Quadrajet Part Question

[Old60Driver]

Quick question for all you Quadrajet Gurus.

I pulled the Q-Jet off this morning for a refresh. The truck in question is my recently acquired 1983 K20 with cruise control and A/C. As I was pulling the carb off, a nipple broke off of this part. (Not sure how to post directly, so I'll have it below on a link). Okay, it's technically NOT on the carb, but it connects to it....

Anyway, I'll try to find one today at a pick and pull, but I have low hopes on being successful. Moreover, I don't even know what it is! lol If it's simply related to CC, I can just plug the line and be on my way. If it's something else? Well, that's where y'all come in. LOL

Thanks in advance!!

https://drive.google.com/file/d/1NXcjay-WGJoSWJy7eTn30RExmdcCJwNz/view?usp=sharing

https://drive.google.com/file/d/1vEWf6bXQoJJC1Sgejf5Fa9a2P7wa8hwL/view?usp=sharing

 

[Danderson]

Can't see your pictures!

 

[Blue Ox]

Can't access the pictures without allowing access to my contacts. If you have these pictures on your computer or phone you can use the upload a file button to post them here. Or possibly you can use the photo button on the top row to link to your drive file.

 

[Old60Driver]

Sorry about that. Looking for the 'upload a file' button now. LOL

 

[Old60Driver]

Let's see if this works!

 

[Old60Driver]

How's about now?

 

[Old60Driver]

I must be a special kind of stupid I guess... lol

 

[Old60Driver]

View media item 9480
View media item 9479

 

[Blue Ox]

Hooray!

Looks like an idle stepper control for A/C or something similar. One of the gas engine guys here will know for sure.

 

[Craig 85]

That is part # GM 1997479 available at the Parts Place for $69. It connects to the vacuum pod on the front driver's side of the carb.

My understanding of what it does is that it bumps the throttle from 1800-2000 RPM during deceleration to prevent backfires through the carb. Part #3 in the first diagram is an engine speed switch which gives the signal to the switch to let vacuum go through the valve to move the plunger on the carb. It is for HD emission vehicles. The 1/2 tons have an electrical switch in the same location on the carb, but that it to bump the idle speed for when the A/C is on.

https://www.ebay.com/itm/1979-84-Ch...uburban-TCS-Solenoid-GM-1997479-/330493410856

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[Blue Ox]

Told ya.

 

[Snoots]

Use some epoxy to fix it. Keep most of that $69 in yer wallet.

 

[Raider L]

In that diagram, there is no way in hell that little nut is torqued to 20 FOOT pounds! That has to be a mistake on the part of the person doing the diagram, or the artist. He probably doesn't know "foot pounds" from a whatever. Now, inch pounds for screws, yeah, not a 7/16" or more like a 1/2" nut, or smaller. Long before you got to 1 or 1 1/2 Lb/ft you would have snapped the screw shaft right off, on top of the valve cover, or the switch bracket. I don't have the bolts on my water outlet torqued to no 20 foot pounds. Yeah, they're 9/16", but it's also going into aluminum. They're snugged down. Either way it's wrong. Sorry to whine about it.

 

[Old60Driver]

Hey y'all! Sorry for the delay response. My work schedule these days is pretty danged hectic, and the days are long. Mind you, I'm not complainin', as workin' is better than not, but just wanted to let you folks know why I haven't responded.

Well, to update, last weekend, I was just trying to get the ol' girl moving, so I just taped over the vac line and continued on. She started right up after the carb rebuild with no issues at all. Choke seemed to be working, step downs and all. I thought I'd take her for a spin down the dirt road, and lord, she just fell on her face! She would rev just fine sitting in park, but under a load? She'd bog HARD. And try to die on me unless I backed off on the throttle. Like she wasn't getting enough fuel? Unfortunately, I had to get back to Oklahoma for work on Sunday, so I left her as is.

I get back to KS last night, and start tinkering with the fuel delivery system. I'm thinking either bad pump, plugged lines, or clogged fuel pick-up socks. I take a look, and sure enough, it looks like the mechanical fuel pump has changed out (not sure when, but the pump itself looks new-ish). Continued to trace it back, and yep, it's ALSO got an electric Mr. Gasket fuel pump in there. Now, I wasn't surprised, as I had seen this all before during my walk down, but it got me to thinking. Why would there be a NEW mechanical fuel pump, AND an electric to boot??

I decided to test it all, so I disconnected the fuel line at the QJet, ran a line from it to a bucket, and turned the key to ON. Well, fuel came out, but it was slooooooow. Hmmmm. So I fired her up to run the mechanical pump until the bowl emptied. Not much better. Definitely not enough fuel to keep her going under a load. Tested the electric out of the vehicle and yep, it's shot. The inlet filter looks terrible. I'm guessing the mechanical is shot too, but I'll get to installing one later, and figured I could run an electric for now. Installed a new Mr. Gasket electric pump, and tested her again. Getting lots of good fuel at the QJet now. That's a good thing, right? Nope. Now I have a new problem. High idle. I CANNOT get the idle to come down.

After all that (and thank you if you're still reading), I have a couple of questions, and requests:

• Is it possible that I need a regulator for the new electric Mr. Gasket fuel pump? Could the fuel pump be overpowering the float needle?
• While I was working on the high idle I went to adjust the idle screw and found that it the idle tap wasn't even touch the adjustment screw. Could the choke step down be an issue? I thought it was working just fine before the pump swap, but maybe it wasn't? I took lots of pics of the carb before disassembly, but didn't get a good shot of the choke linkage. Anyone have a good pic or diagram of the choke linkage?
• As nasty as the the inlet filter to the old electric pump was, should I consider dropping the tanks for a cleaning and inspection of fuel gauge sending unit and socks?

Anyway, sorry the the novel I just wrote, and thanks again for y'alls time.

Should I put this in a separate new thread for this?

 

[Old60Driver]

In that diagram, there is no way in hell that little nut is torqued to 20 FOOT pounds! That has to be a mistake on the part of the person doing the diagram, or the artist. He probably doesn't know "foot pounds" from a whatever. Now, inch pounds for screws, yeah, not a 7/16" or more like a 1/2" nut, or smaller. Long before you got to 1 or 1 1/2 Lb/ft you would have snapped the screw shaft right off, on top of the valve cover, or the switch bracket. I don't have the bolts on my water outlet torqued to no 20 foot pounds. Yeah, they're 9/16", but it's also going into aluminum. They're snugged down. Either way it's wrong. Sorry to whine about it.

Agreed! lol It's just two little Torx screws. Ain't no way they'd handle 20 FT/LBS. Inch pounds maybe... lol