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Wednesday, September 03, 2008

Silverado 350 vortec won't start when its cold.

1998 Chevy Silverado Truck Z71
QUESTION: 1998 Silverado 350 Vortec won't start when its cold.i hear the fuel pump running, and tried numerous times to start it, finally gave it one shot of starting fluid and it fired right up. Once it runs for a while and gets warm it will start right up. What could this be? Already Tried: fuel pump 6 months old, injectors one year old, fuel filter is new. ANSWER: Couple of things it could be. 1) Needs new spark plugs (extremely common) 2) IAC (Idle Air Control) is sticking and will need to be replaced. If you press gas pedal about 1/4 way down and it starts , then the IAC needs to be replaced. 3) Throttle body is dirty and is restricting air flow

10 comments:

  1. i have the same problem 98 chevy pickup wont start over nite spray ether starts up ,new fuel pump,crank trigger, scoped and analyzer cant find a problem ,after it starts run great

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  2. I have the same problem !
    Mine has done it for 4 YEARS now !
    All fall & winter IT is hard to start
    unless it sits in the sun for a few hours ????????????????? HELP !
    Carl

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  3. I could be a problem with the computer, I've seen cold have strange effects on computers in vehicles...

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  4. 1997 chevy silverado 350 vortec -changed fuel pump-fuel filter-and starter and still wont start even with ether....back fires when cranking.....

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  5. The lock clamp for these motors come loose quite often and the distributor will turn if your timing is four degrees off your engine will act stupid it should be timed any where between 0% to 4% after top dead. another issue is the plastic distributors get moisture inside them then the cam position sensor gets messed. Don't bother buying another plastic distributor as they are stupidly expensive you can buy a aluminum distributor from northernautoparts.com for 150$ that comes with cap, rotor and cam sensor this should help with your starting issues.

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  6. I have a 1989 Chevy S15 truck to start it have to floor the gas and turn the key over and over until it starts. Has a 403 motor and 6 cyc took three mechanics none can figure it out.

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  7. I have a 2005 z71 4x4 v8 ex cab wont start when its cold i have put new key switch 2 new fuel pumps it will crank and crank after 10 in it will start when it warms up it starts evertime I have had it to a Gm dealer and the computer says the truck is fine summer time I have no problem and a new batter it onlys dose it in the winter

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  8. change both coolant temp sensors and should start fine. one is buy the thermostat and the other is on the side of the drivers side cylinder head

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  9. My 98 Silverado Z71 will not start when it's cold and when the fuel tank is under 1/4 tank. New pump, new fuel pressure regulator. Smell gas in the tail pipe. Tried ether, nothing. It will diesel but probably because there's so much fuel in the cylinders. No Spark??? What would cause it?

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  10. Im having the same issue. 97 vortec 350 starts fine when warmed up, but if it sits over night I have to crank it for 30 seconds and walk away. come back 2 miutes later and it fires up. my thought was a cracked water jacket in the head leaking water into the cylender. the tail pipe spits out a watery black substance. my other thought was stale gas as its sat for 4 years. I drained 5 gallons and added 10 fresh, but I still think I have some bad stuff in there. This has a new short block with used heads. I might rebuild them if it doesnt stop. It even bent a pushrod to the point it looked like a z. I streightened it out slapped it back in and it fired up the first time eventhough it was cold. but this morning no luck back to the 30 second trick. readjusted valves. Ill try again in the evening to see if it changes anything.

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