Necessary electronics

MR2 Formula One · 09-15-2008, 06:56 PM

I am building a go cart from an 87 MR2 4 cyl. Can anyone tell me the minimum amount of wiring harness and electrical components that I will need to keep?

I will likely run new circuits for lights and horn and get rid of all of the other wiring that I don't need, I noticed that the engine wiring harness connects to the accessories wiring harness Can the engine harness be powered from something other than the accessory harness?

te51levin · 09-21-2008, 10:42 AM

First post, huh? Welcome!

So, you're building a go-cart, but you want lights and a horn? Can you tell us a little more about what you are building and how it will be equipped?

MR2 Formula One · 09-22-2008, 09:59 AM

Sure! My son and I are going to build a chassis that looks as close to a Formula One car as possible (considering it will be pipe and sheet metal) open wheeled and open cabin. We will be using the engine, trans axle and probably the front suspension (provided that it doesn't look too funky) from an 87 MR2
I hoped that we would run new circuits for the gages, horn, lights, rad. cooling fans, and ignition.
I suppose that we could go ahead and use the old accessories wiring harness and cut off the excess that we do not need ie wipers, radio, A/C this would probably be the safest way to assure that we have not forgotten anything.

I guess that the engine computer system will require a connection to the temp gauge and oil pressure.

Wow! what a lot of rambling.
Here is the question:

Can this engine operate similar to a manual engine or do I need to keep all of the electronics intact?

te51levin · 09-22-2008, 11:53 AM

The ECU does not monitor oil pressure, and it has own coolant temperature sending unit, separate from the one that feeds the gauge in the dash.

Basically, you can separate the engine and ECU from the rest of the car with minimal electrical drama. It will not by physically easy, because the engine does not have a separate harness, but the ECU doesn't need anything from the car other than constant power, switched power, and ground. All its other critical inputs and outputs are directly related to the engine or fuel injection (i.e. pump, relay, etc).

Your project sounds really interesting. Are you following a set of plans or just designing the whole thing from scratch? These two look like a hell of a lot of fun to me:
http://www.grabercars.com/
Sylva Riot SE

09-15-2008, 06:56 PM	#1 (permalink)
MR2 Formula One Pretty good w/ a bowstaff Join Date: Sep 2008 Location: Mt Vernon, MO Posts: 7 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Necessary electronics I am building a go cart from an 87 MR2 4 cyl. Can anyone tell me the minimum amount of wiring harness and electrical components that I will need to keep? I will likely run new circuits for lights and horn and get rid of all of the other wiring that I don't need, I noticed that the engine wiring harness connects to the accessories wiring harness Can the engine harness be powered from something other than the accessory harness?

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09-21-2008, 10:42 AM	#2 (permalink)
te51levin LithiaToyotaParts.com Join Date: Oct 2005 Location: Oregon Posts: 2,245 Thanks: 40 Thanked 172 Times in 148 Posts My Google Map iTrader Rating: (141/100% )	First post, huh? Welcome! So, you're building a go-cart, but you want lights and a horn? Can you tell us a little more about what you are building and how it will be equipped?

09-22-2008, 09:59 AM	#3 (permalink)
MR2 Formula One Pretty good w/ a bowstaff Join Date: Sep 2008 Location: Mt Vernon, MO Posts: 7 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Sure! My son and I are going to build a chassis that looks as close to a Formula One car as possible (considering it will be pipe and sheet metal) open wheeled and open cabin. We will be using the engine, trans axle and probably the front suspension (provided that it doesn't look too funky) from an 87 MR2 I hoped that we would run new circuits for the gages, horn, lights, rad. cooling fans, and ignition. I suppose that we could go ahead and use the old accessories wiring harness and cut off the excess that we do not need ie wipers, radio, A/C this would probably be the safest way to assure that we have not forgotten anything. I guess that the engine computer system will require a connection to the temp gauge and oil pressure. Wow! what a lot of rambling. Here is the question: Can this engine operate similar to a manual engine or do I need to keep all of the electronics intact?

09-22-2008, 11:53 AM	#4 (permalink)
te51levin LithiaToyotaParts.com Join Date: Oct 2005 Location: Oregon Posts: 2,245 Thanks: 40 Thanked 172 Times in 148 Posts My Google Map iTrader Rating: (141/100% )	The ECU does not monitor oil pressure, and it has own coolant temperature sending unit, separate from the one that feeds the gauge in the dash. Basically, you can separate the engine and ECU from the rest of the car with minimal electrical drama. It will not by physically easy, because the engine does not have a separate harness, but the ECU doesn't need anything from the car other than constant power, switched power, and ground. All its other critical inputs and outputs are directly related to the engine or fuel injection (i.e. pump, relay, etc). Your project sounds really interesting. Are you following a set of plans or just designing the whole thing from scratch? These two look like a hell of a lot of fun to me: http://www.grabercars.com/ Sylva Riot SE