Drakar

My Dad and I are currently wrecking a 96 Roadmaster wagon for parts for his and the LT1 is going to be dropped into my 85Z, trouble is no computer was in the car (previous owner took it) so My question is which computer should I go with?

I can get any year pretty easy and pretty cheap but want to the know the advantages and disadvantages.

I always see most people go with OBDI 94-95 instead of 96-97 OBDII is there any reason besides an extra sensor and 2 more O2 sensors.???

TexasLT1

'94 or '95 is the way to go because they are the OBD1 computers, while '96 and up is all OBD2. OBD1 is much more responsive to mods and doesn't require the same amount of programming for the slightest change to the engine, OBD1 can account for mods to some extent.

84'fxrupr

how do these work. I was planning on going headers to mufflers(Kansas has no emissions). I thought that the sensors were in the cats. How would i mod this?

Drakar

O2 sensors (Texas correct me if im wrong) work best in the collector of the header or manifold, they provide data back to the computer telling if it is rich or lean and adjusting the fuel accordingly, if you have no O2's it will run like **** and you will end up with mileage worse then a poor tuned carb.




Also Does it matter if I start with a computer from an M6 or A4 car or if it is one from a buick as well, if I plan on using my T-5 and then a T-56. or should I look for one from an M6 Z or T/A?

Trans Am#5

I used a '95 9C1 Caprice computer. My car has a t56 and the computer was for a 4l60e. It started the car and it did drive but not too good until I had Ion reprogram it. Now it's fantastic.

ShiftyCapone

iTrader: (7)

He hit it on the head. OBD1 doesn't have to worry about rear O2's and is way more responsive to mods. Lots of '96 and '97 fourth gen guys convert back to OBD1. I know '93's use a PROM just like a thirdgen set up but I have no idea how easy it is to reprogram but I don't think it likes mods. You can throw a full exhaust and a mild cam ay an OBD1 set yp and have it run pretty good. It's best to have any computer changed when the car that is is running in has been modded but it will adjust to some extent.

cd90rs

OBDII can be programmed the same for mod-wise same as an OBD1. The rear two O2's are a non issue because you simply delete them in programming. It is more expensive to have someone program a OBD2 pcm. The main reason people use OBD1's is because it is cheaper to have someone program them and the software to do it yourself is MUCH cheaper too.

TexasLT1

Yes, but thats not what we were saying. OBD1 is more responsive to mods is what we are saying, whereas OBD2 must be programmed for the slightest mods. Yes, it can be programmed just the same, but you have to do it for fewer mods is all we meant.

TexasLT1

Correct, the O2's should be placed as close to the exhaust ports as possible, one in each header preferably, and provide info to the ECM. The farther away from the ports you get, the longer it takes for the O2 to heat up, or if they are heated, the less accurately they read the exhaust. Trust me, you will know pretty quickly when you lose an O2, all of a sudden your car starts running like complete junk. First thing you should check when that happens is the O2's



I ran my car for quite a few months with an A4 program in the computer even though I had a T-5. Once I got the right program, however, it idled correctly and it stopped throwing codes for the transmission that wasn't there.

Drakar

Sounds good, looks like Ill start the search for a 94/95 M6 computer. Thanks for the starter, ill be back with more Q's no doubt as I progress this winter.