1980 Throttle stop on Quadrajet??

[Mark A.]

I have a 1980 with 15K miles. In the engine compartment is a loose 14ga. wire, not connected to anything. It is black w/ green tracer. According to the wiring diagram, it should go to the throttle stop on the carburetor. There is no such thing on the car. Was a throttle stop used on the 1980's, or could this wire be for something else? It ends right about at the front of the carburetor. Anybody run into this before? Thanks, Mark

[Patrick H.]

Re: 1980 Throttle stop on Quadrajet??

I Googled 1980 Corvette carburetor, and easily found pictures of the throttle stop.

[Mark A.]

Re: 1980 Throttle stop on Quadrajet??

Guess you are better at finding pictures than me, because the ones I found show a throttle stop but are all on a CA. 305 Ci engine. Maybe you could forward to me what you found? I have the base 350 engine.

[Mark E.]

Re: 1980 Throttle stop on Quadrajet??

This may not be relevant, but 1973 L82s have what you describe. It's energized when the ignition is on. It functions as an antidiesling device: when turned off, it retracts allowing the throttle plates to fully close. The "normal" idle speed screw is adjusted just a crack from fully closed to prevent galling/jamming.

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

Is idle stop same as throttle stop? Here are a couple of images of L82s, 73 and 74 with the throttle stop

1973 L48 idle stop solenoid

emissions_idle_73_l48.jpg

1974 L82 idle stop solenoid
emissions_PCV_L82_74.jpg

[David H.]

Re: 1980 Throttle stop on Quadrajet??

I have a 1980 with 15K miles. In the engine compartment is a loose 14ga. wire, not connected to anything. It is black w/ green tracer. According to the wiring diagram, it should go to the throttle stop on the carburetor. There is no such thing on the car. Was a throttle stop used on the 1980's, or could this wire be for something else? It ends right about at the front of the carburetor. Anybody run into this before? Thanks, Mark

Mark

Some photos from my 1980. But as you see, still a work in progress.

Dave

IMG_3713.jpgIMG_3711.jpgIMG_3712.jpg

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

The configuration change rather significantly...and not a surprise. Need to get part numbers.

[David H.]

Re: 1980 Throttle stop on Quadrajet??

The configuration change rather significantly...and not a surprise. Need to get part numbers.

Tom

If that request is directed to me, then I'll get whatever PN you need. However, this car as had a hard life - not sure how much you should depend on it.

Dave

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

If that request is directed to me, then I'll get whatever PN you need. However, this car as had a hard life - not sure how much you should depend on it.

Dave
It was a general response to all posts.. C3 years used throttle stop solenoids and it would be instructive to create a table showing part numbers by model year and application. Application being engine option RPO by transmission option. You may recall, when first introduced, they were called anti-diesel solenoids...they stopped engine dieseling. In later years, their application became more closely aligned with emission control, controlling engine idle.

I should add that the 1980 TIMJG states that the idle speed solenoid is used on 1980s equipped with automatic transmission and A/C. it fails to confirm application for manual transmissions. One could assume the solenoid was not used on manual transmission equipped 1980 Corvettes.

1974 solenoid with part number
emissions_Idle_L82_74.jpg

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

Mark
Your search has piqued my curiosity, so you can see I've been poking around attempting to narrow the solenoid application in 1980. The photo below is taken of a 79 L82 with M20...four speed! But, what do we see...NO idle stop solenoid. You don't state, but if its a a four-speed, then the lack of a solenoid is consistent with manual transmission applications in 1979. Look at the screw locations where the bracket would have been located...do they look like they have been removed? These clues could help conclude your search.

BTW, the part number when used in 78/79 is 1997409. These notes (and photo) come from work underway for the 78/79 TIMJG. You can see how we have worked to note applications by engine and transmission RPOs.
1979 L82 M20 engine overview
engine_L82_M20_79.jpg

[Mark A.]

Re: 1980 Throttle stop on Quadrajet??

Tom,
Thanks for checking. Yes my car is a 4 speed. The Judging manual says absolutely nothing about the solenoid. But I am curious as to why I have a loose wire in the engine compartment that should go to a solenoid according to the wiring diagram. I will pull the air cleaner again and look at the screw holes. Mark

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

Loose wire...not a surprise! My 78 was an early and the intermittent wiper option was not available. Yet the pink wire and connector dangles from the wiper motor along the fire wall. Remember that automatics were equipped in some 75 percent of Corvettes built, so it could be that solenoid wire was included in the wiring harness. We could look at the AIM and see if it it calls out two different harnesses. Only 14 % of buyers ordered four speeds in 1980.

[Mark E.]

Re: 1980 Throttle stop on Quadrajet??

Loose wire...not a surprise! My 78 was an early and the intermittent wiper option was not available. Yet the pink wire and connector dangles from the wiper motor along the fire wall. Remember that automatics were equipped in some 75 percent of Corvettes built, so it could be that solenoid wire was included in the wiring harness. We could look at the AIM and see if it it calls out two different harnesses. Only 14 % of buyers ordered four speeds in 1980.

Tom,


Another example of a harness for multiple applications from 1970: auto and 4 speed cars share the same dash harness, so the connector for the neutral safety switch isn't used on 4 speed cars.

[David H.]

Re: 1980 Throttle stop on Quadrajet??

Tom

Re: Information from my 1980.

Believe carburetor is original to car. "204" on a L48 Automatic. Car's Build is 1 April 1980 (Yes, I know, April Fools!) Carb date is 58th day of 1980.

UNLIKE your #9 post of a 1974, there is no part number stamped on plunger body. Only pn is "61769" stamped on attaching bracket. Bracket and plunger do not appear to be easily separated - so I think "61769" is units pn.

Not that we're going to take things apart during judging, but, unit is attached to carburetor with two 5mm 1.00 pitch Philips head screws with tapered body. Taper length on screw close to bracket thickness.

Dave

AC Standard in 1980, so that would not be a factor, at least for 1980-81

IMG_3718.jpgIMG_3715.jpgIMG_3717.jpg

[Tom R.]

Re: 1980 Throttle stop on Quadrajet??

[QUOTE=David Houlihan (36425);951166]Tom Re: Information from my 1980.

Great work on the photography! You would be a good recruit for the 78/79 TIMJG revision...if you had a 79. LOL