Saxondale

iTrader: (2)

High idle 1650 rpm. It is not the kicker, which is disconnected. It is not the exterior idle speed screw, which is backed off fully.

CCV is disconnected and carb ports capped. PCV is still connected to carb. Air cleaner doors port is capped.

L69 T5.

Set top of float toe 3/16 from top of bowl.
Set lean mixture screw using stop gauge from Thexton.
Set rich mixture stop 4/32 from lean, using a Thexton ruler.
Set idle air bleed using U-shaped Thexton gauge.
Idle mixture screws are 2 & 5/6 turns out from closed, as they were from GM.

At closed loop the dwell meter moves far left (low number).

The only thing I tried so far were turning idle mixture screws each in one turn, and no channge.
And then tried couple turns in and couple turns out with idle air bleed and no changes.

I've gone no further.

sofakingdom

iTrader: (1)

Look closely at the choke linkage; particularly the little lever that the throttle shaft comes to rest against.

Saxondale

iTrader: (2)

Will check it out. Looked at spare carbs in basement and understand what you are describing.

Saxondale

iTrader: (2)

Cracking open the '84 shop manual, after the following testing.

Choke linkage may have been early issue which is now resolved.

Dwell is 6 degrees with Sears Penske meter. Monitor 2000 says closed loop and lean, and 6 degrees. Currently waivering idle 600 to 925. RPM based on both Penske and Monitor devices.

The somewhat arbitrary twisting of idle air mixture has had no effect in either direction. Have gone up to three turns in and three out from base setting.

Currently all items are back to base settings as described in first post above, including 2 & 5/6 turns out on each idle mixture screw.

'84 Shop Manual states if dwell below 25 degrees and idle air bleed valve has no affect, then back out idle mixture screws one turn each.

Manual says idle air bleed valve should be adjusted in 1/8 turn increments. Noted.

Will do these steps in a couple hours unless I hear otherwise here.

sofakingdom

iTrader: (1)

The idle mixture screws have almost no "authority"... I usually set em to about 6 or 7 turns out and leave em. Make all further adjustments with the IAB.

1/8 turn on the IAB is a tiny tweeeek. If it's a long way off now, you'll take forever and a half to dial it in, and might not be able to even tell that anything is happening. I'd suggest doing it in ½ turn increments until you get close, then ¼ as you get closer, then 1/8 or maybe even less as you zero in on it. Also note that a torn / crinkled up / damaged O-ring on the IAB will cause a serious lean condition, check that it didn't get hurt during the build.

I suspect the car will run ALOT better with more advance than 6°; probably will prefer more like 12°. Of course if you're going through inspection it'll need to be pretty close to stock, but for daily use it'll be MUCH more responsive, get better mileage, and run cooler, with more.

Saxondale

iTrader: (2)

Hitting a wall with testing.

O rings appear good. Lower one is new.

Choke is always 1/2 closed. Perhaps itself failing. But forcing it open including the linkage stops doesn't seem to matter regarding setting dwell.

Getting mostly readings of around 6. Occasionally it will rise to 25 and hold for a short bit, but then drop back down to less than 10. Doesn't seem to matter where the idle air bleed valve is set.

Idle mixture screws are out about 6 turns now. They didn't seem to matter.

I've had this carb apart in past, but never a rebuild until now. The car has always run rich with poor mpg. But it was better after I last worked on it, swapping a few items from spare carbs. And then I had no trouble getting dwell to 30.

At a loss. I thought I knew these carbs pretty good by now, but failing miserably at this point.

I don't like that the choke only half opens. But I still don't think that's the primary cause. Air leaking past throttle shaft? It has some play, but did not seem enough to cause this.

Saxondale

iTrader: (2)

Planning to work off these pages for the next steps.

Saxondale

iTrader: (2)

After more time with it I think it may be related to AIR system. I ran out of time before I could be certain, but it appears in closed loop that air is still being directed to the manifolds.

sofakingdom

iTrader: (1)

Keep in mind, those troubleshooting charts are for NEW cars; basically where you're working on brand-new perfect factory-stock showroom product, and ONE thing has failed outright, and you're trying to zero in on it. Not the same as, an ANTIQUE car, with possibly multiple unknown wear-and-tear and deterioration issues, not to mention potential misassembly and such, which can lead to things happening that the chart creators did not envision. In a word, the chart is the "expected" things that might go wrong. You need to prepare to expect the unexpected. Note carefully that I am NOT saying "the chart won't work", or "you messed it up so bad it's off the chart", or "the chart is wrong" or "useless" or ANY such; only, be mentally prepared that the chart might not lead you in a straight line to your trouble(s), and may instead lead you around in circles that totally miss the actual defect(s). At best, it may be a serious zig-zag, and might take ALOT longer to decipher all of that, than to simply go back and check your work carefully.

As to the AIR system, you can direct the pump output anywhere you want with acoupla alligator clip leads. Dump, cat, or manifolds. However I don't think that having full-time into the exh manifolds will do that... I've actually plumbed cars that way to fake them through sniffer inspection (obviously not visual), when the line to the cat was fornicated somehow, with no ill effects.

If you know that the chole only half opens, you ALREADY KNOW of one thing that's effffed. STOP and fix it before any "chart" or anything else. No sense trying to work around something you ALREADY KNOW is bad, that's perfectly capable of causing the kinds of problems you're having. Fix that first.

sofakingdom

iTrader: (1)

I forgot to ask: did you repair the well plugs?

Saxondale

iTrader: (2)

Late evening response so will be brief. Unhooked AIR hoses and capped blowback from exhaust lines. Carb calibrated right on. Had to replace choke fuse which I managed to cook at some point. Choke fixed. Carb calibrated as it should via air bleed valve.

It’s not perfect yet. But better than ever. Excellent drivability. Excellent throttle response. On the secondaries side can readily feather the quadrajet howl on and off and feel the immediate response.

Saxondale

iTrader: (2)

I pressure and soap tested the plugs and they are good for now.