Wanted: ECU for 16v

[Matt H]

Hello,

After more than a week of messing about with coil packs, crank sensors and ignition amps, with no success... I finally called in an auto electrician who traced the problem of my starting issues to the ECU.

I think it probably got damp, as the carpet is dry now, but I did notice a bit of damp a few weeks back.

£50 to the first person who can post one to me for Wednesday?

Or if anyone has a spare I can borrow until I find my own replacement... I'll cover any postage costs to get it to me and owe them a big favour

Thanks
Matt

[Mike P]

Hi Matt,

There is this one on ebay at the moment:

http://cgi.ebay.co.uk/mi16-Citroen-BX-1 ... 2559f1dbee

Although it's been a while since I got involved with ECUs. so don't know if this is suitable for you.

Also, if you look on the 16V website, there is a seller ("Himbo" aka Mark in Sheffield) who has one for sale at the moment. £30 and comes with a BBR chip.

Otherwise, I'd take a look on the 205 Gtidrivers forum.

Hope this helps,

Mike P.

[Matt H]

Cheers Mike.

The ECU in that add appears to be for a 405 Mi16, so I'm not actually sure it is an ideal solution. I seem to remember that the BX runs a slightly different map to compensate for the HP pump at low revs.

This is the picture of my ECU:



Cheers,
Matt

[douglas851]

A few weeks ago TRIPLE A CITROEN in Brede had an ECU on eBay, I think it failed to sell.

Their number is 01424 883200

[Matt H]

I think I'm sorted now... Thanks everyone.

[Mike P]

That's good news Matt.

Where did you manage to source one from

Mike P.

[Matt H]

I bought the one off eBay.

The code is different, but I thought it would work fine. 2-row Motronic 4.1... the same as mine. Either the new one is dead too, it is wrong for the car too, or it isn't the problem at all.

I think basically, my 16v never wants to drive again. It's getting to the point where I want to kill it, and that really isn't good.

It now sparks once from the coil, and then nothing.

[Mike E (uk)]

These ECUs are normally very reliable.

Welding the car without unplugging them can do damage though.

Did the auto electrician say why he thaught it was the ECU?

A weak spark suggests an HT fault or ignition amp failure.

You have changed:
coil packs, crank sensors and ignition amps.

Could it be faulty wiring/dodgy connections,
King HT lead, faulty distributor cap/rotor arm/fouled sparkplugs?

It is a pain, but try to check all the connections between the ECU,ignition amp and sensors. Use an ohmeter for this.

Don't assume a replacement part is working, especially if it is 2nd hand, unless it swaps OK with a working car. Keep the battery well charged between tests.

Get a helper to try and start the engine wilst you look under the bonnet in the dark-you may be able to see where the spark energy is leaking to chassis.

bon chance,

Mike

[Matt H]

These ECUs are normally very reliable.

Welding the car without unplugging them can do damage though.

Did the auto electrician say why he thaught it was the ECU?

A weak spark suggests an HT fault or ignition amp failure.

You have changed:
coil packs, crank sensors and ignition amps.

Could it be faulty wiring/dodgy connections,
King HT lead, faulty distributor cap/rotor arm/fouled sparkplugs?

It is a pain, but try to check all the connections between the ECU,ignition amp and sensors. Use an ohmeter for this.

Don't assume a replacement part is working, especially if it is 2nd hand, unless it swaps OK with a working car. Keep the battery well charged between tests.

Get a helper to try and start the engine wilst you look under the bonnet in the dark-you may be able to see where the spark energy is leaking to chassis.

bon chance,

Mike

Basically, the 'Bosch approved' auto electrician apparently (I wasn't actually there due to being in Essen) tested everything and found that all the signals were getting to the ECU, but nothing was coming out. He then tested the ECU with diagnostic equipment which confirmed it... But to be honest, I'm not going to take any of this for definite, because I wasn't there at the time, and this is quite an old Bosch system, it wouldn't surprise me if the guy had never seen a Motronic 4.1 box before.

Testing directly from the coil now, it sparks once, and then nothing. This is the same on both ECUs and coils, but the when the old ignition amp is fitted, I get no spark at all. My mechanic assures me that this isn't the problem, but the replacement part isn't Bosch (Lucas I think), so I'm not going to rule it out until my Bosch part arrives.

This car was running absolutely flawlessly up to the point it decided not to start. New Magnecor leads about 6 months ago, new plugs, new cap, new rotor arm, new... well you get the picture.

I'm totally gutted that this has happened, and will be getting it home soon to actually have a proper go at sorting it myself... Which is what I would have done in the first place, if my Dad hadn't decided to kill it outside a very competent mechanic's place... who isn't afraid to work on old cars or Citroens.

If I can't get it going again soon though I'm going to have to buy another car, because it is really starting to interfere with work.

I can handle a BX that pisses LHM everwhere... because at least you know how to fix it, but when it won't even run... what am I supposed to do?

I'll let you know how I get on.

Thanks,
Matt

[Tim Leech]

What happened to the 14TGE/16v Matt?

[Matt H]

That's a bit of a sore point... Put simply: Terminal rust

Still, your SD1 looked good on Saturday. I would have said hello, but I didn't get catch you in the end...

[Tim Leech]

That's a bit of a sore point... Put simply: Terminal rust

Still, your SD1 looked good on Saturday. I would have said hello, but I didn't get catch you in the end...

Thats a shame mate is it mendable?, I didnt see you Matt sorry bud, and only got to chat to your dad for a few minutes.

[mat_fenwick]

If it helps, I have an ECU in the 205 you may be able to borrow. I wouldn't want it gone for too long as it would be a pain to have an immobile car in the way, but I guess you know that already!
I can't guarantee it works perfectly as I have a small idling problem for the first minute or so when cold (suspect the AFM) but absolutely no problems with sparks.
For what it's worth, I had a brand new genuine Land Rover king lead fail within a couple of months of purchase...

[prm]

I would still be inclined to go for a CAS fault if it has fired once. Usually at the onset of any testing procedure, then the ECU shuts down.

Not sure if you’ve fitted a new unit?
Worth checking the 3 wires are reaching the ECU, pins 23 and 25, from the connections on the plug/socket by the battery tray.
CAS Plug connections. With central casing locating pin uppermost and left and right lugs underneath, pin allocation, left to right - black, yellow/cream and then screen.
Screen joined to Pin 23 @ ECU.

The car will fail to run if the ECU is not seeing a constant AC voltage generated from this unit to operate the fuel pump relay, and believe, also to activate and ECU injector driver.
The static resistance on this unit - black and yellow wires, should be in the region of 525?.
Remove the distributor cap and CAS connection plug/socket, set test meter to AC voltage, connect between black and yellow/cream wires. Crank the engine, output from the CAS should be about 4 volts AC. Remove the plugs and crank again, voltage should between 4-8 volts AC.

Worth a try.
Best of luck if you’ve fitted another ECU, and new CAS.

Regards

[Matt H]

I'm going to get it home this week and probably have a crack at diagnosing it properly.

prm - You seem to know a lot about it, so I might ask you some questions when I get started on it...