2001 SuperCrew AC problems
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2001 SuperCrew AC problems
So.... here's my issue. I have a 2001 supercrew 5.4 and runs great all day long, no problem starting or anything. After I have driven it for a while and turn the AC on it cools off very good then after about a 1/2hr. the truck tries to stall. It almost sounds like a vacume leak and really bogs down. I can wait about 2hrs and then with the AC off the truck starts and drives like it should. I am stearing to the IAC valve but would like to know if this is it. Any help would be great.
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Bluegrass 7-
I will answer in order...
No it does not idle lower in rpm...
No the motor does not stall at all it seems to act as if it has a vacume leak and is trying to get air/fuel but never stalls. I had a problem a while ago and found the hose from the brake buster to the throttle body was bad. Replaced and after about 3months this started. I did check the hose again and it is good.
The motor never stalls...
I checked the fuel rails with gauge and that was good, so I don't think that it is fuel related. Everything that I have been reading seams to point at maybe the IAC valve but I hope that I am wrong and someone can help.
I will answer in order...
No it does not idle lower in rpm...
No the motor does not stall at all it seems to act as if it has a vacume leak and is trying to get air/fuel but never stalls. I had a problem a while ago and found the hose from the brake buster to the throttle body was bad. Replaced and after about 3months this started. I did check the hose again and it is good.
The motor never stalls...
I checked the fuel rails with gauge and that was good, so I don't think that it is fuel related. Everything that I have been reading seams to point at maybe the IAC valve but I hope that I am wrong and someone can help.
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I re read your original post but still can't get a feel for what is going on.
If the idle is correct, the IAC is working as it should.
Is there a problem with the A/C on when this happens?
Reason I ask is the A/C clutch bearing or the compressor can go into a bind from age. Since it is belt coupled to the motor it loads the motor down.
If the idle is correct, the IAC is working as it should.
Is there a problem with the A/C on when this happens?
Reason I ask is the A/C clutch bearing or the compressor can go into a bind from age. Since it is belt coupled to the motor it loads the motor down.
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That could be it... but it does not happen all the time. I have driven with the ac on and works fine all day long. The ac blows cold air great and I have never had a problem with it not working.
The reason I was thinking the IAC is that when this happens I can give it gas and the problem seems to go away as long as I am pressing the gas pedel. The ac still blows cold air when this is going on. Oh by the way Thanks for your input never did say that.
The reason I was thinking the IAC is that when this happens I can give it gas and the problem seems to go away as long as I am pressing the gas pedel. The ac still blows cold air when this is going on. Oh by the way Thanks for your input never did say that.
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If the A/C continues to work ok when the issue is present, it's not the compresor.
If the idle stays at about 650, the IAC would seem to be good.
When you throttle up, the IAC is no longer a factor.
I still don't get what your experiencing.
Have you checked for any codes?
Check that the Mass Air and IAT plugs in firmly in place.
Also is there any difference with the motor in gear or out of gear?
If the idle stays at about 650, the IAC would seem to be good.
When you throttle up, the IAC is no longer a factor.
I still don't get what your experiencing.
Have you checked for any codes?
Check that the Mass Air and IAT plugs in firmly in place.
Also is there any difference with the motor in gear or out of gear?
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Ok, I will try this... I can leave my house and go to work and the truck starts and runs fine. I then turn the ac on and still no problem. After about 30-40min and driving down the road the truck starts to bog down, feels like its missing, and that is the way it runs until I shut it off for about 1-2hrs. I then get back in it starts just fine, and drives great. I have gotten to my drive way and put it in park and you can hear the engine having problems like a vacume leak or it missing. I have had it checked for codes and nothing comes up. I just cleaned the mass air and the IAT plug is in firmly in place.
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Lead Driver
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Let me ask if you feel the motor begins to studder or missfire in OD and very light throttle opening between 45 and 60 mph when this happens?
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Lead Driver
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The only thing you keep coming back to is a vacuum leak.
What dose it sound like?
A vacuum leak is unaccounted for air some place between the Mass Air Meter and the intake tract.
If big enough it should set codes 171 and 174.
Why; the Ox sensors detect the extra oxygen "at first" {then} move the fuel tables to their rich side causing the codes 171/174 in an attempt to make up for the extra air.
The rubber fittings and hoses attached to the intake can open up with engine bay heat, and high vacuum levels upon decelleration.
If you feel you have such a leak you have to do a good check of all the fittings hoses and hardware to find it.
So far there is nothing to pin it on until you take a good look and feel of the parts.
What dose it sound like?
A vacuum leak is unaccounted for air some place between the Mass Air Meter and the intake tract.
If big enough it should set codes 171 and 174.
Why; the Ox sensors detect the extra oxygen "at first" {then} move the fuel tables to their rich side causing the codes 171/174 in an attempt to make up for the extra air.
The rubber fittings and hoses attached to the intake can open up with engine bay heat, and high vacuum levels upon decelleration.
If you feel you have such a leak you have to do a good check of all the fittings hoses and hardware to find it.
So far there is nothing to pin it on until you take a good look and feel of the parts.
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