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Need some ideas to prevent detonation

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Black Sunshine

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Joined
Aug 7, 2007
Messages
236
Hi, I've been having problems with detonation for years. Last year a vacuum leak was found that helped quite a bit but didn't go away completely. Now I got that RJC Boost controller and the knock goes through the roof. Can barely put the pedal halfway down until the knock reads about 6 degrees on my scanmaster. If I floor it it shoots to around 15-22 degrees! :eek: Other than the setup in my sig everything else is stock. I run Mobil premium gas. Thanks in advance. My trans is going bad and starting to slip don't want to fry the engine too. :frown:
 
Hi, I've been having problems with detonation for years. Last year a vacuum leak was found that helped quite a bit but didn't go away completely. Now I got that RJC Boost controller and the knock goes through the roof. Can barely put the pedal halfway down until the knock reads about 6 degrees on my scanmaster. If I floor it it shoots to around 15-22 degrees! :eek: Other than the setup in my sig everything else is stock. I run Mobil premium gas. Thanks in advance. My trans is going bad and starting to slip don't want to fry the engine too. :frown:


How much boost are you running?
 
Oh crap time for my inexpierence to shine

Umm... I never see it go past 12-14 on my VDO guage before I let off the gas, and that's if I floor it. It usually just shows 6-9 psi on the VDO when the pedal is pressed halfway. Don't really know how else to tell how much boost besides driving the car. The Ultra Chip limits how much boost can be used I think the max is 16 psi on the setting I use if I remember right. Can the turbo put out more boost than the chip allows? Maybe the wastegate is set wrong. Not sure haven't really messed with it cause I though the chip controlled boost output regardless what the wastegate was set at.
 
First get rid of that TPS enrichment doodad... could be puttin too much fuel causing rich knock, What is the timing on that caspers chip?

Does knock shoot right up or steady climb? DP hitting arm?
 
get another known good boost gauge first and verify that you actually seeing 13-14 psi of boost.


i have seen boost guage lines have a few kinks in them and they will be off several psi.


my firend yr ago had a 4.1 in his gn and it ran like hell @ 10psi but keep having a knocking isue to the point it broke 2 pistons. come ot find out the boost gauge line had 3 kinks in it under the dash.
 
ummm what's E85?

It's an alternative fuel you can buy for some vehicles...it's an ethonol type of fuel..

Does the knock start low and increase? or does a 6 just appear out of nowhere?

I agree...have you verified your downpipe isn't hitting the pass side upper control arm?

Maybe something rattling around that would cause the KR sensor to go off?

Have you tried racing fuel only in the tank?

How about alky injection?
 
get another known good boost gauge first and verify that you actually seeing 13-14 psi of boost.


i have seen boost guage lines have a few kinks in them and they will be off several psi.


my firend yr ago had a 4.1 in his gn and it ran like hell @ 10psi but keep having a knocking isue to the point it broke 2 pistons. come ot find out the boost gauge line had 3 kinks in it under the dash.

any idea of how much boost he was really running?
 
I don't think the dp hits the arm. It doesn't make any noises like that plus doesn't look like it trying to look under the hood. It's a sudden rise. Just high range knock instantly. I'm a bit too strapped for cash to get another VDO guage. It's only a couple years old anyways. I'm using what money I have fixing my emissions problem then working on this detonation. Oh yea the timing on the setting I use for the Casper's chip is 18. It knocks on the stock setting too which has a spark degree of 22. Nah haven't tried racing fuel yet. Just the 93 octane Mobil premium. No I don't have an Alky system yet.
 
Is the fuel pressure rising with the boost? The knock sensor might be bad, check those lines to the boost gauge,look at the plugs as you might have a clogged/malfunctioning injector and leaning one cyl(been there).
 
I don't think the dp hits the arm. It doesn't make any noises like that plus doesn't look like it trying to look under the hood. It's a sudden rise. Just high range knock instantly. I'm a bit too strapped for cash to get another VDO guage. It's only a couple years old anyways. I'm using what money I have fixing my emissions problem then working on this detonation. Oh yea the timing on the setting I use for the Casper's chip is 18. It knocks on the stock setting too which has a spark degree of 22. Nah haven't tried racing fuel yet. Just the 93 octane Mobil premium. No I don't have an Alky system yet.

timming set at 22 with 18#s of boost is high. timing should be around 20/18 if your running pump gas and no alky. that what my TT street chip was set for.
 
Yes fuel psi rises with boost as I push the gas. It does the same regardless if I have the stock setting of 22 spark degrees or setting 3 of 18. If the knock sensor is bad wouldn't it throw a code?
 
Yes fuel psi rises with boost as I push the gas. It does the same regardless if I have the stock setting of 22 spark degrees or setting 3 of 18. If the knock sensor is bad wouldn't it throw a code?

Wendy was making a funny... remove knock sensor and wala no knock:p

Remove that TPS enrichment part and take it for a drive.
 
I know, I was responding to ITSAV6 who suggested the sensor itself may be bad. I'll try unplugging the TPS-TEC in a little while. I gotta take it to take my 3rd emission test in a bit anyways. :frown:
 
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