2.9EFI engine and Octane service socket.

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simmit
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2.9EFI engine and Octane service socket.

Post by simmit » Fri Apr 14, 2017 7:32 pm

Been having bit of discussion in the Middlebridge forum which has been great but am seeking a wider audience for comments so have moved on to this forum.

I wish to set subject engine to run on the 97 RON fuel for which the engine was designed. There is however an octane service socket which has wiring that can be arranged to instruct the ECU to retard the engine timing so the engine can run on lower grade fuels. We are told this octane service socket has three wires, Red, Blue and yellow and instructed that if we cut the blue wire it will retard the ignition timing by 2 degrees, cut the red wire for 4 degrees, cut both blue and red for 6 degrees retardation.
However, when I look under my bonnet I find ................ blue and yellow wires are both cut! The remaining red wire is connected to the ignition coil mounting bracket (earth connection). All this is at odds with instruction above so what's going on?
To ensure correct function of ECU with 97 RON fuel I suppose I ought reconnect the blue and yellow wires with the red and earth (original factory setting?).
I should say the engine seems to be running OK but perhaps it will be even better with all three wires in operation.
Comments would be most welcome.



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Old and Slow
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Re: 2.9EFI engine and Octane service socket.

Post by Old and Slow » Fri Apr 14, 2017 7:50 pm

Next time you are passing Bracknell, call in and we can use my strobe, if you like.
Philip


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Re: 2.9EFI engine and Octane service socket.

Post by AJL Electronics » Fri Apr 14, 2017 7:59 pm

This is from the genuine Ford wiring diagrams.
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Re: 2.9EFI engine and Octane service socket.

Post by simmit » Fri Apr 14, 2017 8:02 pm

Old and Slow wrote:Next time you are passing Bracknell, call in and we can use my strobe, if you like.
Philip
Your offer is most appreciated and will be taken up if the opportunity arrives.



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Re: 2.9EFI engine and Octane service socket.

Post by simmit » Fri Apr 14, 2017 8:11 pm

AJL Electronics wrote:This is from the genuine Ford wiring diagrams.
Thanks AJL.
Ashamed to admit the diagrams do not help this numpty.
From what I can see of it they seem to show just 2 wires to the octane socket whereas my car has 3. Also I am not able to work out how the wires ought be connected/ cut to achieve the various octane rating options.
Shall be grateful if you will clarify.



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Re: 2.9EFI engine and Octane service socket.

Post by AJL Electronics » Fri Apr 14, 2017 8:18 pm

The red wire if grounded will retard the ignition by X degrees. The blue wire if grounded will retard the ignition by Y degrees. The yellow wire is nothing to do with timing, but will increase the idle speed if grounded.

So to answer your question, nothing should be grounded for full (standard) advance.

X and Y used because I can't recall the figures, maybe 3 and 6 degrees.


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Re: 2.9EFI engine and Octane service socket.

Post by midscotscim » Sat Apr 15, 2017 12:26 am

Hi, as AJL say's, no connections are required for 97 Ron fuel. The octane adjustment plug can be removed.
When these cars were new, the engines were supplied ready to run on leaded 4*. To run on unleaded it was recommended to have an octane adjustment plug fitted by the dealer, this consisted of the plug ( with all 3 wires connected to 0 volts ) being fitted by the mechanic who would snip the appropriate wires leaving one wire for the retardation and possibly the tick over increase connected.
Modern unleaded fuels have a higher octane rating than the unleaded available in the late eighties so this adjustment feature is pretty redundant unless you take your car to the States.
When checking the ignition timing, the octane adjustment plug must be removed, the ECU must be in diagnostic mode and the engine must be at full operating temperature. The ECU can be put in diagnostic mode with a Star diagnostic reader or by disconnecting the spout signal between the dizzy and the ECU. This later method is catered for in Mustangs and the like but isn't available on British machines.
The octane adjustment plug will move the timing by 2 or 4 degrees on 4 cylinder units, or 3and 6 degrees on 6 cylinder units. Under no circumstances should all 3 wires be grounded on a 6 cylinder unit.
There is a good source of info regarding the 2.9 12V Cologne on the Scorpio website, it caters mainly for the 24v eec v but there is still a lot of useful information available.

Hope this helps to clarify things for you.

Regards, Mark, MB47, no adjustment plug fitted and running just fine.


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Re: 2.9EFI engine and Octane service socket.

Post by simmit » Sat Apr 15, 2017 8:55 am

Many , many thanks to all who commented, especially to AJL and Mark for simplifying the issue.
MB50 has the red wire connected so will be running 6 deg. retarded it seems (probably came out the factory like that). I'll disconnect the wire and hopefully will have a more efficient engine.

Next thing will be to have the timing checked and, as Mark says, ECU needs be in code 60 (whatever that is) so I guess that's a trip to a spanner man down the road.

Thank you gentlemen.



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Re: 2.9EFI engine and Octane service socket.

Post by AJL Electronics » Sun Apr 16, 2017 9:45 am

Some more info here, some of it conflicting! :

http://www.andrewc.org.uk/tvrgit/ford29diagnostics.pdf


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