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Location ECU

Lennart - 31/5/06 at 07:17 AM

In the other topic I made a small topic-hi-jack so I've made a new topic.

quote:
Originally posted by JB
Put it (ECU) where it will never get damp or wet (so this rules out the floor), keep it away from the starter, HT side of the ignition and alternator and the main battery lead.

Also consider the wiring to it, this also wants to avoid the starter, alternator, ignition and battery lead.

Then it wants mounting as low and far back in the car as possible for weight distribution.

John

My question was why to keep it away from the starter and ignition and altenator and main battery lead?
And what is the HT side of the ignition?

I'm trying to find out why my ford dohc 2.0i won't start.
I've got petrol feed, starter is running but no sparks from the coil. Ignition coil and spark plugs are oke, so could the place of my ecu be the problem?
My ecu is in an aluminium box on the scruttle top above the startermotor.

Help appreciated!

kiwirex - 31/5/06 at 08:01 AM

> why to keep it away from the starter and ignition and altenator and main battery lead?

' cos these are where the big voltages and/or big currents happen.
Which cause interference, etc with computer type stuff.

Probably the location won't be preventing your beast starting, but will cause interference so maybe rough running or lesser performance (guess).

Don't know where to go next - are you sure the ECU is plugged in?
Still working?

Good luck.

JAG - 31/5/06 at 08:15 AM

I wouldn't worry too much about the HT leads, starter cables, alternator etc...

This ECU was designed to be used in a car - just like your planning. The whole ECU will be designed to cope with all manner of electromagnetic emmissions without malfunction.

We build ABS units and tyre pressure sensors and spend a huge amount of time bombarding these units with electromagnetic radiation to make sure they work in these conditions.

Your ECU will have had similar testing.

I placed my ECU at the end of the passenger footwell and fitted a plywood bulkhead over it to protect it from clumsy feet. It's worked a treat for the last 4000+miles.

martyn_16v - 31/5/06 at 10:58 AM

quote:
Originally posted by JAG
I wouldn't worry too much about the HT leads, starter cables, alternator etc...

This ECU was designed to be used in a car - just like your planning. The whole ECU will be designed to cope with all manner of electromagnetic emmissions without malfunction.

We build ABS units and tyre pressure sensors and spend a huge amount of time bombarding these units with electromagnetic radiation to make sure they work in these conditions.

Your ECU will have had similar testing.

Unfortunately not, Megasquirt isn't a commercial product so hasn't gone through anywhere near as rigorous testing as you would put something as safety critical as an ABS unit. On the plus side it has had several years and many thousands of users field-testing it, the experiences gained here have fed back into the design of current boards so noise on the whole isn't a worry.

That said, while the ECU itself may well be protected from noise and happily tick along, you still need to take care to avoid noise in the wiring loom. Any ECU is only as good as the information you give it, if your inputs are noisy then odd things wil happen. Try to avoid running the loom close to the ignition circuits and the starter, and make sure all your earths are good clean connections (preferably earth all the sensors as close together as poss. with the ECU as well). Take particular care with the input from the crank position sensor (if you're using one), as this is particularly vulnerable to interference. If at all possible use the shielded cable from the original ford loom, and make sure to earth the shielding at the EDIS module end only.

As for the non-starting, can you get a log to see what is happening? Does the ECU see an rpm signal while you crank? Is it staying on during cranking, or are you getting any resets?

JAG - 31/5/06 at 12:39 PM

Is it a Megasquirt then? No-one said so in this thread.

If it is then I would agree with martyn_16v.

Lennart - 31/5/06 at 04:14 PM

It's the original ford ecu but I'll take care not to run the cable to close to any hi-power lines.

tks - 31/5/06 at 04:25 PM

mhh

The HT lead is the one that touched the sparkplug...

or the one that goes from the coil to the dizzy? (verdelerkap)

Tks

phoenix70 - 31/5/06 at 07:23 PM

Put mine under the dashboard.

Description

martyn_16v - 31/5/06 at 10:14 PM

quote:
Originally posted by Lennart
It's the original ford ecu but I'll take care not to run the cable to close to any hi-power lines.

oops, my bad

I'm sure 'the other thread' was about MS though...