Afternoon,

A while back we took the MNR to Mtech in Westbury for a rolling road session. It was a bit of a frustrating day, as the car came home in more pieces than it was in when we left.... it wasn't developing enough power, and after a while (and after taking the nose off the car so we could shine a timing light at it), we discovered that the timing advance was fixed at 10 degrees. The megatune software is showing changes to the ignition advance, but this isn't actually happening at the engine.

The setup is a 2 litre Pinto, MS1 on V3 board, built for for hall effect input / outputs, with an EDIS4 and Zetec coil pack. Stuff I've already checked:

PIP and SAW are the correct way around.
The board build is correct (I didn't build it, but been through the manual and double-checked, and removed a couple of capacitors that weren't supposed to be installed for the HE circuit).
the frequency of PIP and SAW changes with engine speed (not got a full scope though, so can't tell if it's a nice square wave)
I've checked that the software settings match the documentation for an EDIS install.
The cable screening on the VR sensor and EDIS are both connected, and earthed to the same point.

I've just been out and tested it with a timing light, and it's still fixed at 10 degrees...

Does anyone have any suggestions what I might have missed?

Thanks,


Vince

Have you checked that the additional jumper lead has been fitted on the board from IGN to IGBTOUT

See section 28 here

That jumper's only required for driving a coil directly from MS - for EDIS, you need to jumper IGN to JS10, which is done....

No ideas, but is it some sort of EDIS limp home mode?

There are a couple of ways of feeding the SAW signal out of the Megasquirt, for example taking it off one of the LED outputs or using a dedicated spare output on the microcontroller. You need to make sure whichever way your MS has been wired internally both matches what's been done externally and what's been set in the software.

For example, when I build Megasquirt ECUs for people using EDIS I'll reuse the IGBT position on the board and heatsink for something else, for example a fan control output or high-current driver for a solenoid type idle valve. There is an IGBT-OUT pad on the MS that can be used to divert the signal to a more appropriate place on the connector but you can't guarantee that this is what's been done.

My advice would be to ask the person who built it exactly where the SAW is derived from and where it's output on the connector, then setup the software to match.

Also note that your tach signal needs to come from the EDIS via the PIP line so if the engine runs at all it shows PIP is working as it should and your problem is with SAW.

(Then again, if you've mistakenly driven tach from the coil that could be why timing isn't working. The SAW signal must be sent a certain number of degrees after the PIP signal is given to the Megasquirt, and PIP doesn't happen at the same time as either of the coils are fired)

Chris

yeh, EDIS defaults to 10 degrees, but as far as I can tell the inputs to the EDIS are good...

No expert, but maybe the EDIS is at fault rather than the MS as you say the I/Ps are good.

If EDIS doesnt see an input from the Megasquirt it will default to 10 degrees.

You need to check to see if Megasquirt is configured for EDIS.

Two ways - one the circuit board itself, the second within tuner studio under Tach/ignition setting

V3.0 main board:

DB37 pin #36 to the SAW pin (#3) on the ignition module
DB37 pin #24 to the PIP pin (#1) on the ignition module
On the V3.0 main board:
use the 'Hall sensor circuit' (step #50.a in the assembly guide) - jumper D1 and D2,
jumper OPTOIN to TACHSELECT on the bottom side of the PCB, near the DB37 connector, opposite the heat sink,
jumper TSEL to OPTOOUT on the bottom side of the PCB, near the center.
jumper JS10 to IGN (this uses the processor port for the SAW signal directly),
jumper XG1 to XG2 on the bottom side of the PCB, near the 40 pin socket,

[Edited on 2/11/11 by big-vee-twin]

Thanks for the replies chaps, ChrisW, you first:

(Then again, if you've mistakenly driven tach from the coil that could be why timing isn't working. The SAW signal must be sent a certain number of degrees after the PIP signal is given to the Megasquirt, and PIP doesn't happen at the same time as either of the coils are fired)

The PIP signal into EDIS is direct from the VR sensor. I've swapped the VR polarity and the engine wouldn't run at all - swapped back and it starts fine again.

Big Vee Twin:

Those are the instructions I've checked against, the correct jumpers are jumped, and PIP and SAW are configured on the correct pins on the DB37 connector, and I've continuity checked through to the correct EDIS pins...

Anyone nearby got a spare EDIS hanging around that I can try out?

