Operation Megasquirt!

[hybrid]

The stock code is nothing fancy.

It's the MSEXTRA guys who have really made the ECU the special thing that it is.

[boofhead]

found this in that link:

Note that the FIdle circuit on the relay board is limited to 1.1 Amps by the polyfuse. The relay is capable of handling much more current, but the traces on the relay board are NOT. If you wish to use the FIdle relay, do not use it to drive a device that requires more than 1.1 Amps (though you can use it to drive a second relay and control much more current - like an electric fan relay)

so even though a relay is in use on the relay board you can use it to drive anothe relay

Interesting point. I would be making changes to the board anyway since your by passing the fIdle. Hence use some medium gauge wire and on the bottom just rewire as needed and by-pass the poly fuse (and much of the thin tracks).

The pump relay output is a direct output - goes straight to the pump.

[gbx78]

found this in that link:

Note that the FIdle circuit on the relay board is limited to 1.1 Amps by the polyfuse. The relay is capable of handling much more current, but the traces on the relay board are NOT. If you wish to use the FIdle relay, do not use it to drive a device that requires more than 1.1 Amps (though you can use it to drive a second relay and control much more current - like an electric fan relay)

so even though a relay is in use on the relay board you can use it to drive anothe relay

Interesting point. I would be making changes to the board anyway since your by passing the fIdle. Hence use some medium gauge wire and on the bottom just rewire as needed and by-pass the poly fuse (and much of the thin tracks).

i read that like broken english .. lol i didnt understand any of that ! not from you but because of my lack of understanding of the relay board..

is this why you guys didnt choose to use the relay board? cause of this limitation?

[boofhead]

I used a relay board for my first install and it really helped with the setup process as it does make the wiring simple with the benefit of it being far less likely to make any critical wiring mistakes. I have never used a fIdle (always a stepper) and as such never used the third relay. I do not use the relay board for my installs now because:
1) The screw in terminals can come loose so you need to support the wires connected to it so they do not pull on the terminals. Not so much an issue if you support the wires though double check them a few times after install. If I used one again (it does make it far easier) then I would solder the wires instead of the terminal blocks and use alternate connectors for disassembly.
2) There are not enough relays for the extras that you tend to think of so your building relays any way, so what are a few more.
3) Grounding of the MS wiring schemes have changed a bit recently. It is almost all fine as per the latest thoughts though some ignition setups just need to be grounded back the MS and there is not a terminal block for extra grounds. Minor and not really an issue in your case.

The relay board really makes it easy - so there is no real reason to not use it. It does make it easier to set up and debug the system if something goes wrong. Also your not going to send 12V down a CPU pin as it protects against those types of mistakes. It has the fuses etc all build in so please do not be concerned with using it.

You can add in a relay somewhere and forget using the third relay on the board then your will understand it better. I was just suggesting using the existing relay in place and add the wires directly to it so the boards copper track are by passed. Just to keep it neat. You need a soldering Iron, a knife, some wire (proper gauge) and off you go the convert the fIdle relay into a Fan relay which can handle 20 Amps draw. You will need to make a small change any way to pickup the fIdle feed going into the board to wire directly to the ford fIdle device you have in your throttle body.

It is not hard and I am happy to help.

[gbx78]

I used a relay board for my first install and it really helped with the setup process as it does make the wiring simple and your far less likely to make an critical wiring mistakes. I have never used a fIdle (always a stepper) and as such never used the third relay. I do not use the relay board now because:
1) The screw in terminals can come loose so you need to support the wires connected to it so they do not pull on the terminals. Issue it not so much an issue if you support the wires. If I used one again (it does make it easier) then I would solder the wires instead of the terminal blocksd and use alternate connectors for disassembly.
2) There are not enough relays for the extras that you tend to think of so your building relays any way, so what are a few more.
3) Grounding of the MS wiring schemes have changed a bit recently. It almost all fine as per the latest thoughts though some ignition setups just need to be grounded back the MS and there is not a terminal block for extra grounds. Minor and not really an issue in your case.

The relay board really makes it easy - so there is not real reason to not use it. It does make it easier to debug the system if something goes wrong and your not going to send 12V down a CPU pin as it protects against those types of mistakes. It has the fuses etc all build in so do not be concerned.

