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Hard start when cold?

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Old 07-05-2010, 04:36 PM
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Default Hard start when cold?

I've been having this problem when my car has been sitting for at least a couple of hours. Such as overnight in the garage or it was really bad last night after sitting outside all night at my girlfriends.

The car is crazy hard to start. It cranks and cranks and will occasionally hiccup a bit out the exhaust. The crank time has been increasing over the last week or so. It eventually starts though. Once it has it seems to run and drive fine. Gas mileage is the same. At idle I occasionally get an extra burble through the exhaust but the idle seems consistent. My tach isn't correct so I'm not exactly sure what the idle is at. I think around the factory tahoe ~600rpm. I get no CEL but I have no scanner to get the actual sensor outputs. I hear the fuel pump priming when I switch to key-on. Ideas?
Old 07-05-2010, 04:52 PM
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Start at the lowest common denominator. When was the last time you changed your fuel filter.
Old 07-05-2010, 04:52 PM
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Could be the check valve in the pump.Put a fuel pressure gauge on it after it sets and check your fuel pressure.Or cycle the key 5 or 6 times before you try to start it. If it starts right up the pump is bad.
Old 07-05-2010, 04:54 PM
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Originally Posted by 02*C5
Start at the lowest common denominator. When was the last time you changed your fuel filter.
Fuel filter will not keep one from starting.
Old 07-05-2010, 05:01 PM
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Originally Posted by 02*C5
Start at the lowest common denominator. When was the last time you changed your fuel filter.
The filter is less than a year old. ACDelco version of the C5 filter/regulator asm.

Originally Posted by BaddBird
Could be the check valve in the pump.Put a fuel pressure gauge on it after it sets and check your fuel pressure.Or cycle the key 5 or 6 times before you try to start it. If it starts right up the pump is bad.
I tried cycling the key five or six times this morning and it actually took the longest yet. I think that's more because the problem is getting worse though. I'll have to get my pressure gauge back from a friend before I can check it for sure though. The pump is a "newer" walbro, installed ~05 or so.
Old 07-05-2010, 05:06 PM
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Originally Posted by BaddBird
Fuel filter will not keep one from starting.
If your fuel filter is clogged or partially clogged you will have a hard time starting even if you have fuel injection.

Ask me how I know, had a friend w/ a fuel filter partially clogged w/ 85K miles and sometimes it would take me 2 or 3 cranks. Even with fuel injection fuel drains the system does not stay primed specially after a long stand (ie overnight)
Old 07-05-2010, 05:08 PM
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Originally Posted by iansane
The filter is less than a year old. ACDelco version of the C5 filter/regulator asm.



I tried cycling the key five or six times this morning and it actually took the longest yet. I think that's more because the problem is getting worse though. I'll have to get my pressure gauge back from a friend before I can check it for sure though. The pump is a "newer" walbro, installed ~05 or so.
Get a gauge on it and check your KOEO pressure.You might also check spark as your cranking to rule that out.
Old 07-05-2010, 05:28 PM
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Originally Posted by 02*C5
Even with fuel injection fuel drains the system does not stay primed specially after a long stand (ie overnight)
Hate to break this to you but the supply line is never drained if it is the check valve is bad in the pump. The prime cycle when you turn the key on is to get pressure against the injectors. Fuel filter issues cause poor fuel mileage with extended cranks and sometimes lean codes. Not "It cranks and cranks and will occasionally hiccup a bit out the exhaust". Now ask me how I know this Because I do this **** for a living not a ****** internet hobby.

Last edited by BaddBird; 07-05-2010 at 05:38 PM.
Old 07-05-2010, 05:38 PM
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Originally Posted by BaddBird
a ****** internet hobby.
you know xanax or Valium will help the stress level no need to be disrespectful.
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Old 07-05-2010, 05:47 PM
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Originally Posted by 02*C5
you know xanax or Valium will help the stress level no need to be disrespectful.
No thanks, don't believe in meds they make me irritable. No disrespect meant.
Old 07-05-2010, 06:28 PM
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^^ Thank You

You are the professional and you're right this is a hobby to me just do it for friends and self.
Old 07-05-2010, 08:07 PM
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Originally Posted by BaddBird
Get a gauge on it and check your KOEO pressure.You might also check spark as your cranking to rule that out.
By KOEO you mean key on, engine on? or engine off?

BTW, thanks for resolving your issues guys.
Old 07-05-2010, 08:12 PM
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Originally Posted by iansane
By KOEO you mean key on, engine on? or engine off?

BTW, thanks for resolving your issues guys.
Key on engine off KOEO Key on engine running KOER
hook up your gauge and cycle your key KOEO and check your reading.
Old 07-12-2010, 05:20 PM
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Originally Posted by BaddBird
Key on engine off KOEO Key on engine running KOER
hook up your gauge and cycle your key KOEO and check your reading.
I finally got around to checking the pressure since the schrader valve was broken I had to extract that. KOEO; ~55psi. During cranking I get ~60psi. Crap. Any ideas?
Old 07-12-2010, 08:03 PM
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So... Now it won't start at all. Getting no spark whatsoever. Crank shaft position sensor?

Last edited by iansane; 07-12-2010 at 08:09 PM.
Old 07-12-2010, 08:25 PM
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Not sure how its wired up but could be the ignition relay.
Old 07-13-2010, 03:40 PM
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Originally Posted by HotSilverBird
Not sure how its wired up but could be the ignition relay.
Tested, it's good. TY

Gets all the fuel it could need. Plugs are wet, just no spark. What causes a no spark condition?
Old 07-15-2010, 01:12 AM
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Ended up being the connector for the crank sensor. Pin pushed back inside the connector body.
Old 07-15-2010, 02:15 AM
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Moving to General Maintenance for future reference. Glad you got it fixed.



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