Fuel knock

Is there a solution to the fuel knock even with 91 octane ? Two Dealer service departments haven't been able to correct the problem with my 2001 Lincoln LS,V8.

Welcome to the forum!

Are you sure it is knock and not a misfire? Do the knock sensor pick up on the knock? Did the service departments mention if there were any diagnostic codes or run through the emissions component parameters?

-Rod

The dealers agree it's a gas knock and say they have checked everything and I'll have to live with it. The problem is with a warm engine and light throttle applied on an incline or when first accelerating from a stop. No problem with cold engine or higher rpm's. Runs fine otherwise.

You may want to try premium fuel from another station to see if that has any effect. Also, make sure the coolant temperature sensor is registering the coolant temperature accurately. You may need a scan tool with the datastream capability to do this.

-Rod

Is there a solution to the fuel knock even with 91 octane ? Two Dealer service departments haven't been able to correct the problem with my 2001 Lincoln LS,V8.


There is no reason why a good dealer service department could no fix it.
Call the 1 800 service no in your owners manual.
Here is some tips on going to the dealer for repair.
Tip on going to the dealer
Ask that only a factory certified gasoline engine performance specialist work on your car.
Not all dealerships are concerned with how repairs are dispatched, and not all dealership techs bother to take advantage of the training offered by Ford (the vast majority of which is paid training). If the dealer is uncooperative, ask for your money back and call around for a dealer that will accommodate you.

If the spark is loud enough to hear is it is to much and will damage or melt down the pistons if you let it go.
The pcm system sould retart the timing if you have a fuel octane problem.
Something is not doing it job right.
Things to check are EGR valve operation and knock sensor and base timing and see if the pcm is able to control the timing.
But also engine pistons or bearings or pulleys or flywheel problems can cause a sound like engine fuel knock

Thanks, I'll go back to the Dealer armed with your information. I'll probably have a battle because it's out of warranty now.

I can tell you my LS has had the same pinging from time to time - in fact it only seems to not ping on Shell v-power gas. Anything else and I get pinging driving up hills. Even sometimes I get pinging on the v-power. I'm convinced that different batches of gas are higher or lower quality.

Thanks, I'll try a few tanks of Shell and see if there is a difference. My problem seemed to start last spring and didn't improve until the summer fuels came out. The problem is back now and I can only guess winter mix is back. I'm sure everything is worse here in California.

After the dealers response I thought I'd discover more of you had the same problem.

I was taught that knocking under part throttle was usually a problem with EGR system.

You know - now that you mention it mine is pinging more now than it did all summer also. I'll bet you're right on that "winter mix" thing.

I don't believe it's an EGR issue - mine is only pinging under a heavy load at low rpm (like up a residential hill). I would expect the EGR is closed during this time - and given the fact that it runs fine everywhere else, even at highway exit ramps where EGR's notoriously stick open - I would rule out the EGR.

The owners manual say's "Do not be concerned if the engine sometimes knocks slightly. However, if it knocks heavily under most driving conditions with the recommended octain rating, see your dealer or qualified service technician to prevent engine damage". I'm trying to find out if Ford conciders my knock light or heavy. I bought my LS new and don't remember having this problem from the beginning.

I expected to read about many owners with the same problem, but after reading all of the LS complaints on the forum, you are the only reply with a fuel knock under identical conditions as mine.

I have to believe it can be corrected.

The owners manual say's "Do not be concerned if the engine sometimes knocks slightly. However, if it knocks heavily under most driving conditions with the recommended octain rating, see your dealer or qualified service technician to prevent engine damage". I'm trying to find out if Ford conciders my knock light or heavy. I bought my LS new and don't remember having this problem from the beginning.

I expected to read about many owners with the same problem, but after reading all of the LS complaints on the forum, you are the only reply with a fuel knock under identical conditions as mine.

I have to believe it can be corrected.

I am not sure what ford has to say about it.
But if you can hear it and it does it very often it is to much and may cause engine damage if not fixed.
Get on there case about it.
The newer computer systems should not let a engine have any spark knock.
MT

Thanks, I copied your first reply to take with me to the dealer next week. I thought I read a post that said only a Lincoln Dealer is Qualified to diagnose an LS. Doesn't the T Bird have the same engine as the LS?---so am I correct to assume a good Ford Dealer is as qualified as a Lincoln dealer?

There is only one Lincoln Dealer in my area. I purchased the car from them but won't trust them to touch it again.

I have this problem too. Two dealerships claimed they could not duplicate the problem:banghead: a private mechanic could. The private mechanic could find nothing wrong with the car harware wise. He sugested I get in touch with the Lincoln area rep.

Thanks, I copied your first reply to take with me to the dealer next week. I thought I read a post that said only a Lincoln Dealer is Qualified to diagnose an LS. Doesn't the T Bird have the same engine as the LS?---so am I correct to assume a good Ford Dealer is as qualified as a Lincoln dealer?

There is only one Lincoln Dealer in my area. I purchased the car from them but won't trust them to touch it again.


As far as I know any Ford dealer can do waranty on Lincoln or Fords.
But the key is that they have good factory trained tech/mechanics to work on it.
I would think that a good trained tech/mechanic could get to the bottom of the problem and fix it for you.
If the dealer does not fix it for you.
There is a 800 customer service no. in your owners manual that you can also call.

Yes the Lincoln and Ford has the same about the same 4.6 engine but the computer/pcm system may be set up different.
Tip on going to the dealer
Ask that only a factory certified gasoline engine performance specialist work on your car.
Not all dealerships are concerned with how repairs are dispatched, and not all dealership techs bother to take advantage of the training offered by factory (the vast majority of which is paid training). If the dealer is uncooperative, ask for your money back and call around for a dealer that will accommodate you.

Good luck and let us know how it goes.
MT

I have this problem too. Two dealerships claimed they could not duplicate the problem:banghead: a private mechanic could. The private mechanic could find nothing wrong with the car harware wise. He sugested I get in touch with the Lincoln area rep.

There is a 800 customer service no in your owners manual to call if the dealer does not take care of or fix it.