LT1 tunning issues.. please help
10-25-2008, 11:46 AM
#1
Registered User
Thread Starter
Join Date: Apr 2008
Location: Pittsburgh PA
Posts: 15
LT1 tunning issues.. please help
This is a brand new rebuilt LTx engine (97 engine/harness, 94 computer OBD1 PCM pre tuned for the specs of the engine, and its also is in my 86 Camaro) I built from the bottom up... I just started it and did the break-in process the other day and everything seems to be going good excecpt for a few small tuning things that I was hoping someone could help me diagnose and fix.... First when I go to start the car i have to have the butterflys on the TB open a bit then it will start and idle at around 800rpms on the 3rd gen tach. The car is running rich and seems to have a small miss. My dis-4 light shows a constant red light, then a small flicker which indicates to me the miss. But when the car is reved up and kept at a constant higher RPM range the miss is gone. Could the break in of the car with the fuel running rich foul the plugs? or should I try putting in a new IAC sensor in? (i used the original iac off the motor when i purchased it to save money, so should i get a new one from GM?) So should I change the plugs and the iac, start it up again and see what happens? Or does anyone think this problem might be due to something else? Thanks a lot for your help.. .and heres a few engine specs on my motor and other info that may help.
-im not running the opti, I have a delteq setup through an MSD Dis-4 ign. module.
-when I checked the fuel pressure, its at around 45psi, then when reved up goes to 50psi, but does not exceed 50psi.
-the fuel injectors I'm running are 30lb ford SVOs
-I'm running 3rd gen Hooker Lung tubes, with an add on piece to the collector with O2 sensors in that piece.
-im not running the opti, I have a delteq setup through an MSD Dis-4 ign. module.
-when I checked the fuel pressure, its at around 45psi, then when reved up goes to 50psi, but does not exceed 50psi.
-the fuel injectors I'm running are 30lb ford SVOs
-I'm running 3rd gen Hooker Lung tubes, with an add on piece to the collector with O2 sensors in that piece.
10-27-2008, 07:18 AM
#2
Registered User
Join Date: Oct 2004
Location: Houston, TX
Posts: 809
This is a brand new rebuilt LTx engine (97 engine/harness, 94 computer OBD1 PCM pre tuned for the specs of the engine, and its also is in my 86 Camaro) I built from the bottom up... I just started it and did the break-in process the other day and everything seems to be going good excecpt for a few small tuning things that I was hoping someone could help me diagnose and fix.... First when I go to start the car i have to have the butterflys on the TB open a bit then it will start and idle at around 800rpms on the 3rd gen tach. The car is running rich and seems to have a small miss. My dis-4 light shows a constant red light, then a small flicker which indicates to me the miss. But when the car is reved up and kept at a constant higher RPM range the miss is gone. Could the break in of the car with the fuel running rich foul the plugs? or should I try putting in a new IAC sensor in? (i used the original iac off the motor when i purchased it to save money, so should i get a new one from GM?) So should I change the plugs and the iac, start it up again and see what happens? Or does anyone think this problem might be due to something else? Thanks a lot for your help.. .and heres a few engine specs on my motor and other info that may help.
-im not running the opti, I have a delteq setup through an MSD Dis-4 ign. module.
-when I checked the fuel pressure, its at around 45psi, then when reved up goes to 50psi, but does not exceed 50psi.
-the fuel injectors I'm running are 30lb ford SVOs
-I'm running 3rd gen Hooker Lung tubes, with an add on piece to the collector with O2 sensors in that piece.
-im not running the opti, I have a delteq setup through an MSD Dis-4 ign. module.
-when I checked the fuel pressure, its at around 45psi, then when reved up goes to 50psi, but does not exceed 50psi.
-the fuel injectors I'm running are 30lb ford SVOs
-I'm running 3rd gen Hooker Lung tubes, with an add on piece to the collector with O2 sensors in that piece.
10-27-2008, 07:53 AM
#3
Registered User
Join Date: Jul 2002
Location: Phoenix, AZ
Posts: 1,277
Listen to Dave. You are asking alot from a distance with minimal information diagnostically.
Sadly, we don't know what you changed with the rebuild. My first thought however is the TB is not allowing enough air in at startup. Cracking the blades is a short term answer but may work.
Sadly, we don't know what you changed with the rebuild. My first thought however is the TB is not allowing enough air in at startup. Cracking the blades is a short term answer but may work.
10-27-2008, 03:25 PM
#4
Registered User
Thread Starter
Join Date: Apr 2008
Location: Pittsburgh PA
Posts: 15
thats true, i do have to crack the TB a little at start up for it to fire up, and yes the PCM was tuned for the SVO injectors, i had the computer tuned for everything I did to my engine. diagnotics, i havent been able to get a read from my computer, for some reason it will not communicate with diagnostic because the harness is a 97 harness with the OBDII connector, and the computer is a 94 computer and I just havent been able to get a read off the computer yet.
Thread
Thread Starter
Forum
Replies
Last Post
Cam95aro
Show and Shine / Paint and Body Care
5
09-01-2001 10:35 PM