Proper Octane for a '93 Grand Marquis

[Dain]

Hi, new here.

My father recently gave me his '93 grand marquis.

He no longer had the owners manual, so I have no refence.

We have been using normal octane, but have noticed a bit of pinging.
Need to find out if we've been giving her the wrong fuel, or if we need to have the compresion/timing checked.


Does anyone know the octane, or have an owners manual for a '93 they can check?

Kind Regards,
Dain

[Grandmarchris]

Should be just regular 87. You might want to check your pulgs and wires just to see if they are ok and go from there

[drock96marquis]

87 octane.


Your EGR channels are probably plugged up:

http://www.lincolnsonline.com/tech/00015.html

May want to run some seafoam through it. How many miles? New plugs would be a good idea if old - go with double platinum to extend service life.


You could also run a higher octane to prevent the pinging, but it's only a 'band-aid'

[1987cp]

What they said. The usual rule of thumb I'm told is that the only reason to run anything other than 87 is to eliminate detonation/preignition if the overall tune is otherwise as desired. The obvious thing I'd check for if experiencing spark knock is overadvanced ignition timing, but that would seem improbable with a distributorless ignition system unless someone's reprogrammed the spark advance curve. Of course, in that event, the same someone could theoretically have dialed in a leaner fuel map..... I guess this is part of why I switched to a carburetor.

Another possibility (and one that's far easier to remedy) is spark plugs of the wrong heat range. A plug that is too "hot" can contribute to a preignition problem, whereas one that's too "cold" can lead to poor performance and carbon buildup. Rumor has it that even the factory-recommended heat range might not always be spot-on, depending on your driving habits and possibly the engine's overall condition. Cheap parts-store Haynes manuals always have little guides to reading your spark plugs, so it can't hurt to pull one and see what you can make of it. Which reminds me, I need to have a look at my own sparkers one of these days and see how happy they are.

By the way, to GMN!

[p71towny]

There is an octane pin that can be pulled which will reduce the timing a bit.

[seneeb]

the proper octane is:

CH3NO2


fuck yea

because gasoline is for cleaning parts
alcohol is for drinking
NITRO IS FOR RACING!