Knock Retard at WOT

J

jshaw

New Member
Joined
Nov 17, 2014
I bought an 1987 GN several months ago, and I have been trying to sort out all of the performance issues. The previous owner was meticulous about making things look nice, but I don't think that he ever stepped on the gas. It is basically stock, but has an aftermarket cone air filter and hard piping for the intake. It also has a Kenne Bell chip.

I've sorted out almost all of the issues (the most interesting was dying at idle because the PO did not wire the fans to the compressor and the head pressure was getting high enough to kill the engine), but I am still having knock retard issues at WOT. First I discovered that the TPS was only reading 3.6 V at WOT. I fixed that, and performance improved drastically. However, I discovered that I was getting Knock Retard at boost over 12 psi.

I ran a fuel pressure gauge with a long hose, and I discovered that I was losing fuel pressure under boost. First I installed a hot wire kit. That helped with the fuel pressure a little, but not enough. So, I put in a 255 fuel pump from TurboTweak. Now I have good fuel pressure, but I am still getting up to 6* retard at WOT. However, it runs significantly better.

I do plan on getting a TurboTweak chip and 60# injectors at some point, but I really want to get a baseline with things working first. I do know that I have an exhaust leak on the driver's side header, and I plan on pulling that and repairing it in the next couple of days.

I am logging data with WINALDL. I am reading BLMs in the 105-118 range, O2 around .9 at WOT, and my MAF is getting up to around 245-250. My BAT readings range from 12-12.9 and are slightly higher when I turn off the AC blower. The ODPA3 value increases by 1 or 2 when I see a knock retard during WOT.

My questions are:
  • Do Kenne Bell chips have any issues with KR? Before replacing the fuel pump, I put the stock chip back in, and the KR and performance seemed identical so I don't think that is the problem.
  • Can the slight exhaust leak cause KR under boost? I wouldn't think so, but I am fairly new to turbos.
  • Are the BLMs way out of line? I've seen some postings state that around 105 might be the lower limit allowed by the computer, but I've also seen postings that refute that.
  • I do plan on getting a scanmaster at some point, but won't those values be the same as those shown by the WINALDL? I am also planning on getting Tunerpro working. But again, won't that just put out the same data?
Sorry this got kind of long, but I wanted to be complete.

Also, if there are any GN guys in the Houston area, feel free to hit me up. I have a fairly equipped shop at my house with a couple of lifts and don't mind sharing if it can help someone out.
 
Let's start with some basics. Are you using dash for boost guage or is it aftermarket? Stock one isn't accurate. Is there a way to read 02 millivolts? With the scanmaster you're able to see what the 02 sensor is doing and able to narrow it down. Could be false knock rich knock or lean knock. Is the wastegate adjustable? If so lower as low as you can. I don't know if kenne bell makes street chips and race chips but if you're not putting right octane in could be a problem as well. I'm not familiar with the sorfylt ware you are using hopefully someone who knows can help but those are just some guesses. Might be spark related as well...
 
I few observations:
Your BLM are quite low, were those readings you stated at WOT or idle? I'm betting WOT based on the fact you stated your O2's were .9 which is EXTREMELY rich. This is no surprise with the KB chip.
Yes, KB chips, whether they are street or race all run TOO much timing for today's gas. Get rid of it as QUICKLY as you can.
Which a header leak, what are your BLM's at idle? High, right?
The Scanmaster will read at a much faster data rate if you get that function programmed into your new chip.

Once the header leak is fixed, and you get your new chip, you'll likely notice a MUCH better car!!!
 
I have not gotten a scanmaster yet. I have been driving around logging everything with WINALDL. I've been waiting to buy the Scanmaster because I think I have a friend that is not going to need his. I am using an Autometer after market boost gauge, and I do not have an adjustable waste gate yet.

The BLMs range from 105-115 idle and WOT (but will occasionally go up to 128). The high O2 readings are only at WOT, and it switches between low and high the rest of the time. WINALDL lets me log both of those and watch them real time.

Also, I am using 93 octane pump gas.

I guess maybe I should go ahead and get the new chip and injectors. I just really wanted to get a baseline before I start getting a bunch of aftermarket stuff.

On a side note, would the stock chip show knock retard with today's gas?
 
New chip, inectors, fuel pump, hot wire and adjustable fp regulator are a must for any buick that is gonna be driven.
 
jshaw said:
Now I have good fuel pressure, but I am still getting up to 6* retard at WOT. However, it runs significantly better.
Click to expand...
where are you getting the kr?wot in what gear?i prefer the tt chip myself but my car ran real good with the kb chip and my friend used it in his car on pump gas with no kr up to 15psi.try a 3rd gear pull rolling into it and see if it still gets some kr that will eliminate the trans and downpipe kr potential,if you still get kr with 02s above 800 you will need a new chip with reduced timing.
 
