Detonation at WOT

[harrycalahan]

My 2011 Vic is suffering from this. I don't think its every cylinder and seems like its favoring the right bank but that just a guess. Car has new NGK's with a heat range of 5 which is colder than the factory Motorcraft plugs. I have not tried high test yet. This has been happening for a while so its not just a bad batch of fuel. I know some vehicle makes prefer certain plugs ie Chryslers-Champion, Honda-NGK's etc. I'm wondering if I should have stuck with the Motorcrafts now. When accelerating from a stop, it doesnt do it. But dropping to 2nd gear from 60 mph will do it. Thoughts?

 

[BillsCamino]

Right bank intake leak or off idle vacuum hose leak ?
EGR stuck ?

 

[Ken Ford]

My 2011 Vic is suffering from this. I don't think its every cylinder and seems like its favoring the right bank but that just a guess. Car has new NGK's with a heat range of 5 which is colder than the factory Motorcraft plugs. I have not tried high test yet. This has been happening for a while so its not just a bad batch of fuel. I know some vehicle makes prefer certain plugs ie Chryslers-Champion, Honda-NGK's etc. I'm wondering if I should have stuck with the Motorcrafts now. When accelerating from a stop, it doesnt do it. But dropping to 2nd gear from 60 mph will do it. Thoughts?

When the timing chain gets beyond tolerance, you will get that.

 

[harrycalahan]

I have not verified the EGR, yet...

 

[harrycalahan]

When the timing chain gets beyond tolerance, you will get that.

If it were a cam timing issue, I would think that would present itself accelerating from a stop also. At my previous job, operating and maintaining E350's with 5.4's and 6.8's as well as Vics...all with 200-300k and all but one with original timing components. I never had a detonation issue with them. So I wouldnt expect mine to be sensitive to a slightly retarded cam. Based on my experiences with the Tritons anyways..

 

[Ken Ford]

If it were a cam timing issue, I would think that would present itself accelerating from a stop also. At my previous job, operating and maintaining E350's with 5.4's and 6.8's as well as Vics...all with 200-300k and all but one with original timing components. I never had a detonation issue with them. So I wouldnt expect mine to be sensitive to a slightly retarded cam. Based on my experiences with the Tritons anyways..

I had problems when I was fleet manager of a police department.
Timing, catalyst, and fuel pumps were my biggest problem. Other than coil packs... grrrrr

Also compression increases slightly with RPM and fuel load.

 

[harrycalahan]

I had problems when I was fleet manager of a police department.
Timing, catalyst, and fuel pumps were my biggest problem. Other than coil packs... grrrrr

Im going to swap O2’s soon to rule them out. The numbers on them are good but that may not be accurate. I have not checked my fuel pressure yet either. I’ll get on that and the egr this weekend. And I replaced all cops with Bosch when I did the plugs 10k miles ago.

 

[harrycalahan]

EGR checks out good as far as I'm able to test. Passages are clear. The only thing it could be doing is hanging open a little too long when hitting WOT causing a lean condition. I'll go ahead and hit the shaft with some CRC.

But I'm starting to think I may have a plugged injector. Its had a slight intermittent skip at idle since I bought it. Not bad but just bad enough to notice. That paired with the detonation makes me think its leaning out under high demand. And would explain it sounding like its coming from one bank or a single cylinder. I may run a tank of BG 44K cleaner through the fuel system and go from there. A set of injectors is only $216 if I do go that route.

 

[gh1950]

I would go back to MC plugs.

 

[MRM]

I'd run the bg, clean the mass airflow, and look into the coil packs.