Cheers


Vince

quote:

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Originally posted by vinny1275
Thanks for the replies chaps, ChrisW, you first:

(Then again, if you've mistakenly driven tach from the coil that could be why timing isn't working. The SAW signal must be sent a certain number of degrees after the PIP signal is given to the Megasquirt, and PIP doesn't happen at the same time as either of the coils are fired)

The PIP signal into EDIS is direct from the VR sensor. I've swapped the VR polarity and the engine wouldn't run at all - swapped back and it starts fine again.

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Thanks Mike,

I was trying to figure out how to word that - I should just have said VR signal....

I've tested continuity from the 37 pin connector on the MS to the inside of the EDIS plug, and there're no breaks - obviously that's not possible with the engine running, so I measured the frequency of the PIP and SAW from one of the multiplugs I put into the loom. Like I said in the original post, the frequency of both increased as engine speed increased, so EDIS seems to be generating the PIP, and MS is sending back the SAW - I don't have the gear to test both at the same time though....

Had the exact same problem with mines with wasted spark. VR polarity was wrong. I was adamant that it was right but on further investigation i found it WAS indeed wrong.

Will check it again, but it doesn't start at all with them swapped.....

possibly won't start as the timing will be altered slightly IIRC. I had to change mines then set the timing using a gun to make sure that it was correct.

You say its an MS1 ECU?

If so then JS10 is NOT the PIP output, it will be coming out of LED14

The output must be wired using a 750R resistor between the top wire of the LED and the 5V pad of the proto area.
Then wire the top of the LED to IGN out pin 36 of the db connector.

thanks,
Phil

daxtojero - That's what the guy at Mtech tried, made no difference. Having been through the build docs for the version board I have, JS10 is correct for using an EDIS.

I've checked, double-checked the VR sensor, and it is the correct way round. If I swap them, I'm not getting any sparks at all. I've done a continuity test from the sensor plug all the way back to the EDIS plug and it's all good.

2 questions - the diagrams I have show a 25uF capacitor between the +ve to the EDIS & Coil and ground. Adding a capacitor doens't seem to make any difference though. Is this necessary, and will the 100V capacitor I've got be a problem?

I did test the AC voltage of the PIP and SAW with the engine running (both wrt ground) - PIP was 2.3V, and SAW was around 0.3V, with the engine idling. Increasing revs increased SAW, but not PIP. The info I have says that PIP should be 12V and SAW 5V - could that be the problem (or a symptom?)


ETA: it's using MS1 Extra, firmware 029y4.

Thanks,


Vince

[Edited on 6/11/11 by vinny1275]

quote:

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Originally posted by omega 24 v6
Had the exact same problem with mines with wasted spark. VR polarity was wrong. I was adamant that it was right but on further investigation i found it WAS indeed wrong.

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I've got a diagram at home which shows which one's signal and which one's ground - can't remember off the top of my head, I'll try and remember to scan it in and upload it on the thread....

Cheers


Vince

quote:

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Originally posted by garybee

quote:

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Originally posted by omega 24 v6
Had the exact same problem with mines with wasted spark. VR polarity was wrong. I was adamant that it was right but on further investigation i found it WAS indeed wrong.

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Can you clarify which is the correct way please? I've found a few threads on here that aren't clear (don't state whether any pictures are looking towards the sensor or towards the harness plug) and would like to hear from someone who's clarified which is right.

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quote:

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Originally posted by vinny1275
I did test the AC voltage of the PIP and SAW with the engine running (both wrt ground) - PIP was 2.3V, and SAW was around 0.3V, with the engine idling. Increasing revs increased SAW, but not PIP.

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Thanks for all the replies everyone - have tried a different EDIS and plug, and found the Ford supressor shown in some of the Megasquirt documentation. Nothing's changed..

One weird thing though, the 2nd EDIS I got has a different missing pin on the connector - on my original one, pin 11 was missing, on the new one, it was pin 7. Both EDIS units are labelled EDIS4. I'm not sure if the connector I originally had came from the same car as the EDIS unit. The new ones are from the same car though, and it's no different.

Anyone got a dual-trace scope I could borrow for beer tokens?

Cheers


Vince

Vince,
I wrote a lot of the code for MS1 and I have built hundreds and hundreds of them.
I can assure you JS10 is NOT the SAW output on an MS1 ECU, you MUST USE LED14 and wire it via a 750R reisistor to 5V on the proto area. It will never work using JS10, post a picture of the inside with this mod carried out to it and I will double check it, proabbly best to email me a pic as Im not on here often philip.ringwood(at)ntlworld.com you can also send me the msq file and I will double check that,
thanks,
Phil

Thanks Phil, I'll give that a go next...

Cheers


Vince

quote:

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I can assure you JS10 is NOT the SAW output on an MS1 ECU, you MUST USE LED14

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