Spark Plug Knock

[Sherri Paxton]

I had my plugs, wires and coils replaced and now I have the dreaded knocking sound. Can someone talk me through how to figure out what it is. I’ve had the original mechanics that did the tune up try to figure it out and I took it to Pep Boys and specifically asked them to check the plugs and wires. They didn’t do any of that. Instead they heard the knocking. Said it needed a new bottom end and charged me $89 for the “diagnostic”
When I asked if they checked the plugs and wires like I asked the guy got pissy with me and gave me the “I’ve been doing this for a lot of years” speech. I walked out.

 

[donalds]

If you can make a vid of the sounds that would be very helpful

Why not check the plugs and wire's yourself ?

What plugs and wire's were used did this happen at the shop on the first start-up when you got it back ??
These trucks are very finicky on their plugs and wire's

More details please.

 

[Sherri Paxton]

If you can make a vid of the sounds that would be very helpful

Why not check the plugs and wire's yourself ?

What plugs and wire's were used did this happen at the shop on the first start-up when you got it back ??
These trucks are very finicky on their plugs and wire's

More details please.

I had a mobile mechanic come to the house and do the install. I can’t check it myself unfortunately since I had back surgery I have severe mobility issues.

After they replaced the plugs It was misfiring and throwing a code. But not knocking. I went to Autozone and they checked the code. It was #5. I had them come back out. Then they said it needed wires I gave them money and they went and got wires. It didn’t fix it.

They told me I needed new coils so I went and bought those. It didn’t fix it. But it now was knocking too.

I did reset the computer using a technique I found on here and it cleared the codes. But it was still misfiring. I made them come back out and pull the plugs and check the gap even tho they kept saying they “haven’t checked a gap in years”. I said humor me and check the gap. They found out one of the spark plugs was the wrong plug.

After that the misfiring went away. And I reset the computer again. But the knocking didn’t go away.

I’d be willing to toss new plugs and wires if you could suggest specific ones for my Dora?

Could I check by having it running and pull the caps from the coil one by one? I can reach the coil packs, but not the wires near the plugs.

Thanks for the help!

 

[Sherri Paxton]

Oh. I also had them replace the IAC.

 

[donalds]

If we can hear the knock ....in a vid youtube ....
We can narrow this tons
But be patient because people will respond

Good luck

 

[shucker1]

As @donalds said.

More details please.

Knock at idle, knock during acceleration?

Cheap gas or name brand gas? (To me it make a difference)

Which engine are do you have?

 

[EB4X]

Did this "knock" only appear AFTER having your plugs / wires etc replaced? ...or was happening for a while..?

 

[Mbrooks420]

The firing order needs double checked. It’s counter intuitive, and running it for prolonged periods without the proper firing order could have caused internal engine damage.

 

[donalds]

She said he put in he wrong plugs I'm thinking
Plug was to long and hit a piston

Wonder do you have the wrong plugs or did he take them?

 

[Mbrooks420]

Some early models had two different plugs based on the bank, but that was over by 2000 I think.

Be extremely cautious if you are going to pull plug wires. Ignition coils are no joke and will LIGHT you up.

 

[donalds]

Some early models had two different plugs based on the bank, but that was over by 2000 I think.

Be extremely cautious if you are going to pull plug wires. Ignition coils are no joke and will LIGHT you up.

Really I never heard of that

I know some of the rangers take 8 plugs in a four cylinders

 

[shucker1]

Ignition coils are no joke and will LIGHT you up.

I can agree with that...

 

[Mbrooks420]

Really I never heard of that

I know some of the rangers take 8 plugs in a four cylinders

I believe they had platinums on the side that took the wasted spark. The dual plug Rangers had a set of plugs to start on, and another to run on. I used to do work out of my garage and when a customer brought in his 8 plug 4 cylinder it caught me off guard, lol.

 

[J_C]

What I vaguely recall about the different plug per bank setup was one bank had a platinum center electrode and the other a platinum ground electrode, based on the spark direction since it's a waste spark setup. AFAIK that should not prevent use of normal/same spark plugs on both banks... not sure if you can even buy platinum ground (only) plugs today.

I'm wondering if misfiring for so long has damaged the catalytic converter.

It seems like the lesson to be learned from all this is don't let anyone touch your vehicle unless they are trusted. Mobile mechanics are a gamble, some good and some not. Pep Boys, ignoring your complaint and still charging a diagnostic is not the work you asked for?

I would have argued with them a bit more before handing money over because best guess based only on hearing a sound in a general location, is not a proper diagnosis for pay. Granted they might have then said the engine needs torn down and they don't do that... so I wouldn't take a vehicle into a shop that limited in their abilities for work more advanced than brakes/shocks/alternator/etc.

Was the vehicle misfiring before the initial plug swap? Is that what initiated changing the plugs? I am wondering if the same problem, unrelated to plugs and wires, persisted and got worse or caused further damage, though obviously having the wrong plug installed is a big red flag and yet, could be a coincidence.

 

[Hacra]

Incorrect Spark Plugs or Wrong Spark Plug Gap
If any spark plugs other than what is recommended by the manufacturer is used, it can cause the knocking sound you hear. The spark plug has a certain heat range, which means it withdraws heat from the combustion chamber. Using the wrong part can prevent it from working correctly. It's also common for engine knocking to occur when the spark plug gap is not correctly set.

The spark plug gap is the place where the spark plug ignites the air-fuel mixture that helps power the car. Too narrow of a gap creates a spark too weak to perform this task, and too wide a gap might stop a spark from firing at all, or to only misfire rapidly.

I'll throw my money on this one.

 

[CDW6212R]

I gather at least one plug was the wrong one, and the same mechanic/service discovered it, plus didn't gap the plugs.

Plug wires can last for ages, but after a couple of years they are very fragile and pulling them from the plugs often ruins them. So with long age both the plugs and wires should be done together.

It sounds like the first work done may have caused an issue, and getting the firing order wrong could have been part of it too. Finding a trusted mechanic should always be the first step, poor mechanics can cause more trouble than the vehicle had to start with.

For this truck, I'd want to see the plugs, check the gaps, inspect the wires, the firing order, plus all wires under hood etc. Check to see that the cam synchronizer is tight and not able to move at all. Disconnecting the battery won't help, concentrate on the engine itself, the timing etc. Has it had fuel injector cleaner or similar run through it recently? Those products help to stop various things like a knocking noise.