help it fire. But this car doesn't have a throttle cable, it's electronic. So maybe the gas pedal is a placebo? shrug
I'd check the coolant temp sensor. If it's out of range and reading too warm when it's cold you may not be getting enough cold start enrichment (or too much). The gas pedal is also interesting. It may be worth a check to see if the resistance or whatever it uses is out of spec when it gets cold. I could think it may be sensing either too much pedal or some odd thing and once you move it, it sees correct voltage. Kind of like a scratchy volume knob on a stereo.
 
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26,432
Location
MA, Mittelfranken.de
GM used to recommend running a lower octane fuel in cold conditions, I don't know if they still do but it did seem to help. If everything checks out do a compression/leak down test if for nothing more than peace of mind, lower compression can cause hard starting especially in the cold. Dirty injectors can also cause this, when cold the ecm call them to open for a longer duration to allow a richer mixture basically operating like a choke, the temp sensor triggers this action as the other poster mentioned.
 
Like Trav said, gasoline is harder to vaporize the colder it gets. Lower octane doesn't overcome this issue, but it is easier to burn because of the lower octane. Top your tank off with only the recommended octane for a tank or two, and see if it starts better.
 
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1,782
Location
Toronto Canada
Take the intake boot off of the throttle body and drop a cap full of fuel into the engine, re-install boot and crank it. If it starts faster then you know it's a lack of fuel problem. Dirty injectors, low fuel pressure, some temp sensor reading to high or and intake air leak. This might help put you on the right track.
 
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6,727
Location
Lake Havasu City, Arizona
My 1991 F-150 5.0 V-8 is starting to do this when cold. It always started right up without touching the gas. Now it requires more cranking, (2 to 5 seconds more), if it's dead cold, (say below 45 F). But if I pump the gas while turning the key, it fires up normally. Which tells me it's a fuel delivery issue of some type. It's due for a "tune up". So I'm going to replace the plugs, wires, rotor, and cap. Then put in a new fuel filter and air filter. I might throw in a new coil as well. Just because it's easy and fairly cheap to replace. It's easier to just remove the cap and rotor, then rip the wires off the plugs without being careful. Because they're a PITA to get off the plugs without damaging them anyway. Regardless of how much dielectric grease I squirt into them. They really manage to get themselves stuck on the plugs.
 
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25,050
Location
ON, Canada eh?
Before starting it next time, cycle the key on/off 4 times with about 3-4 seconds in the ON position each time, without starting it. Once that is done, crank it over and see if it takes less time to crank. Might have a leaking check valve that might be just on the edge of leaking or leaking at a slow rate when temperatures are normal but when it's colder it leaks more or leaks all the fuel pressure. Priming the fuel system a few times before cranking will see if that is the problem.
 
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Messages
6,727
Location
Lake Havasu City, Arizona
Originally Posted by StevieC
Before starting it next time, cycle the key on/off 4 times with about 3-4 seconds in the ON position each time, without starting it. Once that is done, crank it over and see if it takes less time to crank. Might have a leaking check valve that might be just on the edge of leaking or leaking at a slow rate when temperatures are normal but when it's colder it leaks more or leaks all the fuel pressure. Priming the fuel system a few times before cranking will see if that is the problem.
It helps a little. Bit it still cranks more. Only when cold. When it's up to operating temperature, it pops right off.
 
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25,050
Location
ON, Canada eh?
Do you have a way to see what the coolant temperature is digitally before you crank? If you let it sit overnight it should be within a degree of the outdoor air temperature. Mine matches as per my scan-gauge and the reading on my gauge cluster. This would prove if the coolant temperature sensor is inaccurate.
 
