Coughing and choking??Help
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Teching In
Joined: Mar 2008
Posts: 29
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Coughing and choking??Help Ill drive the car everything seems fine then when i turn it off and go to start it after like 10-15 mins,it starts to sound like its dieing when i start to driving it. Itll happen for about 2-5 mins and feels like its not getting enough gas and bogs down. I changed the fuel filter and the problems still there,the car has 65k and the original fuel pump. Any suggestions would be great thanks
Use your scanner to see if your o2's are osilating within the range they are supposed to.
I would also try to disconnect your MAF and your o2's and drive the car around to see if your symptoms disappear.
You can also disconnect the vacuum line to your EGR and drive it around and see if anything changes.
Also check for vacuum leaks like corroded air hoses or a torn intake elbow. Good luck man.
On The Tree
Joined: Jun 2006
Posts: 126
Likes: 0
From: Novi, MI
^^you seem pretty smart 
, After MUCH research on the internet on the problem I am having this is where I am at: so I got my car scanned and did not write down the codes like an idiot, but the guy said the codes were for the drivers side first O2 sensors and the MAF. following advice I cleaned the MAF, checked all fuses and voltages and the car still bogged after it entered closed loop but only while trying to accelerate on the highway at approx 70mph. I unplugged the MAF and the car proceeded to bog in all gears upon acceleration. I reset the PCM with the thought that it will clear any MAF "memory" and the car would go into S/D. well the car still bogged in all gears at all speeds.
As for the O2's I had a meter hooked up to the O2's and the voltage was ~.625 V with car at operating temp and seemed to fluctuate a couple tenths and then made significant jumps when I blipped the throttle.
I also checked the MAP sensor and it was free of debris.
So the question is:
1) If I go ahead and unplug both O2 and keep the MAF unplugged should I expect the car to stop bogging and perform like it is in open loop (when it is cold and first few minutes of engine on time)
2) Is there any way to force the car to stay in open loop, granted it will run rich but at least it will be drivable?
I am going to try to get it scanned again and this time write down the codes, but I guess if there is some creative way to figure out conclusively if I need to buy a new MAF or O2 sensor before I drive out there that would be great.
Thank you!
, After MUCH research on the internet on the problem I am having this is where I am at: so I got my car scanned and did not write down the codes like an idiot, but the guy said the codes were for the drivers side first O2 sensors and the MAF. following advice I cleaned the MAF, checked all fuses and voltages and the car still bogged after it entered closed loop but only while trying to accelerate on the highway at approx 70mph. I unplugged the MAF and the car proceeded to bog in all gears upon acceleration. I reset the PCM with the thought that it will clear any MAF "memory" and the car would go into S/D. well the car still bogged in all gears at all speeds.As for the O2's I had a meter hooked up to the O2's and the voltage was ~.625 V with car at operating temp and seemed to fluctuate a couple tenths and then made significant jumps when I blipped the throttle.
I also checked the MAP sensor and it was free of debris.
So the question is:
1) If I go ahead and unplug both O2 and keep the MAF unplugged should I expect the car to stop bogging and perform like it is in open loop (when it is cold and first few minutes of engine on time)
2) Is there any way to force the car to stay in open loop, granted it will run rich but at least it will be drivable?
I am going to try to get it scanned again and this time write down the codes, but I guess if there is some creative way to figure out conclusively if I need to buy a new MAF or O2 sensor before I drive out there that would be great.
Thank you!
Last edited by ws6chicken; Feb 15, 2009 at 07:37 PM.
Staging Lane
Joined: Nov 2008
Posts: 74
Likes: 0
From: Ashland KY
I would definatly not recommend driving with your 0'2 or MAF unplugged.(or at least for long) My car doesnt even run if the maf is unplugged however you can get your car's o2 sensors tuned out so it doesnt throw a code but i would not leave them unplugged and (untuned) for long. I had to buy a new MAF for my car and it was freaking expensive!
^^you seem pretty smart , After MUCH research on the internet on the problem I am having this is where I am at: so I got my car scanned and did not write down the codes like an idiot, but the guy said the codes were for the drivers side first O2 sensors and the MAF. following advice I cleaned the MAF, checked all fuses and voltages and the car still bogged after it entered closed loop but only while trying to accelerate on the highway at approx 70mph. I unplugged the MAF and the car proceeded to bog in all gears upon acceleration. I reset the PCM with the thought that it will clear any MAF "memory" and the car would go into S/D. well the car still bogged in all gears at all speeds.
As for the O2's I had a meter hooked up to the O2's and the voltage was ~.625 V with car at operating temp and seemed to fluctuate a couple tenths and then made significant jumps when I blipped the throttle.
I also checked the MAP sensor and it was free of debris.
So the question is:
1) If I go ahead and unplug both O2 and keep the MAF unplugged should I expect the car to stop bogging and perform like it is in open loop (when it is cold and first few minutes of engine on time)
2) Is there any way to force the car to stay in open loop, granted it will run rich but at least it will be drivable?
