2001 4.3 Vortec Warm Start Problems
January 12th, 2013, 2:34 AM
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2001 4.3 Vortec Warm Start Problems
I'm an older guy and so I'm very good at carborated engines. Most automotive aspects I can diagnose and repair but this particular FI issue is making me a little crazy.
Auto Specs:
2001 Astro 4.3 Vortec - Rear wheel drive - AC - PS - Gasoline Fired
EDIT: This is a CSFI system
Fresh oil change recently
Fresh Trans change recently.
All vacume hoses replaced recently.
New Distributor recently.
New AC Delco Spark Plugs and Wires Recently.
New Air Cleaner.
MAF cleaned recently.
New TBI Idle Engine Replaced recently.
Issue:
When cold start:
Engine cranks and starts up almost immediately with normal crank up sounds. No gas peddle is necessary, the engine simply cranks and starts up beautifully and idles a little high but it's fine.
When engine is warmed up:
When engine is turned off and restarted within a minute or so:
It will start the same as above except idle is perfect now. No problems.
When engine is warmed up, turned off and allowed to rest for 5 to 10 minutes:
You can only start the engine now one of two ways.
1) a. Slightly depress the gas pedal (approximately 1/8 throttle or less),
b. crank the engine and it will start up fine.
2) a. Do not touch the gas pedal
b. crank the engine continually until you hear it slow idling. Takes about 3 to 5 full seconds of cranking before it is idling without the help of the starter.
c. Idle stays very low until you drive it a little, then the idle will become perfect.
Further Explaination of 2:
The same symptom could be reproduced on any vehicle by turning down the idle screw to almost zero but just enough to keep the engine barely running. If you crank the engine without adding pedal it will finally continue to "pull its weight" where you can stop cranking it and it will continue to idle slowly on its own.
My hypothesis:
Whatever tells the TBFI system that "it's time to start now so lets give a little extra airfuel mixture for a moment to get the engine going" is not doing it.
I am a TBFI novice although I understand the basics. If someone that has real exprience with these systems could give me something to go on I'd surely appreciate it.
I'm thinking maybe the IAC and TPS are off but would that effect the difference in starting performance between Cold and Warm starts? Any suggestions is greatly appreciated.
Thank you,
GoodOlJoe
Auto Specs:
2001 Astro 4.3 Vortec - Rear wheel drive - AC - PS - Gasoline Fired
EDIT: This is a CSFI system
Fresh oil change recently
Fresh Trans change recently.
All vacume hoses replaced recently.
New Distributor recently.
New AC Delco Spark Plugs and Wires Recently.
New Air Cleaner.
MAF cleaned recently.
New TBI Idle Engine Replaced recently.
Issue:
When cold start:
Engine cranks and starts up almost immediately with normal crank up sounds. No gas peddle is necessary, the engine simply cranks and starts up beautifully and idles a little high but it's fine.
When engine is warmed up:
When engine is turned off and restarted within a minute or so:
It will start the same as above except idle is perfect now. No problems.
When engine is warmed up, turned off and allowed to rest for 5 to 10 minutes:
You can only start the engine now one of two ways.
1) a. Slightly depress the gas pedal (approximately 1/8 throttle or less),
b. crank the engine and it will start up fine.
2) a. Do not touch the gas pedal
b. crank the engine continually until you hear it slow idling. Takes about 3 to 5 full seconds of cranking before it is idling without the help of the starter.
c. Idle stays very low until you drive it a little, then the idle will become perfect.
Further Explaination of 2:
The same symptom could be reproduced on any vehicle by turning down the idle screw to almost zero but just enough to keep the engine barely running. If you crank the engine without adding pedal it will finally continue to "pull its weight" where you can stop cranking it and it will continue to idle slowly on its own.
My hypothesis:
Whatever tells the TBFI system that "it's time to start now so lets give a little extra airfuel mixture for a moment to get the engine going" is not doing it.
I am a TBFI novice although I understand the basics. If someone that has real exprience with these systems could give me something to go on I'd surely appreciate it.
I'm thinking maybe the IAC and TPS are off but would that effect the difference in starting performance between Cold and Warm starts? Any suggestions is greatly appreciated.
Thank you,
GoodOlJoe
Last edited by GoodOlJoe; January 12th, 2013 at 5:31 AM.
January 12th, 2013, 4:03 AM
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Just starting to have similar problems with my 2001 AWD Astro. Van cranks and idles fine cold, but after short time restart is reluctant to turn over. Have owned this van since 2006; and also others - never had this problem before. Just replaced battery, amp meter showing low when running ( 12V) and suspect starter or cable connection. Have had extensive motor problems. Recently replaced timing chain gear and tensioner. Stay tuned.
