Dr. Teeth

Tried the search function but found nothing useful. Anyone know what exactly is entailled in switching from obdii to obdi? So far i hear the o2 sensors and the main computer and that I can keep the harness.

Anyone do this?

Thanks in advance for any help fellas.

SS RRR

02 sensors do not need to be changed. Only thing that needs to be changed is the knock sensor (NOT the module) and swap for a OBDI PCM, of course.
Why would you want to do this?

IDAREU

Nothing needs to be changed....

http://www.madtuner.com/index.php?pa...mart&Itemid=26

sbs

Well, yes, if you'd rather pay $250 for a modified PCM instead of $50 for a stock PCM and $20 for a knock sensor...

SS RRR

lol... indeed.

Dr. Teeth

I have a 96WS6 now, and I am planning to put an LT1 into my wife's project car (67 Chevy II) and I feel that the software to tune multi-pcm obdii's is too cost prohibitive. LT1edit looks like a great program, but the punitive cost of the obdii tuner (or the Jet performance tuner) is insulting to me. I guess I feel fleeced by the cost difference.

Most of the reading I do also for the LT1 tuning relates to the obdi tuner. I live in Michigan in the extreme Northern area of the Lower Peninsula and the performance crowd up here is limited, so I am a minority and dyno tuning involves trailering the car 300 miles to a shop, leaving it, and returning. This weekend I am swapping rearends to a 4.10, and now I'll have a speedo out of calibration. I have another compter, but when I put major mods on it will be more of a headache.

The Engineer

The mail-order tunes (i.e. PCMforLess) for the OBD-II systems perform extremely well and are an inexpensive alternative to dyno tuning, or purchasing your own edit.

Personally, I like the OBD-II system best along with the PCM tuning format.

WD

IDAREU

Well lets see 50 for a pcm you buy from someone that "may" have issues, 20 for the sensor, and then you'd have to pay for a tune for ~125 unless you have tunercat and know what you're doing, then unless you know someone with correct Cable you'd have to buy that for 90. So instead of jacking up my car to remove the sensor I can just unplugged the stock PCM (which you have to do anyways)and plug in a Tuned One that I know will work and I can switch it back just as easily if i want to sell it, or in my case pass Inspection/smog? Not such a bad price IMO. I'm happy with mine and I think it's worth the money.

Tricked-Out-Toy

I personally didnt want to have swap in and out the knock sensor if I ever wanted to swap back to OBD2 so what you do is head down to radio shack and pick up a 3.9K ohm resistor. Open up your OBD1 pcm and solder the BLue pin 22 and 21 together with one end of the resistor and solder the other end to the PCm ground. worked like a charm and cost about $20.50 including the PCM. and I can swap to OBD2 whenever I want. when you get yoru ALDL cable made make sure they know your using an OBD2 connector and a OBD1 PCM.

EDIT: My reason was I already had TunerCats for my TPI setup and couldnt see shelling out the money for LT1edit when 20 bucks later I had the ability to tune. The cable was something I needed to buy anyway to datalog.

sbs

He's doing the swap so he can tune it (which is the usual reason why people do this swap) so he's paying for tunercat and a cable either way. Hopefully he won't spend $90 on a cable that can be bought for half that, or built for $5.

As someone else said, if you want the modified PCM instead of changing the knock sensor you can modify it yourself with a resistor. That will cost you about $2 if you have to buy the resistor from Radio Shack.

Apparently you're the kind of person who would prefer to pay a lot more $ to have some assurance that something was done correctly and to avoid jacking up your car and unscrewing a sensor. There's nothing wrong with that. But I think most people on this board are looking for more economical solutions and aren't adverse to jacking up their car to work on it.

Since you don't do tuning, why did you do the swap?

Dr. Teeth

That piques my attention. Can you explain this to me? PM if you'd like. I would always rather put together a kit....

Thanks

stereomandan

Here is how you can get a OBDI PCM and modify it so that you don't have to swap knock sensors. Completely seemless. It's what I have.

http://web.camaross.com/forums/showthread.php?t=519946

Dan

sbs

It's been a few years since I was shopping for cables, so I don't know what all is currently available. But looking at this one source:
http://www.akmcables.com/ic.htm

you can get an assembled cable for $50-120 depending on how fancy of one you want or a kit for $35.

If you are comfortable with building from schematics, the parts to build one will run you $5 or so. There are several schematics on the web. I modified an existing MAX232 schematic to use the MAX233:

https://lh4.googleusercontent.com/-f...o/aldl_sch.png
You can get free samples of the MAX232/233/etc from Maxim.

If you're going to use it a lot, you'll want to get an actual OBD connector. I eventually bought a molded connector+cable from http://www.obd2cables.com/products/ for about $10, but haven't yet gotten around to hooking it up.

Tricked-Out-Toy

I bought my cable for 90 and it was worth it to me since I didnt have time before my trip to build and test a home built cable. It had the USB connection instead of the serial and the obd2 plug it was extremely well put together and very durable, if I had to do it all over again I still would have bought the cable pre-made. I just didnt want to have any problems loading a tune and having an issue mid download and loosing the PCM. I worked hard soldering two connections and spent damn good money on a 4 pack or resistors