I am going to try to get it scanned again and this time write down the codes, but I guess if there is some creative way to figure out conclusively if I need to buy a new MAF or O2 sensor before I drive out there that would be great.
Thank you!
, After MUCH research on the internet on the problem I am having this is where I am at: so I got my car scanned and did not write down the codes like an idiot, but the guy said the codes were for the drivers side first O2 sensors and the MAF. following advice I cleaned the MAF, checked all fuses and voltages and the car still bogged after it entered closed loop but only while trying to accelerate on the highway at approx 70mph. I unplugged the MAF and the car proceeded to bog in all gears upon acceleration. I reset the PCM with the thought that it will clear any MAF "memory" and the car would go into S/D. well the car still bogged in all gears at all speeds.As for the O2's I had a meter hooked up to the O2's and the voltage was ~.625 V with car at operating temp and seemed to fluctuate a couple tenths and then made significant jumps when I blipped the throttle.
I also checked the MAP sensor and it was free of debris.
So the question is:
1) If I go ahead and unplug both O2 and keep the MAF unplugged should I expect the car to stop bogging and perform like it is in open loop (when it is cold and first few minutes of engine on time)
2) Is there any way to force the car to stay in open loop, granted it will run rich but at least it will be drivable?
I am going to try to get it scanned again and this time write down the codes, but I guess if there is some creative way to figure out conclusively if I need to buy a new MAF or O2 sensor before I drive out there that would be great.
Thank you!
I would definatly not recommend driving with your 0'2 or MAF unplugged.(or at least for long) My car doesnt even run if the maf is unplugged however you can get your car's o2 sensors tuned out so it doesnt throw a code but i would not leave them unplugged and (untuned) for long. I had to buy a new MAF for my car and it was freaking expensive!
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Staging Lane
Joined: Sep 2006
Posts: 81
Likes: 0
From: Springhill, LA
Just keep the maf unplugged and it will stay in open loop.
Not sure what the deal is but your the second person I have seen that says you can have your o2s "tuned out" you need your front o2s! the monitors after the converters can be tuned out and wont cause problems, all the monitors do is check the operation of the cats the front o2s read your afr and keep things in check and allow the engine to stay close to 14.7 constantly changing the stft (short term fuel trim)
I would definatly not recommend driving with your 0'2 or MAF unplugged.(or at least for long) My car doesnt even run if the maf is unplugged however you can get your car's o2 sensors tuned out so it doesnt throw a code but i would not leave them unplugged and (untuned) for long. I had to buy a new MAF for my car and it was freaking expensive!
Not sure what the deal is but your the second person I have seen that says you can have your o2s "tuned out" you need your front o2s! the monitors after the converters can be tuned out and wont cause problems, all the monitors do is check the operation of the cats the front o2s read your afr and keep things in check and allow the engine to stay close to 14.7 constantly changing the stft (short term fuel trim) LS1 Tech Stories
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Verdad Gallardo On The Tree
Joined: Jun 2006
Posts: 126
Likes: 0
From: Novi, MI
So I got the car scanned and this time the car had one and only one code the P0100. Not to be fooled, I cleared the codes with the scanner and took the car for a spin and the car ran like hell, hesitating, stalling ect. Then a funny thing happened the SES light decided to show it self and the car just started to drive normally. I got the car scanned again and it had the same P0100 code, so I borrowed a supposedly working MAF. I installed it cleared the codes and the car ran fine for a few minutes then once again ran like hell (no SES). Then once again the SES turned on and the car appeared to figure it self out and began to run fine. So as has been said the problem I guess lies elsewhere.
One more note is that the problem seems really bad (the car shakes like mad) when I lightly give it throttle on the highway ~70mph and then 50% to WOT it smooths out. But again once that SES turned it seemed to eliminate any problems.
Any final guesses before I cough 45 bucks for a diagnoses at the local shop
. Thanks
One more note is that the problem seems really bad (the car shakes like mad) when I lightly give it throttle on the highway ~70mph and then 50% to WOT it smooths out. But again once that SES turned it seemed to eliminate any problems.
Any final guesses before I cough 45 bucks for a diagnoses at the local shop
. Thanks On The Tree
Joined: Jun 2006
Posts: 126
Likes: 0
From: Novi, MI
I would try to get a vacuum gauge hooked up to your car, I consulted the ever wise GM factory Manaul on the P0100 and it recommend checking the vacuum and the PCV valve.
The reading I got was ~16"Hg at idle at operating temp, which according to the good book is on the low end.
My guess on my car now is that the intake manifold gasket is blown (again).
And the reasoning:
When the engine is cold it is in closed loop therefore the contributions of the MAF and O2 is irrelevent so it will run fine. Also, the various engine parts are not yet heated up so everything is pretty sealed and the pressumed vacuum leak is not very prevalent. Then I'm thinking that once you let the engine cool a little bit the various engine components (intake manifold, heads, block) expand/contract and you get vacuum leak that is throwing off the MAF and setting in my case the P0100. Also, I figure this might mess with MAP and thus throw off the SD readings.
