AXiS & Alky

[ShaunKris]

Hey Eric, just transferring back to this thread from the AEM W/B thread.
Battery volts fixed
Wideband O2 has a proper ground
I re-adjusted the Fuel pressure
I will re-attach that log here for simplicity. There is a knock still that does seem to be attached to RPM as you mentioned at about 3200-3600rpm.

Now I'm just curious what would cause a knock between 3200-3600RPM, any thoughts from past experiences??
Could an exhaust leak or bad lifter cause that?

The second Log is from this evening, all I did was add low fuel one notch. I got some strange readings on the Wideband again.

 

[EricM]

A bad lifter or anything in the valvetrain, but really could be anything that can cause a knock-like sound.

You had the wideband reading good at first, then it went back to erratic. I wonder if there is an intermittent connection somewhere.

 

[ShaunKris]

A bad lifter or anything in the valvetrain, but really could be anything that can cause a knock-like sound.

You had the wideband reading good at first, then it went back to erratic. I wonder if there is an intermittent connection somewhere.

Ok, I'll check it again.

 

[ShaunKris]

Hey Eric. I fixed a few issues.
- My drive shaft was rubbing the exhaust pipe occasionally, could that be the cause of the false knock?
- I changed my exhaust gaskets, went SCE Copper. Much better, the primary openings are bigger than the Malhe gaskets(which burnout way too fast).
-The readings look way better now from the W/B now. I changed out some vacuum hoses and it helped a bit as well, and it helped the Alky Control too.
- My timing is still backed off for now, but I definately want to advance it. Had the car out last night @ about 6⁰C. Nice cold night to cruise a bit. I noticed a small amount of knock at certain rpm (as you mentioned to me), so i looked a lot closer and noticed where the prop shaft was grazing the exhaust. No damage just a perfect circle paint scratch around where the shaft had touched. I moved the exhaust tonight, I'll log a run tomorrow. Thanks for all the help, I appreciate it and so does the car! Here is a file.

 

[ShaunKris]

Hi Eric, Here are the files I logged today. The temp outside was 21 degrees C. I have a feeling that the exhaust is still touching the driveshaft occasionally, I am going to get under it and see if I can more it. The knock I'm seeing does seem to be rpm related in some cases but not all. I also noticed I could probably back my boost off a bit. I would like to run a bit more timing and I'm curious if it would make more power with Timing vs. Boost.
I would love to get your thoughts on this.

 

[EricM]

What alky kit do you have? I see that when the alky kicks on, it goes real rich, like maybe too much. The knock at high boost could be real, so I would back off on boost for now. Maybe no more than 22-23psi.

Sometimes the best way to identify real knock is to add a bunch of octane and see if the knock goes away (indicating real knock). Race fuel or a decent octane booster would work. I have used Lucas octane boost or Boostane, with good success.

 

[ShaunKris]

Here is a follow up on this thread for anyone having the same issues.
after a lot of head scratching and LOTS of conversations with many people, a friend of mine who is a HD mechanic and a SyTy guy suggested that I switch my coil wires 180degrees out. It sounded really odd but he told me that GM motors specifically the SB chev would run wired on the exhaust stroke. Turns out he was correct!! it works on the Buick too! so I switched my wires around and the car was NIGHT AND DAY different.
All the hassles I was trying to deal with were because the coil was changed before I got the car and the mechanic at the time changed over to an 87 coil but the coil mounts backwards compared to the original 84 version. so the wires were 180 out.
BOY WHAT A LESSON.