Spark plug gap help

[grodri1972]

Just bought some denso k16r-u standard plugs they are pre gapped at 28 I been reading these forums to gap plugs at 31 or 41 need help guys thanks

[RobMilkshakes]

~31 for 90-92 4afe
~41 for 88-89 4af

[grodri1972]

Thanks

[ericdude]

Originally Posted by RobMilkshakes

~31 for 90-92 4afe
~41 for 88-89 4af

According to the factory manual, page IG-5, the correct
gap for 4AF (1988) is .43 inch.

[RobMilkshakes]

yeah I couldn't remember the exact gap so I used the little ~ to say "about".

[Xen2050]

The toyota dealer spark plugs come gaped 0.28, and my 4A-F wants 0.43?? The parts guy even said they were pre-gaped and ready to go (but I don't recall F or FE talk), and my dad had trouble with a friend "helping" gap toyota plugs and really messing things up, so I dropped them right in.

But, what could be going wrong using 0.28 instead of 0.43? Runs great for the past year, but could it be better?

[RobMilkshakes]

thats a pretty large difference in gap so I imagine it would make a bit of difference in power/mpg. but about the F/FE talk, if you answered with what year you have that would answer what engine you had(well other than 4age, but thats a different story)

yeahh plus there's always a little conflicting info on the gap range but mostly I've seen .031 and .041-.043 after looking back some.

That little search button can do wonders you know

[Xen2050]

I'd imagine it would affect something, being like .015 too small (really meant 0.028 and 0.043 earlier, not quite a half inch gap yet!)
But the mpg have been excellent, was getting like 36mpg (Imperial/Canada MPG's) in the city in summer, 32 in winter, with a very light foot. Power does seem really low, but with the little 1.6L and automatic I figured that's just the way it is. Might try regaping them & maybe compare a road test before/after... sometime maybe ;-)

Was using cell earlier, a big search would've been a little too annoying with the tiny screen, will try now, thanks.

Almost forgot, but I read somewhere that the 89 Corolla Sedans & Coupes had the 4A-FE EFI engines, but they left the DX Wagons with the old 4A-F, so I'm left with one of the last Corolla carb's (in North America at least), so 89 could've been either one.

[kathyricks]

Originally Posted by Xen2050

The toyota dealer spark plugs come gaped 0.28, and my 4A-F wants 0.43?? The parts guy even said they were pre-gaped and ready to go (but I don't recall F or FE talk)

Your owners manual says to use Nippondenso Q16R-U11 plugs and these come pregapped to .040-.041" if you buy them from a Toyota dealer. That .040-.041" setting will give you maximum power and fuel economy.

If the plugs you got from the dealer came pregapped to .028" then you got plugs for the 4A-FE engine, not the 4A-F. Throw those plugs away as you cannot adjust them up to .041" without hurting power and fuel economy because they are simply the wrong plugs (not designed to work with the 4A-F ignition system).

After installing the correct Q16R-U11 plugs, be sure to check your ignition timing or else fuel economy and power will suffer.

[Flashmn]

Oh no not this again