monsterjam5000

i have a 1991 firebird with a 1994 lt1, i want to switch to a obd 2 computer, what all is involved in doing this, can this be done?


if not i would like to switch to a obd 2 plug and use the obd 1 computer, the local speed shop told me to get rid of the obd 1 plug.

they said to switch to obd 2 plug and use my obd 1 computer or switch everything to obd 2.


i would like to do what ever is the easiest, so that i can get my car tuned.

monsterjam5000

anybody

Z28ricer

iTrader: (2)

Just install the OBDII port, its that simple.

Although if your source for getting it tuned doesnt even have the cable to hookup to both, or enough brainpower to workaround this, I wouldnt be getting a tune from them anyway.

86White_T/A305

^^^^+1

And for the record..switching your diagnostic plug from obd1 to obd2 doesnt change the way the ecu needs to be tuned..its still an obd1 ecu with different end on the obd port.If the tuner doesnt have an obd1 conector..I bet he doesnt have the ability to tune anything older than 92+ with an obd2 ecu anyway. Which at that point means 0 experience on your style motor which to me means..Im shopping elsewhere.Just my .2

Z28ricer

iTrader: (2)

His reason for asking is because 94/95 LT1 pcms were odd, they had the obdI connector in car generally, but have the ability to use the obdII, but you have to change the connector.

86White_T/A305

I forgot those yrs were odd ball for ecu style.Then at that point the easiest cheapest way is switching ports.I know there are adapters you can buy $10 but do not recall if all the serial data wires are present on that specific obd1 port.Its been a long time since Ive dealt with obd1 anything lol.

monsterjam5000

how can you tell what pcm you are useing?

the guy i bought the motor from said its a 1994 but a lot of thing are leading me to think its a 1995, if its a 1995 it may have the obd2 computer in it.

if there a number on the computer that will tell me what it is?

86White_T/A305

should be a model number on the ecu casing, you have a good chance its a ob2 ecu with the obd1 port.

vetteoz

iTrader: (13)

"The 1994-95 ECM numbers are either 16181333 or 16188051.
1995 LT1 used an OBD2 port, but were not OBD2 vehicles. These did not have a Serial Data on Pin 2. These used pin 9.
In 1996 the ECM numbers are either 16214399 or 16242921, this is the first true year of the OBD2 systems"

Why?
Most OBDII owners wanting to do tuning mods change back to OBDI because the tuning software is cheaper and for tuning ease
https://www.thirdgen.org/forums/post...402-post9.html
https://www.thirdgen.org/forums/post...164-post4.html

86White_T/A305

Sounds like his local tuner would prefer odb2 in order to tune the car.But Id really be asking if the tuner knows his lt1's first before spending a dime.Sorry id still suggest finding another tuner that doesnt require you to change the setup just to get on the rollers.

Lets say you change to obd2 and bring the car to them based on their recommendation,do they offer any guarantee it can be tuned properly or if they get the tune wrong and pop the motor chances are they send you on your way very unhappy customer.

What is your setup anyway,stock lt1..heads cam?

monsterjam5000

i have a lt1 with the lt4 heads and cam, nothing fancy i just got a deal on the stuff and thought i would put it together

this is the only shop i could find in the area i live, i went back to the shop and was told they do not have obd 1 software any more they only deal with the obd2 software and that they mostly work on LS platforms not LT platforms

Z28ricer

iTrader: (2)

The LT1 obdII software is different than OBDI, and different from LS1 software, are you sure they even have OBDII LT1 pcm software ?

You can buy tunercat and the definition files cheap for the LT1 OBDI, I would suggest checking to see if they would tune it that way if you have the software and bring in your laptop. Then you get the software for later work.

86White_T/A305

If anything since they deal mostly with ls stuff might be worth your time to send the ecm out for a mail order base tune from a reputable tuner which wont cost alot.This will atleast get you to safely drive around,set whatever parameters you need untill someone can dynotune the motor for fine details.Check ls1tech etc sites for standup guys who tune ltx and turn around time is pretty quick too.