Low RPMs bucking

[XfireZ51]

Is the car driveable for long distances? What level of computer savvy do u have?

[secondchance]

Originally Posted by MuRCieLaGo

Usually, I always run the car with the heater OFF. Yesterday, I pressed AUTO and forgot to turn it OFF. The car ran pretty bad. Just look at the idle when I press the AUTO button:

Once again, as far as irregular clanking noise when HVAC is turned on, check how close belts are at belt tensioner pulley to belt coming up from the water pump. I had very similar noise. Turned out to be belt being too long.

[Billy Mild]

If you need a cheap scanner buy ALDL droid for Android phone or tablet plus the Bluetooth dongle.

http://www.corvetteforum.com/forums/...d-android.html

[MuRCieLaGo]

Originally Posted by Paul Workman

Well, my sense of it is: (1) it isn't anything too big, but (2) it is beyond your current knowledge/(ZR-1) expertise.

I hate to see anyone struggle so. I'm thinking that perhaps you should consider either taking it to someone that IS ZR-1 savvy, or paying someone that is skilled to visit your location w/ tools in hand.

If neither of these are going to work, but you have reasonable mechanical skills, then I suggest you pick someone that is knowledgeable that will be willing to work with you, off-line. By "huddling" w/ someone off-line you have better continuity of thought and the troubleshooting process and less chance of distractions - albeit in the best of intentions. Just a thought.

I don't think it's a good idea there, Paul. I'm pretty far from everything here and I got a LOT of tools in my garage. If I lived in a big city, of course I would have been to a ZR-1 specialist...

Originally Posted by XfireZ51

Is the car driveable for long distances? What level of computer savvy do u have?

Just did a 150 miles trip today, so yes the car is driveable for long distances.

My computer level is easily intermediate-advanced. I'm the one that people call when their computer is broken (and full of virus most of the time).

Originally Posted by secondchance

Once again, as far as irregular clanking noise when HVAC is turned on, check how close belts are at belt tensioner pulley to belt coming up from the water pump. I had very similar noise. Turned out to be belt being too long.

secondchance, you've been useful to me a couple of times. I saw the thread that you posted a bit more than a month ago about that issue. Did you have some buckings/hesitations at low RPM? Did you have any other symptom other than that noise? As I can see, I can not adjust the tension on this belt, that's the tensioner's job, right? I tried to find a model number or something on the belt, unfortunately without success.

Originally Posted by Billy Mild

If you need a cheap scanner buy ALDL droid for Android phone or tablet plus the Bluetooth dongle.

http://www.corvetteforum.com/forums/...d-android.html

This, is interesting...

[secondchance]

I think it's possible that you have more than one issue. YouTube posting of clanking noise at idle when HVAC is on (compressor engaging) is very similar to my experience. Bucking and hesitation maybe another issue.
Belt tensioner cannot be adjusted but belt lengths are available in 5 mm increments. When the drive belt is too long (and some belts sold as correct length for LT5 are 80.5 mm. I am currently running 80 mm) when AC pulley engage and disengage creating a light fluttering, tensioner bottoms out and starts tapping.

[MuRCieLaGo]

Originally Posted by secondchance

I think it's possible that you have more than one issue. YouTube posting of clanking noise at idle when HVAC is on (compressor engaging) is very similar to my experience. Bucking and hesitation maybe another issue.
Belt tensioner cannot be adjusted but belt lengths are available in 5 mm increments. When the drive belt is too long (and some belts sold as correct length for LT5 are 80.5 mm. I am currently running 80 mm) when AC pulley engage and disengage creating a light fluttering, tensioner bottoms out and starts tapping.

But like I said, I couldn't find a part number on the belt, so that's pretty sad... And yes, maybe I got more than one issue... Oh my god.

Reliable GM V8 they said...

[secondchance]

Originally Posted by MuRCieLaGo

But like I said, I couldn't find a part number on the belt, so that's pretty sad... And yes, maybe I got more than one issue... Oh my god.

Reliable GM V8 they said...

You don't need a part number. Look at the gap between the belt pushed in by the tensioner and the belt going up from the water pump pulley to the alternator - narrowest pinch point. If this gap is less than 1-1/2", belt is too long and maybe causing the tensioner to bottom out. At $35-40 per belt, pretty cheap fix that takes one issue off the table. As for the stumbling, as others have suggested scanning May be the only way to avoid wild guesses and throwing parts on it. Problem with dealerships, perhaps not all but most, are more interested in making money than fixing cars. Furthermore, most LT5 certified Mr. good wrench have retired.

Don't get discouraged and check the belt for proper length. Also, figure out a way to access engine parameters when stumbling.

[KJL]

Any follow up?

[MuRCieLaGo]

Took a break - currently working far away from where I live.

To be continued.

Thanks!