If you add in a relay somewhere and forget using the third relay on the board then your will understand it better. I was just suggesting using the existing relay in place and add the wires directly to it so the boards copper track are by passed. Just to keep it neat. You need a soldering Iron and a knife some wire (proper gauge) and off you go the convert the fIdle relay into a Fan relay which can handle 20 Amps draw. You will need to make a small change any way to pickup the fIdle feed going into the board to wire directly to the ford fIdle device you have in your throttle body.

It is not hard and I am happy to help.

ahhh ok, i must admit the relay board IS helping with me learning because its already laid out for you. and i have supported the wires so there is no pull on them but if it proves to be unreliable i might look at alternatives.

yes i understand now what you mean. SOrry i must be doing your head in with my lamo questions. Im a simpleton and need things explained in lamen terms before i can grasp the concept

ok so this is what ive gathered from the discussion soo far.. and please correct me if i have not understood.. :

1.i appear to have a ford pwm IAC? the factory workshop manual calls it Throttle Air bypass valve but strangely mentions "cold Fast Idle"

2. it has 2 wires, which 1 will be a ground trigger wire and the othe probably 12v ignition feed.

3. i can reprogram iac ports 1 or 2 (s1 or s2 on the relay board) to be a fan control based on coolant temp criteria (thats cool! no pun) and/or A/C control based on TPS position

4. not sure how to wire the A/C just yet. The compressor has a 2 pin wire.. ground and positive with a diode in the middle that matt mentioned is used so if you put the wires around the wrong way it will blow the fuse. ( Sean at BossKraft said the container is due to arrive next week so should get my A/C in a few weeks) thats another story. worry about it later.

5. The FIDLE can be reprogrammed for fan control but i will be using it for PWM which hooks up to the IAC valve see points 1 and 2.

6. Fuel Pump port on the relay board.. is in fact the "after relay" feed for the fuel pump .. however i remember reading somewhere or seeing a diagram that mentioned to use a fuel pump relay outside of the relay board which made me think this port was only a trigger feed TO an external relay, but you are saying its the ACTUAL feed to the fuel pump.. instead of changing my fuel pump port wiring to a thicker gauge.. i wonder if i can still use the standard gauge wiring that came with the MS kit as a trigger feed to another external relay where from THERE i can use decent gauge wiring?? therefore i dont burn out the standard gauge wire i already have in my loom or wont that work how i think it should? It was suggested to me to use 2 bosch 044 pumps into a Y piece to the engine .. and a low pressure pump from fuel tank to surge tank. so i potentially will be using 2 or 3 pumps which need to be wired together to run at the same time.. Matt showed me a diagram how to wire 2 relays together for each pump. Which essentially was 1 relay piggy backing off another.

7. according to page 2 of this link http://www.bgsoflex.com/mspower/mspower_ShemV1.2.pdf

there is a jumper i need to check to see whether the fast idle relay on the board is supplying GND or 12v to the solenoid

8. for the fan control to use the relay directly to bypass the thin channels on the circuit board to support higher current. Much like the fuel pump idea i put fwd, I wonder if instead i could just use an external relay thats triggered by a wire from the relay board? or will this still be the weak point and draw too much current on the relay board? I already have a 12v igntion power wire for the fan sitting at the front of the car.

*DEEEEP BREATHE ace ventura style*


hopefully i havent missed anything or hopefully im comprehending some of whats been discussed.

enjoying it though. This would be something i would give up on in earlier stages but im sticking with it and i will get through it!!

[gbx78]

also just got an email back from DIYAUTOTUNE

The IAC ports will handle the current for a fan RELAY, but cannot drive
> a fan directly. You can use pin S1 for one relay and pin S3 for another.
> They'll supply 12 volts to power the relay when active.
>
> Current MS2 firmware does not have an A/C control feature.
>

that makes sense!! which is what i was kinda hinting at above..


and also:

""Ford 2 wire PWM valves are pretty easy to control. Jumper out the fast
idle relay and run one wire to 12 volt power, the other to the fast idle
output.""

[boofhead]

You have your answers. So the easy way is

1) Yes you have a standard Ford IAC - Yes bypass the relay to drive it.
2) You know above that as usual the MS grounds when triggering an external entity.
3) S1 and S2 are the same though in inverse so you have S1 and S3 as programmable ports.
4) AC control is started to be officially introduced in the latest beta firmware though I suggest to forget it for the moment.
5) Use another port S1 for fan control.
6) Doubling up the relays is silly [e.g. what's the point of the relay board] - just go straight to the fuel pump.
7) Indeed but it is mute as you bypassing the relay (jumping it) so no need to consider this factor.
Wire in an external relay (apart from the relay board) since you basically have the system set up any way. S1 will be on the switch side of the relay obviously as it powers the relay so ground the other side (which is opposite way it normally works so do not get confused).

