1986 Engine Wiring Question

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

JKRamsey1991

Member
Joined
Sep 22, 2022
Posts
48
Reaction score
85
Location
Kentucky
First Name
Justin
Truck Year
1985
Truck Model
K20
Engine Size
350
As I am in the process of rebuilding the engine in my truck I wanted to clean up the wiring while I am able. My truck has all of the emissions stuff deleted (AIR smog pump EGR etc). I want to delete the AIR control module. I see the AIR module feeds the distributor from the white wire. Looking at the diagram I believe If I just splice the white wire to the distributor with the white/brown wire that feeds the AIR module that should be enough to eliminate the module. Any thing I am missing here?

You must be registered for see images attach
 

Attachments

  • 1698841558684.png
    1698841558684.png
    119.9 KB · Views: 48

JKRamsey1991

Member
Joined
Sep 22, 2022
Posts
48
Reaction score
85
Location
Kentucky
First Name
Justin
Truck Year
1985
Truck Model
K20
Engine Size
350
I guess everyone is about like me and hates wiring/wiring diagrams lol.
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,302
Reaction score
2,271
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
I don’t mind reading the diagrams. However, unless I understand what the functions are for each component, it hard to know what to disconnect or bypass. For example, if the AIR pump has been removed, what is the AIR module trying to do with the feed to distributor?
 

JKRamsey1991

Member
Joined
Sep 22, 2022
Posts
48
Reaction score
85
Location
Kentucky
First Name
Justin
Truck Year
1985
Truck Model
K20
Engine Size
350
I don’t mind reading the diagrams. However, unless I understand what the functions are for each component, it hard to know what to disconnect or bypass. For example, if the AIR pump has been removed, what is the AIR module trying to do with the feed to distributor?
I'm with you really. I have no clue how the AIR module works or any of that. It just appears the white/brown wire is the 12volt feed to that module and the white wire to the distributor plug. So I think just splicing those two together and bypassing the module would do it. Currently all other wires from the module are cut.
 

MikeB

Full Access Member
Joined
Apr 4, 2014
Posts
1,782
Reaction score
1,020
Location
North Texas
First Name
Mike
Truck Year
1969
Truck Model
C10
Engine Size
355
An A.I.R system (Air Injection Reactor) used a belt driven pump that injected fresh air into the exhaust manifolds via tubes right next to the exhaust ports. The idea was to burn off any gases that are a product of internal combustion. I didn't know the pump had an interface to the distributor, but I never did work on an engine with the A.I.R. system. If your diverter valve is tied to the distributor, I don't know if it was sending info to the distributor, or vice versa.

You must be registered for see images attach


I just found this description of a diverter valve, but don't know why it would be tired to the distributor:

"To prevent the startling and potentially damaging effects of the explosive combustion of this raw fuel, a diverter valve is used. This valve senses the sharp increase in the intake manifold vacuum resulting from the sudden closure of the throttle, and diverts the air pump's outlet to atmosphere."
 
Last edited:

59840Surfer

Full Access Member
Joined
Oct 8, 2020
Posts
212
Reaction score
336
Location
Montana
First Name
Joe
Truck Year
1986
Truck Model
K5
Engine Size
350 Stroker to 383 with a 400 crank, Crane Cam, Q-Jet, single 3.5" exhaust..
There are DIVERTER Valves and then there is a thing called a GULP Valve.

The Diverter valve sent excess air into a sorta muffler on the side of the A.I.R control valve where it was dumped out to the atmosphere - ostensibly quietly as the muffler was full of fiberglass to keep the noise of the tri-bladed pump vanes from being heard.

A GULP Valve, just allowed uncontrolled atmospheric air INTO the exhaust flow during deceleration and that was a big problem.
---> This design was good until the carburetor developed interior fuel control problems and would let excess fuel still flow through the intake and out the exhaust, basically unburned and ready to explode - and DID explode - usually in the muffler.

Many mufflers exploded/died when that happened and GM did away with the Gulp Valves pretty fast!

To your statement -----

"To prevent the startling and potentially damaging effects of the explosive combustion of this raw fuel, a diverter valve is used. This valve senses the sharp increase in the intake manifold vacuum resulting from the sudden closure of the throttle, and diverts the air pump's outlet to atmosphere."

There never was any electrical connection from the A.I.R. pump system.

I've explained the 'why' of a Gulp Valve and how it was quickly replaced with a Diverter Valve ..... and I restate ---> there never was any electrical connection of the A.I.R. pump, diverter valve or any other sensors (of which I cannot remember any) and the distributor.

ALL changes in smog pump discharge were controlled by a vacuum signal from a modulated vacuum supply and a manifold vacuum supply to correct the position of the pump discharge into the air injection nozzles at the exhaust ports.
 

JKRamsey1991

Member
Joined
Sep 22, 2022
Posts
48
Reaction score
85
Location
Kentucky
First Name
Justin
Truck Year
1985
Truck Model
K20
Engine Size
350
Well maybe I called the module the incorrect name. It is the Emission Control Module not technically the AIR module.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,585
Reaction score
9,065
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Deleting things is not always a good idea. I d k what engine you have,but the 305 likes having egr. EGR has no downside,only upside. Less emissions,cooler combustion chambers,ability to run more ignition timing,more mpg. And it is disabled by design when you are in the throttle so you're not gaining anything performance wise. And PCV is another good emissions device with no downside.
 
Last edited:

Forum statistics

Threads
44,391
Posts
956,269
Members
36,681
Latest member
91k5user
Top