Another 2.3 ping/spark knock thread

Hey all-

I've had multiple 2.3 Rangers with varying degrees of spark knock (pinging) and I thought I'd share my experiences chasing this issue out in case anyone else can benefit from it. As I understand it is a common and somewhat elusive problem with these engines. Two of three 2.3 trucks I've had developed it.

My current truck, 1996 2.3 4x4 with 150k miles does not burn any oil to speak of and otherwise seems pretty healthy, but alas, has begun spark knocking. It has gotten worse over the last 6 months, and is worst under load (trying to make it up steep hills for example).

So far I have done the following basic maintenance:

-plugs (platinum as I recall)
-replaced both 02 sensors (both were bad when I bought it)
-wires
-adjusted throttle cable at pedal so that slack is reduced (was only opening 75-80% before)
-new coil packs
-new WIX air filter
-cleaned MAF
-cleaned the IACV multiple times
-switched to synthetic blend oil, then full synthetic (Mobil 1 advanced protection or something like that)
-fuel filter

Despite all these things, spark knock still developed. Today I tried seafoaming the truck in three different ways (in gas tank before filling up from 1/4 tank, in crankcase, and through intake) and I have to say I am very impressed at what seafoam can do. I drove the truck several hundred miles today and while the spark knock is still there, it is dramatically reduced. For most of my driving today, it was knock free. Now the spark knock occurs seldom, even under load. Even when it does spark knock, it seems quieter than before. I have never used seafoam before and would highly recommend it to anyone dealing with this issue. I plan on running seafoam through the next few tank fill ups and see if that helps further. I may run seafoam through the crankcase before the next oil change in 5k miles as well as through the intake again, since I had such good results.

I plan on pulling a few plugs and taking a look at them as well, possibly changing again. Plugs were done 15k miles or so ago.

I will continue to update this thread with my results as I change/try things. I am hoping to completely eliminate the spark knock.

I just did a really thorough coolant flush with distilled water (10 whole gallons!!) and prestone radiator flush, the improvement on spark knock after this was HUGE! Also, my temp gauge used to read a little over halfway before and now gets to 1/4 up the gauge if that at operating temp. I have a new thermostat and my heat works great, so I know that change in temp is all from having brand new coolant.

Here's what I'm confused about though. Now on 87 and 89 gas, I have basically no spark knock ever, EXCEPT under hard load (say driving uphill in 4th, approaching the threshold of when you should downshift to avoid lugging), the truck will spark knock still, though lighter than before. And I have to push it harder to spark knock. Also, if I let off the knock immediately stops.

Now I don't drive like that normally but I tried to drive a lot of different ways after my flush to see how the spark knock behaved after since it was basically gone.

Can anyone explain why it would spark knock like that under load? I don't really understand why exactly that would happen. On 93 octane it will not spark knock EVER, just lug.

Chris

Pretty straightforward answer as to why it knocks worse under load, the harder you push the engine the hotter the cylinder temps get. Higher temps means more chance of the fuel mixture igniting before the spark plug fires (aka pre ignition or knock). It will be more noticeable if you have carbon buildup because A. Carbon takes up room in the combustion chamber which increases the compression, and B. carbon can act like a glow plug and stay red hot igniting the fuel mixture.

When you did your coolant flush you cleaned out gunk making the engine run cooler, lowering cylinder temps, lowering the effects of knocking.

My suggestion would be to de-carbonize the cylinders again with seafoam through the intake. The fuel and oil additves are nice but wont help much with the knock issue unless you have a gummed up fuel system causing a lean condition The intake stuff will do the most good. Might even do it 2 or 3 more times over the course of a couple weeks. And also may try a slightly lower temp t-stat. Check your fan/clutch. And read your plugs to verify you dont actually have a lean condition but normally the CEL would be on before that could happen.

You can do a steam tune-up by spritzing water from a Windex-type sprayer into the intake with the engine hot and running at fast idle. Squirt some H2O, and let the fuel burn turn it to steam inside the combustion chamber. Repeat a few times, and the combustion chamber will be cleaned up a bit by the steam. If you do youtube, ETCG1 may have done a demo of the process. I have not watched, but think I saw that title in the recent past.
It was a method used before Seafoam existed that de-carboned chambers without the need for disassembly. Old owners manuals used to give instructions on doing the 'de-carboning process', which involved removing the cylinder heads, etc. Apparently SU carburetors ran a bit rich?
tom

You need to be careful with the water method, too little does nothing, too much can hydrolock the engine (very very bad). That's whats good about seafoam, its pretty well metered to come out of the can at a safe but useful amount. Eric the car guy does have the water method video on youtube. No results though, just a diy instruction. Project farm has a good comparison video seafoam vs water ( one of which he basically destroyed an engine with water by using too much ).

