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Discussion Starter #1
Greetings...
I'm prepping a 3800 SC (02 bonneville motor, ecu and harness from 98 GS) for an engine swap into something very different. (upgrading mutant Corvair from 87 3.8 to above package)

So - I have the engine/trans/subframe set up on the floor with power, coolant, and fuel.
It happily starts, runs about two seconds, and shuts off.
From what I can determine, it is the anti-theft.
I do have factory key and stuff, but do not have BCM installed. Would rather not use it.
I see relearn procedures and such - I'm guessing that those are talking to the BCM, not the ECU. Do I need to get the ECU flashed to ignore anti theft?
Sometime in the future I may want to mod the motor, but right now I don't intend to. I just want the beast to run, I'll swap it into mu car, and enjoy it that way for a while.
- the LG3 is rated at 180 HP, and it isn't bad in this 2400 lb car. The Series II s/c is rated at 240- that's about 50% increase - it should keep me entertained for a while.

So- do I need to have this ECU flashed to remoce anti-theft? Anyone here in SoCal/San Gabriel Valley want to do it for a semi-reasonable price?

Or- should I just (at least for now) connect the BCM to the system with the column /key detector so it thinks everything is kosher?

(the fuel pump power stays on for a sec after the engine shuts off, and the oil pressure sender seems to be working fine. I don't think it is either of those)
Thanks for any suggestions.
Regards
Jay
 

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Yes, you will need the PCM reflashed to disable VATS (anti-theft) since you aren't using a BCM or VATS system in your swap. Bonneville and Regal GS tunes both had VATS enabled in all their OBD2 L67 tunes.

Alternatively, many 1998-2000 Grand Prix GTP stock tunes I've seen didn't have VATS enabled from the factory. So if you got your hands on PCM with one of these stock tunes on it, you might be able to use it in your swap and it should run.

However, you will probably get a lot of codes that will set in the PCM if you try to use a stock tune since, I assume, you won't be transferring ALL emissions equipment (sensors and such) from the donor car into your swap vehicle. Therefore, a custom tune would still be your best option.
 

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Discussion Starter #3
Thanks for the info.
If I wanted to make those changes myself - is there a current summary of software/tuner packages? I understand that some packages lose support, etc.
Presuming I just want to tweak this particular vehicle - what are my options - cost and learning curve?
Yeah, I'm kind a techie, but I might be better off farming this out.
Regards
Jay
 

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There isn't much available for V6 PCMs. HP Tuners and Jet DST are the only two I can think of that work with these PCMs. There are pros and cons of both setups.

Your issue is getting the VATS disabled in the GS tune - if you decide to keep it. I don't know if either of these programs can do it.

You could upload a GTP tune to the PCM and then edit that, but again, I don't know what it takes to do that with either of these tuning software programs. I use something else to tune these PCMs that is not longer sold to the public.

That being said, it would be cheaper to "farm out" the PCM tune in all likelihood. By the time you bought the software/hardware package to do it yourself, you would probably have more than triple the cost invested than you would pay someone to tune your PCM for you. But if you bought your own tuning setup - then you could use it to make any changes you want now and in the future; as well as perhaps use it on other vehicles.

As far as the learning curve is concerned, turning off codes and such is pretty straightforward. Making changes to get the engine run right for performance parts (such as cam, heads, other mods) is a lot more difficult. You would need an in-depth understanding of how to interpret scan data and know what changes to make in the tune to correct what you see going on in the scan data.
 

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Another option you have is to contact DYNO TUNE MOTOR SPORTS. They can probably give you the best results. They have a good track record doing this. And, as was mentioned, you can skip the learning curve as well as save some bucks. Their knowhow and results speak loud and clear. Jake
 

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VATS is a pain in the butt! I had to deal with VATS and training two new ignition keys in a 2003 Buick Regal. Training the keys took three hours.
 

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First off.. There are modules you can buy on eBay. And you tube videos of hardwire bypassing even wiring schematics.

The earlier VATS had old school pellet keys there's 15 different codes or resistances ( Radio Shack sells resistors you can use to disable VATS )

When GM went to eliminate the key from VATS they used a magnet in the lock cylinder (remove the magnet and its disabled)


Passkey 3 has an exciter ring module that ( get this ) energizes and reads the key. Its like an antenna so I unplugged and removed mine on my 2k GtP and now an uncoded, correctly cut key works.
 

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Discussion Starter #8
update on passkey

Thanks for the info and suggestions.
I suspect that the bypasses interface with the BCM, telling it that the proper key is present.
I actually have the key, and I might be able to find that part from the steering column that interfaces with/reads the key. Or get one from the junkyard.
But I'd rather not deal with the BCM at all - my car won't be using any other functions from it, so why deal with the complications?
I was kind of hoping for someone close, but Intense can certainly do the job.
Just for fun, here's a link to a video of my test run a couple of days ago.
As you can see, it really is standalone.

https://youtu.be/6CYvQcZQVIY
A pic of my car that the motor is going into:

Jay's Automotive Corner | Cars and such
 

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BCM Bypass

For kicks and giggles ... have you tried scrounging up the BCM from the engine donor car and then doing some electrical diagnostics on it to see exactly what it's feeding back to the ECU?

