420A Split Second VC2 voltage clamp wired into ECU

[Ricecar]

I have a 97 Mitsubishi Eclipse GS with a turbo kit on it from the previous owner, it’s had tons of money dumped into it but I don’t want to run it until it’s been serviced and with an aftermarket ecu since the stock ecu is still in the car with a “split second voltage clamp” wired in, my friend said it “makes the car think it’s being pushed harder than it is” so more fuel for when the turbo makes boost? The car has a boost timer too but I’m a noob when it comes to turbos, I’ve had a lot of N/A eclipses but nothing like this one and I want to hold onto the engine for down the road and for a side project to tinker on until I have the components to put the turbo 420a in so it won’t immediately kill itself and have the bone stock one to fall back on. I appreciate any help or advice even if you have the 4g63, whatever you guys would do let me know, thanks!

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[BLACK'98DSM]

The wiring looks like a total mess. I would tear it all out and start over. Which would pretty much need to be done to run an MS3 anyway.

 

[Ricecar]

Thank you for the reply and the honesty I do want it to look good, but I got this car all mangled like this and I personally don’t have any experience cleaning up wires because all of my cars have been stock and untouched, I’d love to learn how to clean it up with something to neatly hold them all together. I take it I should yank the “voltage clamp” out before trying to run the new motor without the turbo kit and before tidying up the ECU wires?

 

[Canadian_CD9A]

The stock 420A ECU was never programmed to handle a turbocharged application at all. It goes berserk when MAP voltage goes beyond atmospheric pressure (essentially when the car goes into boost), and cannot run the car properly. Say for example 1 bar of pressure (atmospheric) is 4.0V on the MAP (just throwing a number out, this isn’t accurate), the ECU will flip out once the MAP goes 4.01V and above. The MAP clamp’s job is to ensure that the signal never goes beyond the maximum that you set it at, to prevent the ECU from going crazy. You then must control the added fuel requirement with either increased fuel pressure or an auxiliary fuel system. It’s an antiquated way of doing things and it’s not safe. A wholesale change to a standalone ECU that controls ignition and fuel is the only proper way to run a turbo 420A car.

 

[Ricecar]

Thank you for the info! So to run my non turbo 420a motor I’d cut it out of the ecu and it will go back to normal?

 

[Canadian_CD9A]

Thank you for the info! So to run my non turbo 420a motor I’d cut it out of the ecu and it will go back to normal?

If you're running without a turbocharger, the clamp is not doing anything and it's not going to affect the way your car drives (unless it's wired badly and is causing electrical issues). There's no need to remove it unless you absolutely won't need its services anymore.

 

[Ricecar]

Ok thanks for the advice, I really appreciate it!