Well if anyone remembers from a few weeks back I had my motor cleaned out with Ford engine cleaner to remove the carbon from my motor . Got it back with a knocking sound inside the motor . Mechanic had me drive it around hoping it was just some loose carbon floating around . Well the noise is gone but the pinging/knocking isn't . Tried removing the jumper inside the firewall that is supposed to retard the timing 2-3 degrees and the pinging is gone . Only problem is so is the power . Tried high octane but it's still pretty sluggish. So now I have to decide if I should put the jumper back in and use high octane gas or live with a slower truck that doesn't ping . Thanx for the feedback , lots of good knowledge out here ! Ron
I don't recall all of this thread so.... Have you cleaned your MAF sensor (or replaced it)? My 92 used to ping in hot summer weather but after cleaning the MAF is no longer pings. Others have traced the pinging to leaking lower intake manifold gaskets that cause the mixture to be too lean (sucks in crankcase fumes which dilute the fuel/air mis). Is it possible you are running too hot a spark plug? Maybe the wrong heat range got put in and they are causing a hot spot and pinging.
I've heard conflicting things about that jumper you disconnected. One story is it retards the spark 2-3 degrees but otherwise no other changes. The other story is that it sets the advance to "base" and allows no advance at all, hence the lack of power. I thought I read it was to be used to check base advance which lead me to suspect the second story was the true on.
Yep that's what I just did . The power reduction was too severe so I put the jumper back in and it runs much better with high octane anyway with more power .No pinging with the high octane gas so far . I was wondering if anyone with this problem tried using one of those performance chips to help on this problem , I didn't hear anyone mention it . My MAF sensor was clean , there was no EGR valve , and the bolts on the intake manifold were tight . So high Octane it is , I give up ! Thanx for all the help out there ! Ron
with Ford engine cleaner to remove the carbon from
I didn't notice any loss of power in our 93 Expl after removing the pin. The truck runs great. However, I haven't put it on the dyno for a before and after.
I did try using higher octane gas before removing the pin but that didn't stop the pinging. As more miles are accumulated on the engine, more carbon builds up in the combustion chamber and cylinder pressure increases. Firing this old engine at the timing specified for a new engine will then cause the engine to knock.
I can't agree that removing the pin will set the timing to the base value with no advance at all since there is no noticeable difference in driveability (at least for the 93 Exp).
Before retarding the timing our Exp only knocked under mid to high accelerations, but the sound just sent chills down my spine, very ugly sound. I think Ford was trying to squeeze every ounce of fuel economy out of this engine so they timed it on the ragged edge, just below the knock threshold. Some newer cars use knock sensors to keep the ignition timing as far advanced as possible (to increase fuel econ and power) but avoid knocking by pulling back timing according to the knock sensor feedback.
If higher octane gas with the pin in place is most economical then that is what I would do; provided the knock was gone. However, if lower octane gas with the pin removed was most economical then that would be my course. It should be perty easy to do some fuel economy measurements with both configurations and come to a conclusion.
Some of the discussion here sounds like pinging is normal as the truck gets older. I'll just input here that my truck has 193,000 miles on it and it doesn't ping.
It used to ping, but I found some info about the lower intake manifold gasket leaking because of a poor design. The #5 spark plug would carbon up so that you could see the difference between the other spark plugs. Some folks replaced the gasket with success, ie. the pinging went away.
But, I found that the intake manifold lower bolts loosen with engine cycles.
So, you might want to just tighten the intake manifold lower bolts, very carefully, in the pattern recommended in Helms. They only tighten to 180 inch pounds or so, so make sure you don't overtorque as you might crack the intake manifold.
I don't think pinging is normal. But, sometimes, the root cause is hard to track down.
My '94 also started to ping with regular gas at about 80k miles. I had 2 problems:
1) I had the leaking manifold problem. The small aluminum alloy bolts will loosen up over time. Check the spark plugs for black, sometimes oily deposits. If one or 2 have it while the others are clean you may have a manifold leak at that location. Re-torquing all bolts will usually stop the leak - mine did. But I've heard others had to replace the intake manifold gasket. Check manual for pattern and torque limit.
2) My modulator (vacuum diaphram) on side of transmission leaked. Pull off the vacuum line that goes to modulator at the intake manifold vacuum tree. If it's oily, your engine is sucking trans fluid through the modulator. Replacing modulator eliminated problem. Let me know if you need to replace, there is an easy method.
Other things to check: Fuel pressure at the fuel rail. If low, check for clogged gas filter, leaking injectors or weak pump. Also check the vacuum connection at the fuel pressure regulator while you're there. MAF sensor as mentioned below, cracked or loose vacuum lines/connections, computer codes, dirty fuel injectors. And of course the basics should be checked - engine vacuum, plugs and plug wires, ground connections, cylinder compression or cylinder leak down.
At 120k miles my engine does not ping on regular gas.
Good luck
with Ford engine cleaner to remove the carbon from
had me drive it around hoping it was just some loose
isn't . Tried removing the jumper inside the
pinging is gone . Only problem is so is the power . Tried
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