random knock is effecting performance

[Jesse]

This problem has been happening for a while but just recently started to get worse. I can be driving the car and all of a sudden when i go to accelerate i'll get about 40 knock, and if i stay on the gas pedal the turbo will spool but the car won't go. Then i'll let off and do it again but this time it runs fine and the car takes off like it should all the way to redline.

Things i have tried: fuel filter, stock injectors back in the car, fuel pump has pressure, ignition coil, spark plugs and wires, pcv valve, cleaned the air filter, disconnected the o2 sensor, ecu, fuel pump relay, new knock sensor about 2k miles ago.

I am pretty sure it's not a boost leak because the problem only occurs once every five times that I accelerate. The motor also has fresh lifters and does not make any noise.

Any help will be appreciated.
Thanks,
Jesse

 

[mhockeyjock]

in a way you just helped me out if that makes you feel any better. My car does the Exact same thing and now i know what the term knock ment. Does yours feel as if a giant rubber band was pulling back on the car upon acceleration and then as you let off it returns to narmal? Also, Does your car jerk around at a constant speed, like say your going around a constant 50 mph does your car jerk around?

Mark

 

[Jesse]

Originally posted by mhockeyjock
in a way you just helped me out if that makes you feel any better. My car does the Exact same thing and now i know what the term knock ment. Does yours feel as if a giant rubber band was pulling back on the car upon acceleration and then as you let off it returns to narmal? Also, Does your car jerk around at a constant speed, like say your going around a constant 50 mph does your car jerk around?

Mark

No, my car does not jerk around at all, at 50mph.

 

[newports01]

mine is doing the same thing as yours bro.. check out my post "i cant get this thing right" but mine doesent buck.. but does the exact same thign yours does... ive done everything you have... but i dont have a nock sensor reader so.. but it does feal like a rubber band kinda like the other guy said

 

[98TsiAWD]

Your car is knocking, causing the ECU to retard the timing, thus your loss in power even tho boost it good.

Moved to tuning forum.

 

[Jesse]

Originally posted by 98TsiAWD
Your car is knocking, causing the ECU to retard the timing, thus your loss in power even tho boost it good.

Moved to tuning forum.

Your right. The timing is being pulled when it is getting knock and thats why the turbo spools but the car won't go.
The problem is, that this also happens at part throttle , even when i am not boosting the car.

 

[supergoat]

Mine is doing this too.

 

[Antilles]

The problem is lifter tick and or phantom knock. Buy a can of seafoam, pour half into your oil. Run the engine for about 5 minutes. Change the oil. I use 15W40 Rotella T oil. It works well in the summer months.

The key is keeping your oil clean. If it starts to turn brown on the dipstick, change it.

If all else fails, buy a set of the new style mitsu lifters or pull out the ones you have and clean them.

Mine are getting to the point where I may just give up and buy the new ones. Clean oil and seafoam cut down the tick significantly, but its never gone for very long.

Chris

 

[Jesse]

Originally posted by Antilles
The problem is lifter tick and or phantom knock. Buy a can of seafoam, pour half into your oil. Run the engine for about 5 minutes. Change the oil. I use 15W40 Rotella T oil. It works well in the summer months.

The key is keeping your oil clean. If it starts to turn brown on the dipstick, change it.

If all else fails, buy a set of the new style mitsu lifters or pull out the ones you have and clean them.

Mine are getting to the point where I may just give up and buy the new ones. Clean oil and seafoam cut down the tick significantly, but its never gone for very long.

Chris

That sounds like it would help, however, I allready have the new style lifters in the head on my car. They only have about 20k miles on them, and are much more quiet than the original lifters.
The original motor that was in my car had a lot of lifter tick and it never effected the performance like this.

 

[awdsquat]

I've heard good things about seafoam but I can't say enough good things about mopar combustion chamber cleaner. I was getting 43 knock sum and -1 deg timing on my logger in neutral, part throttle, wot you name it. I read about mccc on vfaq.com and picked up 2 cans of it from the dodge dealership. Used one in the pcv hose to the intake manifold while idling and the other split into each cylinder with spark plugs out and let it soak for a day. After I cleaned up all the carbon and mccc and changed my oil and plugs, i was getting 0 knock and a lot more timing than before at wot. Not saying this will solve your problem but it solved mine. Good luck.

 

[Jesse]

Originally posted by awdsquat
I've heard good things about seafoam but I can't say enough good things about mopar combustion chamber cleaner. I was getting 43 knock sum and -1 deg timing on my logger in neutral, part throttle, wot you name it. I read about mccc on vfaq.com and picked up 2 cans of it from the dodge dealership. Used one in the pcv hose to the intake manifold while idling and the other split into each cylinder with spark plugs out and let it soak for a day. After I cleaned up all the carbon and mccc and changed my oil and plugs, i was getting 0 knock and a lot more timing than before at wot. Not saying this will solve your problem but it solved mine. Good luck.

I'll look into that. If it solves my problem I'll be sure to let you know.
Thanks for your input.

Jesse