hrcslam

This is just a basic explanation of what is needed to get data logging on an OBD1 LT1. I see many guys trying to fix something on their car, but don't have a way to access the PCM on their car to look up codes or see what is going on with the engine. So I thought this may help. I'm not going to provide any direct links, Google is your friend.

To most people, a computer on a car is voodoo. But, for us LT1 guys having the ability to access the information on the PCM is crucial. Unfortunately, most places (even some GM dealerships) lack the equipment to properly access the PCM (especially the 95 cars). This leaves many of us in a tight spot. At least it seems that way; it's not.

Thanks to LT1 addicts and tech guru's that are also members here and on other LT1/Camaro/Firebird forums like Gary Doug and Steveo_ (among others), this problem isn't any more. All you need is an ALDL cable and a laptop and what you can access in the PCM is beyond what most dealerships and certainly all Auto Parts stores can offer to any customer of any car.

So what do you need? First you need the ALDL cable. There's 2 types (well actually 3). The first one is a 12 Pin ALDL, the second is a 16 Pin ALDL (the third is a combination of both a 12 pin and 16 pin). All the cables should have the ALDL connector on one end and a USB connector on the other. The cable you need will depend on the connector in your car, which changed over the 3 year F-Body OBD1 LT1 run. The easiest way to find out which connector you need is to look under the drivers side dash and look at the ALDL plug. The 12 pin will have 12 holes in it and be rectangular (6 pins on top and 6 pins on bottom). The 16 pin will have 16 holes in it (8 on top and 8 on the bottom) and be trapezoidal in shape. A simple Google search for "12 Pin ALDL Cable" or "16 Pin ALDL Cable" should get you to the results you seek, add in LT1 to the Google search if you doubt the results shown. Expect to spend about $60 for the cable and the driver software that should come with the cable.

Now that you have the cable, you need a computer. Most of us now days have a laptop already so this is really a non-expense to us. If you don't already have a laptop go get one. It doesn't have to be fancy or expensive, Craigslist is your friend. All it needs is Windows XP or newer (so pretty old) and at least 1 USB port, having a good working battery is a very nice bonus but not needed as you can leave it plugged in and run the laptop off an extension cord (if not driving). If you need to drive for a datalog, you'll want the battery. If the laptop you bought is so old they no longer make the battery or it's unavailable, get a 12V to 120V inverter from a local parts store or bargain store (I'd make sure it's rated to about 150W at least) so you can plug in the laptop to the car 12V outlet.

Last, you need the Data Logging program. There's many options available, but the ones I use are Scan9495.exe (by Gary Doug) and EEHack (by Steveo_). Both of these programs work great and best of all are free, but donations are certainly nice to give those guys. Google search any one of these programs to find where to download them.

Now that you have everything you need, you need to get them to all work together. First install the Cable and device driver to your laptop. Then install the data logging program to the laptop. Then connect the cable to the laptop and car and turn everything on; car (usually it's running at this point), laptop, program. The car will not automatically connect to the data logger on the first try. You will have to select the Com Port following the instructions from the Data Logging program you decided to use. Then it should connect. From there you'll see the program doing what it does, data logging.

Understanding what the data logger is showing you takes sometime, and it will come as you continue to use it. But, you don't learn a new language without first listening to and reading it, same goes here. If everything is hooked up correctly, you wont hurt the engine by monitoring what it's doing. There's plenty of guys here (and other forums) that are willing to help read the data logs if you can't, just post em up.

So there you have it. For $60 (sometimes less, if you know how to solder- see below), you can be data logging away. The best part is that if you're a 94-95 car, you're a free program away from Tuning the car (you may need to get a Flash program to load the tunes you do, but that should run $20 IIRC -WinFlash from TunerCats. Although EEHack does have Flash capability for free). But, for $60 what you get is the ability to not just pull codes, but see everything the PCM (and even more for some programs; like Scan9495 can do ABS and SIR too! This is great for bleeding the brake system after an ABS module change as almost no one will have the ability to do it correctly) is seeing to properly diagnose your car.

This really is a necessity for anyone with an OBD1 LT1 vehicle. It's not expensive and will make your life much easier.

