2.0 Efi Experts - Help With Octane Plug Please

[FERRINO]

Evening all - (Quick bit of background on my question). I bought Derek's 2.0efi engine/electrics package about a year ago for my 2B build which I know was working fine when he removed it.

 

I'm finally starting to get to the wiring stage of the build so have been going through the process of laying the supplied injection/ignition loom in and wire checking so I know exactly what goes where and how it all works. I'm pretty much on top of it and have it 99% sussed now but I have a query which hopefully you guys that run the same 2.0efi setup can answer straight away?

 

On the 3 wire octane plug, the red wire has been cut and trimmed right back and is not used. The yellow wire has a fairly large crimp connector added to it and the blue wire has a smaller crimp connector added. Both these connectors look 'used' as if they were bolted down.

 

From the small amount of info on the net about the octane plug - it seems that earthing the blue wire will mean the ignition is retarded 2 degrees and earthing the yellow increases the idle rpm by 60-75 rpm or so.

 

My question is - Is this right for a bog standard 2.0 sohc efi setup? What is everybody else running with regards to the octane plug? The Sierra manual shows the yellow wire earthed with a note saying "earth link manual gearbox only"

 

Any advice would be gratefully appreciated.

 

Cheers

Tony

[Longboarder]

Ford put the octane adjust wires in there to make it easy to retard ignition for low octane petrol without turning the distributor. These wires Bn/R and Bn/B can both be isolated and insulated as you will time up by turning the dizzy whilst using a timing light and a bit of trial and error.

Debatable if you want to increase idle speed. Can be helpful if the engine is set-up a bit rough and doesn't run well at slow idle. Increasing the idle lets it run a bit easier while you fiddle with it. The EFI won't let you effectively use the throttle stop to vary idle as this is set in the software. So I would earth the B/Y wire for starters. Problem is this fast idle can take the engine speed just out of conditions that the EFI recognises as idle and it starts making ignition and fuelling changes confusing set-up process. It should be disconnected for final ignition set-up.

 

Nigel

[FERRINO]

Thanks for the advice Nigel - much appreciated.

 

I didn't think the Red or Blue wires would be necessary for this particular engine (1989 2.0 efi) as the car came set up ready to run on standard unleaded from the factory as far as I'm aware?

 

It was just the fact the both yellow and blue ring crimps look like they had been earthed down recently as the crimp is shiney where the washers would have dug in. If the crimps had just been hanging around the engine bay unused I would expect to see them both fairly dull or dirty.

 

That was why I just wanted to double check with other 2.0efi runners before taping them up.

 

Cheers again

Tony

[Jez Morton]

On my efi set up Oct 86 vintage, (must be the first batch of injected engines) it is as per factory and has the yellow wire only connected to earth. It doesn't have the octane plug fitted with the red, blue and yellow wires, just a factory fitted one wire link. Tick over is just below 1000 rpm which would make sense but why it's set up like this at the factory who knows. I find all the talk of the octane adjust confusing, red for two degrees, blue for four degrees both for six degrees makes sense but the manual says you can't adjust the timing on the esciv for unleaded? But you set the timing by turning the dizzy? So would it be right to assume that connecting the red and blue wires to earth would effect the spout signal and the map not the normal or pip timing. If that's the case what would be the required retardation for unleaded 2, 4 or 6 degrees? After all that shall I just leave it alone it runs OK as is.

 

Jez

[FERRINO]

On my efi set up Oct 86 vintage, (must be the first batch of injected engines) it is as per factory and has the yellow wire only connected to earth. It doesn't have the octane plug fitted with the red, blue and yellow wires, just a factory fitted one wire link. Tick over is just below 1000 rpm which would make sense but why it's set up like this at the factory who knows. I find all the talk of the octane adjust confusing, red for two degrees, blue for four degrees both for six degrees makes sense but the manual says you can't adjust the timing on the esciv for unleaded? But you set the timing by turning the dizzy? So would it be right to assume that connecting the red and blue wires to earth would effect the spout signal and the map not the normal or pip timing. If that's the case what would be the required retardation for unleaded 2, 4 or 6 degrees? After all that shall I just leave it alone it runs OK as is.

 

Jez

 

HI Jez - Sorry, but I totally forgot to reply to this!

 

Cheers for the info about your setup. I'm in exactly the same boat as your self regarding being confused by the blurb in the manual about this. It definitely says that the timing is fully controlled by the EEC IV unit and that earthing the red/blue wires will have no effect - so why have the octane plug fitted in the loom for this model then?

 

I've had some more info from Derek last week about this octane plug actually. He said that when he had running problems at the roadside (which he eventually traced back to a dodgy earth for the TFI module) - the AA man came and started making adjustments to the octane adjuster to try and get it running again. So that explains why there is a strange 'possibly used at some point' crimp on my loom.

 

So I'm going to snip the blue wire with it's crimp off as it does seem that these octane plugs are fairly pointless. I'll make sure the yellow wire is earthed when it comes time to start up - but am going to see what effect and how it runs if I remove it once everything's up and running.

 

Thanks again for everybody's help with this!

Edited June 30, 2014 by FERRINO