Pre-ignition, pinging/knocking means the air:fuel mix is igniting on the compression stroke before spark can ignite it.
The "noise" is caused when 2 or more separate explosive wave fronts meet inside the cylinder
This "noise" causes real damage to gasoline engines, pits in head and piston, and eats away at softer metal of head gasket ring.
Diesel engines run on compression caused explosive force, but are build for this, much heavier metal in heads and pistons, they normally sound pingy, but not too much or something is wrong with them as well

Compression causes heat, which is why we need it, liquid gasoline can't be ignited by a spark, only gasoline vapor can ignite by spark.
Compression is used to heat up the gasoline so it vaporizes and can then be ignited by a spark.

Octane is a heat rating, octane is the amount of 8 chain carbon molecules in a gallon of gasoline, these are more stable and less likely to self ignite from heat.
So lower octane fuel has more "broken" chains that are less stable so can self ignite when heated.

Heat causes pinging, and pinging causes MORE heat, so it is self sustaining, once engine starts to ping it will keep pinging until you do something to let it cool off, i.e. take foot off the gas pedal
Engine load causes heat build up, the higher the load the higher the heat.
EGR systems help reduce the heat, adding exhaust gases to air:fuel mix slows down the rate of the explosion in each cylinder so reduces the heat produced, especially under load.
Higher cylinder temps also causes a spike in NOX, a toxic exhaust gas, which is why EGR systems were installed.
But the EGR system also allowed more aggressive spark timing because there would be less pinging with the lower cylinder temps.
If you remove an EGR system you will get more pinging unless you can change spark advance.

Carbon build up is a triple whammy, the carbon coating reduces head dome area, which increases compression ratio, so increased compression heat.
Carbon coating also holds in the heat, less heat is transferred to coolant
Carbon coating gets "hot spots" which will pre-ignite the air fuel mix

Compression ratios
9.5:1 is about the limit for 87 octane gasoline without adding a knock sensor, knock sensor detects ping/knock before you even hear it, it causes spark to advance so air:fuel mix is ignited before it can self ignite, this reduces power since full explosive force occurs closer to ATDC than optimal to add power to crank.
2.3L compression ratios here: http://therangerstation.com/tech_library/4cylinders.shtml

1994-1997 2.3l were 9.4:1 so wouldn't take much to make them pingy
Not sure if they all came with EGR system but they could sure use one

3.0l Vulcan engine ran 9.3:1 so another engine that can get pingy

So anything you can do to keep the heat within a good range, i.e. cooling system working well
Spark system set up correctly, no millisecond delay in spark.
If you are going to be pulling a load or climbing longer grades put in some higher octane for that trip, if tank is 1/2 full then add 91/93 octane, if under a 1/4 then 89 should be OK

Spark knock is usually due to heat. Do you have a EGR valve on your engine? Does it work properly? It cools the cylinders quite a bit. I don't on mine, but my problem turned out to be carbon deposits.

I fixed it with Marvel Mystery Oil (MMS). 2 ounces per 10 gallons of gas or basically I use 4 ounces on a 18 gallon tank. I could avoid the spark knock using premium gas, but after a tank of MMS I can just burn cheap regular for the first time in 7 years. I used different cleaners, but MMS was the only one that worked completely for me.

Hey guys,

Thank you all SOOOOOO much!

I appreciate all the info about spark knock. I understand it is caused basically by heat hence the coolant flush (great thing to do anyway for the health of the engine, I figured)

Thank you for helping me understand the worsened pinging under load. I was trying to guess what the correlation was and I figured cylinder temps got hotter but I didn't know that for sure, so I really appreciate you all clearing that up for me. Out of curiosity, why exactly do cylinder temps increase under load? Sorry if that's a dumb question, I've just never had anyone explain to me why that happens.

Oddly enough the spark knock has actually continued to get better which is my latest conundrum... I don't understand why it should get better on its own gradually post coolant flush?

Thanks RonD as always you are the man. I appreciate you always answering my threads and messages.