January 12th, 2013, 5:34 AM
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Just starting to have similar problems with my 2001 AWD Astro. Van cranks and idles fine cold, but after short time restart is reluctant to turn over. Have owned this van since 2006; and also others - never had this problem before. Just replaced battery, amp meter showing low when running ( 12V) and suspect starter or cable connection. Have had extensive motor problems. Recently replaced timing chain gear and tensioner. Stay tuned.
Do you mean that when you try to start it after it warms up, nothing happens? No noise as if you never turned the key to crank it? Or is there some indication that you have it in crank position?
Assuming it just wont crank (does basically nothing) these are the things to check.
1) Battery terminal connections (both ends).
2) Starter of course (if it's an old starter it's not unusual for the selonid contacts to go bad but if this is the case, you should hear a 'click' when you try to start it and it does not crank over)
3) The ignition switch. This would be the most likely case if it does nothing (no noises at all) when you try to crank it.
4) and finally, the neutral saftey switch. Check to see if it helps when you move the shifter a little bit.
Ok good luck,
Joe
Last edited by GoodOlJoe; January 12th, 2013 at 6:19 AM.
January 13th, 2013, 12:57 PM
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Yes, I get a very random ... nothing. But it does start right up on the second or third key twist. So, I'm thinking the starter is weak or the GM rebuilt motor is somewhat "tight". Good suggestion on the neutral safety switch, as my shift indicator is "lazy". Could also be ignition switch, though have had no problems with it and it feels fine. Thanks for the suggestions Joe. Love the Astro, have owned six of them.
January 15th, 2013, 2:09 PM
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Ahh Joe... You've described my issues very well. Have had it in the shop 4 times in 8 days and they can't get it to stall.
Per another Astro owner, I've been instructed to switch out my pickup coil. He does so once a year when the van starts acting up and it takes care of the problem. Said they go through distributor caps/rotors/pickup coils quickly because of where they're located. Already did my cap & rotor in August (supposed I could have received bad parts..) but I know they didn't replace my pickup coil.
Please update if you every figure it out- this problem consumes me.
P.S. We switched it out last night, and so far, it's running like a top. Better than ever. Haven't run into a stall yet but I haven't TRIED either. Don't want to ruin this good feeling just yet. But I have hope.
Per another Astro owner, I've been instructed to switch out my pickup coil. He does so once a year when the van starts acting up and it takes care of the problem. Said they go through distributor caps/rotors/pickup coils quickly because of where they're located. Already did my cap & rotor in August (supposed I could have received bad parts..) but I know they didn't replace my pickup coil.
Please update if you every figure it out- this problem consumes me.
P.S. We switched it out last night, and so far, it's running like a top. Better than ever. Haven't run into a stall yet but I haven't TRIED either. Don't want to ruin this good feeling just yet. But I have hope.
Last edited by DorisTheFunkasaurus; January 16th, 2013 at 11:10 AM. Reason: Correction
January 19th, 2013, 8:26 PM
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Hi guys... and gals tisk tisk....
I will update soon. I'm going to attempt to clean the throttle body. I actually plan to remove it, clean and trim the blade. The problem is they are so hard to reach. Good idea regarding the coil but I don't think that is my particular problem. Will return with an update as soon as I have one, supposed to work on it tomorrow (Sunday the 20th).
GoodOlJoe
I will update soon. I'm going to attempt to clean the throttle body. I actually plan to remove it, clean and trim the blade. The problem is they are so hard to reach. Good idea regarding the coil but I don't think that is my particular problem. Will return with an update as soon as I have one, supposed to work on it tomorrow (Sunday the 20th).
GoodOlJoe
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January 29th, 2013, 8:16 AM
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For whatever it's worth, mine was definitely the coil. Have been driving 2 weeks now without a stall, and in temps ranging from 5 degrees to 55 degrees. Cold starts, warm starts, short trips, long ones... I'm 10 feet tall and bulletproof.
Good luck!
Good luck!
January 31st, 2013, 4:40 AM
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Do you mean that when you try to start it after it warms up, nothing happens? No noise as if you never turned the key to crank it? Or is there some indication that you have it in crank position?
Assuming it just wont crank (does basically nothing) these are the things to check.
1) Battery terminal connections (both ends).
2) Starter of course (if it's an old starter it's not unusual for the selonid contacts to go bad but if this is the case, you should hear a 'click' when you try to start it and it does not crank over)
3) The ignition switch. This would be the most likely case if it does nothing (no noises at all) when you try to crank it.
4) and finally, the neutral saftey switch. Check to see if it helps when you move the shifter a little bit.
Ok good luck,
Joe
Assuming it just wont crank (does basically nothing) these are the things to check.
1) Battery terminal connections (both ends).