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Messages
2,273
Location
Cincinnati, USA
Hook up an OBDII code reader capable of live data and check the temperature sensor reading and once started, whether your long term fuel trim #s are too lean.
 

tony1679

Thread starter
Messages
1,322
Location
Central Oklahoma
Originally Posted by Trav
GM used to recommend running a lower octane fuel in cold conditions, I don't know if they still do but it did seem to help. If everything checks out do a compression/leak down test if for nothing more than peace of mind, lower compression can cause hard starting especially in the cold. Dirty injectors can also cause this, when cold the ecm call them to open for a longer duration to allow a richer mixture basically operating like a choke, the temp sensor triggers this action as the other poster mentioned.
I'm not removing the tune unless I absolutely have to, as it's been the best thing that ever happened to this car (for it's own health, I could care less about any performance gains). But I do understand your point. I may do the compression test for peace of mind, but she still hauls [censored] whenever asked. I don't suspect it. As for injectors being dirty, is it possible? Yes. But considering it gets a 20oz bottle of Techron (in a 17 gallon tank) once, sometimes twice, per 4K OCI for the last 57k, I would have a real hard time believing it.
Originally Posted by SubieRubyRoo
Top your tank off with only the recommended octane for a tank or two, and see if it starts better.
The recommended octane IS 91, but stock it allowed 87 with a power penalty (and ran like crap, not to mention the abysmal gas mileage). The tune is for 91. It's been perfect for 5 years now... shrug
Originally Posted by StevieC
Before starting it next time, cycle the key on/off 4 times with about 3-4 seconds in the ON position each time, without starting it. Once that is done, crank it over and see if it takes less time to crank. Might have a leaking check valve that might be just on the edge of leaking or leaking at a slow rate when temperatures are normal but when it's colder it leaks more or leaks all the fuel pressure. Priming the fuel system a few times before cranking will see if that is the problem.
I'll try this the next time I start it and report back. Not sure why I didn't try this. I'll also keep the coolant temp sensor on my radar, although it seems to work just fine. Thanks!
 
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5,767
Location
Fort Worth, Texas
A starter doesn't care about mileage....It could have 300,000 starts in 50,000 miles for all we know? The Mini-Delco planetary reduction starters are known the crank slower as they wear out.
 

tony1679

Thread starter
Messages
1,322
Location
Central Oklahoma
Well, it's 16°F. It has been parked outside since 4pm. I turned the key to on and let the fuel pump prime until it shut off, then turned the key back off. Repeated twice (three total pump cycles), then cranked on the 4th turn without touching the gas pedal. No change. Still took 5+ seconds to fire. I think fuel is scratched off the list. shrug
 
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5,640
Location
Ohio
I had a similiar situation with a fuel pump on its way out on a Buick. Started and ran good warm but the pressure was just below specs and was very difficult to get started in the cold where the demands are greatest. I would check for low fuel pressure.
 
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7,378
Location
MIchigan
My guess is that your battery doesn't have enough CCA. I'm sure 16 degrees isn't normal for your area. Up here in Michigan you have to have a battery with high CCA....my trucks battery has 770 CCA. What's yours?
 

tony1679

Thread starter
Messages
1,322
Location
Central Oklahoma
Originally Posted by Lubener
I had a similiar situation with a fuel pump on its way out on a Buick. Started and ran good warm but the pressure was just below specs and was very difficult to get started in the cold where the demands are greatest. I would check for low fuel pressure.
But wouldn't priming it 3x like I did build enough pressure for it to start easily? shrug I'll keep it on my radar. Thanks for the tip.
Originally Posted by mclasser
Have you tried cleaning the MAF sensor? A dirty/worn one may cause an extended crank.
I have not. Never heard of that. I may try it as a last resort. Thanks.
Originally Posted by Warstud
My guess is that your battery doesn't have enough CCA. I'm sure 16 degrees isn't normal for your area. Up here in Michigan you have to have a battery with high CCA....my trucks battery has 770 CCA. What's yours?
Well I can't go look at the moment, but I know it's a NAPA Legend spec'd for the car. So that would be the 7585 - 650CCA. While I do agree CCAs are everything, this has never been an issue before, and it's had the same battery (on the 2nd identical one) for 6 years now. Very interesting thought, I just don't think it's the culprit. Is there any way to test it by somehow giving it a boost without buying a higher CCA battery (perhaps using jumpers to a second battery)?
 
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5,640
Location
Ohio
Priming several times did not help my situation. The pressure would build up to the low level it would peak at. It won't keep building up pressure with more keystrokes.
 
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