Technical How reset engine light after fuel starvation?

[John R Smith]

But surely in a system where the fuel is the lubricant stopping the supply at the injector to stop the engine is massively different to stopping it even entering the fuel pump?

Fair point. Unfortunately my own experience with diesels is, as I explained above, confined to rather elderly machinery, including some gorgeous engines though - like the big six-cylinder air-cooled Lister diesels we had on board the boats where I worked years ago. You won't damage a Simms or CAV pump by running it out of fuel, though, because the engine just stops dead - the compression sees to that. Remember that the pump runs at half engine-speed in a four-stroke, and these are low-revving engines anyhow (1,800 rpm max for the Gardners). Good grief, just think of all the zillions of farmers out there running diesel-engined tractors, combines, loaders and so on. Farmers in general are the most mechanically incompetent bunch I have ever come across (apologies to any of our farming brethren who may be present), and they will do their level best to wreck any piece of machinery you give 'em. They certainly do run them out of fuel. And yet, in my experience, the diesel engine always comes through still working just fine, even when it has been subjected to appalling abuse and the rest of the machine is disintegrating around it. All this is a bit of a digression, of course, and probably has no bearing whatsoever on the Fiat Multi-Jet engine. But I enjoyed the trip

P.S. Hmm. Just been doing some reading-up on common-rail diesel injection systems. It does rather seem that things have moved on a bit since my day, principally in exactly this area of fuel pumps and delivery systems. It looks as if a Fiat JTD engine would not really be terribly suitable for the average farmer, or the local inshore fishermen either, for that matter. Therefore my friends, if you are the proud owner of a 500 with a 1.3 Multijet powerplant . . . . ignore everything I have said. I'm also glad I didn't buy one (ah, no, didn't mean it, honest guv)

John

 

[rallycinq]

We have a 1978 BMC 1500cc diesel tractor at work. If it runs out, as sometimes does, its a matter of opening the injector supply pipes at the injectors and cranking it until it starts.

Fairly standard procedure on an indirect injection unit.

Can't do that on a common rail.

Cheers

GC

 

[T14086]

On the other hand, every time you stop the engine, you do actually run it out of fuel - turn off the supply to the pump and injectors - it's the only way to stop a diesel. And it does no harm, of course.

Just been doing some reading-up on common-rail diesel injection systems. It does rather seem that things have moved on a bit since my day, principally in exactly this area of fuel pumps and delivery systems. It looks as if a Fiat JTD engine would not really be terribly suitable for the average farmer, or the local inshore fishermen either, for that matter. Therefore my friends, if you are the proud owner of a 500 with a 1.3 Multijet powerplant . . . . ignore everything I have said. I'm also glad I didn't buy one (ah, no, didn't mean it, honest guv)

John

sure have, modern diesels have lift pumps in the tank to start & shutter valves to stop.

 

[The Sultan]

if you run a modern diesel out of fuel you simlpy have to fill it up again and turn the ignition on and off a few times to allow the lift pump in the tank to prime the pump and the injector rail unless of course you have a ford diesel in witch case there is no lift pump and your buggered

it's not posible to damage the pump if you run out also as you have run out so your engine stops there for the hp pump is no longer turning right pretty obvious

one thing that's got me thou is that the engine light should not illuminate if you run out of fuel in a petrol or diesel

the reason for this is that the engine ignores running faults like misfires and fuel pressure problems when the fuel light is illuminated this is put in place simply so you don't have to visit the dealer every time you run out of juice

i would there fore be interested in what the error stored is i wonder if the op could ask for me when they go in

 

[John R Smith]

It's a good job that you're around to straighten us out from time to time, Littlepip. So there are in fact two pumps on the (for example) 1.3 Multijet, a lift pump back at the fuel tank and, as I would have thought, the high-pressure pump on the engine which delivers fuel to the rail. This makes much more sense, otherwise you would have to have high-pressure lines all the way from the tank to the engine. So, as you say, there is no reason for the engine management system to log a fault code just because the fuel has run out.

John

 

[The Sultan]

It's a good job that you're around to straighten us out from time to time, Littlepip. So there are in fact two pumps on the (for example) 1.3 Multijet, a lift pump back at the fuel tank and, as I would have thought, the high-pressure pump on the engine which delivers fuel to the rail. This makes much more sense, otherwise you would have to have high-pressure lines all the way from the tank to the engine. So, as you say, there is no reason for the engine management system to log a fault code just because the fuel has run out.

John

yes correct it should simply ignore it when the light is on the lift pump in the tank circulates fuel into and out of the high pressure pump low pressure side in order to aid cooling and also to prime it

i haven't looked closely at one of those fuel systems yet so couldn't tell exactly were all temprature and pressure sensors are but i'm thinking it may have been something along those lines as i suppose if the temp became to high it would have to warn you of that along with lowering the pressure and changing the injection time's to reduce the temp

ford diesels rely solely on the hp pump to draw fuel from the tank so if for example at work we change a fuel filter on one if we end up with a little to much air in the system it all goes to pot and we have to tow start them in order to turn the pump quick to prime them either that or carefully fill the filters and line with a small funnel and some diesel before putting all the lines back it's a complete hassle

we now get proper ford filters not ek's as they come with little plugs to block every line and stop all the fuel escaping

 

[Most Easterly Pandas]

modern mercs have no sump plugs so only they can change oil

Yea, how do they do it? Perhaps they stick a big straw in the dipstick tube

 

[Venters]

They stick a straw down the dipstick hole and pump it out.

 

[jmcd]

But if i remember rightly after a certain number of engine startups the EML light should turn itself off because it does a self test everytime the engines run and after it sees that there is no problem after said amount of startups it should turn out the light but retain the code in the memory. thats if i remember right that is...

The engine management light came on on my Idea Multijet the other day. The missus was driving it and apparently had the handbrake on a bit for the journey too (if that would make any difference) It was very low on fuel at the end of the journey. She didn't know when it had come on. But I had enough fuel to get to the garage the next day. That was Saturday night and as of today at 12 it is still on. It goes off for a second after starting but then on again. I would have started it at least 20 times since then. Performance doesn't seem in any way compromised. Any other ideas - no pun intended!?

J

 

[baxwalker]

With less and less services staions remaining it would be very easy to run out of fuel in an area you are not used to. In Canterbury there are only 3 service stations left and only one is open 24 hours. I hate to think what it is like in more remote areas of the country.

 

[jmcd]

Update:

The other day, the car was very low on fuel again. What I mean here as with the last time is that the trip meter went to ----- for the number of miles left in the tank. The car didn't splutter or anything but it was quite low, I presume. Anyway, the engine management light went out again! I did nothing about getting it read and it didn't seem to affect the driving. Just for your information. By the way, the car seems to do about 53 to the gallon.

John

 

[123fran]

My check engine light has been on for two years and won't go off it passes its not and the mechanics say they don't no why it won't go off

 

[ahmett]

My check engine light has been on for two years and won't go off it passes its not and the mechanics say they don't no why it won't go off

LOL 2 years! Surely there is an error code. What does it say?