General non-starter

[k5krc]

Hello, new to this!!!
Ive got a ducato 18 jtd longwheel base, on 03 plate and its a common rail type. It wont start when cold but will start with easy start and then it'll start ok once the engine is warm. I've took it to my local garage and they've tried sensor in the rail and he seems to think its the diesel pump. He's bought it back doesn't seem to be to interested in working on it! Could anybody give me any advice on this?
Much appriciated Keith

 

[Arkk]

Hi, advice is SELL IT.
Check my post from 4 days ago, Ducato 2.8JTD starting problem, it won't fix it for you, but may give an indication of what not to spend money on. I tested 578 lasted night with an oscilloscope, and found the crank sensor output was only .65 to.78Vac. After adjusting the clearance ( increased the air gap), voltage increased to .9 to1v ac. Still no start. At this stage I'm getting a price on building up a Denso gear reduction starter to crank the engine at a higher speed. Hopefully that will work.
Cheers, Ray

 

[Torq]

Hi Guys,
I've been thinking about this problem and my guess is that both your problems are down to compression or fuel atomisation issues. From reading the bosch common rail yellow back books, the engines only need the preheated fuel at minus temperatures and rely on compression and fuel atomisation to start the rest of the time.
Arkk, I see yours is an ambulance, high mileage? Have you done a compression test? If it is down you could get a head skim and a thinner gasket to bring it up to spec.
K5kcr, pour a full can of diesel injector cleaner into the diesel filter with a warm engine, so that it will start, and run for a while. leave to cool down then give it a go.
Keep well,
Torq

 

[Arkk]

Hi Guys,
I've been thinking about this problem and my guess is that both your problems are down to compression or fuel atomisation issues. From reading the bosch common rail yellow back books, the engines only need the preheated fuel at minus temperatures and rely on compression and fuel atomisation to start the rest of the time.
Arkk, I see yours is an ambulance, high mileage? Have you done a compression test? If it is down you could get a head skim and a thinner gasket to bring it up to spec.

Hi Torq, No Ambo 578 has only done 175000km. Compressions ok. Ambient temp shouldn't be an issue, just come out of summer with Temps in the low 30's cel. Have just removed, cleaned,tightened every connector plug I could find in eng bay. Found plug on top of pump was not seated fully (3rd
piston deact ?), but made no difference. Used cold start Friday am to start it, had it running on & off for 90 min while testing various sensors. 5 hours later I started it numerous times and couldn't get it to fault. Saturday am it started first go, 3 hours later it struggled to start even using starting fluid, to the extent that I all but flattened a battery. Fuel pressure is definitely low when the fault occurs, but I can't determine whether fuel pressure is low due to cranking speed, or vice versa- (chicken or egg). Measured crank speed is ok, fuel pressure varies 60 -110 bar, leaps to 300 on start up. These systems have pilot injection, and I think the ECU has to detect adequate fuel pressure and crank speed before switching main injection on- perhaps someone out there could advise me on this.
To recap: mechanically everything tests ok; compressions fine, new HP pump & injectors, etc.
Electrically all injection related components have been replaced, with new or 2nd hand(off vehicles without faults- if that is possible for Fiats), some more than once, ck, cam, pressure sensors, press reg, etc. ECU has been substituted. On occasions faults log on Fiat Examiner scanner, but more often not. The ECU has to detect a fault for a certain no. of cycles before it logs a fault, so if a sensor was playing up it certainly should log a fault in the time it's taken us to get it started. The best theory anybody has given me yet came from a hillbilly looking dude from a country garage. I went thru its history when he was in my workshop , he tried to start it, stood back and said dryly "It's probably got a ghost in it, maybe someone died in there". Could explain a lot.
Thanks for replying Torq, any more ideas gladly received, even if we've tried them before, it could be some procedure we've applied wrong or overlooked. Cheers, Ray

 

[Torq]

Last things I can think of are the clutch pedal sensor and the accelerator sensor, they are the only things you haven't said you had changed. I think someone here had a problem with a high resistance on one of the wires from the accelerator and that was the cause of their starting problem.
Keep well,
Torq

 

[Arkk]

Last things I can think of are the clutch pedal sensor and the accelerator sensor, they are the only things you haven't said you had changed. I think someone here had a problem with a high resistance on one of the wires from the accelerator and that was the cause of their starting problem.
Keep well,
Torq

Hi, Yes Torq I have replaced the TPS. There is no clutch sw in our versions, they started life as manuals, but were converted to ZF autos by the NZ importers, apparently the same box used in the Euro LHD version, quite troublesome too. There are 3 or 4 in the fleet that have had the auto done on 2 or 3 occasions. 578 left me today to move in with the Fiat dealers for a while, but she was replaced with yet another (556), that has apparently an identical fault. Its starting fine for me and when I scanned it, there were no codes. The pump pressure on cranking is definitely higher than 578, about 200 bar. I found some info yesterday stating that the ECU will only switch the main injection system once it has detected high enough cranking speed & pump pressure. Until then it runs on pilot pressure, which I suppose in theory should be enough to initially fire and increase crank speed, therefore increasing fuel pressure. 578
needed starting fluid today, ran for 1.5 hrs, turned it off for 12-15 min, then refused to go again, requiring yet more starting juice. My biggest fear is the dealers will find and fix the fault in 5 minutes. Thanx Torq, Cheers, Ray.

 

[T14086]

My biggest fear is the dealers will find and fix the fault in 5 minutes.

surely with a fault of this 'magnitude' examiner (fiat diag) would easily be able to locate the fault simply through observing vehicle parameters.

 

[daza001]

Get someone to do a dielsel leak off test at the injectors have seen it before if they start when warm and not from cold give it a go.

 

[Arkk]

Update on this old problem vehicle. I forgot clean about this one till scrolling through old posts, and realised I'd never updated it. The vehicle 578 went to the Fiat dealers, who replaced injectors and sent the vehicle back a week later fixed. When I queried them, saying the vehicle had already had 2 sets of injectors, they said "Oh we did a few other checks also". Say what????? The fleet manager spoke to them and they actually said "there were obviously other faults the auto sparky fixed first, when it came to us we couldn't find much, so fitted new injectors". Didn't help me get to the bottom of the problem though.
We had another one keep going into limp home mode a couple of years before that, replaced all sensors, ecu, etc. It got sent to the dealers as I couldn't fix it (not to mention their own fleet mechanics, 2 other auto electricians, and 2 diesel injection specialists). It got sent back from the dealers in the same condition, unfixed, but fixed itself a few weeks later. One of the more experienced drivers was cruising about 90k, the van lost power, backfired (strange for a diesel), picked up revs, and hasn't missed a beat in the last few years!!