Thread: Knocking when it shouldn't

Hey guys,

I have an '01 GTP with a few mods. PLog to 3" DP to 3" catback, intake, ZZP 1.0 PCM, 3.5 pulley, poly mounts, 104 plugs and 180 t-stat.

First gear pull today with newly installed Aeroforce gave me shocking results. 3.5* KR and 1.5 LT at WOT shift point. I was sure these supporting mods would have been good for the 3.5 pulley but apparently I was wrong lol

Anyone have any insight on why? I don't know much about tuning KR fuel trims but I figured I would start here by recommendation from other 3800 people.

Aslong as the fuel trims are within 5% of zero, they are fine. So thats not even something I'd be looking at here.

I wonder how much timing advanced it's calling for, it might just be too much with a canned tune.

Figure if it asking for 17-18, thats too much and it might like 14-15 better.

Can I check for that on the Aeroforce? Ignition advance would it be?

Yeah, you can.

It might be hard to know what the real number is though. Because if it start to knock, it will pull timing out and thats the number you will see on the gauge. But you may be able to catch it at whatever number it is before it see's kr.


Drive it around again and see if it knocks in 2nd gear or when you roll into it at 50-60mph or something.

So it seems that my WOT timing is about 15.5* but HOLY FALSE KR. Spiking all over the place, hitting 7* then coming back down to about 2* then hitting 5* and coming down again. I don't think true KR is much higher than 2* or so near shift point

I'm betting your kr is real.

Log your kr with timing.

Sounds to me like you just need more mods.

Just for the 3.5 pulley!? On the tread about "safely modding 3800 cars" the only thing I don't have is a ported SC case and LIM. Do you think I just got a bad tune from ZZP?

if you had a tuner, you could fix that kr. its not that the tune is bad, your engine just dont like it. why canned tunes are hit or miss.

Blah that's what I feared. So what are my options here?

Find someone who can give you a in car tune.. Not that generic mail order crap. It's a hit or miss.


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How much would that cost? I'm on a tight budget, college and **** lol

depends on who your working with. some may want 50 others may want 100. you need to find someone first.

i got a tuner, not sure if you want to drive to NJ tho.

NJ is like 5.5 hours away lol I can afford $50-$100, not as bad as I thought. I'm gonna see if there is anyone in New England but if it comes to it... I might be driving down to NJ hahaha I appreciate the offer btw

there used to be more active guys who tune up there. seem to be slimming out. best to start a thread in the ne region area looking for a tuner.


i know NJ is a trip. but is closer to 3 hours. im at the top of NJ right over the GWB in hackensack. i know that makes it a shorter trip. lol not by much tho.

That actually isn't too bad, I have driven to Maryland before right through that area.

I'm actually apart of a NE page with about 20k members lol not a Wbody specific page but there are some of our people on there haha

that page sounds like the place to start then. if you find people with hp tuners that can be used, but you may need to pay to unlock your car, you need to buy credits per car its used on for hpt.

dhp is free to use these days.

Thanks for the help man, I really appreciate it. Trying to get this motor to be a decent DD with some fun haha all I have left really is to install my 10mm wires, maybe a larger TB, and this tune lol

Put on a larger pulley, stay out of the throttle, or save up for an intercooler. You could tune it out with a tuner, but it's not going to make you much more power than going to a 3.6 or stock pulley.

I don't hammer on it very often, its my DD so its gotta last haha. I'm searching around now for people who can tune it out. I'm just curious on what you think it would make with power as it sits with 0KR?

Maybe 220-230 whp.