WAZOO Day Success 1/21/17

[Roadster]

That's why Yun and Jim use the "famous" block of wood to keep the front of the plenum raised to make sure everything remains in place....but valid points made....again appreciated....

Sent from my SM-G935P using ZR-1 Net Registry mobile app

[Roadster]

Originally Posted by mike100

If you have a scanner, you can look at the IAC counts. If that number is zero, then the iac is closed off as much as it can and will not be able to lower the idle any further. zero counts is usually indicative of a stuck open throttlebody, leaky throttle body, or large vacuum leak.

Ok checked out throttle cable for play, seemed fine. Changed the IAC since I had one, and went out for a ride with the Tech 1 to get some results. At first start-up the IAC was at 20. TPS was at .52v
And off I went. Engine is very responsive and idle was somewhat under control. Most of the time it was under 1000 r's when stopped. Although there times when it was a 1000 r's or slightly higher, it did seem to fluctuate slightly. I did notice that the IAC did register "0" at any idle speed whether higher or lower after driving for a few miles. As soon as I would come off idle the IAC would go higher.
TPS was now reading @ .54v and would come down to .52v and back to .54v when stopped and idling.
So I imagine that although the throttle cable seem fine, it may be possible that there some slight play because of the idle difference as opposed to a vacuum leak. I will have to check out the throttle body blades further.

On a side note, I did a hot restart before going in the garage and I got the alternator fan blade noise back again. And I thought I corrected that yesterday, oh well!!! Either going to change the fan blade if I can with the alternator in place or just changing out the alternator. If it ends up coming out, that unit is not going back in!!!!

[Racinfan83]

Sounds to me like the bearings are bad in the alternator. Not sure how the blades could just bend themselves?

[secondchance]

Something strange is going on... Never had any issue with fan blade hitting alternator housing. Maybe spacer/washer was installed incorrect when it was rebuilt?
There should be 1/8" clearance from the fan blade edge to the housing.

Tom,
If you have a good elect. impact wrench, with a universal and extension, you can break the nut loose with the alternator on the car. Also, take the nut off your old, dead alternator and take a mental note of sequence and look where the spacers/washers are. See if the alternator on the car has same stacking.

[Roadster]

Originally Posted by Racinfan83

Sounds to me like the bearings are bad in the alternator. Not sure how the blades could just bend themselves?

That's what I thought myself, but being it is a rebuilt alternator, that shouldn't be or is the case. Not that it can't happen.
When I take the tension off the belt, I can then rotate the alternator pulley in either direction. Not only can you see, but also feel where parts of the fan blade actually scrape against the housing. After numerous attempts to correct this I thought it was a done deal. But after yesterday's ride, I was proven wrong.
And when the blades were pried or bent by me, and not rubbing, alternator was quiet as could be. Don't think the blades just bent themselves, rather the housing is slightly wrapped, or the blades are, or as Yun mentioned below, maybe the spacer/washer was installed incorrect.
Of course the fan blade is now toast and will probably get hung up on the garage wall.

Originally Posted by secondchance

Something strange is going on... Never had any issue with fan blade hitting alternator housing. Maybe spacer/washer was installed incorrect when it was rebuilt?
There should be 1/8" clearance from the fan blade edge to the housing.

Tom,
If you have a good elect. impact wrench, with a universal and extension, you can break the nut loose with the alternator on the car. Also, take the nut off your old, dead alternator and take a mental note of sequence and look where the spacers/washers are. See if the alternator on the car has same stacking.

Will try that Yun, I hope my electric impact is strong enough to do the job. Otherwise might take a breaker bar and the persuader to it. But really leaning on either re-clocking the 200 amp unit that I had also purchased, or reinstalling the original one that was taken out. If I go that route, will check out the brushes and other internals first. Was going to do some tonight, but might just wait until tomorrow, as I have all day. No big rush anymore.

Other than that, the LT5 runs fantastic........

[Roadster]

Doing some research on the idle, butterflies opening and closing, and WOT adjustment. And learning as I go along...

