hey guys, I recently within the last month or so noticed the durango is making a knocking/ticking sound which gets faster with the rpm.

My dad thought it was me hearing a valve cover but that doesn't sound right at all.

I think i have spark knock. my buddy told me running 87 octane in a v8 for too long can cause it. which is what i usually run.


Spark knock is really just from the carbon and crud build up in the cylinders right? so would sea foaming help me any?

I ran Lucas fuel injector cleaner already.

in what manner would i want to sea foam the 4.7l? i hear people say pour 1/3 bottle straight into the throttle body and i have heard others say let it get sucked into the brake booster line.

Which line is the brake booster line? would it work all the same if i sea foam the durango with the vacuum line thats attached to the stock air box? it looks like it splits three ways down a foot or so.

Suggestions guys? Spark knock, sea foam....one thing after the other right? lol

 

If you're sure it's a spark knock the most common causes for that are a overheated engine, too hot of intake air, or you're running lean. I'd first start by checking all your vacuum lines and making sure there's not a leak that's causing too much air to get into your mixture and screw up your stoichiometric air/fuel ratio.

I'd also measure the pre-CAT O2 sensor(s) to make sure they're functioning properly and not causing your computer to lean the mixture out un-necessarily. Lastly, if you want to do SeaFoam I'd recommend either using the brake booster vacuum line or the air intake line. Both are good lines to use and the brake booster line is the vacuum line that goes from the brake booster along the firewall towards the engine.

Use about 1/3 of the bottle in the booster line and dump the rest in the tank to clean out your injectors and lines and such. IMO, pouring the SeaFoam straight down the intake is a really great way to blow your intake seal.

 

Well if you can recall widow roughly a month ago my engine was giving me some overheating issues.

But ok so I'll rule out dumping straight to the throttle body. and I'm sure both my o2 sensors are fine but I'll check em and my lines.

Also i hear sea foam is safe for the engine so would i be safe letting it run through any vacuum line? The easiest one for me to get to and know is the one on my air box. and I'll see if i can locate my brake booster line. is it kind of the only air line in the general area?

 

I'm sure it's safe running thru any vacuum line, the brake booster line is just the easiest to use. With the vacuum line vs. just dumping it down the throttle body is, it's more of a regulated flow that way with the vacuum line rather than risking your engine stalling out because it's drowned itself in SeaFoam.

Here's a picture, I circled where you should pull the flexible vacuum line from the hard plastic connector and the SeaFoam should go thru the flexible vacuum line:

 

yeah that sounds logical. pouring it straight down the throttle body could stall. And my brake booster is setup differently from that but i think i can handle it.

so to sea foam just have the engine idling at operating temp add the sea foam than let it sit for 15 mins and start her up? there should only be one line coming off the brake booster right? and it'll lead to the cylinders?

 

running 87 in a v8 being the cause of spark knock is both true and untrue, if your engine is 100% running 87 should be just fine and cause 0 knock, however when it does knock upping the octane rating can make it go away thereby giving you a diaganosis on the problem and at least confirming your suspicions so that you arent chasing something that isnt there.

 

well i was hoping the seafoam would help it shrp.

So i went to work and bought some seafoam. I tried pulling the vac line of the brake booster and it didn't wanna slide off nice and easy so i didn't force it.

Any ideas why it didnt wanna come off and would i be ok yanking it off? Shrp sisnce you have the same year and engine the brake booster is right behind the steering wheel right?

 

the brake booster line should be right where the steering shaft comes through the firewall yes, seafoam will very likely help, but higher octane fuel will 99% of the time eliminate spark knock, even if you only use it for diagnostic purposes, try the seafoam and if that doesnt help fill up with mid grade gas and get back to us.

 

Yeah i was trying to pull the brake booster line and it didn't wanna come. its pretty much the only line coming off the brake booster going towards the engine block.

And when i do fill up I'll let you know if it goes away or not. hopefully it takes care of it. i might even run 91 octane instead of just bumping up to 89.

 

im having the same problem with my dakota , mine only does it under a load usually in 3rd or higher , and ive tried 180t-stat, new plugs, wires, d cap and rotor with not much improvment.

but i have a ram air intake , magnaflow muffler and no cat plus superchips 87 oct tune, ive treid puting it back to stock and it still had ping so i put it back to 87 tune again. i tried 89oct gas before i put in plugs and wires but i will try it again next fill up

if sea foam works let me know i would use it if it does fix my spark knock