Does anyone know what this sensor goes to?

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Turbo4whl

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The distributor only has the hot wire and vacuum. The wire on the connector is light blue and is routed behind the alternator to the harness. The truck is badges with spark control, but I didn’t see anything above the blower box. It believe from the factory it was originally a 305 with a 400 transmission. After tearing into it recently, I confirmed it’s a 90/91 350 with a 350 transmission. It has standalone hei, Edelbrock intake and 1406 carburetor since last weekend. The only emissions equipment I see is the charcoal canister routed to the tank vent and a catalytic converter. All else has been removed at some point. The sensor concerned me when I found it squirreled away. I’m starting to think it’s a sensor that’s not hooked up to anything and just hanging out there.

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The control processor is not mounted near the blower box. It would be mounted near the parking brake assembly.
 

Ricko1966

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The control processor is not mounted near the blower box. It would be mounted near the parking brake assembly.
When did they move them behind the glove box?
 

Turbo4whl

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When did they move them behind the glove box?

Never, this is where Alan said he looked for it in a previous post. I was re-stating like I said in a previous post where the ESC processor is located.
 

SirRobyn0

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The control processor is not mounted near the blower box. It would be mounted near the parking brake assembly.

I think you are mistaken, on all the ones I have seen they are above the heater box accessed by removing the glove box.
 

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I just looked by the emergency brake area and found the wiper delay box, lighting wiring and the alarm system box. I didn’t see an esc module. There is an empty 5 pin connector above the airbox behind the glovebox when followed goes through the firewall to a thicker harness with another empty connector below the distributor stem. Might be a frakentruck, but been trying to clean up unused wiring and parts since tracking down a sound which was a cracked flexplate.

Anyhow, I appreciate all the assistance and feedback.
 

Ricko1966

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I just looked by the emergency brake area and found the wiper delay box, lighting wiring and the alarm system box. I didn’t see an esc module. There is an empty 5 pin connector above the airbox behind the glovebox when followed goes through the firewall to a thicker harness with another empty connector below the distributor stem. Might be a frakentruck, but been trying to clean up unused wiring and parts since tracking down a sound which was a cracked flexplate.

Anyhow, I appreciate all the assistance and feedback.
Take off the distributor cap and look at the module is it a 4 pin module or even a 5 pin but only 4 wires hooked up? Then it wouldn't matter if you had the controller and sensor in place because your distributor won't electronically retard. If you have a 4 pin module tape that wire somewhere inconspicuous put the harness back behind the glove box and make it appear unmolested. It won't hurt to leave the wires in case you or someone else decides they want to go back to esc.
 

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It’s a 4 pin module in there. I plan on tucking the connector by the distributor back onto the thicker harness then taping over it to give a cleaner appearance. The one behind the glovebox is going to get zip tied to something to keep stationary.
 

Turbo4whl

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I think you are mistaken, on all the ones I have seen they are above the heater box accessed by removing the glove box.


I am correct about my 1982 305, assembled in Canada. Sold in Pennsylvania, 50 state Federal emissions. I ordered it in July or August of 1981, Took delivery in November, 1981.

Other years or models may well have the control mounted differently. As I stated earlier, there was nothing special about the distributor except the added on spark control.
 

fast68chevy

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1982 305 K10 pickups had an EST small emblem on the tailgate. i can verify.. because ours was.
before we disassembled it and totally rebuilt/restored it a few years ago,, from a couple other 81-up parts trucks as donors for sheetmetal parts etc. it was a 305 700r4 factory now it is 350 and TH350. with original 208 case and original 12 and 10 bolt 2.73 ratio axles('82 was the final year for the rear 12 bolts an first year for the 700r4 trans)

in 1982 model year GM called this electronic spark timing. and our spark control module box was in the dash center area. with 5 pin ICM with vacuum advance distrib(federal non-cali) and no smog

the motor in the above pics has '87-up style heads and 1980-up exh manifolds, and FYI the car ones(above-spark plugs style)had two stud outlets,, and the truck ones had three-stud outlets..
and the cars including the F and B-body the LG4 and L69 305 motors were still factory 4 bbl Q-jet, with ESC/EST system with E4ME Q jet carbs and no vacuum advance in the HEI distribs, almost always. unlike alot of the truck 305 motors that did have still vac advance, wth the EST/ESC, at least the federal basic/least amount of emissions equipment installed ones anyways. no smog/A.I.R. pump and injection tubes.

