LS Swap the world!
Time to ditch the lame engine in your 240sx, whether it’s KA, SR, or even RB and move on to the LS1! Lets face it, you wouldn’t be reading this if you weren’t already in the process of swapping it in now, unless you are doing your research before you start,”If that’s the case, KUDOS to you.” If you are in fact already swapping it in you are probably looking up how to attack the most common issue with the swap, the GM Vats System.
Bypassing VATS on LS1 for 240sx Swapping
What is VATS?
Vats stands for Vehicle Anti Theft System. Lots of people refer to this type of key, as a ” computer Chip key”. This key or “Chip” has nothing to do with a computer, nor is it a chip. But because of the popularity of calling it a computer chip key, so will we. So that we don’t confuse. The black chip on the blade of the key is actually a resister. GM first started using the Vats key in 1986 on the Corvettes, then some of the Cadillac’s, ect. GM uses 15 different resistors in their vats keys. Just looking at the keys you can’t tell the difference. What is GM’s VATS
So now you know VATS is a form of security system GM started using around the mid to late 1980’s. The theory behind it is there, but when it comes down to swapping these into our Nissan 240sx, it is usually an issue since we usually buy the swap with T56, Long Block, ECU, and Wiring harness. Hardly ever with the ignition system/Key and BCM (Body Control Module). Dropping in the motor and transmission is the cake part but 9/10 times people freak out about the wiring. It’s honestly the easiest part about the entire swap.
Methods to Bypass VATS
Resistor Pack (cheap)
This is a pack of resisters you solder in which give the proper resistance as the original key would to the system to allow it to start. It usually takes some time to figure out which resistor is the right one. Very Time Consuming.
Standalone EMS (expensive)
This is the easiest method but probably the most expensive rout to go with. FAST XFI 2.0
ECU/ECM Reflashing (HP Tuner)
This is probably one of the most cost effective vs time methods there is. You simply send your LS1 ECU to a tuner or purchase HP Tuner and do it yourself. If you decide to send it to one the cost is usually between $50-$150 which really isn’t bad. Depending on the tuner again, they may change a few parameters for you since they have the ecu already. A few simple Fuel and Timing map changes for more power, even remove the MAF and convert your ECU to Map only. A very popular method to use it the one from wiring specialties. If you get the SIKKY LS swap kit, it offers a good discount on this method: Wiring Specialties HP Tuners.
Finally my favorite method! VATS Confusion BCM Trick.
This method is FREE! The only part you need if a friend or someone with a early 2000 Chevy truck with a LS style engine. 4.8L, 5.3L 5.7L or 6.0L it doesn’t matter.
Example: You get your ls1 and t56 in, you wire up the harness (tutorial will come if requested) and you try to start up and it starts and shuts off right away…. VATS is enabled and you will not be able to fire up the LS. Lets call Tyler and get his 2002 Chevy 1500 5.3L truck over here. Remove the negative on Tylers truck, remove his ECM/ECU which is under the hood behind the driver headlight/core support. Remove (2) 7mm bolts and unblock the harness from the ECU/ECM. Plug yours in and bolt it back up. Try to start the truck and you will notice it won’t start and act just like your LS! Tell Tyler or your friend to relax, it’s cool bro! I got this!
Now remove the lower panel under his steering wheel, you’ll need to get under there in about 10 minutes. Now turn the key in the (on) position but don’t crank it. The security light on the cluster will flash, don’t do anything but Start your stopwatch on your phone. Have a smoke, Vape, Beer for exactly 10 minutes. At the 10 minute mark the security light should go away. Turn key off and wait 10 seconds, then proceed to the method 2 more times. (make sure Tyler’s battery is fully charged, you can even put a charger on it if you think his battery is shit. If the truck already had a security light flashing this should still work but a slight chance it won’t if the BCM is already bad.
On the 4th try, fully crank it up. If done correctly the truck will fire up. If it does ALRIGHT!! If not, try again. If it did, go under the steering wheel, and now unplug the BCM. By doing this you are telling the ECU/ECM that there is an issue with the BCM and it will stop searching for it and pretty much lock VATS out. Turn it off and put everything back together and put your LS ECM/ECU back in your 240sx and fire it up! This method had worked many times and is pretty simple and free so I suggest trying it if you can.