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Still sputters to life sometimes.

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Old Aug 24, 2007 | 11:04 PM
  #1  
MP81's Avatar
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From: Michigan
Car: 2007 Cobalt LT
Engine: M62'd 2.2L L61
Transmission: 4T45E 4-speed Automatic
Axle/Gears: Stock
Still sputters to life sometimes.

Okay, I've been trying to fix this sputtering start I have on my car.

It did it originally, then it started to get really bad, like I mean, a cold start could take up to a minute to get the car started. It would almost fire, but it just wouldn't go. You could smell pre-ignition, and it was definately a fuel-related issue. The prime fuel-pressure was 3psi, and the pressure was not held at all. I put a new fuel filter on, and that didn't do anything. But the fuel that spilled out when changing the filter was silver, until it dried. And the pump sounded like it really wasn't working...at all. (The car would run fine once it got started, but still). So now I have a brand-new 67gph BBK Fuel Pump installed, and generally it fires right on start, and if it does sputter to life, it generally doesn't take a minute, but I really have to have it cold to check. What's odd is generally, it'll start the best if no electronics are on when you start (so it's the best to put the key in and immediately crank, not play around with the radio before starting), and the car had actually stopped running the other day, and then would not crank. I got it jumped, and it started. I replaced the battery (650 CCA) with a brand new battery (700 CCA), and it didn't do anything to help start. So, I'm really lost as to what to do to fix this. I'm sick of replacing crap, and I don't really want to invest into the TPI, since eventually, once **** stops breaking, and I get enough, I'm getting a carb'd 383. The one thing I'm thinking about is the fuel-pressure-regulator. I've heard these things go bad a lot.

Any ideas?

Thanks.
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Old Aug 25, 2007 | 09:36 AM
  #2  
Viprklr's Avatar
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From: N. Illinois
Car: 92 GTA/ 00 TA
Engine: 383/350
Transmission: 700R4/T-56
Re: Still sputters to life sometimes.

Put your fuel pressure gauge back on. Give 12v constant power to wherever your fuel pump test port is located. Note pressure. Start pinching the return line. The pressure should rise. If it doesn't then your regulator is bad. If you're stock, don't go above 60psi.
You could also check the vacuum line going to the regulator for gas. That is not always the easiest thing to do though.

Your prime fp of 3psi is way too low. Was that before and/or after the new pump?
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Old Aug 25, 2007 | 11:54 AM
  #3  
MP81's Avatar
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Joined: Jul 2007
Posts: 248
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From: Michigan
Car: 2007 Cobalt LT
Engine: M62'd 2.2L L61
Transmission: 4T45E 4-speed Automatic
Axle/Gears: Stock
Re: Still sputters to life sometimes.

The prime pressure was with the old pump. I'm pretty sure the new one is much higher.

I don't think anything is a huge problem right now, the car fired right up this morning, but I still should check.
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Old Sep 9, 2007 | 01:09 PM
  #4  
MP81's Avatar
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From: Michigan
Car: 2007 Cobalt LT
Engine: M62'd 2.2L L61
Transmission: 4T45E 4-speed Automatic
Axle/Gears: Stock
Re: Still sputters to life sometimes.

Today, just fired it up (cold), and it took a minute to start again. Doing the same bull it did before. I can hear the pump working, so it's not that. I'm thinking it's that damn regulator, because I can't think of anything else that it could be. I gotta get a fuel pressure gauge here now.

Which line is the return line? The one that comes out of the plenum right behind where the regulator "plugs into" the plenum?
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Old Sep 10, 2007 | 02:05 PM
  #5  
MP81's Avatar
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Joined: Jul 2007
Posts: 248
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From: Michigan
Car: 2007 Cobalt LT
Engine: M62'd 2.2L L61
Transmission: 4T45E 4-speed Automatic
Axle/Gears: Stock
Re: Still sputters to life sometimes.

Also, I'm thinking, since it seems to happen only on cold starts, could it be the cold-start injector? How could I test it?
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