Spark KNOCK!

My Ranger has a few problems as you guys may have read on the board.. It is a good truck but has these little problems that just dont seem to ever to away..

My truck spark knocks unless i put midgrade or high grade gas in it..

I was told i could get the computer reprogrammed and that may fix it. i was also told the timing could be off.. Evidently my truck does not have a knock sensor according to the mechanics.. we looked it up.. cant find a part for it..

Any help will be appreciated..

Thanks

I would also guess the timing is off.

Ford has had a lot of problems with their DPFE sensors, which control the EGR cycling.
A somewhat easy and FREE thing to try is to clean the EGR port in the throttle body. While you've got the EGR off, start the motor and let the EGR tube blow any loose debris out.
You might be able to see the carbon accumulation just by taking intake tubing off and looking into throttle with plate held open.

Did you ever solve the Spark knock problem on your Ranger? I have a 1994 4.0/AT and am having the same problem. I do not have to accelerate hard to get pinging, and if I go up hill even out of OD, I still get it at 30 mph and higher. I don't find any way to adjust the timing.

Any help you can give would be appreciated.

Thanks

no i have not found anything yet on the spark knock. I wish i could.. u find anything yet??

I spoke to the original owner and was told that the truck started to need mid grade or premium to avoid pinging about 18 months ago. Second point, I have not tried the suggestion you received to your original post about cleaning/purging the EGR line, but I did open the throttle plate and look down the body with a strong flashlight and saw quite a bit of carbon along the right side near where the EGR tube screws in. Why carbon might cause a ping, I do not know.

Until I get to trying that I am just going to use the higher octane gas. If it 2.45 or 2.55 as opposed to 2.35, that not a lot to eliminate the ping.

that is the same thing i have been doing.. sometimes i still get the ping with the midgrade..

anybody have any ideas yet about this spark knock problem.. i took the intake off and cleaned all the carbon out..

anybody have any ideas yet about this spark knock problem.. i took the intake off and cleaned all the carbon out..

I have looked in past the throttle plate down toward the place where the EGR plugs in and can see a lot of carbon. I am wondering if your carbon clean out helped reduce the pinging problem. I am running midgrade and now and most but not all of the knock has gone away.

i was told to put in a better spark plug..like a expensive one that sparks easier/earlier. this should solve the problem..

i was told to put in a better spark plug..like a expensive one that sparks easier/earlier. this should solve the problem..

Please let me know if the spark plugs help. I am running stock Autolite and have pulled the plugs and see nothing unusual. Could it be that there is carbon inside the heads and this is increasing compression? If so I wonder how to get it out without throwing in something that messes up the catalytic coverter? Did cleaning the carbon out of your intake help?

cleaning the intake helped some.. i have the same autolite plugs you have.. i am sure there is a bunch of carbon built up in the heads.. some garages will clean all that stuff for a price.. some say like 100 bucks + .. no exact cost..

Mine did knocked when i put a chip in it and only ran cheep stuff in it. and i could never get it fixed. But the weird thing is after i blew the engine up i replaced the engine and started running cheep stuff from the start and it has never knocked again. I was told all you have to do is run one take of good stuff through the truck and it reprograms its self for the high octane but you cannot go backwards with it
so my new engine has never seen high octane and never will

The EGR regulates the amount of exhaust gas that is allowed back into the cylinders for combustion. The exhaust gas is low on oxygen and displaces space that would have atmoshperic oxygen content. This reduces the amount of combustion capable and has the effect of cooling the combustion chamber. Spark knock is caused by pre-detonation (effected by advanced timing, reduced combustion chamber volume--carbon buildup--which results in higher compression, cylinder temp too high which ignites fuel before spark w/ the help of compression forces. Faster firing spark plugs will not fix the problem. If your truck is spark knocking w/o a service engine light on, the first thing to do is check and clean the EGR port. Even if it isn't the sole cause, it contributes and needs to be cleaned regardless.
These trucks don't have adjustable timing. The PCM makes adjustments based on sensor inputs.
A second common cause (it really sucks) is a bad MAF sensor. The sensor can give bad PCM input without triggering the service light and can even pass a scan tool test w/o showing bad. You're left with either swapping a known good part or just replacing it ($$$$).
The sad fact is that w/o the help of at least an OBDII code to guide you along, you need to have an expensive scan tool or you're just left guessing and replacing parts.

Freeclimber,

Thanks for your informative post. I have heard that you can help reduce spark knock by resetting??? the engine computer. Is this correct and if so is it as easy as disconnecting the negative terminal on the battery for 30 minutes? I have run two full tanks of Moboil super premium and I still get an occasional knock.

How do you clean the EGR port without a lot of fancy tools? Is there any clemical like a spray in carb cleaner that will help? Any other relatively cheap fixes. At $4 per tank extra for super premium, I am willing to try other things.

Thanks again.

