Pre Ignition Problem

[1rstar209]

Hey there i have a 96 ford ranger 2.3 that i just baught and cant seem to figure out why it has this random preignition problem. Some time while driving the tachometer is anywhere from 500 to 1000 rpms of and i can here a very mild case of preignition i have changed all the plugs, wires, and timing belt. and cant figure out what is wrong could this be caused by a fuel problem it is not throwing any codes either. Any help would be much appreciated. Thanks

 

[feellnfroggy]

Hey there i have a 96 ford ranger 2.3 that i just baught and cant seem to figure out why it has this random preignition problem. Some time while driving the tachometer is anywhere from 500 to 1000 rpms of and i can here a very mild case of preignition i have changed all the plugs, wires, and timing belt. and cant figure out what is wrong could this be caused by a fuel problem it is not throwing any codes either. Any help would be much appreciated. Thanks

Carbon on the valves. This sometimes causes it. The carbon heats to a glow and ignites teh fuel prior to full seating of the valves. Maybe. Try some seafoam through the intake.

 

[shadetree]

What you are hearing is detonation, pinging, not pre-ignition. Occasional pinging is normal, but if it is frequent, there is something going on. Pinging can be caused by bad gas, bad driving habits, compressiom chamber contamination, wrong spark plugs.

Use a good brand of gasoline, not the cheap stuff at the corner arabian market.

Driving habits: Don't "lug" the truck around. This is a small engine and you need to keep the engine rpm up in it's power band. Don't go 30mph in 4th gear, downshift, the engine likes rpm.

Make sure the correct sparkplugs are in the engine. Use double platinum, Autolite or Motorcraft.

The combustion chamber could be contaminated with carbon build-up. Give the truck a good, hard run thru the gears. Take it to max rpm before shifting.

You can also use water, or aftermarket additives to help clean out the combustion chambers. There are several types available. Use one that requires "soaking" to free up the carbon.

You can also use water. Use only about 10 to12 ounces, rev the engine and pour it directly into the intake manifold not allowing the engine to die. It will smoke white like crazy. This is normal as the water is turning to steam, and the steam is what is cleaning the combustion chambers. shady

 

[feellnfroggy]

What you are hearing is detonation, pinging, not pre-ignition. Occasional pinging is normal, but if it is frequent, there is something going on. Pinging can be caused by bad gas, bad driving habits, compressiom chamber contamination, wrong spark plugs.

Use a good brand of gasoline, not the cheap stuff at the corner arabian market.

Driving habits: Don't "lug" the truck around. This is a small engine and you need to keep the engine rpm up in it's power band. Don't go 30mph in 4th gear, downshift, the engine likes rpm.

Make sure the correct sparkplugs are in the engine. Use double platinum, Autolite or Motorcraft.

The combustion chamber could be contaminated with carbon build-up. Give the truck a good, hard run thru the gears. Take it to max rpm before shifting.

You can also use water, or aftermarket additives to help clean out the combustion chambers. There are several types available. Use one that requires "soaking" to free up the carbon.

You can also use water. Use only about 10 to12 ounces, rev the engine and pour it directly into the intake manifold not allowing the engine to die. It will smoke white like crazy. This is normal as the water is turning to steam, and the steam is what is cleaning the combustion chambers. shady

New knowledge for me, I didnt know you could use water for this.

 

[rch10007]

I would:

check my timing/vacuum lines - may be advanced to far
check mixture ratio - may be too lean
check compression - discrepancies could indicate which cylinder is knocking
check plugs - may need a cooler plug
try another gas station - could be "bad" gas
try a higher octane - will help determine the knock
clean the intact tract - may remove deposits

If I hadn't figured it out after doing the above, I may get ready to do some rebuilding or swapping.

 

[shadetree]

I would:check my timing/vacuum lines - may be advanced to far

Timing is fixed, can't be changed.

check mixture ratio - may be too lean

Possibly, but it should throw an 02 code if it is that far off. Maybe the 02's are weak.

try a higher octane - will help determine the knock

But, if it quiets the ping, don't continue to use higher octane as it is only covering up your problem. The engine is designed for 87 or E85 whichever truck you have.

clean the intact tract - may remove deposits

True, the MAF may need cleaning.shady

 

[feellnfroggy]

Cam timing?