Fiat 2.3 multijet 2011 X250 130bhp
When I start the engine the alternator won't start charging unless I blip the throttle.
So monitoring the Voltage charging if i start engine and don't touch the throttle it stays at 12.5v then after 30 secs the engine automatically increases engine RPM to about 1,500, still no charge voltage. It stays at that RPM.
Now if I blip the throttle voltage will rise to 14.2v and engine will then drop back to tick over and stays at 14.2v. All good.
I know as the ECU doesn't see the battery charging then it increases RPM to 1500 to compensate.
If I start engine and then blip throttle to aboui 2K RPM for a few seconds the Voltage rises to the charge voltage 14.2 and then engine stays at idle.
I have replaced the earth strap, engine to chassis as this braided wire is known to have issues with corrosion and the ring crimps.
Do alternators get 'Stuck' and need a kick of RPM to get going sometimes?
All the time the battery dash charge light goes out.
I don't have a problem with it being like this as it charges OK when driving, But something must be wrong.
in the boot
My alternator doesn't kick in for about a minute after starting the engine. It has been like that since I fitted it, so I assume it isn't a fault. It certainly works well enough when it starts. Revving the engine doesn't make it start any sooner.
I had a similar problem with mine some time ago and under the ecu where the loom drops after passing over the engine and dropping down to come up to the ecu it had worn through by rubbing against a support bar and the D+ wire was shorting. You could probably try this by reaching down and flexing the loom it's not easy to see but you may just spot with a lamp where it's against the bar bolted to the inner wing. Its quite common on Fiats
I think you may have a "smart" alternator fitted? They are setup so most of the charging is done when the vehicle is in the decelerate phase. Thus, when you blip the throttle it kicks in as the vehicle revs drop.
I'll put the diagnostic OBD2💻 on it later and see if that comes up with anything, and also check the loom routing as per witzend post. 🤞
I've had this Moho about 20 months and it started doing this about a year back, and sometimes the heater plug icon flashes for a while too after starting, a common fault. I just have a bit of time now to try and sort it.
And report back.....
in the boot
No smart alternators were fitted to pre Euro 6 Ducatos, and only on Euro 6 with Stop Start.
I don't know if this might help. I know you've replaced the earth strap, but I saved this from another forum some time back as a reference in case of future problems. The author recommends an additional earth strap made from welding cable or similar, not just relying on a replacement braided strap.
Before you do anything else, you must check the charging rate of the alternator. Use a multi-meter across the jump start points under the bonnet with a multi-meter and make sure that you are getting at least 14V. It's not the ideal place to do such checks but it will give you an indication of the output.
If you see less than 14V you will need to check and/or upgrade your earth strap.
There are some very frustrating electrical issues with the X250 van. We have had many instances where, completely without any warning a van has refused to start. This is normally due to degradation of the earth cable that runs from the gearbox to the chassis. For some insane reason the ECU gets it's power through this route and if there is insufficient current it just will not play ball. While driving you can sometimes see the battery warning light on and this suggests a lack of charge being returned to the battery. It never actually is though; it is the ECU flagging a problem in the only way that it knows how.
The first thing to do is to clean the joint between the earth strap and the chassis. This may help, but if you see any oxidisation on the cable it will almost certainly need replacing. Get a new one made up by an electrician and make it 6" longer. Attach it securely to the chassis point and then remove one of the screws on the gearbox end cover. Put the other crimp terminal in place and screw it down tightly using a shakeproof washer. This is the best you can do and appears to be the 'fix' recommended by Fiat to the dealers. We have had no further problems with vehicles so modified, but more than half of the vehicles we have over 2 years old have had to be repaired.
The first thing to do is PROVE it is the earth strap. You might have a dodgy alternator but to be honest you would probably have a warning light on or at least elevated revs while idling.
What you need is half a pair of jump leads. You only need one cable with clamps on each end but they need to be good ones; no feeble budget Halfords rubbish!
With the engine off, connect one end to the earth point at the top of the front grille and the other to the lifting eye at the rear of the top left-hand side of the engine. Once this is all secure, start the engine and measure the voltage as you did before. If this additional earth is working, you should see a much better voltage which proves that with sufficient earthing, the alternator can pass on the power to not only the battery but most importantly; the engine ECU.
Assuming I was right, you need to get a new earth lead and attach it to the chassis point where the existing one is secured (straight down behind and to the right of the air filter). Leave the old one in place. It won't do any harm.
The other end goes to one of two places. If your vehicle is a EURO4, you will have to secure it under one of the gearbox end cap screws (a lead of about 12" will do for this) but if you have a EURO5 there is an even better place to fix it. The EGR cooler tube (square aluminium, about 8" long has some curiously long screw threads exposed and Fiat have left enough room to place the loop of the earth strap over it and fit a new nut on. It's tight but it can be done and it's the better option if you can do it. You need a strap of about 18" to do this.
Earth leads need to be long enough to allow for a little engine movement and need to be guided around and away from any obvious sources of chaffing. Any excess should be looped in a 'pig tail'.
All you need (apart from the new lead) should be a 13mm socket, a ratchet and 6" extension plus a 13mm spanner and 8mm (flanged if possible) nut. If you are removing a screw from the gearbox end plate, I think it's a Torx 40. You would need to be underneath for access to the gearbox but EURO5's can be done from above. It may help to remove the air filter cover to give you some more space and remember to put some grease on those screws before you put them back.
By the way; NO those braided things are useless. You need a lead made from 'welding cable' and terminated in proper crimps with 8mm holes. I believe that Halfords can make these up for you as can auto electrical specialists but I don't see any point in adding another crappy braided cable that will probably not even last as long as the Fiat original one!
I replaced the earth strap with 16mm CSA earth tri-rated cable and crimped ends myself so am confident that's OK, did the jump lead test too.
Now Just trying to find my OBD2 BT box...... last used about a year ago to trace the fault when the throttle body failed and I had to replace that over last Xmas !
in the boot
After an hour of looking for the OBD2 box found it, doh, still plugged into the OBD2 socket on van 🤣been there the last year. Sadly didn't come up with any fault codes.
The alternator, consistently, always starts to charging once the engine is revved to 1,510 RPM. Then it behaves itself.
in the boot
It sounds like a faulty regulator in the alternator to me.
I would take it to an alternator specialist (or at least ring them) they will be able to advise you and most likely repair it.
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