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Discussion Starter #1 (Edited)
Hi!
My name is Luis, I'm from Portugal and I need your help.

I have a 147 JTD 16v Distinctive, bought new in 2003. It has now 356.000 Kms, and has been an incredible reliable car. Repro for 180hp (main cat off and EGR blocked). No smoke. Turbo, MAF, MAP, EGR, etc, were never replaced. :)

A couple of months ago I had the very first problem. Turbo, EGR, glow plugs, MAF, etc, all stopped working. Result: Limp Mode. Several errors in MES.
I knew they wouldn't all have got damage at the same time, so something else would be causing this.
After several hours and several test and after replacing all components that were getting errors (my friend has an extra engine on the workshop, used, so it is easy to test) we could check the errors were the same and that these components weren't getting electric current.
So, we tested with an external wire direct from the + on the battery to a wire that goes to the turbo solenoid. Suddenly, everything is working again, just fine.

I still haven't found where the problem is. Maybe a broken wire? But where?
I replaced the glow plugs relay for another one (again, used) and it didn't change anything.
I believe it's this relay that sends current to the glow plugs and also to the turbo solenoid, EGR, MAF, etc. Am I right?
Can this used one be also bad?

One thing I also replaced is the gas pedal. MES said only track 1 is OK. No reference to track 2 error, but I can see it measures double the voltage on track 1 than on track 2. Is this normal?
With the "new" pedal nothing changed, again, and same measurements.

Car is running just fine since, no errors except the Main Relay error, but since I already replaced it with the other used one and nothing changed, I don't know it this is the problem or if this error is just caused by that external wire, somehow...

Anyone has any suggestion?
Many thanks,
Luis
 

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Discussion Starter #2
Anyone, please?

I'd like to clarify this, in case anyone can help:
One thing I also replaced is the gas pedal. MES said only track 1 is OK. No reference to track 2 error, but I can see it measures double the voltage on track 1 than on track 2. Is this normal?

Many thanks,
Luis
 

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I only have information for the 156, but they are probably similar. I think the maf,turbo vnt, egr and glow plug control are all powered from the same fuse, so that is the first thing to find and check. It will be in an auxiliary fusebox but I don’t know where.


The glow plug warning may mean a plug has failed, if you pull the connectors off you can measure the current each one draws with an ammeter connected straight to the battery. Iirc it’s about 9A initially falling as they heat up, they should all be the same anyhow.


I think it is right for one track of the throttle to give twice the voltage of the other one. If the car is running well and not flagging a warning about it I would not worry about it.
 

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Discussion Starter #4
R.T., thank you for your help.

Fuses were all checked and all good.

Question is, if I remove the external wire I'm using at the moment to "inject" current directly from the battery, no current get's out of the glow plug relay (or should I call it temporizer?) to any of those devices, although the relay has power (there's a cable directly from the battery to it).
I'm not sure if it's a broken wire elsewhere...
Can it be the ECU that controls the glow plug relay that isn't doing it? I tried another ECU and the problem was present, also. Broken wire between the ECU and the relay?

Good to know about the gas pedal.

Many thanks,
Luis
 

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The glow plug relay has two power supplies. The high current glow plug supply straight from the battery fuse box, and a low current supply it shares with the other devices (egr etc.). The fuse I refereed to feeds a common point from which all the devices including the glow plug relay are supplied, so if the fuse is good the wire to the common point must be broken, but also the wire from the common point to the GP relay, since ‘injecting’ current with your wire does not restore GP function. While possible two breaks seems a little unlikely so checking the plugs, the high current supply to the GP relay and its earth would be worth doing. Also the control lines from the ecu, but see below.


If the problem really is with the low current supply to the GP relay (and other devices) finding the break(s) may be difficult and it may be easier to continue to use your wire and extend it to the low current feed of the GP relay, to get that working. It needs a fuse: 15A, and should be taken from an ignition controlled relay so that the battery is not drained when the car is standing.


(The GP relay is controlled by the ecu but since your car is multiplexed and the 156 not the means of doing this may be different. Hopefully the power supply arrangement I described is common.)
 
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