Spark knock problem, tried the obvious, next steps?

[8thTon]

This is from the U.S. Energy Information Administration

Yup, that's consistent with what I understood. Higher octane fuel does not contain more energy or produce more power, it's just less likely to spontaneously combust. If your engine needs that then it will help, if not it has no benefit.

A 3.0 Vulcan should not need it. If there is carbon in the combustion chambers of a modern engine with port injection, O2 sensors and feedback control of fuel mixture, then where did it come from? Carbon is from incomplete combustion, usually cumulative over time. If it's from gasoline then something has been quite wrong with the fuel control system for some time. Alternatively it could be from oil, suggesting excessive wear on rings or cylinder walls, or problems with valve guides or stem seals. But then the carbon build up idea is just a guess and may have nothing to do with it in the OP's case.

 

[4.0blue98]

Probably the same for the 3.0 carbon knock:

Engine - Carbon Knock On Acceleration
Article No:
01-19-7

10/01/01
^ ENGINE - 4.0L OHV - CARBON KNOCK ON ACCELERATION

^ NOISE - CARBON KNOCK ON ACCELERATION - VEHICLES EQUIPPED WITH 4.0L OHV ENGINE ONLY

FORD:
1990-1997 AEROSTAR
1990-2000 EXPLORER, RANGER

ISSUE
Some vehicles equipped with the 4.0L OHV engine may exhibit an engine noise which may be perceived by the customer as a piston/connecting rod bearing knock. This carbon knock is heard only under load during the drive cycle. Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.

ACTION
Verify condition. If normal diagnostics fail to correct the condition, de-carbon the combustion chamber to help quiet the carbon knock noise. Refer to the following Service Procedure for details.

SERVICE PROCEDURE
1. Use Motorcraft Carburetor Tune-up Cleaner PM-3.

2. Carbon removal:
a. Disconnect canister purge line from throttle body.
b. Attach a vacuum line to the canister purge port.
c. At hot engine idle, allow the engine to ingest 1/2 to 2/3 of a can of Motorcraft Carburetor Tune-up Cleaner. Use caution not to ingest too quickly due to potential hydro-lock issues.
d Shut engine off and allow it to soak for one hour.
e. Start engine, allow engine to ingest the remainder of the Motorcraft Carburetor Tune-up Gleaner.
f. Remove vacuum line and re-install canister purge line.
g. Road test vehicle at 3500 RPM for 2-3 miles.
h. Repeat above procedure two times for a total of three times.
i. Change oil and filter.

3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.

 

[8thTon]

Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.

3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.

So add short drives, and not running it hard enough I guess. Interesting that "Mid-grade and Premium fuels may increase the probability of carbon buildup" - I didn't know that.

 

[4.0blue98]

Carbon will give you hot spots so the more volatile 87 octane will ignite at the wrong "time" and cause the pre-detonation.

So 8thTon is right in that something is wrong, but cbxer55's remedy works for him and I've done that for extended periods when I didn't have the time to treat the engine.

Mine will ping at WOT even when it's fairly clean with 87 but not 93.

If I run 93, no pinging regardless of whether I change the tune I'm running.

This newish Gasoline Extreme from HotShots definitely helped mine if you just want something to dump in the tank. Not a cure but helped. Need to follow the directions carefully.

I've been a bit more heavy footed more often and that seems to help the time between cleanings. "But officer the TSB told me to do it..."

 

[sgtsandman]

The above procedure sounds a lot like the one using other cleaners to remove carbon fouling. Like with seafoam and the vacuum line from the brake booster. I’ve done it before and it seemed to work.

 

[cbxer55]

Three of the five vehicles in my signature line are "Premium Only" vehicles, minimum 91 octane. So I prefer to go 93 as the more the merrier IMHO. And thus, I don't have a problem running the 93 in the other two. BTW, I beat my Ranger like a red-headed step child, whip it like a rented mule. The JET chip raises the sift points noticeably as well. I'm not demodding my truck, I love the way it runs as it is. Once again, if running 93 octane is needed to keep it running like this, it's not a problem in my book.

Also, my truck doesn't burn any oil. It has a small drip leak that it's had for many years. leaves a spot about the size of a silver dollar when parked warm. Once it cools down, the leak stops. I can start the truck cold, move it to another location while still cold, no drip. Only does it once warmed up. That thick ass 20w-50 likely helps in that regard. LMAO!!

Since Ford seems to have acknowledged carbon buildup as a problem, the OP likely has this condition. He can try the Sea Foam through the brake booster hose, like I did twice. Did nothing for my truck. Smoked out the neighborhood when started afterwards. Neighbors thought our house was on fire. LOL!!

I've always known there is no "performance boost" from running premium. But there is if the vehicle is knocking or pinging. And if the vehicle has knock sensors and is retarding the timing due to the 87, then there will be a performance increase with higher octane fuel. I've ridden motorcycles longer than I've driven. Back in the late 70's/early 80's, we used to refer to the 87 of the time as bilge water. No bike rider used 87 octane if they cared for their bike. I still do to this day. And with a lot of places only selling 87 octane with ethanol in it, it's even worse. I know for a fact that the 93 I use doesn't have any alcohol in it.