BeachBoy

Sprays aren't going to work. You need to remove the throttle body and scrape out the big chunks with a screwdriver and then use carb cleaner and a brush. The throttle comes off with 4 bolts. The EGR comes off with two bolts.
Don't drop any chunks down the intake manifold.
Resetting the PCM can be done by removing power for ten minutes, but the basic programming for the specific vehicle isn't changed. I doubt if any improvement will happen. Something else is not working properly.

main cause of spark knock is when deposits build up in cylnder heads and on valves it raises compression slightly. these new engines are pushed to the max on compression so any little deposit will do that. steady doses of good fuel inj cleaner!!!

main cause of spark knock is when deposits build up in cylnder heads and on valves it raises compression slightly. these new engines are pushed to the max on compression so any little deposit will do that. steady doses of good fuel inj cleaner!!!

As I mentioned previously, I am willing to try almost anything that I can do which won't cost a lot and that can be performed with regular hand tools. If after cleaning the the EGR and throttle body, how do I clean out the carbon from inside the heads (without pulling them)? I remember my Dad telling me about pouring something called "Caseite"??? into the carburator and that it burned out the carbon inside of the heads. Is there still such a thing and does it harm the catalytic converter?

I've never read any objective data stating that any particular fuel additive has enough of an effect to fix a problem (ie spark knock). I've never had much faith in any of the oil additive/fuel additive products out there, but that may be due to my lack of experience with them.
I have experimented with BG and Prestone fuel additives w/o any discernable benefit.
I have experimented with Motor Honey and Duralube oil additives w/o any discernable benefit.
I'd like to hear if anyone has had experience with an additive, etc. that really does a great job.

BTW- the little tube of aluminum powder you can add to a leaky cooling system ($1!!!!) works like a charm. Think it's called Silver Stopper?

I did some serious reading today all over this BB and read something repeatedly. Yes carbon build-up inside the cylinders can cause knocking as well as a vacuum leak, MAF sensor build up etc. What I was wondering about was the repeated refrence to lower? intake manifold bolts getting loose and that being a cause of a vacuum type of leak, high oil consumption and a few other things in addition to knocking.

My question to all readers, have any you had this (intake bolt) problem?

If so how do you tighten the intake manifld bolts (upper? vs. lower), how much torque and what kind of socket.

Have you had a Mass Air Flow sensor problem?

How did you fix it? (I have heard that you spray electrical contact cleaner. Is this OK?

Thanx to all.

I've never had a Ranger loosen the intake manifold bolts on its own. It was probably suggested merely because it can be an overlooked cause of vacuum leak. If the manifold was never taken off, then the bolts are probably fine.
I have seen a handful of MAF sensors go bad. I hear that cleaning the element with contact cleaner can work wonders. It has to be a solvent that leaves no residue.

Sounds like the voice of experience talking. With all of the keystrokes dedicated to 'spark knocking' Ford products, has the Company that built the engines ever provided any sound advice? After reading all of the posts dedicated to knocking Ford engines and hearing from other Ford owners about the same thing, usually tolerated and "sort of" solved by using premium, what does the factory have to say. I love the truck, but I hate the knock!

I see the last post was in october, so I'm guessing no one has fixed the spark knock issue as of yet.

I've done a ton of reading on it, and from this site i get cleaning out the egr, or a bad MAF.

I'm about to try new plugs, I've got an 01 ranger 6 cyl. 4.0 and it has knocked for awhile, even when it was still under warranty. But of course I couldn't get it to knock when I took it in that day, must not have been warmed up enough. It only does it under load. I remember reading somewhere else about replacing the air intake temp. sensor, haven't done that one yet, but figured I'd start with the plugs. Correct me if I'm wrong but I thought that I wouldn't have to do that until 100k miles? It doesn't really bother me as I've gotten used to it, but I wonder what it does to my gas mileage. I"ve put in 93 a few times, when I had a good pay check and it seemed to quiet a bit but not entirely. Another board said to get the ECM flashed, but not sure how to go about getting a dealership to do that. Thankfully I got an extended warranty so I might take it back in after trying the plugs.

Let me know if anyone's found any solutions...I wont be getting a ford again, at least a truck if all of them knock like this unless you spend half a paycheck a week filling the tank (1.93 for a gallon where i'm at)...

Thanks in advance!

[QUOTE=slundy]I see the last post was in october, so I'm guessing no one has fixed the spark knock issue as of yet.

I've done a ton of reading on it, and from this site i get cleaning out the egr, or a bad MAF.

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WELL I have tried everything including chemical additives, 91 octane, and etc. What I have found is that with a high enough octane, the knock goes away. Some 91's knock (like Exxon) others do not. Go Figure?

My uneducated guess is as follows. The Ranger engine is built to be on the edge of knocking and as soon (mileage not years) you build up enough carbon inside the cylinder heads, it's 'knock city.' I went for a full month after driving 85 down a stretch of interstate for an hour. Again I see it as a carbon issue. I pulled plugs and found a little carbon too, but not enough to indicate that there might be a heavy build up inside. My guess, very uneducated is that the engineers pushed these Ranger engines to a bit more compression than is appropriate for a vehicle designed to run over 50 K miles.