driving a fast 90/LS2 TB Setup untuned?
Thread Starter
Pro
Joined: Aug 2007
Posts: 619
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From: ATLANTA GA
driving a fast 90/LS2 TB Setup untuned?
Ive been driving it for a bout 80 miles untuned, Here lately its gotten to where the throttle is almost "dead"
Like you push the accelerator and nothing happens for a second then al lthe sudden it comes alive. it works if you variablely play with the throttle and it seems like its responsive when u blip the thottle in other words it goes up and down like its suppose to.
is some of my driveability issues due to not having a tune and running the 90MM ls2 throttle body?
Like you push the accelerator and nothing happens for a second then al lthe sudden it comes alive. it works if you variablely play with the throttle and it seems like its responsive when u blip the thottle in other words it goes up and down like its suppose to.
is some of my driveability issues due to not having a tune and running the 90MM ls2 throttle body?
Burning Brakes
Joined: Mar 2008
Posts: 983
Likes: 36
From: Middle Of Kali CA
Is it still a Drive By Wire Pedal and TB? If it is getting worse a tune might not be the issue unless something else has changed. Is it just throttle response or other drivability issues?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Unless you get it tnned, the VE tables are all wrong! Until the VE tables are correct, you will have driveability issues. The fast 90 has MUCH more TB surface area when the throttle is opned.
Do you hava any DTCs ???????????????
BC
Do you hava any DTCs ???????????????
BC
Thread Starter
Pro
Joined: Aug 2007
Posts: 619
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From: ATLANTA GA
My driveability issues are:
Im crusing in 6th at 1500 and if i lay my foot on the accelerator all the way it begings to surge really badly almost like a plug is out??
Its stalling out everywhere i let the clutch out. I pull off at a light and the car doesnt like want to go anywhere... Its actually kinda dangerous its like it the throttle just doesnt work If i push the clutch in and rev it up some i can get it to move and drive away
Another thing its doing if I get on it in 1st(testing that sputtering probem) It wont sputter/miss but I swear when i get on it its like its dead in the upper throttle ranges.
When i first started the car up and went on an innitial drive i didnt notice all this..
I guess what im trying to say here is is this common? If theres an issue somewhere I guess i need to correct it before it goes into the tuner.
Last edited by vettekidc5; Sep 10, 2008 at 02:42 AM.
Burning Brakes
Joined: Aug 2006
Posts: 956
Likes: 12
From: Eastern PA
You need a tune, there is so much more air to deal with now. As mentioned earlier you VE tables are off. Going from a 78mm to 90 mm makes a difference. This is also going to sound really stupid but going from the LS1 TB to LS 2 TB, did you use the proper harness? This affects throttle position.
If you take it to a tuner I'm sure that your issues would go away.
If you take it to a tuner I'm sure that your issues would go away.
Race Director
Joined: Mar 2001
Posts: 11,405
Likes: 26
From: Whippany NJ
CI 6-7-8-9 Veteran
St. Jude Donor '08-'09
NCM Sinkhole Donor
You need a tune, there is so much more air to deal with now. As mentioned earlier you VE tables are off. Going from a 78mm to 90 mm makes a difference. This is also going to sound really stupid but going from the LS1 TB to LS 2 TB, did you use the proper harness? This affects throttle position.
If you take it to a tuner I'm sure that your issues would go away.
If you take it to a tuner I'm sure that your issues would go away.
I had to buy a LS2 TB conversion harness to work with my oem wires. Get a tune
Thread Starter
Pro
Joined: Aug 2007
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From: ATLANTA GA
ok I found out where all my midrange problems came from, Last night The coupler at the maf popped off, so I was running filterless, non metered air.. Great LOL.
That was the reason for the stalling, part throttle surging and the fact it wouldnt go anywhere.
reconnected it and its back to normal, the throttle seems to work good and everyything so im assumeing its wired properly. It does need a tune though.
Has anyone noticed the LS2 throttle body response is slower than the LS1? i read where someone changed a value in the PCM on the tune and got better response
That was the reason for the stalling, part throttle surging and the fact it wouldnt go anywhere.
reconnected it and its back to normal, the throttle seems to work good and everyything so im assumeing its wired properly. It does need a tune though.
Has anyone noticed the LS2 throttle body response is slower than the LS1? i read where someone changed a value in the PCM on the tune and got better response
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You should up-date your personal data and add where you live. A good tuner can take care of all your issues. Yes, the trottle will be a LOT more responsive with the proper tune. If you post where you live, we can recommend a TUNER or list the tuners that you should consider.
Dont try to correct this issue with a hand held tuner. It will NOT work. You need someone with EFI Live or HP Tuners to get the job done.
Bill
BC
Dont try to correct this issue with a hand held tuner. It will NOT work. You need someone with EFI Live or HP Tuners to get the job done.
Bill
BC
Burning Brakes
Joined: Aug 2006
Posts: 956
Likes: 12
From: Eastern PA
ok I found out where all my midrange problems came from, Last night The coupler at the maf popped off, so I was running filterless, non metered air.. Great LOL.
Cool
Has anyone noticed the LS2 throttle body response is slower than the LS1? i read where someone changed a value in the PCM on the tune and got better response
Cool
Has anyone noticed the LS2 throttle body response is slower than the LS1? i read where someone changed a value in the PCM on the tune and got better response
Instructor
Joined: Oct 2003
Posts: 111
Likes: 0
From: Chandler AZ
do you have any other mods? I have a large cam with the 90/90 and on my last dyno/tune I was told the surge at idle is a problem with my set up.
Mine drives fine but when i come to a stop I get idle fluctuation from about 500-1200rpm 2-3 times. if I give a quick blip of the peddle it will stop faster.
Mine drives fine but when i come to a stop I get idle fluctuation from about 500-1200rpm 2-3 times. if I give a quick blip of the peddle it will stop faster.
Burning Brakes
Joined: Aug 2006
Posts: 956
Likes: 12
From: Eastern PA
No issues
do you have any other mods? I have a large cam with the 90/90 and on my last dyno/tune I was told the surge at idle is a problem with my set up.
Mine drives fine but when i come to a stop I get idle fluctuation from about 500-1200rpm 2-3 times. if I give a quick blip of the peddle it will stop faster.
Mine drives fine but when i come to a stop I get idle fluctuation from about 500-1200rpm 2-3 times. if I give a quick blip of the peddle it will stop faster.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Honestly with the LS2 TB, your throttle response should be way quicker than the LS1. 1st time I drove the car after putting in the LS2 TB it was like night and day. I barely touched the gas and off I went. Like you mentioned in your post, when you get it tuned you will see how much of an improvement that will make with the response.
There is enough info about an unported LS2 tb, is very sluggish and that they are not worth changing too. Now a PP LS2 tb that is different.
and yes any major changes like these needs a tune, maybe two or three times with a some good driving in between.
Burning Brakes
Joined: Aug 2006
Posts: 956
Likes: 12
From: Eastern PA
AU I guess the more I think about it I may have spoken without sufficient detail. Being that my LS2 TB is ported my experience has been a quicker throttle response than previously so thank you for clarifying that.