I was thinking about doing another seafoam treatment or two or three lol to see if that would continue to help. I did know about carbon buildup. Cool to know about the steam clean but I think I will leave that to the pros and stick with my seafoam!!

I do have an EGR valve and I assume it works properly because I get 27-28.8 mpg consistently (I calculate it every fill up). But I do plan on buying a new motorcraft egr valve when I can.

I am also afraid that I may have a lean condition (which as I understand would lead to a more combustible mix, hotter temps, pinging etc). No CEL for it, but I tested the fuel pressure a while ago and it fell way too fast KOEO and after the truck had been running. I was only able to test it once before the tester crapped out, and I wasn't super confident in it, but I'd still like to look into that further. Has anyone found a good fuel pressure tester and if so could you link it?

While we are talking about carbon buildup, is there anything I can do to try to slow down carbon buildup over time? Regular seafoaming? Fuel additives?

cstarbard said:

While we are talking about carbon buildup, is there anything I can do to try to slow down carbon buildup over time? Regular seafoaming? Fuel additives?

Click to expand...

Quality fuel helps. All gas in the US is regulated and basically all the same but there are stations that sell what are called "top tier" gasoline. They are sold by all different names but they just have more detergents in them to help keep things cleaner. Google "top tier fuels" and there is a list of stations and brands that meet these standards. But you can just add fuel system cleaner like techron and make "normal" gasoline basically the same as "top tier".

Keep your pcv valve and egr system in good shape. Both can introduce carbon into the intake/cylinders if neglected. Good quality oil and proper oil change intervals are important as well. Just basic maintenance overall. Everything you can do to keep clean air, clean fuel, and clean oil in the engine will help stop carbon buildup.

When you accelerate you are causing a Richer mix, a Rich mix burns faster and hotter.

And then a couple of other things happen that causes pinging

Spark advance is needed because of the time it takes from "the spark" to full explosive power in the cylinder that pushes the piston down adding power to the crank shaft.
You want full explosive power at about 10deg ATDC so piston and connecting rod have some leverage to push down on the crank, closer to TDC and less leverage, farther after TDC and you don't get the full power of the explosion.
And to top it all off the piston doesn't move at the same speed, piston is moving 3 times faster from 10deg BTDC to 10deg ATDC between 1,000rpm and 3,000rpm

Standard 14.7:1 air fuel mix has a fixed burn rate, so you need centrifugal spark advance for RPM changes to get full explosive power at 10deg ATDC, distributors did this with weights and springs, the weights would move farther out as spin increased, advancing spark timing so spark would happen earlier as RPMs increased to give mix enough time to fully ignite.
Back to Rich mix, it burns faster that standard 14.7:1 mix so Vacuum Advance was needed
When you accelerate the vacuum level in the intake drops this makes the spark timing less advanced, retards it, so instead of 20deg BTDC at 2,000rpm Rich mix spark is at 15deg BTDC to get full explosive power at 10deg ATDC.
These are all just examples of the principles involved

So under load the Rich mix burns faster and hotter AND spark timing is LESS advanced
The less advanced spark leaves the door wide open for pre-ignition/pinging which is corrected by advancing the spark timing to prevent it.
So a double whammy under load, increased heat and retarded spark

Yes, a Lean air fuel mix is more prone to pinging, Richer mix actually helps cool a cylinder a bit as fuel is vaporized, so less fuel is less cooling and more pinging.
At WOT(wide open throttle) computer ignores O2 sensors and uses a WOT RPM table to basically give the engine as rich a fuel mix as practical, economy is out the window .
So if pinging clears up a bit at WOT then there could be a problem in the sensors or computer causing a slightly Lean condition at other throttle positions

RonD,

What don't you know?? Thanks a ton as always! You are an invaluable resource to us all. I owe you one.

Chris

cstarbard said:

RonD,

What don't you know?? Thanks a ton as always! You are an invaluable resource to us all. I owe you one. [emoji481]

Chris

Click to expand...

I'm definitely in Ron's fan club. Ping and knock just seem to come with ownership of a ranger whatever engine that has. both of my Rangers the one I sold in the one I have now, ping on regular gas, I thought the manual shift truck with ping less but actually pings more! Other than that it runs perfectly.

We all should be! Ron is a great guy.

It does seem to be a constant problem. My current truck is almost ping free finally thanks to all of you guys and some toying. I would hope that these trucks didnt leave the dealership floor pinging 20 years ago, lol, so where there's a will there's got to be a way

Gas is way way different now than it was 20 years ago also