Fhew...

[ozbilt]

You do have an inertia switch George? If so mount it on the A pillar as that is the strongest pert of the car in an event & also easiest to reach to reset.

[gbx78]

You have your answers. So the easy way is

1) Yes you have a standard Ford IAC - Yes bypass the relay to drive it.
2) You know above that as usual the MS grounds when triggering an external entity.
3) S1 and S2 are the same though in inverse so you have S1 and S3 as programmable ports.
4) AC control is started to be officially introduced in the latest beta firmware though I suggest to forget it for the moment.
5) Use another port S1 for fan control.
6) Doubling up the relays is silly [e.g. what's the point of the relay board] - just go straight to the fuel pump.
7) Indeed but it is mute as you bypassing the relay (jumping it) so no need to consider this factor.
Wire in an external relay (apart from the relay board) since you basically have the system set up any way. S1 will be on the switch side of the relay obviously as it powers the relay so ground the other side (which is opposite way it normally works so do not get confused).

Fhew...

ok cool got it!! yes i made a mistake with the s1 and s2 ports being programable i meant s1 and s3.

ok so i will change the fuel pump wire to a heavier gauge .. however can i just piggy back off this "live" wire to power the other fuel pumps? or is this too much load for this 1 wire and 1 relay on the board..and do i need a second relay for this.. (i think thats what i was kinda hinting before aswell).

i understand the rest of the points better now too. thanks for clarifying.

[gbx78]

You do have an inertia switch George? If so mount it on the A pillar as that is the strongest pert of the car in an event & also easiest to reach to reset.

i dont have an inertia switch, i was going to put one but i think the way the megasquirt controls the pumps, if there is no engine activity then there is no power to the pumps or if megasquirt is off, the same thing.

so it acts in a similar way so fuel isnt still being pumped to the front of the car if the engine isnt going.. i think thats right, if that makes sense.. but hybrid and boofhead can clarify if i understand this correctly.

however if its still a good idea to put one and its not an unnecessary double up then im happy to do it if it means more safety.

hybrid/boofhead? can you clarify if im understanding this correctly?

[hybrid]

Yes you understand correctly, but I guess if it was your return line punctured, the engine would still have pressure to keep running, and if you were unconscious and didn't turn the engine off, you could be BBQ'd.

I don't have one in mine though.

[gbx78]

Yes you understand correctly, but I guess if it was your return line punctured, the engine would still have pressure to keep running, and if you were unconscious and didn't turn the engine off, you could be BBQ'd.

I don't have one in mine though.

yes this is true.. there could be a scenario where its still going but a firehazzard still present..

[boofhead]

By default they recommend a 10 amp fuse for the fuel pump relay. This is also the case for the relay board so you know it can handle at least a 10 amp draw. I have use this level of fuse safely on several main pumps (with and without the relay board) - now my up lift pump is 0.7 amps so it would be unlikely to add enough to blow the 10 amp fuse.

I would wire both up to the same circuit. In the event it becomes an issue (e.g., blow the 10 amp fuse all the time) it is easy enough the change later.

[gbx78]

By default they recommend a 10 amp fuse for the fuel pump relay. This is also the case for the relay board so you know it can handle at least a 10 amp draw. I have use this level of fuse safely on several main pumps (with and without the relay board) - now my up lift pump is 0.7 amps so it would be unlikely to add enough to blow the 10 amp fuse.

I would wire both up to the same circuit. In the event it becomes an issue (e.g., blow the 10 amp fuse all the time) it is easy enough the change later.

ok cool .. so just to confirm .. FP port wire (decent gauge) is the live wire (after relay) so run it to the back of the car to the positive terminal of 1 pump and then from there a wire to the positive terminal of the other pump and both just ground to chassis. then see how it goes regarding current draw and if its blowing fuses etc..

appologies for being cautious i just want to make sure im on the same page as you guys and i dont damage anything like the relay board or burn wires and cause fires! and understanding it correctly!

thanks again!

[gbx78]

actually just read some specs on the bosch 044 and issues people are having with fuses.. looks like it draws 15amp and people are using 20amp fuses with a decent gauge wire for 2 pumps (i assume 1 044 and a low pressure one)

so thats fine to change a fuse but what does that mean for the rest of the relay board as far as relay and the circuit handling that draw ?