Bfenty

My knock sensor code threw today. When I accelerate I do sometimes get a popping sound, but I’ve got straight pipe exhaust and the engine is so loud it’s hard to tell. It doesn’t sound like metal pinging at all. To me it just sounds like the engine is chugging a little. Don’t want to damage my engine by driving it with a knock though.

billschroeder5842

Take your knuckle and "knock" it on a wooden table. Thats what it sounds like to me anyway.

383vett

To me it's a metallic tic or rattle.

s carter

The Kind of Knock Being Described here is the Mechanical type. Bottom end Rap, Broken Cat. Converter even a cracked Flex Plate. But the kind that mostly that throw a code from Knock Sensor is the Timing type (PING) Cheap Fuel Timing OFF, Weak/Dead Cylinder.

So Follow the Procedure to Set Timing, once set and Distributor is plugged in and running in a normal manner, Raise Idle to about 1200/1500 RPM look at timing mark and have a Friend with a real long Extension give some LITE raps on a Head bolt on Passenger side of block timing Should Jump Back with the Raps. Proving Knock Sensor is working.

Bfenty

I think its closest to a pop or rattle. How should I go about diagnosing what’s causing the knock?

s carter

Good Wires,Good Plugs,Firing Order Correct,Timing Set Correctly,Gas That Didn't come El-Cheapo,Good Cap & Rotor, Check Compression that Numbers are at-least semi Balanced. Start Basic and work out.

Running an Open Exhaust Car may Run a Little Crappy I know I don't like it

Bfenty

wires, plugs, cap, and rotor are all new-although the plugs may have fouled before i got the injectors fixed-I will pull those and check them soon.

Timing was checked by a shop I trust (meaning I didn't touch it myself). I've double-checked the firing order a few times, I'm certain that's not a problem.

Gas was regular unleaded from Speedway-do I need to run higher octane?

Compression is good on all cylinders, I checked it trying to fix a bad misfire.

Open exhaust was how I bought it. I'll be honest, I like to make some noise, but you're right it could cause issues.

I'll probably put in new gas and pull the plugs first. Out of the list, those are the only two I think could reasonably have an issue. It's only doing it under load-when I hit the accelerator or drive up a hill. On flat ground or downhill the noise isn't there.

383vett

Put premium gas in and see if it goes away. If it does, start using premium (good choice) or retard timing.

Bfenty

I will do that.

It occurs to me PO might have advanced timing. I will check timing myself I think.

aklim

What exactly is the code it threw? I thought you said timing was checked by a shop you trust?

Bfenty

Code 43. And yea i trust the shop. Just wanting to see it with my own eyes.

aklim

Let's put that Asian for a while. If they screwed up the timing, they are morons. OTOH, it could be wrong because your harmonic balancer timing mark is moving because the balancer is screwed. Let's hold off on this.

Find the knock sensor and disconnect it and clean the connection. It might be loose. If the connection is bad, I'd change it and the connections

drcook

run some good gas, premium, run some Sea Foam through it. if you got some build up in the chambers you can get hot spots. Speedway is not the best gas, that is why it is cheap, at least around where I live it is cheap, one of the bottom tier places to get fuel

aklim

I doubt the snake oil will do much. Cheaper to use water, or so I've been told.

You ever see that in a functional modern engine? I can't say I have except I old carbs

It probably is OK for you to put it in the lawnmower but before I go there, I'd check the connection first.

drcook

why yes, I have. here are the heads from a mid-90's Beretta engine. Not the best pic, but if I have to prove my point I will take a better one. Notice the intake valves. A very significant buildup and the combustion chambers have a bit of carbon buildup. These were 50,000 mile heads we bought to fix the car after it cracked a head after 200,000 miles. Ultimately we junked it.

Mid 90's technology, just like our cars. Still subject to buildup on the valves and combustion chambers due to cruddy gas, and or just plain impurities in the fuel.

I never said it was a miracle treatment, but it helps. I actually have a can in my fuel tank right now to help overcome a tankfuel of cruddy fuel I got. It came from a top tier provider, but every station owner can specify what additives he/she wants in their fuel. Around where I live, Speedway is one of the cheaper places to purchase fuel

Of course the valve springs and such got some rust from sitting, but down in the intake ports the deposits on the valves are easy to see

JrRifleCoach

FWIW a loose bracket could be rattling and cause the knock sensor to respond.

Straight pipes sure don't help you hear a problem. so try a stethoscope.

drcook

I will concede that my perceptions are based on the quality of fuel in Ohio. Ohio does not have the best fuel standards in the country.

Here is a read on fuel quality

http://www.aaa.com/AAA/common/AAR/fi...ull-Report.pdf

When the knock sensor went out on my 454 engine, it sounded like popcorn or like shaking something in a can. It was very distinctively a different sound. I hear lower level frequencies better so I picked up on it right away. It especially was noticeable on pulling a hill.

Bfenty

Something shaking in a can is a good way to describe what I'm hearing. It's a metallic rattle.

Also, I'm originally from Cincinnati. I always went to Speedway because it was cheap and (usually) fairly clean with good coffee. Never much cared about gas quality because I never had a car that it mattered for.

aklim

OK. Fair enough. All the times I have boroscoped an engine combustion chamber, I can't say I have every seem much even on my diesel Mercedes with 480K on the clock when we took the heads off at 55K and later 200K for the glow plugs getting stuck. Since then we pull the plugs annually. My other cars in the past have gotten the same look over when plugs come out. My experience has been that the buildup doesn't happen much unless the rings or the valve stem seals are leaking or something is FUBAR.

Not sure how Seafoam can overcome bad gas but there are plenty of testimonials about it. I generally dismiss products that rely on unscientific testimonials that have been weeded out to prove their point. IMO they are crafted to separate the fool from his money and rightly so.

drcook

and I will agree with you that there are snake oil products sold by Mr Haney, but for 10 bucks it will help clean out any deposits, but 1.00 a bottle injector cleaner will also help. Sea Foam can also be detrimental to an engine if poured into the oil and it dislodges so crud and the oil isn't immediately changed

you ought to see how bad the filters on my diesel get. I had an auxiliary one put on so I could run a 10 micron primary and a 2 to 4 micron secondary both with water traps to protect my $450.00 each injectors (dang diesels are expensive)

but we are getting the thread off topic.

I was just trying to throw in a little of what I had experienced based on living here

try some GOOD gas as others have said. in my truck it was the knock sensor failing that didn't let the engine time itself back that allowed the knock to creap in BUT I would try the good gas first.