Just my WAG, I will without a doubt post what the shop says (don't necessarly want to tear the intake apart on a guess)
The reading I got was ~16"Hg at idle at operating temp, which according to the good book is on the low end.
My guess on my car now is that the intake manifold gasket is blown (again).
And the reasoning:
When the engine is cold it is in closed loop therefore the contributions of the MAF and O2 is irrelevent so it will run fine. Also, the various engine parts are not yet heated up so everything is pretty sealed and the pressumed vacuum leak is not very prevalent. Then I'm thinking that once you let the engine cool a little bit the various engine components (intake manifold, heads, block) expand/contract and you get vacuum leak that is throwing off the MAF and setting in my case the P0100. Also, I figure this might mess with MAP and thus throw off the SD readings.
Just my WAG, I will without a doubt post what the shop says (don't necessarly want to tear the intake apart on a guess
) I would try to get a vacuum gauge hooked up to your car, I consulted the ever wise GM factory Manaul on the P0100 and it recommend checking the vacuum and the PCV valve.
The reading I got was ~16"Hg at idle at operating temp, which according to the good book is on the low end.
My guess on my car now is that the intake manifold gasket is blown (again).
And the reasoning:
When the engine is cold it is in closed loop therefore the contributions of the MAF and O2 is irrelevent so it will run fine. Also, the various engine parts are not yet heated up so everything is pretty sealed and the pressumed vacuum leak is not very prevalent. Then I'm thinking that once you let the engine cool a little bit the various engine components (intake manifold, heads, block) expand/contract and you get vacuum leak that is throwing off the MAF and setting in my case the P0100. Also, I figure this might mess with MAP and thus throw off the SD readings.
Just my WAG, I will without a doubt post what the shop says (don't necessarly want to tear the intake apart on a guess)
The reading I got was ~16"Hg at idle at operating temp, which according to the good book is on the low end.
My guess on my car now is that the intake manifold gasket is blown (again).
And the reasoning:
When the engine is cold it is in closed loop therefore the contributions of the MAF and O2 is irrelevent so it will run fine. Also, the various engine parts are not yet heated up so everything is pretty sealed and the pressumed vacuum leak is not very prevalent. Then I'm thinking that once you let the engine cool a little bit the various engine components (intake manifold, heads, block) expand/contract and you get vacuum leak that is throwing off the MAF and setting in my case the P0100. Also, I figure this might mess with MAP and thus throw off the SD readings.
Just my WAG, I will without a doubt post what the shop says (don't necessarly want to tear the intake apart on a guess
)
On The Tree
Joined: Feb 2009
Posts: 163
Likes: 0
From: Texas
That is what one of my friends cars is doing but it was his ignition switch the car would just crank and crank the it will tern on and sound all muffeld and like its bogging out but then it will clear up and it will work fine it might be that
On The Tree
Joined: Jun 2006
Posts: 126
Likes: 0
From: Novi, MI
According to the Chilton Manual:
Normal engine operation is 17-22"Hg steady
Leaking manifold gasket 15-20"Hg steady; a minor intake leak will cause the needle to drift.
Note: before this mess started I was at 22"Hg steady
Normal engine operation is 17-22"Hg steady
Leaking manifold gasket 15-20"Hg steady; a minor intake leak will cause the needle to drift.
Note: before this mess started I was at 22"Hg steady
On The Tree
Joined: Jun 2006
Posts: 126
Likes: 0
From: Novi, MI
well...
It was the rear 02's, and a fouled plug.
Should of done better research on the O2 sensors, I believe the 02;s were outputting the right voltage but they were no oscillating. As for the lack of vacuum, engine was probably retarding itself with the fouled plug.
Meh, Fail.
BTW, Thanks for the all the advice, especially SS you were right on!
It was the rear 02's, and a fouled plug.
Should of done better research on the O2 sensors, I believe the 02;s were outputting the right voltage but they were no oscillating. As for the lack of vacuum, engine was probably retarding itself with the fouled plug.
Meh, Fail.
BTW, Thanks for the all the advice, especially SS you were right on!
well...
It was the rear 02's, and a fouled plug.
Should of done better research on the O2 sensors, I believe the 02;s were outputting the right voltage but they were no oscillating. As for the lack of vacuum, engine was probably retarding itself with the fouled plug.
Meh, Fail.
BTW, Thanks for the all the advice, especially SS you were right on!
It was the rear 02's, and a fouled plug.
Should of done better research on the O2 sensors, I believe the 02;s were outputting the right voltage but they were no oscillating. As for the lack of vacuum, engine was probably retarding itself with the fouled plug.
Meh, Fail.
BTW, Thanks for the all the advice, especially SS you were right on!
