foxtrot

Hi I have essentially a stock 98 and for a while noticed under load and heavy acceleration I get bad pinging and loss of power. I replaced the plugs/air-filter but wonder what else I can do as part of the tune up that might help with detonation.

lizzyfan

Try some 93 octane

socalwrench

The first thing I would check is my ignition timing. It is probably too far advanced.

cliffyk

How many miles on it, how has it been driven?

If a lot of miles (150k+) and it hasn't been driven hard ("driven hard", not "beat to shít") then it is likely that the combustion chambers are carbon'd up, which can raise compression to the point that regular grade fuel doesn't do it anymore--this hurts performance because of incomplete combustion and you backing off when you hear the pinking ...

Load it up with some high octane fuel and make a habit of winding it out to at least 4500 rpm once in a while to blow the crap out of the heads...

foxtrot

Ok well its been "adult driven" by me so not beat. Its got 99K on it and maintained pretty well. I already use 93 octane and it still suffers. I was looking for a possible tune up pointer that might help. Maybe there is some carbon build up like cliffyk has mentioned (thanks cliff).

If it is carbon build up any chance I can us any additives to blow it out? I have tried winding it up a bit but I consider that beating it since its pingning while I do this.

De-carbonizer help?

Oh an without a distributer how do I adjust timing?

cliffyk

Do you know what the AFR is under heavy load (beg, borrow or steal a wideband O2 system)? You may also want to change the fuel filter if it has not been changed recently, if badly clogged you could be going lean when fuel demand is high.

Have you tried using OEM spark plugs, or a colder plug? I have seen premature ignition issues with some of the fine-wire plugs.

The base timing can only be changed through the tune's Global Spark Adder scalar value, or by using a device such as Steeda's timing adjuster.

I am not a believer in miracle working additives, but most of them don't do any harm...

foxtrot

Thanks Cliff, it looks like I should change the fuel filter first since it should be simple to rule that out. I have not done this before I on this car. Can you tell me where I might find this on the 4.6 and if there are any tricks to replacement?

Thanks,
Ron

Jay-rod427

You might run a high quality fuel system cleaner like BG 44K at the same time as the filter, poor injector function could cause lean condition as well.

foxtrot

91 Octane only
New Fuel Filter
Treated gas with Seafoam and run two tanks after clean out
New plugs 10mm Ford racing
New plugs
New intake manifold (found a leak but did not stop the pinging)
Fresh oil change
Still pings at WOT under load mainly mid-range 2500 - 3500 and then goes away when its up high around 4K.....

Maybe clogged injectors? What is BG44K? Will is clean fuel injectors well?


Any other ideas?

cliffyk

You have done about all that can be done without pulling timing in the Spark Borderline Table (you'll need a tune/tuning system to do this).

I suspect that it is carbon buildup in the combustion chamber/piston tops--fixing that will mean pulling the heads. This is actually a fairly common problem on older cars that have been babied and/or used mostly for short trips (<10-15 miles) at in-town speeds.

The engine never gets hot enough to fully burn off the deposits, and they accumulate and by reducing combustion chamber volume effectively increase the compression ratio--or hold enough heat to cause pre-ignition.