switch's for plug and play harness
 

I want to put switch's on my plug and play harness so I can go from stock to MS control on ignition and fuel.

I have seen a few of you guys using this type of setup as well, what type of switch's should I be looking for?

I was in the local electronics parts store the other day, they had a bunch of different ones, most were not labeled, some had a rating marked on the site normally referencing a maximum ac voltage.

Any suggestions?

I really don't see the point of switches, just take control of one thing at a time.

Ya, I have been thinking the same thing about all the switches stuff. The moment you put in something like 550's you can forget about using the stock ecu for anything. Plus, if the MS is running its not just gonna fuck up all the sudden. If you look inside the stock ecu it has the same components as the MS. It is no less reliable. Its reliability is only limited by the tune that it has for your motor. Tune it well and there is no reason that it won't outlast the life of the car.

I keep reading about you MS guys wanting the ability to switch fuel control to the stock ecu. Do you really think the stock ecu will run your big ass injectors?

It won't. I've tried. Though I got it to idle, kind of.

Yeah, I have the switches. They're ok. But much more hassle than they are worth and I'm thinking of removing them. When i remove the MAF and install my 550s the stock ECU will be worthless anyway. It pretty much triples the amount of wire if you do it like mine.
You're looking for 2pdt or something similar switches. They have a common input and switch the connection between poles when you switch the toggle.

What year is your car?

With all due respect Al, you don't see the point in gauges either (duh?). These things are for TROUBLESHOOTING and INITIAL tuning. If something goes wrong, you can have a reference (known good) point to revert back to and work your way from there. I for one, thank myself time and time again for building my PnP box with individual switches for injectors and coils. It's a must for a daily driver.

Jim

I am making a plug and play harness for my megasquirt so i can run either all stock ecu or all megasquirt. So far I have power, grounds (all four, hope its not a big deal to just join em all?) and CKP/CMP hooked up, but have not gone further as I am trying to diagnose why I am not picking up an rpm signal.

I dont know about the rest of the guys but i am going to do a NA tune first and then modifie from that adding biger injectors later, once i get the small ones working right. I dont have to have MS controll spark for me but it is a nice option, so the ability to switch to the stock map is nice. Once i get the fuel right and install/tune the bigger injectors i shouldnt need to switch back. But if something goes wrong i can switch back and trouble shoot from the begining something like leaving a trail of breadcrumbs i can always find my way back to where it all worked. Wish i had that abillity on our 96 but that is another story :rofl:

I used spade connectors to switch back and forth when i was troubleshooting, but switches/switchbox work fine too, I just see them as being more hassle.

What I was getting at was that it seems like those who want switches want to have a limp home mode like you could have with an Emanage, which really isnt possible with an MS.

And gauges, yeah, don't need gauges. Only datalogging.:cool:

Spade connectors are easy. But when your ECU is under the driverside dash like mine it's easier to install it and forget about it than having to take the coverpanel off and pull and that wiring out that you "attempted" to place so carefully in there.

I don't forsee the MS ever stopping working by fault of itself once you have it working in the first place.

Me either, long as your tune is good when it comes to hot and cold starts. Things of that nature.

Yeah I will be running the car NA for this summer, still parting the turbo kit together.

I want to be able to switch between MS and stock ecu during tunning/trouble shooting as mentioned above.

Obviously once Im running boost the stock ecu will be useless for fuel and spark.

As for injectors the stock ones on my 2004 should be good for close to 200rwhp, I will be upgrading them before I get close to this point but will be running the stock injectors during the early install of the turbo kit.

For the cost and added complexity of adding the switch's I think they are worth it.

Another issue is we have to do emission testing every couple of years, not sure how this will work out. Worst car I will have to go back to NA for testing. And with the switches I can easily go back to the stock ecu if needed. Although taking out the whole turbo system will be the major pain in the ass.