Note: If anyone wants to add or correct anything stated here please do so below and I'll quote it into this first post. Thanks!

Here's how to do the USB Solder Mod to those savy enough to do it. Thanks Englundjd!

AINT SKEERED

iTrader: (2)

thanks. I have tuner cat for my dads old Malibu with a obd1 lt1 setup. never been able to data log, the cables I use for tuner cat seem like the same ones needed for this data logger correct?

hrcslam

Yes. Same cable.

BTC

I finally broke down and bought a laptop from Microsoft over Black Friday, along with an ALDL cable. I downloaded Scan9495, which also works for 93's.

You can find decent deals on laptops by keeping an eye on SlickDeals.net

It was very simple to use after getting a laptop, cable and software. It's kind of cool to see all of the information that is available.

myltwon

iTrader: (1)

Thanks for posting, definitely helps break the mental hurdle many of us have towards the pcm.

94zpearce

Nice write up. Great for newbies trying to figure this out.

Prototype007

iTrader: (2)

Sad that a write up is even needed for this, but great job nonetheless!

94zpearce

This site is here for the real gearheads to share their knowledge and opinions with each other and anyone willing to put in some wrench time to make their car their own. Don't knock people for wanting to learn the right way to do things.

My 2¢

englundjd

for those that are good with a soldering iron... you can make your own ALDL cord real cheap. you need two wires( i used some 18 gauge wire about 6' each), a usb to micro usb (same cord that most digital cameras use), and a FT232RL FTDI USB to TTL Serial Adapter Module ( is the one I used)

Now all you have to do is solder a wire to the ground prong on the chip, then solder the RX and TX prongs together with a wire, then connect the rx/tx wire to the data wire in your ALDL port and connect the ground wire to the ground wire in your ALDL port. pretty easy. MAKE SURE YOUR CONNECTIONS ARE GOOD!!!! A bad connection can ruin your pcm if your in the middle of uploading a new tune...

hrcslam

I think he's saying that it should go without saying that you'd need the necessary tools to access the PCM on your car, and that I shouldn't need to even make this write up. I understand his position, but disagree.

I made this write up because I have accepted that there are a lot of younger guys buying up LT1 F-Bodies. I can't blame them either, the $/performance bargain is easily at the top of any list. However, many people buying these cars don't realize that the LT1 is something special; Optispark, Reverse Cooling, and OBD1 with chip/OBD1 w/o chip/OBD1 with OBD2 Port. Combine all these things and you end up with a lot of questions without a lot of the typical support to properly diagnose it.

The programs I mentioned here (and others) are not commonly known to people new to the LT1. Add in that they don't know that they need them to even access the Error Codes (95 LT1) and it leaves people frustrated.

Then they end up here, asking questions to LT1 "guys" hoping for simple straight forward answers. Instead they often get "You should datalog it". But, they don't know the first thing needed to do so. I've explained how to do this so many times in so many threads I decided it deserved it's own thread. And here we are.

Everyone is entitled to their own opinion, and I respect that and appreciate any and all input.

Honestly though, the main reason I made this thread was so I can hyperlink it in other threads to guys asking questions requiring a data log. LOL. So it was mostly selfish because I didn't want to keep typing the same thing over and over again.

stevo9389

This should be sticky material since useful threads get buried really easily under pages of subjects that have been beaten to death. Not like many newbs read those either but it would be easy to find.

BTC

I think a lot of people avoid doing this because they don't know how simple it is. It's probably the easiest thing you'll ever do on these cars.

94zpearce

If you've got a soldering iron, their really not hard to make.

Prototype007

iTrader: (2)

Get a little more bent out of shape for me please.

Anyone that's truly dedicated to doing something right will RESEARCH and not feel their entitled to information just being spoon fed to them.

Welcome to being a real gear head and the price that comes with it.

94zpearce

Not trying to start a pissing match here, but I would say coming to an LT1 specific forum for helpful information counts as doing research. I don't know about you, but working 60 hours a week hard labor doesn't exactly give me a lot of free time to learn all there is to know about data logging. Sorry for defending the newbs..

chevyn8

Your so smart Jon, how did you figure that out???