550 Non Start

Hi Everyone
My Name is Andy Caddick and thank you advance for any help that you can provide on the problem with my 550.
A few weeks a go I noticed a buzzing sound when the car was turned off which turned out to be the right hand idle control valve. It was chattering away (ignition off) so I disconnected it to stop it flattening the battery. I assumed it was a faulty valve and that it has its own supply that does not shut down when the ignition is turned off ? I then drove the car a few times but on the last one forgot to disconnect the valve... The next time I came to drive it was completely, so I put the battery on a slow charger and it came back up and the car started and ran normally.When I got home and turned it off I restarted to check it was all OK and it started normally. I then read the workshop manual which pointed me to the cut off switch on the nearside wing which I switched of overnight so not having to disconnect the the idle valve. The next day it would turn over but not start, the battery was up and the check said OK on the dash? The problem is no fuel pressure and the pumps are not priming when the ignition is turned on? Am I right in thinking it could be the alarm interface not talking to the Motronic (i think the drivers side UK RHD) ? I have not checked for a spark or if the injectors are firing.

 

My 2 550's will not crank if the immobilizer is not disarmed. So my guess is it is not your immo if the car cranks over. You might just have a coincidental new problem. I have no idea what is up with idle control valve. I don't think they buzz and all. You are the 2nd person who has had an issue with one. I have never had an issue with one or seen an issue with one. Are you sure you disconnected an idle control valve? Make no sense to me. The 1st thought I get when you say buzzing is a dying alarm box in the right front lower area. I hate those alarms and I just leave mine disconnected and the immobilizer still works. I would want to get to the bottom of the buzzing thing...what is that? Then I would be looking in the fusebox area at the fuel pump relays to start. Sounds like you got some Ferrari electrical ghosts to chase on a couple of levels. Maybe the buzz was the warning shot.

 

Or whatever was failing in the electrical system that was causing the malfunction of the idle control valve has gotten to be a bigger problem. In my experience cars do not fix themselves and problems get bigger, not smaller.

 

Andrew,

have you tried resetting the inertia switch (see diagram)?

Stefano
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Thank you for both your thoughts and I will carry out a pin check tonight and check backwards from the fuel pumps. I have the workshop manual wiring diagram but it a reprint and its not clear. I was thinking the same as you Bob that as it will turn over the immobilizer is working? Do i guess the immobilizer sends a signal to the right ecu witch then energizes the pump relay for the 2 second initial prime and then constant when it picks up the crank signal? It definitely was the idle valve that was chattering and getting hot but since it will not start the valve has now stopped so i am wondering has this damaged the ecu?

 

Hi Stefano
I wondered if this could be the problem and pressed it but it seemed that it was not open (no click). Do you know if it just cuts the fuel pump circuit?

 

http://www.ferrarichat.com/forum/142340181-post2.html

 

I crossed a few more things off tonight but found some thing that I think points to the right hand ecu. I checked and there is no current to the pumps and no switching to the pump relays. Again I checked all the fuses and they all are ok and current for both ecu's. All dash lights are normall and the check is ok. Now the thing that is wrong (I think) is the left hand idle control has 12v in the middle pin and 3v on the outer pins with the ignition on and is chattering slightly as you would expect. The right hand valve has no current on any of the 3 pins. Am I right in thinking the feed is supplied directly from the Ecu and maybe it is linked to the pumps not running? I have ordered a new inertia switch and new battery just eliminate both items.
Thanks andy

 

Andrew- Have been problems on 550s with corrosion of the connectors on that right hand Motronic ECU. Make sure everything looks clean and dry in there.

 

Good evening
I changed the inertia switch as a precaution (it was dry) and fitted a new battery. The right hand ecu (drivers side RHD) was clean and dry but the left hand looks to have been damp but the casing is dry with no obvious water staining. As you can see the board is burnt and any thoughts on if you think it's repairable or buy a used or used ECU?

 

Here is the ecu
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Definitely water damage combined with voltage. It explains why it kept powering the valve and it also explains why now it stopped working.
As long as there is no additional damage to components (often not visible, not too common in minor cases like this) the electrical circuit breaches caused by the oxidation should be fixable by an experienced electronics shop. What is on the other side, is ... It looks like a power IC, if it is there is a good chance its busted.
Are the fuses to the ECU intact?

 

Yes the fuses are all ok and I'm guessing the power stage is for the fuel punps ? I turned it over before removing the Ecu and it did fire so I'm assuming the ignition side ok?

 

We have life ! My 550 is now up and running and I cannot believe how it was fixed and how close to home the it came from! I thought it would make sense to purchase a new ECU, although expensive I intend keeping the 550 so if I purchased new one I would get a warranty and it would be fit and forget. The only problem was the ECU is no longer available from Ferrari. Ok next option purchase a used part but Euro spares had no stock and it would have to be from E-bay and the only ones available were offered in Denmark and Australia. My good friend and neighbour Jon asked why the 550 had been parked up and I told him the problems with the ecu. Well Jon said let me have a look, (he works for BAE systems as there lead magnatronics persons in the uk) the next day hands it back identified the 'digital to analogue processor is faulty and this has caused the board damage which he sourced and replaced. 166&456 you were spot on and thank you for all the members that posted on the problem.
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Was it the passenger side ecu? And do you drive in the rain?

 

Andrew, did your friend source & replace only the D/A converter, or did he source a complete replacement ECU board?

Would he be interested in performing repairs in the future?

Always good to know about and have sources to sort out these types of problems!

 

I think Ferrari should be required to recall all the cars that they put (Cobbled) the Motronics Computers into and install a proper Computer system that is designed for each particular car at their expense.
The Motronics Computers are junk and should never of been installed in these cars in the first place.
Sometimes the Motronics Computer in my 550 works so well it tells me to slow down as I am backing out of my garage.

Chuck

 

Chuck,

The motronic functions only as well as the weakest link...and there are a lot of them.

 

I have not driven it in the rain since I purchased it last year but before I owned it it lived outdoors under a lean to garage. The interior is very dry and no signs of water ingress but this is the uk!

 

which ECU? passenger or driver

 

Passenger in rhd

 

My friend just replaced the da converter and said the board is in good condition. I think I will check them regularly for any signs of damp. I can always ask if he would look at any other faulty Ecu's.

 

If he's good (and it seems that he is) he could have a very nice little cottage business repairing these. And if he could crack the firmware so that similar Motronics 5.2 ECU's could be used as replacements (think BMW M73's, etc.) he could do well.

And if he's REALLY good and could remap/modify the software without causing checksum errors and CEL's, he'd have more business than he could shake a stick at. There are VERY few people around who can remap/reprogram the 5.2 ECU's.

 

And remove the alarm ECU!

 

The passenger ECU is a known problem area. Moisture weeps here down the wiring into the ECU and corrodes the pins. The driver's side does not seem to be a problem. There is no universal solution. The wires are too short to make a "drip loop." If I was a regular rain driver I would look into mounting the passenger ECU higher to form some kind of drip loop.