I'll be installing a Megasquirt Pro in my 2002 GT 2v car and I'm having some issues with where to connect some wires. Has anyone done one of these that would be willing to answer questions that I have? WARNING: I know NOTHING about wiring but I have wiring diagrams to look at, etc. I've been asking questions on Corral and Matt C will answer one question a day but I have a lot more that I need answered and explained.

Right now I'm trying to understand the wiring for the fuel system using the factory returnless system and wiring the ECU relay.

Thanks for any help.
Kevin

 

The MS is going to be controlling the ground side of any relay for fuel pump, fans, etc.... So the way mine is wired is the MS fuel pump control wire is the closed ground side of the relay switch.

 

Thanks but I need more detail than that. I'm trying to draw up my own wiring diagram with pinouts and wire colors so it helps me check how things are to be wired up and so I have it in my files. I need to know which MS wires are connected to which pins from the cars PCM for the fuel pump?

ks

 

You need a copy of your current wiring in your car. Get a good voltmeter and you can verify the wiring with that. The details are all in there. I know its intimidating at first but if youre willing to learn you can get it. Good luck.

 

never mind..

thanks for trying.
ks

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ms can control an fpdm but the closed loop is not as good as a return style system, are you piggybacking the stock computer to keep the gauges working? or are you going aftermarket gauges

 

Piggy backing it to keep the stock gauges, etc. MS would only be running the engine.

ks

 

do you have some sort of connector to go between the factory harness and eec?
what injectors ar you running?
what do you plan to use for coil drivers?
do you plan to install a return style fuel system?
i just finished putting a coyote in one of these cars, it was the biggest pita ms intall i have ever done

 

1. EEC? If you're talking about the MS box, no connector although I would really like one. I'll just solder the MS wires directly to the proper factory wires near the large connector at the firewall then pull the unused pins out of the connector.

2. 80lb inj.

3. I bought two Quad Sparks from DIY.

4. A return fuel system won't be going in for a few years.

I know NOTHING about wiring so I'm trying to keep this install as simple as possible but it also has to be reliable. I can expand on the MS capabilities in the future once I'm more comfortable with it but I just want to get it running and retuned.

ks

 

I would look into doing a BOB and getting some stock EEC connectors to make up a PnP harness of sorts. I would also abandon the returnless stuff now and go right to the return style.

 

Here's one I recently did...

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Can't abandon the returnless fuel system this year. If I'm lucky it will come next year. In the mean time Matt C said in order to use the PWM type fuel system he said to:

"Connect pin 80 to the fuel pump output with a 1K pull up to 12 volts (I'm not 100% sure on the resistor value). You'll be using PWM fuel pump control."

Do you know what this pull up resistor is and what value it should be? Maybe a Digikey part number? What's it for?

ks

 

no pullup resistor required. ful pump will be hooked to the fpdm via the white/red wire. closed loop settings are a bitch

 

What? The wht/red wire on the MS Pro is for an injector.
Matt said that I need to connect Pin 28 from the white connector (Fuel Pump Relay Out on MS Pro) to the wire from Pin 80 on the factory PCM shown above and add a pull up resistor (whatever that means).

ks

 

pin 80 happens to have a white/red wire, however you wont be hooking the fp out to pin 80 you will be hooking it to that wire that goes to the fpdm removing it from pin 80 of the ecu.

 

Gotcha! THANK YOU!
What's this pull up resistor that Matt mentioned even for? What's it do?

KS

 

no pullup needed, i have run 5 of these things without them

 

Have you wired a MS to a 2v before still using PWM for the pumps? If so, the MS uses a Purple wire to run the pump. Which wire exactly did you connect the purple wire to at the cars PCM? We have tried several different wire connections (pin 80 and pin 40) but we can't get MS to run the pump.

ks

 

its not going to work just hooking the wires up. the fpdm is not an on/off device, it uses a pmw signal so software setup is needed. everything i have done with them has been open loop to slow pumps down to accomodate a smaller return line and lessen stress on the system. they can run a closed loop but is a pita to tune the pid loop.


a description of the logic on how they work
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a sample of open loop settings
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Thanks again for the help. Due to the issues of getting the fuel pumps working using PWM I broke out several CC's and purchased parts to run a return fuel system. Better in the long run, I know, but it just wasn't in the budget for this year. So I'm moving on with different questions which I'll post in different threads.

ks