What is this relay looking module box on my valve cover??

[legopnuematic]

Is this the post in question from Craig 85?

My K30 (454) has it, and after looking through my shop manual I found it. It is a ENGINE SPEED SWITCH related to the Throttle Return Control (TRC). My truck was built 11/84, so all my emissions labels say compliant to 1984 standards. Emissions changed 1/1/85. I know 454's went to dual smog pumps then. Based on what I've read it was used from 79-84.

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[legopnuematic]

Ebay listing for NOS relay

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Another thread here mentioning it

 

[bucket]

Ebay listing for NOS relay

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Another thread here mentioning it

You are spot-on!

 

[Craig 85]

Yep that's it. I know for sure it ties into the emissions system, but I've never hooked up my cruise control, so I'm not sure if controls any part of that system.

 

[59840Surfer]

Was It a twin battery truck? Some of the those used a relay to isolate the two batteries when the engine wasn't running.

Too small for a dual battery setup. This is, at most a 10Amp relay.

My '86 K5 Blazer had the same relay -- it was a CARB/CalEPA mandated relay for the EIS/EIC ... IIRC it had to do with the Diverter Valve signal from the Decel Switch for the A.I.R System and --- as on my K5 --- it didn't have CPFI - it was still carburetted.

The idea was to make the Decel Switch and its solenoid keep the throttle partially open long enough to clear out most of the unburned fuel before the Decel Valve opened - preventing a big KA-BOOM in the exhaust system.

An earlier version also had a switch to turn the AC Compressor clutch ON to help stop the engine from "run-on" after the key was turned off by dragging the engine to a halt with the extra compressor load.

One version having the THM350-C transmission also had an electrical switch that applied the TCC at shutdown for the same purpose.

I often caught transmission swaps from the correct THM350-C for another used unit --- or even a rebuilt core transmission --- and they failed the Smog Inspection and fell into the "M-M-D" category that made it damned near impossible to ever register the vehicle again.


/

 

[59840Surfer]

It's a relay,doesn't appear factory to me I've never seen a relay sheet material screwed to a SBC valve cover factory. Since it is a relay,no telling what it controlled,horn,heater,blower,wipers,starter,ejector seat,etc.

That appears to be a Goodwrench replacement engine --- perhaps?

The relay was originally spot welded on the old valve cover and if you did a full engine, then you just drilled and screwed it on in the same place.

 

[Ricko1966]

Too small for a dual battery setup. This is, at most a 10Amp relay.

My '86 K5 Blazer had the same relay -- it was a CARB/CalEPA mandated relay for the EIS/EIC ... IIRC it had to do with the Diverter Valve signal from the Decel Switch for the A.I.R System and --- as on my K5 --- it didn't have CPFI - it was still carburetted.

The idea was to make the Decel Switch and its solenoid keep the throttle partially open long enough to clear out most of the unburned fuel before the Decel Valve opened - preventing a big KA-BOOM in the exhaust system.

An earlier version also had a switch to turn the AC Compressor clutch ON to help stop the engine from "run-on" after the key was turned off by dragging the engine to a halt with the extra compressor load.

One version having the THM350-C transmission also had an electrical switch that applied the TCC at shutdown for the same purpose.

I often caught transmission swaps from the correct THM350-C for another used unit --- or even a rebuilt core transmission --- and they failed the Smog Inspection and fell into the "M-M-D" category that made it damned near impossible to ever register the vehicle again.


/

You think that relay is less than 10 amps? The camper special 2nd battery relay was like 30 amps, anyway glad someone knew what it was,and we can once and for all rule out ejector seat relay.

 

[Dano500]

I did a search, and google search and came up with nothing. I forget how many, Like 4 or 6 wires connect to via plug.
I should have taken a pic while it was on the engine but did not think of it. What ever it is its factory.

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Mine has it, too! I have been trying to find out what it is also. Mine doesn't have cruise, so idk.

Is there an obvious way to tell if you have a camper special without RPO code?

 

[Radiohead]

Is there an obvious way to tell if you have a camper special without RPO code?

The little badges would be the easy way, but my opinion is if it has a rear swaybar factory installed, it's a camper special.

 

[Dano500]

@Radiohead thanks. This thing was pretty stripped down when I picked it up, but definitely no rear sway bar. I am just trying to find out if it meant anything that it has the 13" rear drums, 8 leafs and G brake code. Maybe just optioned that way.

 

[59840Surfer]

The little badges would be the easy way, but my opinion is if it has a rear swaybar factory installed, it's a camper special.

Uhhhmmmmmmmm ... I humbly disagree.

I have both front and rear swaybars and on the doorpost sticker it says it is NOT designed to carry a camper.

 

[Radiohead]

Uhhhmmmmmmmm ... I humbly disagree.

I have both front and rear swaybars and on the doorpost sticker it says it is NOT designed to carry a camper.

If it's a half ton, I believe it. I'm sure a rear sway bar could be added on, either as an option from the factory or after the fact.

I will guess what you have is a bit of a unicorn. Kewl !

 

[59840Surfer]

If it's a half ton, I believe it. I'm sure a rear sway bar could be added on, either as an option from the factory or after the fact.

I will guess what you have is a bit of a unicorn. Kewl !

I guess it's time for pictures --- but two of my other K5s said the same thing.

 

[squaredeal91]

My mom's 69 c10 has a rear sway bar but I think my dad put it on maybe.

 

[Radiohead]

BIL put one on his c10, didn't come with one and it handles better with it. The fat tires on 20's help a little too.