2) Starter of course (if it's an old starter it's not unusual for the selonid contacts to go bad but if this is the case, you should hear a 'click' when you try to start it and it does not crank over)
3) The ignition switch. This would be the most likely case if it does nothing (no noises at all) when you try to crank it.
4) and finally, the neutral saftey switch. Check to see if it helps when you move the shifter a little bit.
Ok good luck,
Joe
September 26th, 2015, 1:47 PM
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Goodoljoe!
I'm an older guy and so I'm very good at carborated engines. Most automotive aspects I can diagnose and repair but this particular FI issue is making me a little crazy.
Auto Specs:
2001 Astro 4.3 Vortec - Rear wheel drive - AC - PS - Gasoline Fired
EDIT: This is a CSFI system
Fresh oil change recently
Fresh Trans change recently.
All vacume hoses replaced recently.
New Distributor recently.
New AC Delco Spark Plugs and Wires Recently.
New Air Cleaner.
MAF cleaned recently.
New TBI Idle Engine Replaced recently.
Issue:
When cold start:
Engine cranks and starts up almost immediately with normal crank up sounds. No gas peddle is necessary, the engine simply cranks and starts up beautifully and idles a little high but it's fine.
When engine is warmed up:
When engine is turned off and restarted within a minute or so:
It will start the same as above except idle is perfect now. No problems.
When engine is warmed up, turned off and allowed to rest for 5 to 10 minutes:
You can only start the engine now one of two ways.
1) a. Slightly depress the gas pedal (approximately 1/8 throttle or less),
b. crank the engine and it will start up fine.
2) a. Do not touch the gas pedal
b. crank the engine continually until you hear it slow idling. Takes about 3 to 5 full seconds of cranking before it is idling without the help of the starter.
c. Idle stays very low until you drive it a little, then the idle will become perfect.
Further Explaination of 2:
The same symptom could be reproduced on any vehicle by turning down the idle screw to almost zero but just enough to keep the engine barely running. If you crank the engine without adding pedal it will finally continue to "pull its weight" where you can stop cranking it and it will continue to idle slowly on its own.
My hypothesis:
Whatever tells the TBFI system that "it's time to start now so lets give a little extra airfuel mixture for a moment to get the engine going" is not doing it.
I am a TBFI novice although I understand the basics. If someone that has real exprience with these systems could give me something to go on I'd surely appreciate it.
I'm thinking maybe the IAC and TPS are off but would that effect the difference in starting performance between Cold and Warm starts? Any suggestions is greatly appreciated.
Thank you,
GoodOlJoe
Auto Specs:
2001 Astro 4.3 Vortec - Rear wheel drive - AC - PS - Gasoline Fired
EDIT: This is a CSFI system
Fresh oil change recently
Fresh Trans change recently.
All vacume hoses replaced recently.
New Distributor recently.
New AC Delco Spark Plugs and Wires Recently.
New Air Cleaner.
MAF cleaned recently.
New TBI Idle Engine Replaced recently.
Issue:
When cold start:
Engine cranks and starts up almost immediately with normal crank up sounds. No gas peddle is necessary, the engine simply cranks and starts up beautifully and idles a little high but it's fine.
When engine is warmed up:
When engine is turned off and restarted within a minute or so:
It will start the same as above except idle is perfect now. No problems.
When engine is warmed up, turned off and allowed to rest for 5 to 10 minutes:
You can only start the engine now one of two ways.
1) a. Slightly depress the gas pedal (approximately 1/8 throttle or less),
b. crank the engine and it will start up fine.
2) a. Do not touch the gas pedal
b. crank the engine continually until you hear it slow idling. Takes about 3 to 5 full seconds of cranking before it is idling without the help of the starter.
c. Idle stays very low until you drive it a little, then the idle will become perfect.
Further Explaination of 2:
The same symptom could be reproduced on any vehicle by turning down the idle screw to almost zero but just enough to keep the engine barely running. If you crank the engine without adding pedal it will finally continue to "pull its weight" where you can stop cranking it and it will continue to idle slowly on its own.
My hypothesis:
Whatever tells the TBFI system that "it's time to start now so lets give a little extra airfuel mixture for a moment to get the engine going" is not doing it.
I am a TBFI novice although I understand the basics. If someone that has real exprience with these systems could give me something to go on I'd surely appreciate it.
I'm thinking maybe the IAC and TPS are off but would that effect the difference in starting performance between Cold and Warm starts? Any suggestions is greatly appreciated.
Thank you,
GoodOlJoe
Please tell me you remember what you did to fix this problem!? My 97 4.3 is doing the exact same thing. When it's cool or cold it starts fine and after the sun peaks up and warms everything I need to spray carb cleaner or starting fluid to get the old girl started!
Tell me you have some notes on your fix
Thanks
Hogguy