General 1G Mega Knock, Need some help

[Generation1JeY]

Alright guys. I don't understand whats causing this, but i got serious knock in the mid and high rpms at WOT. My car is nearly completely stock. I even have the boost turned DOWN below factory levels. I have a straight boost source routed to the wastegate so at max i get 10psi. Anytime i do WOT pulls i just get a lot of knock and i cant understand why. I have heard that lifter tick can be a large contributor to that if they're excessively loud, which mine ARE, and would also explain why sometimes i get a lot of knock and sometimes i don't because my lifters are not always loud.

On this log i'm looking over right now i downshifted on the freeway into third and started out at about 3600rpms and gave it WOT right when i shifted into it. Right from the start i'm getting 22 counts of knock, 24 degrees timing, .64v o2. Then one frame later in the logger i'm getting 42 knock, 13 degrees of timing, and .87v o2. After that frame nearly all the way up to 6500 rpms from 3600 rpms is the same as the second frame. So throughout the entire pull i was getting around 40 counts of knock, and timing was being pulled a lot.

Does it seem like i need a new knock sensor or something? or could it just be the lifter tick?

Thanks.

 

[spyderturbo007]

You might want to check your knock sensor for "goo leakage". Also, the best way to distinguish phantom knock from real knock is with some race gas.

 

[Generation1JeY]

well phantom knock only occurs at part throttle at random times correct? This is at WOT at the top of third. I don't see how i could be getting that much knock on a stock dsm so it must be my knock sensor of my noisy lifters right?

 

[GVR4592]

Post a log.

 

[Generation1JeY]

i'm still kind of unsure on how to do that. I explained it though, i'm just getting a lot of knock but everything else is fine. It doesn't make sense on a nearly stock car. I'm gonna run some engine restore tomorrow and see if i can get my lifters to quiet down to see if that helps or not. I'll also check to see if my knock sensor is having the oooooz syndrome in which case i will try to replace that to see if that is the problem.

 

[beatshack]

There is no way lifter tick should be showing 40 counts of knock unless your sensor is toast. BTW what type of fuel are you filling up with?

 

[GVR4592]

You have to post a log or you probably aren't going to get much help. What type of fuel are you using? Have you tried changing your fuel filter? What is your base timing? What is your base fuel pressure?

When you datalog, you should be in 3rd or 4th gear around 2500-3000 rpms and you should go wot until redline. Unless you are getting a lot of knock then it's probably best to let off.

 

[92tsifwd]

I was just curious if you figured out the cause yet. I am pretty sure mine was from the boost leaks I had. Mine was doing almost the exact same thing as yours and now mine is good.

 

[King Salami]

What do your fuel trims look like?
Running too lean or too rich?
Have you done a boost leak check?
Have you cleaned your combustion chambers w/ MCCC in the past 6 months?
What's your base timing set at?

By doing these tests/procedures, you should find the answer to your knocking problem.
I don't think it's phantom knock because it is WOT-dependent.

I've had similar problems attributed to:

• boost leak
• exhaust leak (logger reads lean but exhaust is pig rich)
• carboned up combustion chambers (from running too rich)
• base timing slipped/advanced too far

[/LIST]

 

[92tsifwd]

It showed lean on my mmcd and it was not really lean because it back fires on decel and gets poor milage smells like gas produces black smoke ext for low th, and high th there was insane knock and richening up had no effect on reducing it. However race gas did take it down about 4 counts. This I believe was caused by boost leaks in my case.

 

[T9S1i]

Check Base Timing!

Me and my buddy were riding around tuning his car and could not figure out for the life of us why he had like 20 counts of knock right when boost hit to redline.
A few weeks later, he checked his base timing and was at like 16* of base advance. He put it back to 5* where it should be and now his car runs great with no knock.

Just a thought, and i hope this helps

Danny

 

[King Salami]

Check for exhaust leaks by running some MCCC (Mopar Combustion Chamber Conditioner) or Seafoam through your engine (use the Search function on this site, see the vfaq.com or Google if you're unsure how to do this.)
Seafoam or MCCC will show where your exhaust leak is by smoke coming out of it.
After you've blown all the cleaner out of your engine, change your oil.
Works like a charm!