Well, 3 years ago I had an engine built for me. EVERYTHING was supposed to be forged, but nothing was!!!. I put my superhcarger on the old engine and the crank busted at the snout! SO, after getting skrewed, I rebuilt my engine myself after that! And I had to do this right before my wife and I purchased our dream home on Lake Washingtion. Finances were tight to say the least, but thanks to CNCmotorsports, it all came together. My engine has the exact same combe as prior, except it has eagle 4340 crank, rods, weisco pistions. Same cam, AFR 190 heads, compression the same, about 9.5;1.

Now, I just put 3000 miles on the new engine and put the charger on today. Runs great, but when I get into the boost at 6psi and above, I get detionation? I do have a crane hi6s and have to turn it to about 11:00 to stop the detionation. The car never had detionated with the old engine and charger. I run 9psi, procharger 3 core intercooler. Nothings different, same compression, cam, ignition....what gives? I was getting a code 43 but I have not since I cleared the codes and disconnected the ecu and chip, then re- connected them.

I'm going to rule some things out;

I HOPE it's bad gas.

Change the FMU and increase the fuel in steps

I put the stock chip back in the ECU

Timing is at 6 deg advanced, but I will retard 2 deg so it will be at 4 deg. advanced.

Any ideas?

Ty

 

MSD timing control does wonders for me....if your running DFI get a knock sensor, saves you from yourself.

Back it off to stock timing to be safe until you can get your timing right on...

No use in burning a piston over a few degrees....

 

oh and take that stock chip out...it is your timing, mine will do the same thing if I advance over 3 deg.

 

If I recall, 6 deg advanced is the stock setting. So are you suggesting me to set it to dead zero?

And I do have a crane hi 6s with boost retard. I was still getting some detionation with the control at the half way mark

I have a chip burner and was thinking of pulling some timing out of the stock setting for the upper rpm's, and adding some fuel

 

my car was doing the same thing what i found was the 24 pound injectors where to small i install svo 30 pounders pinging was gone and i have a stock chip and timing at 6 degrees.

 

Well, I think I'm on the road to recovery.

First thing, I recently got a code 43 again. That would explain tons. If the knock sensor is not working, it is not pulling out timming when I get a knock, hence detionation in the upper rpms.

Also, I think bad or low octane fuel is partially the problem. I put a bottle of 104 in plus 1/2 tank of 94 and the knock has been cut in half. I think I was putting 87 octane in while I was breaking in the engine.

I'm going to check my KS today and see if it is bad or not, that will tell me a lot. I will chase the problem from there and keep you posted incase this happens to any of you!


Thanks for the help!

Steven

 

24lbs are enough ?
Do you have anything to monitor injector duty cycle? I wouldn't think that 24 would be enough...along those lines when do you need to step up from 24lbs...at what psi on the D1sc?

 

Knock sensor's bad! mine read 1500ohms and it's supposed to read between 3300-5500

 

I don't have your exact engine specs, but I run 36lb injectors...I have higher boost but you may want to call and find out if they recommend 30's for you.

 

OK, now i pullled the knock sensor and i'm getting a correct reading from the one I though was bad??? The car's not knocking anymore, so I still suppect the prior;

Low octane and bad knock sensor. We will see!

TY everyone for the help!

 

I personally knock with 91 octane and do not knock with 93 ...

I keep 4 bottles of octane boost in case I gotta fill up with 91.

Odd

I hope it was just the sensor...get a new one asap

Could you hear the knock>?

 

nope, no more knock I am just hoping that code 43 doesn't come back! I got the same resistance on the bad sensor once it was out of the car, yet, when the old knock sensor was in the car....it only gave me 1700ohm's? We will see in the next few days.

 

I have always been told audiable (sp) knock was a very bad knock, 8 out of a 10 on a scale of 1 to 10.

Be careful