What part of Houston are you in? I don't know much about the turbo buick but I am willing to look at it. Maybe 2 heads looking at it can figure it out.
 
I am off of 45N between 610 and the Beltway.

I have fixed the cracks in the header, but I have not taken it back out yet. I think I am going to go ahead and buy 60# injectors and a chip from TurboTweak. However, they seem to be closed this week. I am under the assumption that the Kenne Bell chip has too much advance for today's gas.

In researching the mods I want to do, I have become a little bit confused. I think I want to get to 19 or 20 lbs of boost. However, I am trying to figure out how the computer figures out how much fuel to put out with no MAP and the MAF sensor maxed out at 255. It seems to me like the computer would have no idea of the amount of air going in and therefore no idea of the stoichiometric amount of fuel to add. People make it sound like adjusting the wastegate rod length is all that is required to turn up the boost. However, I can't figure out how the computer figures out the fuel to add with the MAF maxed out. I have been searching for hours, and I haven't found a decent explanation..... if nobody has a quick link on that, maybe I should start a new thread. I am sure this has been discussed, but I can't find an explanation anywhere.
 
What do you mean by "today's gas"? Compared to what, when your car was made?
 
Back when mine was stock the KB chip was worth 2/10ths v/s the stock chip....2/10 slower in the 1/8th. How much boost are you running? I would like to know the diff in todays 93 and back in the day 93? Do you have the original injectors? You might have one that is running lean causing the knock.
 
The way I think it works out with the turbo tweak chip is he burns the chip with enough fuel at the boost level you want to run. So when the maf goes to 255 it will go to predetermined amount of fueling.

I could be way off but did sleep in a holiday Inn last night.
 
Jiho2, by today's gas, I have been told by numerous people that the additives in current gas cause problems with the older chips. I guess they are referring to Ethanol, but it seems to me like that wouldn't cause a problem. I didn't think that it would be a problem, but a number of people have told me otherwise. Maybe I shouldn't put much faith in hearsay.

Mr. Spool, I guess I will look more closely at the Turbo Tweak website. Do you mean in the description section for each chip? Or do you mean in the forum section? From the description of the chip, I assume I have to adjust the settings in the chip anytime I change the waste gate settings?

ITSAV6, I am getting to 15 psi of boost. I thought that was stock (according to some postings I saw), but it turns out others say stock is closer to 13 psi. Maybe I need to turn back the waste gate actuator to 13 psi. I guess that could definitely be causing the knock retard issues. Also, they are stock injectors. However, I didn't think that any were restricting flow due to the low BLMs and high O2 readings under WOT.
 
I am not sure yet. I put on an aftermarket boost controller, but I haven't started adjusting it much. At first the boost was spiking, but I made some modifications to correct that. I have a hard time messing with it in my part of town do to the low speed limits, but I just bought a company that has a dyno. I hope to start messing with it again in a few weeks, but I have been too busy learning to be an accountant to get to it. I will post when I finally have some free time to mess with it.
 
I know that this is a VERY old thread, but I want to post the resolution for anyone who might see it.

The whole time, this car has had a loud ticking noise that sounded like an exhaust leak or vale-train noise. I replaced rocker arms, pulled exhaust and looked for leaks, listened with hoses and stethoscopes to everything and everywhere under the engine compartment, and had several other of my mechanics look for it. I was going to pull the engine to see if there was something knocking around and causing false knock but decided to go ahead and replace the injectors since that was coming anyway.

I bought new injectors and another Turbo Tweak chip, installed them, and VOILA! No more ticking, no more knock retard, and I am able to turn the boost back up (at least to stock levels) without knock.

I guess the whole time, the noise was coming from an injector which was not fueling sufficiently. Sorry responding to such an old thread, but I just got it sorted and thought the resolution might help someone out someday.
 
I think that is great that you came back after all this time to close out the thread with an actual conclusion. I've spent hours reading threads with issues similar to mine or just some issues that seemed interesting so I wanted to see what the fix ended up being....all dead ends. No conclusion whatsoever.

Thank you for the rest of the story!! :)
 
You must log in or register to reply here.

Similar threads

6gunn
knock from valvetrain
Replies
16
Views
580
6gunn
6gunn
Toddmc66
Fuel pressure too high. Cut off the end of the return lin.
Replies
8
Views
413
dynoman
dynoman
VADR
Losing Power at WOT - No Codes
2
Replies
25
Views
2K
John Larkin
John Larkin
J
Found an 87 GN that has been sitting for 10+ years in storage..
Replies
10
Views
548
granitestategn
G
jshot
MV dropping
2 3
Replies
42
Views
3K
jshot
jshot
Top