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Discussion Starter #1
Ok guys it's been a long time since my car was "done" but I recently decided to make some changes to things I wasn't happy with after 5yrs. So I pulled out the old LT1 edit and cables and my Win7 laptop and proceeded to reflash the pcm. Half way thru it stopped communicating and tried to recover but couldn't. Eventually it timed out and the cooling fans stayed on and then a no start condition. Haven't been able to recover it so I gave up..:|.

So I got a replacement pcm and installed it and now it's running again, but barely. I have a highly modified 383 and I need to get my base tune loaded on the new pcm.

The problem I have is lt1edit won't connect because the VIN on the new pcm is different. I can't get my base tune back on to make it run right and I can't pass emissions with the wrong VIN listed.

How do I fix this?
 

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Ditch lt1edit and get TunerPro and eehack. Find the correct $ee definition file online and then tune & flash to your heart's content. Both of those programs are free.

Before you go down that road, figure out why the last PCM bricked. Do you have a top-quality cable? I bricked two PCM's and it was because I was using a cheap cable that was using fake FTDI chips. Bought a high-quality cable and have been a happy camper ever since.
 

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If you wish to save your old pcm, you need to install & program new chips. These are available to the general public. At least once you find out the chip number.

To accomplish this go to the "gearheadefi" forum. These guys are really into tuning and someone will know chip number or send you to a site that lists GM chips.
 

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Discussion Starter #5
Guys thanks for the feedback.. I realized after I posted that I didn't mention that my car is obd2 since it's a 97. I thought it might have stood out on my profile.

I have seen the tunerpro and eehack software and have been really envious of you obd1guys for years .

I had done 2 successful flashes that day and then the last tweak I wanted to make failed. I've had my cables and Edit for almost 10 years and never had a problem.. Only thing in my equation that changed is my laptop. My old XP laptop died years ago and since my car has been done for a long time I had no reason to worry about Windows 7 8 10 etc and a usb to serial adapter.. So I'm going to see about getting my hands on a older laptop with xp and serial port.

To make this all more frustrating, the guys that did my dyno tune(years ago) won't even talk LT1 now.

Does anyone know if there is a batch file or utility that can be used to change the vin?
 

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that sucks

i think that CATS tuner (now JET DST) for OBD-II can do the vin change thing for you for 300 bucks..

.. or can't the LT1edit author help you out in this case? you did pay for his software..

alternatively, 6 speed cars are easily converted to OBD-I ecms so you have access to better tools and less BS for free or cheap

flashing does fail sometimes, but at least with obd-i kit you just get another wrecker ecm for a hundred bucks or so and be done with it, or solder some sockets into it
 

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Discussion Starter #7
Steveo I just registered with your site and starting to research the whole obd1 switch. A few things I have to convince my self of:
1: I paid a lot of money for Dyno sessions to get the car tuned right years ago 'cause I ain't no hacker,,haha. I do have that tune saved on my laptop, but I think it would be a .lt1 file now since I saved it with Edit.. Will I be able to get that back onto or will it even work on a obd1 pcm?

2: if the answer to 1 is no, do I want to endlessly play with tuning to start from scratch? (Not really) I've been driving my car for years and enjoy it... Kinda done with the experimental lifestyle. The whole reason I'm in this mess is because I got tired of the game with O2 sensors and Long tube headers and insufficient switching dtc's. I decided to remove them and go with short headers and wanted to reset the o2delay settings... I should have left it alone.

3: I read on fbody. That besides the knock sensor change, the only issue may be with the BCM. What kind of issues? I was really careful to make sure that when I did my car that everything worked just as the factory intended ( except for the periodic o2 dtc, every couple months). Issues with the BCM make me worry that stuff won't work right. Last summer I had no issues. This summer 3 times it lit up the SES all from the 02s.

I just want to drive it... They're no fun if they are parked and apart all the time.

And last, and most serious... If I convert it, I will have to swap it back to obd2 every 2 years because in Illinois. we have to do emission tests every 2 years.. Which means more jacking around with it.... Grrrrr?
 

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So in Il. even cars that are old enough to be emission exempt in most states have to be tested! How old must a car be to be exempt?

Actually, going back to obd 2 from obd 1 isn't that bad. Both types on lt1 cars have the same computer connectors that hook to the same functions. The obd 1 computer simply ignores the extra obd 2 wires in your obd 2 engine/trans harness.

So for emission testing just plug your obd 2 computer back in. Hopefully your tune in the obd 2 will pass tests.
 

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Discussion Starter #9 (Edited)
Emission testing in Illinois is a pain, but easy to deal with, mostly. They used to do a tailpipe sniff and visual inspection on carbureted cars all the way through the obd1 efi era. As EFI advanced and obd2 evolved, they just plug in to the Aldl and scan for codes, and test the gas cap. As long as the pcm is happy the state is happy. So only obd2 cars are tested. I'm pretty sure the mandatory year is 1996 and newer. My car has never had a problem passing ��

The other issue is they only test in a few areas. The 6 counties around Chicago and a handful of counties around the St Louis area. I live about 50miles south of Chicago and have to test. They tie it to the license plate.. No successful test? No sticker...

As far as the obd1/2 knock sensor issue, I read about some guys doing the resistor mod. I thought maybe building a small switched circuit to select obd1or 2 with a switch and not have to fight with getting the car on jacks and loosing antifreeze to swap the sensor around might make it a bit more palatable since a pcm swap would only be a 10 minute job uptop... do you know what happens if the wrong sensor is plugged into the incorrect pcm? Does it damage the pcm, or just code out?

Thanks again
 
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