 

[cbxer55]

Restricted is the wrong word to use on a 4-stroke engine exhaust system, no 4-stroke engine runs better or has lower emissions with any exhaust restrictions
2-stroke does need restriction

All Rangers have tuned exhaust, for mid-range RPM band, the tuning gives the engine more power in the mid-RPM band from Scavenged power
Scavenged power comes from exhaust Velocity flowing from a smaller tube into a larger tube, it causes a pressure drop which PULLS exhaust from the cylinder which leaves more power on the crank because it didn't have to PUSH it out

Exhaust ports on the heads can be made smaller to increase the velocity as well, which also carries the heat farther done the exhaust system to warm up the Cats faster, which does lead to lower "cold engine" emissions

But there is no restriction, ever

Many have put larger exhaust pipes on the head of many different engines, this is where the MYTH of Back Pressure comes from
You would LOSE POWER with larger pipes because you lose the Velocity and the scavenged power it creates
Car makes have used scavenging exhaust manifolds since the 1950's, by late 1960's pretty much every engine had this
So people would do a custom "free flow" exhaust and lose power...............
"WTF, I lost power??!!!"
"This engine must need back pressure"
Nope, they just lost the extra power from the factory exhaust manifolds

Exhaust manifolds/headers, can be made for three RPM ranges, low, mid or high, but only one of them
Its a design based on alot of math, you can read up on it
And these can be made, and are made, for a specific RPM, the closer you are to that RPM the more scavenged power you gain, below or above that specific RPM
Racing engines use different headers for different tracks, based on the RPM they will try to keep the engine in during the race, which is also based on gearing and tires

Funny thing when you're talking exhaust. I was looking over the exhaust manifolds on my 4.0 V-6 Mustang the other day, wondering if I wanted to do headers or not. What I observed is three equal length runners on each side, about ten inches long, dropping straight down towards the ground, joining in a collector of sorts. And a FORD stamp on them. Really nice looking exhaust for a stock manifold. So, no, not changing them. Same with my Lightning. We in the Lightning community have always said the stock Lightning manifolds are equal to shorty headers and perform the same. Up to 500 hp or so, tube headers don't do anything but give us better heat dissipation under the hood. So I'm not changing those either. Not worth the hassle of broken studs to bother with headers.

Intake tubes alter the performance range as well. The 3.0s stock tube is pinched from the MAF to the TB. The MAF and TB are both 3.0 inch, while the tube appears to be 1.5. A smaller tube increases the velocity of the air traveling through it, helping with low and mid range performance. The tube on my MAC intake is a full 3.0 inch all the way. Yes, low end performance is a bit less, but it sure screams when the rpms are singing. And sing mine does. And despite the big tube, it will still give me a pleasing chirp anytime I desire it. The JET chip helps with the performance, but I still find myself shifting it manually more often than not. With the big Hellwig anti-sway bars, I am out hustling it through my favorite curvy road a lot, just burning 93 octane for the pure fun of it. And dropping it out of OD, or even into second, to keep the rpms singing, makes it really a fun truck to haul around a set of curves.

 

[Dirtman]

Huh?

 

[RonD]

Translation, not that it needs it, is:
Factory equipment, i.e. intake and exhaust manifolds, are tuned for vehicles designed use

Velocity of the in coming air and out going exhaust is part of that tuning

You can change this for better power for YOUR USE, i.e. transfer power gains from lower-mid RPM range to higher RPM range
Most Pickup truck makers design engine performance for lower and mid range performance because thats what 99.9% of users will want/need

Its why truck engines usually have a different cam than the same engine in a car would have, designed for use

 

[cbxer55]

Exactly Ron. I once tried putting the stock pinched intake tube on my MAC intake, keeping the open cone filter. It ran so piss poorly, I took it back off and threw it away, never intending to use it again. Yeah, it putt-putted nice. But I couldn't get it to sing like it does with that big 3.0 inch tube on there. When the revs are up, that intake makes more noise than the no muffler exhaust does. I love it.

 

[PetroleumJunkie412]

Just posted this. Will fix a carbon issue.

If it can de-coke a ULEV VTEC, it'll handle a 3.0.

Carbon cleaner and injector cleaner that actually freaking works

Ok. This is the intake valve and piston number one on my 2000 Honda Accord 2.3 ULEV. Motor was completely carbon fouled, and intake valves were crusted over. 211,000 on the odometer, and the car has never had a carbon, fuel, or intake cleaning product through it. One can of jectron on one tank...

www.therangerstation.com

 

[McCormack]

An option to fix pinging on a 3.0 is to use a tuner to retard timing. If you don't have a tuner, a Ford dealer or a speed shop will do it for a fee. I bought an SCT tuner when I first got my '00 Ranger and used it to retard my timing 2 degrees and then I could run regular with no pinging. I did notice a slight reduction in power with the retarded timing, but that's a small price to pay for my engine not destroying itself by pinging.

For flex-fuel vehicles, you can mix in 4 or 5 gallons of E85 for every tankful of regular gas and it will eliminate pinging.

 

[19Walt93]

A Ford dealer can't adjust individual items like spark advance, the calibration is a complete program. Modifying the specs- if there was that capability- would be considered emissions tampering and leave the dealer in violation of federal law. An independent might find a way to get around it, independent used car dealers sell cars with open recalls where a dealer would face stiff fines.

 

[PetroleumJunkie412]

A Ford dealer can't adjust individual items like spark advance, the calibration is a complete program. Modifying the specs- if there was that capability- would be considered emissions tampering and leave the dealer in violation of federal law. An independent might find a way to get around it, independent used car dealers sell cars with open recalls where a dealer would face stiff fines.

Aftermarket ecu is an option. Takes me 4-5 mouse clicks to adjust fuel or timing.

 

[McCormack]

A Ford dealer can't adjust individual items like spark advance, the calibration is a complete program.

You might be right, but if a vehicle still passes emissions after having it's timing adjusted, I don't see what the harm would be.