Used the Tech 1 with engine off and key on, TPS setting with throttle closed is..
.52v @ 0% with WOT TPS 4.54v @ 100%
So since I am opening @ 100% with WOT the throttle cable is operating correctly. The only thing I don't understand is if I let my foot off the accelerator normally, the TPS is @ .54v if I let my foot off quickly TPS is @ .52v Could that difference between .54v & .52v be the reason for my idle having a slight fluctuation as described earlier? Or is the difference between the two readings so minor, that it would not have any affect on the idle at all? thanks for any info.......

on a side note, my electric impact is not strong enough to undo any pulley nut on any alternator, just doesn't have the power.....lol looks like the alternator removal job starts tomorrow......

[Blownrunner]

Originally Posted by Roadster

Ok checked out throttle cable for play, seemed fine. Changed the IAC since I had one, and went out for a ride with the Tech 1 to get some results. At first start-up the IAC was at 20. TPS was at .52v
And off I went. Engine is very responsive and idle was somewhat under control. Most of the time it was under 1000 r's when stopped. Although there times when it was a 1000 r's or slightly higher, it did seem to fluctuate slightly. I did notice that the IAC did register "0" at any idle speed whether higher or lower after driving for a few miles. As soon as I would come off idle the IAC would go higher.
TPS was now reading @ .54v and would come down to .52v and back to .54v when stopped and idling.
So I imagine that although the throttle cable seem fine, it may be possible that there some slight play because of the idle difference as opposed to a vacuum leak. I will have to check out the throttle body blades further.

On a side note, I did a hot restart before going in the garage and I got the alternator fan blade noise back again. And I thought I corrected that yesterday, oh well!!! Either going to change the fan blade if I can with the alternator in place or just changing out the alternator. If it ends up coming out, that unit is not going back in!!!!

Thinking about the fan blade issue... have you considered a bad bearing or something bent internally? It seems unusual to me how it rubs sometimes and sometimes it doesn't. When I got my 91', I did a light restoration on the whole car which included having the alternator and starter rebuilt. I would pull the alternator and do a full rebuild on it. After all it is 20+ years old.

[Roadster]

Originally Posted by Blownrunner

Thinking about the fan blade issue... have you considered a bad bearing or something bent internally? It seems unusual to me how it rubs sometimes and sometimes it doesn't. When I got my 91', I did a light restoration on the whole car which included having the alternator and starter rebuilt. I would pull the alternator and do a full rebuild on it. After all it is 20+ years old.

Appreciate the thoughts, but the original alternator is sitting on my garage work bench. It was replaced with a rebuilt unit when the plenum pull was done last weekend. Yes it did seem unusual that during the 2:20hr drive home there wasn't any noise whatsoever. But on the following day during one of the restarts, the noise started. I also thought at first that the noise was a bad bearing. But apparently that is not the case. Rather, the fan blade is the problem. As mentioned earlier, numerous attempts to "straighten" out the blade were and are not successful. Only for a few short times, did it seem to work, where I thought the problem was corrected. There isn't any play with the pulley that I can detect, and unless the housing is wrapped, it has to be the fan blade. So it's coming out, no need to do a full rebuild, just not using this unit at all.
That was my intention, doing a light rebuild which was very successful, but things happen and this is one of them.

[dredgeguy]

Tom, last year when I had my car at the.... (ugh I know, I know,...Chev dealer) I had the same problem. When I took my car to Dempsey to undue all the screw-ups from the dealer he found out why the alternator fan was hitting.....the alternator was missing a bolt! Just make sure they are all there and one did not work itself out. Keep us posted.

[Dynomite]

Originally Posted by Roadster

on a side note, my electric impact is not strong enough to undo any pulley nut on any alternator, just doesn't have the power.....lol looks like the alternator removal job starts tomorrow......

This always works.......Using a 15/16 inch modified Open End Wrench and 5/16 Allen Wrench. Sometimes add another box wrench hooked on the open end wrench for leverage.




All Aluminum Alternator Pulley