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octane adjust plug

13014 Views 37 Replies 14 Participants Last post by  Lynn Schell
one my car 95 lx sedan with a 1.9
what is the octane adjustment plug for?
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octane adjustment plug??? pics please.
it was on a diagram i got off mitchel on demand, it was on the 1.9 motor and located under the center console
My octane adjustment plug is at the gas station where I choose between 87, 89, and 91 octane...
If there is one (there isn't) I've never seen it.
Is it located near the 710 cap, or is it below the muffler bearings?
the octane adjust plug is located under the center console, and when the plug is removed, it allows the use of higher octane gas or if the motor is pinging
my center console isn't where it's supposed to be. so which plug r u talkin about? i just went and looked and i see 4 electric connectors. 2 behind the shifter, 1 before the e-break, and 1 on top of the seatbelt retractors.
il have to look at the digram
I too have several wiring diagrams showing the octane adjust plug. Seems like quite a few early EFI Fords had them. Unplugging it causes the computer to use a much higher timing curve (you have to use premium fuel or the engine will hammer like crazy) and produce more power. I have yet to locate it on the wagon. I am trying to figure out exactly where it is.
According to my service manual CD's wiring diagrams, the '97 has an octane adjust plug also.


*EDIT* I think I found it. There is a plug with a gray component plugged into it. There is a green/white wire and a lt. green/black wire going into this plug, located on the passenger side of the center console, beside the engine computer.
I've also heard about the octane plug. But never seen it in person.
well son of a bitch! i just looked in my chilton's handbook for 91-99 and it shows that all escorts but the gt's have it. guess i'mma hunt this sucker down tomorrow. i don't think anything will happen since i use premium gas anyway. it's worth a shot tho.
i found it on mine. it's by the pcm close to the main relay. i'm not doin anything with this yet till i change my tranny fluid cuz it's on the grey side from overheatin. it's times like this when i wish i had money.
I don't know about the escorts, but this plug is usually removed to check the timing... basically it disables advanced timing.

It was used on the older fords to adjust the distributor (spark) timing... you would unplug it... set your timing.. then plug it back in.

I'm not 100% sure that's how it works on the scorts though...

EDIT::: OK I just pulled up this information.. it's also called a "spout" connector.. and you want to leave it connected, as unplugging it disables advanced timing...

Ignition timing is 10 degrees +/- 2 degrees BTDC (with SPOUT plug removed) and is NOT adjustable. With the SPOUT plug installed, ignition timing is computer controlled.
the 1.9's and 2.0's have a coil pack so they run with no distributor. that means that the pcm controlls the ignition timing.
The spout connector is an entirely different connector. This is an octane adjust connector and not the spout connector. Do not confuse the 2 as the same connector. ALL of my EEC IV and EEC V diagrams for 91-97 2nd gen and 3rd gen Escorts show this connection. After 97, the octane adjust connector was removed and a knock sensor installed. Removal of the spout connector will lock the timing at 10A. Removing the octane adjust connector will signal the computer your intention to use premium fuel and run a much more aggressive timing curve for more power.
that's what i'm goin for :D
Alrighty then...I'm going to have to do some SERIOUS investigation! IF this is the case, it may be the holy grail for the 45 mpg EASY target.
Dave8338, awesome list of cars in your sig! I've got an 86 Capri so I'm a fellow foxbody addict!

As to the topic at hand, I would imagine removal of this plug, in combination with 93+ octane gas, would get much better fuel economy. My suspicion is that the octane adjust plug is under the center console buried in the EEC harness somewhere. Ever take a look inside an 85.5 or 86 Mustang SVO? On the center console is a fuel selector switch to go between regular and premium. This is the octane adjust plug- only on the SVO it was a switch. When in the premium position, the timing was much more aggressive, as was boost and fuel injection. Turning it to regular dropped the boost a few pounds, set a milder timing curve, and dropped fuel injection a little to compensate for 87 octane fuel. Once we figure out where the octane adjust plug is on our cars, a switch can be wired in in its place so we basically have an SVO style setup where we can fill the tank with regular or premium and flip the switch accordingly. One of these days I'll take my console out and start looking. If someone finds it, take a picture of it and give directions on how to get to it!
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