Hi I need help with a 2002 Ducato 2.8JTD. Engine dies intermittently, hot/cold, after a few hundy ks, or 2-3 times in as many ks. We have replaced rail pressure sensor, pressure reg, tank pump/gauge unit. DTC P0191, Diesel Pressure Test is the only code up. The other day the injection light came up and fuel gauge dropped (a few days after tank unit was replaced), so checked wiring. Thought fault was in the 4w plug behind air filter housing, so cleaned and checked that. Thought I'd simulate fault so pulled plug with eng running, obviously stopped, no DTC. Cranked, wouldn't log a DTC. Found that it logged the fault only if plug was discon at above 1200 revs. Also found that once this fault was created, there was no way the engine would restart after plug reconnected, if the key was turned off, straight on, and then cranked. We found the key had to remain OFF for 20-30 secs or so. Rechecked wiring to tank unit, replaced fuel pump relay, road tested with cell phone and tow rope on board. After 1.5 hrs mixed driving, I was decellerating from 130k when it died, DTC P0191. Did it again when decel from hard out in 2nd gear. My next thought is to wire a couple of warning lights to fuel pump input, and relay winding.
Has anyone had this fault before, or have a suggestion as to what it might be? Any help appreciated, thanks.

Hi.
When you say engine dies do you mean cuts out or loses power?

Hi cris1117
Totally cuts out like you have turned the key off. Can go ok for days, very difficult to get fault to occur in workshop. The instant it cuts the injection light comes on. No other warning, doesn't miss or loose power first, just cuts out. I haven't had the chance to check fuel pressure on scanner at the time of the fault, but most scanners lag behind, it might not tell us much- is fuel pressure loss causing engine to die, or is something else happening first? Can anyone tell me more about code P0191 than scanner description- "Diesel Pressure Test". The tank unit was replaced because fuel gauge was not reading. Found out later that the engine cutting out fault was already present before tank unit replaced. Drivers failed to tell us about that little problem!!
Thanks

Just been for a tiki tour with warning lights on pump relay wires. Stopped once, no relay output. Tried again with a light between B+ and relay winding negative. Lost ECU negative at relay momentarily. B+ and Ign+ both ok at relay. Points to ECU fault. I'll redo test with light connected to pump relay wire at the ECU, if it still fails, it means relay and wires are ok, must be either ecu or some other circuit causing ECU to shut fuel off. Any other sensors should bring up their own codes, and feeds and earths all test ok.

Retested last night with warning light between ign and ECU pin 24, connected at the ECU. This is the fuel pump relay neg circuit. The engine never cut out, but the light flashed off a couple of times when slowing at intersections, not long enough to cause engine to cut, or log a fault code. ECU connections all ok, suspect a fault in the ECU. Any ideas welcome, thanks.:bang:

Update-- New Year, Same old problem. Fitted an ECU, KCU, key, etc out of another vehicle, faulted 3 times within 1km of wkshop. Four more trips of a few km each, before it faulted another 3 times. Code is now P0215, Fuel Pump Sugnal not valid. Fiat examiner suggests pump, pump relay, ecu-- all been changed, and wiring connectors, insulation, and continuiity. Have replaced wire from pump relay to ECU. I have proved beyond doubt that the fault occurs on deceleration only, but is often only momentary. I have wired the fuel pump relay winding direct to earth, and installed a second relay on the ecu wire, with a buzzer thru the contacts. This screams when the fault occurs, but the engine keeps running, due to the fuel pump relay bypassing the ecu. It seems that if it is only on decel, then it may be caused by wiring moving, but the pump relay and ecu wiring are all body mounted. The only other areas to check are the main earths/feeds off the engine, but it is odd that the fuel pump relay fault is the only code coming up. This has been checked with Hanatech, Bosch, and Fiat Examiner scanners, all give the same result.

i would have started with the pressure regulator on the pump can you log or graph ecu data?

i would have started with the pressure regulator on the pump can you log or graph ecu data?

p0215 is engine shutoff solenoid malfunction which you have caused
by rewiring the relay

Hi Corkman, thanks for responding. The pressure sensor and reg have both been replaced before the vehicle was brought to me. Perhaps I should revisit this area. I would have thought the regulator would have logged its own code though. I see the error of my ways regarding P0215, thought I was so clever fitting a second relay!!

I just remembered your original post. I got to the stage where I was ready to put in an old 2.5 engine when I discovered I had a dodgy injector - it was AOK 98% of the time then would suddenly spew diesel into the return. I had no MIL.

If you can graph the rail pressure with something like fiatecuscan it might reveal all. I think fiatecuscan has an actuator test for the regulator so you can vary the rail pressure and monitor the result.

I'd do a leak back test to rule out a faulty injector if only because its an easy check. If the pressure dropped under 230bar the engine will cut out.

Two other people have mentioned a small bit of dirt in the pump blocking the pressure regulator so if you're taking out the pressure regulator clean all around it to spotless - clutch and brake cleaner is great for this. I'd suck out the diesel in it and if you turn the key (without starting) I think the tank pump should be sufficient to flush fresh diesel through the pump and out the hole might float out whatevers in there.

If that doesn't resolve it I think I'd be graphing everything I can so see if theres another problem thats not being logged as an error, cam / crank sensor etc.