What I'm wondering is, since you'd like to do away with the BCM altogether, what if you could find the leads feeding back to the ECU and determine what they're actually sending back to the ECU that tells the ECU that everything is "good to go." This would include, presumably, the PassKey stuff.

My understanding is that the BCU and not the ECU actually handles all the security stuff (along with all the other junk like the auto-dimming interior lights, auto-locking doors, etc). Perhaps just rigging something up to feed to your ECU to give it a constant "good" signal from the BCU is all you'd need.

That's assuming it's something as simple as a steady voltage or something similar. If it's actually doing some kind of serial or parallel data communications stream of some sort, then that royally complicates things.

I'm nowhere near an expert ... but it seems more likely to me that this vintage / year model probably doesn't have some complex data communications going on between the BCU and the ECU. I could be totally wrong though, so if someone else who knows this stuff like the back of their hand wants to correct me ... please do!
 

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Discussion Starter #10
how the BCM and ECU communicate, and why I don't want the BCM.

I'm pretty sure the BCM talks to the ECU via the CAN bus. That bus sends info between the instrument cluster, the BCM, the ECU, and about everything else in the car.
So the ECU wants the BCM to send it the proper info, but nothing tidy like an on-off or voltage signal.
Now, of course I could provide the proper key signal to the BCM and use its electronics to tell the ECU that it is happy. But that's additional complication, and I want to disable the 2nd O2 sensor anyway.
(don't need cat in the 1961 car this is going into, and the motor is so close to the back of the car it would be tough to fit a cat and decent sized muffler in.)
 

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I'm pretty sure the BCM talks to the ECU via the CAN bus. That bus sends info between the instrument cluster, the BCM, the ECU, and about everything else in the car.
So the ECU wants the BCM to send it the proper info, but nothing tidy like an on-off or voltage signal.
Now, of course I could provide the proper key signal to the BCM and use its electronics to tell the ECU that it is happy. But that's additional complication, and I want to disable the 2nd O2 sensor anyway.
(don't need cat in the 1961 car this is going into, and the motor is so close to the back of the car it would be tough to fit a cat and decent sized muffler in.)
CAN bus didn't come out until 2004-ish. The only data communications the 98 GS used was Class 2, but you are correct in that the BCM communicated with the PCM, IPC, and anything else in the car on the (class 2) data line.

If I were you I would just get a custom tune to disable VATS in the PCM so you don't need the BCM and also have the codes shut off for other equipment you aren't going to have in your swap.
 

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Discussion Starter #12
3800 passkey - using BCM for now

I went ahead and cleaned up the BCM connectors and figured out which leads are needed. (only about six, including the leads to the key resistor.) Measured the key, found resistors to mimic it, and wired the resistors to the BCM.
The motor now starts and runs. I'll still need to get the ECU tuned to ignore the second O2 sensor, the ABS, and probably some other things - but that can happen over the next month or two as I do the swap.
I want someone here in SoCal to do it, so I can get further work without the time of shipping it back and forth. A couple of local guys have expressed interest - we'll see if either of them come through.
Cheers
Jay
 

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Discussion Starter #13
tune now and in future

Hi, Sinister
Ah, the schematics say class 2, I didn't know the difference.
You're right - for now, a very simple tune as you said would keep me going for quite a while. I don't know if or when I'll decide to go for more power. Unless I stumbled across a 3800 already built, I'd be inclined to pull the s/c and give it a turbo. While I was modding the oil pan (giving it a dipstick reachable from rear of car) I included a fitting for a turbo oil return.
I may yet call on your services - thanks for talking with me the other day.
Regards
Jay
 

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Jay, the factory low oil level sensor hole in the 3800 oil pan makes a good place to mount the oil return line from the turbo (if you don't mind giving up the low oil level sensor). That's where I have it in my Fiero (w/ a 3800 Turbocharged swap) and it has worked great for over 15 years.
 

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Discussion Starter #15
I'm not sure if I even considered the oil level opening.
I think it is on the front of the motor - and I need the dipstick on the rear side 'cause (being mid-engine transverse) that's the side you see when opening the "hood".
So the trans and oil dipsticks are on the same side, close to the power steering pump. (I'm getting lazy - may give it power steering at some point...)
 

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Discussion Starter #17
An update - I did test it with the BCM and it ran on my 'test stand'. Have it in the car, finishing things up. Did get a tuned ecu that will ignore passkey and the other things that a 1961 car doesn't have/need.
 
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