hello everyone . her is my issue i have a 87 gn im getting some knock especially about 70 mph . this started after i installed my cold air kit . i did gain about 2 pounds of boost after installing it and it sounds great . i tried adding 2 lbs of fuel pressure to compensate for the extra boost but didnt help . tried removing fuel pressure thought i might be running rich . ive looked for vacuum leaks all looks good . the knock raises like 3-5-7-8-9 so i think it is real knock and not false . i have checked the fuel pressure and im running 42lbs line off and it is raising 1 lb pressure for every pound of boost . not sure what is going on this is what ive done so far plugs are r42 gapped at .35 afpr /340wpump/hot wire kit/cold air intake /3"down pipe and test pipe/ car is running about 14 lbs of boost now . it is running the stock injectors and chip i have a dutt neck but have not installed yet would like to figure out this knock issue first .thanks in advance and all help is greatly appreciated . have a good day.
knock issue ?????
- Thread starter 87gn1
- Start date
The stock chip has quite a bit of timing in it, and anything much over 14-15# of boost is going to cause knock issues.
You'll be far better off with a chip upgrade, and might as well upgrade the injectors at the same time.
Bob Bailey's chip (Commander/Extender) or TurboTweak chips are about the best you can get.
You'll be far better off with a chip upgrade, and might as well upgrade the injectors at the same time.
Bob Bailey's chip (Commander/Extender) or TurboTweak chips are about the best you can get.
3.8L V-8 eater
Well-Known Member
- Joined
- Jul 22, 2006
As stated above get that stock chip out of there along with those old injectors..Don't have to go with 60lb injectors, but if you plan on modding up the car that is the way to go!! Eric at Turbo Tweak sells a package deal with 60's and the chip!! Good luck.......
as said above stock chip is too aggressive for todays gasoline get a TurboTweak Home chip and your car will love it. another thing do you know what kind of fuel pump you have?
good choice. you won't be disapointed..
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
What was the Ambient Temperature during those runs?
What Octane fuel?
Sounds like you have a Scanmaster so what were the Millivolts during those runs?
Have you ever cleaned your Stock Intercooler and does it still have the fan behind it?
While 14psi might not be a lot of boost, if it was 90 degrees +, you're running 91 Octane and your Millivolts are around 750 during that 3rd gear pull then I'd say, "There's your combo of doom".
BTW, the cold air kits only lower the temps a little, these get way too much credit for actually doing anything to MAT temps and allowing the engine to run safer at higher cylinder pressures.
What Octane fuel?
Sounds like you have a Scanmaster so what were the Millivolts during those runs?
Have you ever cleaned your Stock Intercooler and does it still have the fan behind it?
While 14psi might not be a lot of boost, if it was 90 degrees +, you're running 91 Octane and your Millivolts are around 750 during that 3rd gear pull then I'd say, "There's your combo of doom".
BTW, the cold air kits only lower the temps a little, these get way too much credit for actually doing anything to MAT temps and allowing the engine to run safer at higher cylinder pressures.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
Ya it's probably the combo of ambient temp, your vehicle weight, load in 3rd gear, maybe a dirty and less efficient Intercooler and 91 Octane that all together are playing a role in this. Your fueling is good, your Octane isn't, that's the easiest to change but obviously you're stuck with what the stations carry.
Clean out the IC, consider lowering the boost or timing (either Manual Boost Controller or Timing in Chip) and go from there. You can also add Alky to your car and have more headroom on knock with running an easy 19psi with the proper chip etc.
A side option is Lead Supreme 130, if you're on a test pipe and don't care about changing plugs more often it works, 100 Octane if you pour the whole bottle in.
I used to buy a case of this stuff and carry one in the trunk of my GTO for fuel ups, it works.
Clean out the IC, consider lowering the boost or timing (either Manual Boost Controller or Timing in Chip) and go from there. You can also add Alky to your car and have more headroom on knock with running an easy 19psi with the proper chip etc.
A side option is Lead Supreme 130, if you're on a test pipe and don't care about changing plugs more often it works, 100 Octane if you pour the whole bottle in.
I used to buy a case of this stuff and carry one in the trunk of my GTO for fuel ups, it works.hello back after my tt chip install and new 60lb injectors cleaned the intercooler and put it all back together . took it out for a coupler of runs got it up to about 70 in drive get in to it and im still getting some knock and my milivolts are low . i set my fuel pressure at 44 line off mr recall on my run was 710 milivolts and 2.6 kr this was at about 80 mph knock was coming down slowly as i was going faster . how to adjust milivolts and how can i get rid of this knock im running 93 oactane fuel now . any help is appreciated thanks
Too many variables still remain to pinpoint the issue, although I commend you for getting a new chip and 60# injectors. You can't "adjust" the millivolts per se. That is based on the oxygen sensor's readings and is a crude way of gauging how rich/lean you are running. Generally, a small increase in fuel pressure (1psi at a time) should make the car run a tad richer and raise your overall WOT millivolts. Speaking of which, what o2 sensor are you using?
-MAF readings?
-BLM readings?
-What boost are you running now?
-If you roll into the throttle vs. stabbing it at 70mph, do you still see knock? You could also have a false knock issue during the downshift.
-What is the condition of the motor mounts?
-fuel filter?
You need to back off on the boost and quit hammering the car or you're going to be learning how to change headgaskets too. Read over Eric's instructions and take advantage of the adjustable parameters in the chip, such as WOT fueling, etc. Another thing, each time you make any changes, unplug the ECM wire and let the chip re-learn the new parameters.
-MAF readings?
-BLM readings?
-What boost are you running now?
-If you roll into the throttle vs. stabbing it at 70mph, do you still see knock? You could also have a false knock issue during the downshift.
-What is the condition of the motor mounts?
-fuel filter?
You need to back off on the boost and quit hammering the car or you're going to be learning how to change headgaskets too. Read over Eric's instructions and take advantage of the adjustable parameters in the chip, such as WOT fueling, etc. Another thing, each time you make any changes, unplug the ECM wire and let the chip re-learn the new parameters.
Daniel Jost
Squirtin six
- Joined
- Oct 11, 2003
Another thing said:
i will get the maf and blm numbers at idle is that right ?now im running about 14 lbs of boost . kr and 02 readings are the same wether im stabbing it at 70 or rolling into it at 40.im running a bosch12013 sensor . i has a new fuel filter . thanks for everyones help
BoostedTtype
Member
- Joined
- Feb 18, 2008
A side option is Lead Supreme 130, if you're on a test pipe and don't care about changing plugs more often it works, 100 Octane if you pour the whole bottle in.
I thought that was just for bike engines.... What are the side effects if any??
True too. Go to the hardware store and buy a gallon or two of xylene and throw it in the tank. Try it again and see if you have knock. If not, then you know it is an octane or fuel supply issue. At least then you'll have it narrowed down.
I have gotten a bad tank of 93 octane before. The car basically acted like I put 86 octane in it or something; it was knocking like hell under boost. Just something else to consider.
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