Are you sure the replacement regulator and rail pressure sensor are the correct ones, not unheard of to get the wrong thing from the dealer.

You're not losing electric power completely are you? This might explain another fault not being logged.

Hi Corkman, , have just replaced cam, crank, fuel pressure sensors, and fuel pressure regulator, road tested after each change, fault still active. Stripped loom from pump relay to ecu yesterday, all ok, tightened ecu pins. Checked feeds and earths again. Still have fault. I haven't scoped it yet, I'm not much chop with oscilloscopes, but will try it out. Power supply to the ecu is ok, we have checked inputs, but also the test lights I have rigged up keep going when the vehicle is faulting, and one of them is using the same power supply as the fuel pump relay, which is driven from in the ecu.
Thanks for your ides, I'll try the scope tonite.

During the week we removed and stripped the engine to ecu loom, and removed the battery tray, to inspect the small loom under there. That loom had two wires rubbing on the eng mount, but they were a/con to ecu wires. Still hopeful they may have caused issues, but on first road test it faulted a few times. Also replaced solenoid in top of pump (3rd piston deact), still faulted. Checked fuel sensor with oscilloscope, no difference when faulting. Fuel returns all even.

OMG I feel for you! You must be ready to put it into an auction!

You say its on deceleration you have the problem, is there any chance that something is physically moving like that big rats nest of connectors over the left strut (maybe right strut on left hand drive?) or the earth getting tugged. I suppose you probably given all the wiring a good shake by now.

Where are you getting the parts not new I hope? The only thing thats left really is the fuse box check for water ingress, check relays for signs of arcing. The immobiliser unit on the steering column.

Hard to believe its not throwing a useful mil.

Have checked the wiring over the strut, but thats not always conclusive- a visual check on the connectors. Have had a couple where I've checked the plugs with a Fluke meter, and inspected the terminals under a spot with a magnifying glass, couldn't fault them, ( this was the TPS 6w plug), put new connectors in and solved the problem. The parts we are using are out of the fleet workshop stock, there's about 40 Ducatos of various models, we have used one for donor parts, like the ecu and kcu. I think next I will have to get one the same model, and do tests on both at the same time, to see if there are any differences. The fact that it is an ambulance means it can't go back on the road til it's 100% fixed. A normal van wouldn't matter so much if it stopped in the middle of an intersection, just liven up your day a bit, but an ambo failing is not a good look, and potentially fatal.
I've been thru the wiring diagrams, identifying everything I can that is related, and tried to rule them all out. Have gone back to basics, checking for loose connections, shorts, etc. I'm at the stage now of thinking the biggest loose connection is in my grey matter!!

I have an ex service 2.5td ambulance came with the biggest starter and alternator I've ever seen, twin batteries and immobiliser disabled as standard. I reckon you could take out the piston rings and it would still start.

I don't think common rail is reliable enough for mission critical service. If I had to set out around the world, across the ghobi desert or the outback I definitely wouldn't be bringing a high pressure injected diesel with me. You'd need to be pulling a trailer with spare parts.

Do you have diagnostic software that can graph?

No, I don't think the Fiat Examiner can graph. I've got a mate coming round one evening next week who is a gun on scanners and scopes. I'm also trying to get a donor vehicle at the same time to see if we can nut it out with a few comparisons. In some ways I hope it is something simple so I can get it fixed, but if it is simple, what have I been doing for the last 2 months???? I'll let you know how we get on.

Further testing on this problem van tonight, had a mate with a good scope, tested fuel pressure, and scoped pump relay, compared to another van. Then we set the scope up on fuel pump relay negative wire, and pressure reg signal wire, set off on a road test. Engine faulted twice, scope showed clean break from neg to pos on relay winding, which means it was being switched by ecu, not suffering from loose connection or shorting to something else, and the rail pressure reading hardly varied. We wired pots into the rail pressure signal to try to simulate the fault, but couldn't get p0191 to come up, then tried same at pressure reg, no fault showed even when engine cut due to our introduced faults. At the end of it all we are still stumped, we have ruled out a few more things, but still don't have an answer. The Examiner wouldn't even communicate with the ecu tonight, temperamental rubbish, Hanatech was fine.
Has anyone got a list of ECU pinouts for the 2.8JTD? Would be much appreciated if we could have them. We are doing a bit more research, and will have another try next week. Too much other work on at the mo. Will have to do a couple of all nighters to catch up.
Will keep you informed if we get anywhere.

Hi Arkk
The ECU pinouts for all the various versions of the 2.8 JTD are listed in the 02-06 eLearn manual under - Descriptions> 10 engines> fuel systems
There are also Diagrams & Descriptions of each Sensor showing input/output flows between engine management unit sensors/actuators & also their locations etc.
Cheers

Thanks F.S. Checked them out this a.m, soon as I saw them I thought I've already printed them in the past.
After our tests last night we proved ecu feeds, earths, etc. are ok, fuel pressure was ok at the time of the fault, pump relay winding was still fed, but pump relay neg line through ecu went positive on fault, in other words the computer turned the pump relay off momentarily.
Hope you are high and dry over there, looks like you got more nasty weather coming your way.
Thanks for your quick reply,
Cheers

Inertia switch?