-------------------------

heres some quoted info on 305 1980-1986 motors, and i am actually right now looking for a complete pair of 4416 or 22601 heads and a stock 1980s aluminum intake here in central IL if anyone has oir knows where any are here?):


The LG4 produced 150–170 hp (112–127 kW) and 240–250 lb⋅ft (325–339 N⋅m). Introduced in 1978, the LG4 was essentially an LG3 with the addition of a 4-bbl carburetor and larger valves. The engine saw a series of gradual improvements, increasing reliability, mpg, and power output through its production run. In 1981 (1980 for California models) Chevrolet added GM's new "Computer Command Control" (CCC) engine management system to the LG4 engines (except Canadian models). The CCC system included the electronic Rochester 4-bbl E4ME Quadra-Jet, with computer-adjusted fuel metering on the primary venturis and a throttle position sensor allowing the CCC to calculate engine load. In the ignition system, CCC was fully responsible for the timing curve; mechanical and vacuum advances were eliminated from the distributor. The more precise spark timing provided by the CCC made possible a series of increases in compression ratio from a pre-CCC 8.4:1, to 8.6:1, to a knock-sensor-assisted 9.5:1, all while still only requiring 87 AKI regular unleaded fuel.

In 1983, Chevrolet replaced the cast-iron intake with an aluminum version and used either 14014416 ("416") or 14022601 ("601") heads with 1.84 inch intake valves, 1.50 inch exhaust valves, 58 cc chambers, and 178 cc runners. For 1985, the 4-valve-relief, flat top pistons from the L69 were added to the LG4, which resulted in another increase in compression. Also added was a knock sensor to allow the "CCC" engine management system to compensate for the increase in compression and a more aggressive spark-timing map in the ECM. As a result, power increased for the 1985 models to 165 hp (123 kW) from the 150 hp (112 kW) rating in 1984. For 1986, Chevrolet changed over to a one-piece rear main seal engine block design to minimize leaks and warranty claims; however, some early 1986 blocks retained a two-piece rear main seal.



Years: 1981–1986

The LE9 5.0 L (305 cu in) was a truck/van/car version 4BBL 650 cu ft/min (18 m3/min) that also had a 9.5:1 compression ratio, the LM1 cam and 14010201 casting heads featuring 1.84/1.50" valves and 53 cc (3.2 cu in) chambers. The engine produced 165 hp (123 kW) at 4,400 and 240 lb⋅ft (325 N⋅m) at 2,000 rpm.
 
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fast68chevy

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It’s a 4 pin module in there. I plan on tucking the connector by the distributor back onto the thicker harness then taping over it to give a cleaner appearance. The one behind the glovebox is going to get zip tied to something to keep stationary.

you can cut them off at the firewall it wont hurt anything at all. its the smaller standalone harness next to heater box through firewall. it goes straight to ESC/EST knock control moodule box under dash in there. it is totally separate from rest of the truck wiring and can be easily removed totally cleanly.
 

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From what I see thats not the original motor. looks like a vortec head to me i the pics. Center bolt valve covers...maybe tbi
Also I dont see tip in vac switch ,egr ,or esc wires or modules in place.
 

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Just as a point of reference for anyone that might read this thread in the future some trucks mine included do not have spark control badges, but did have spark control, so it's not like that's a requirement

Mine didnt have badges either but did for sure have ESC.
 

Swearbody

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I think almost all of the emissions items were removed when I bought it. I started looking at a wiring diagram and it may be a detonation sensor/knock sensor per the diagram. There’s only a fuse panel. I don’t believe there’s a computer for spark control. I plead ignorance though.

If you have a knock sensor then it came with ESC...period
May not be there now though
 

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It’s a rebuilt 1991 350 with a th350. Originally came with a 305 with a 700r. The esc components and emissions components has long since been removed. I questioned if the sensor was some sort of old starter cutoff being the light blue wiring looked new.
 

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