Technical 2.5 tdi 1998 fuel pump wiring

[Kveite]

Hi,

I have a 1998 2.5 tdi that just died on me. It had been sitting for a month where I had it on a long trip before that so no issues. It started just like normal, but when I was to set off I seemed to have stalled it and it just would not start up again. Turning over just fine, but no ignition and some white smoke out the exhaust indicating unburnt fuel through the system I think. I checked if any fuel came out of the recycling pipe leaving the injectors and it was very little I would say. Fuel filter was full, but replaced it as it was old anyways. Then I realized that there is no fuel coming from the tank and I thought these guys were supposed to have a low pressure pump to prime the system there. My unit has three wires where I think it is a common ground and one gets 7v for the fuel level and the other one is dead.

Does anyone know if I certainly should have a pump or if some of these do not and only run of the mechanical one?

I have not found a wiring diagram for mine and whatever work shop book I can find it seems not to cover it or not be for my van. Mine only has fuses and relays in/under the glove box where the owners book mentions a fuel fuse in the left side of the engine bay, but none are to be found. I also managed to trace the white/red wire from the pump/fuel sender into a mulitconnector on the left side of the dash where it still has conneciton to the tank, but no voltage - measured with the iginittion just turned on so no waiting too long.

Checked the inertia sensor behind the battery which seems fine. The immobilizer light comes on every third time or so, but a few attempt with the keys and it goes away as it always has.

Anyone with an idea of where to look next? If I have a pump and where it is fed from? Right now I get an open circuit between the white/red and the black in the three pin connector on the tank so seems to me there is no or a faulty pump, but I also get 0v so nothing is asking it to run either. I have also chimed the engine with everything connected except the fuel hose in to the filter and nothing comes out naturally.

 

[Communicator]

Hi Keveite,

From Wikipedia the Iveco 2.5 TDI, 8140.47 engine was used until 1998.

I think that this engine used a mechanical lift pump, which is separate from the injection pump. (See attached link, which shows two examples.)

If your vehicle has a mechanical pump it will be mounted on the engine, as they are usually driven from the camshaft,

Again if you have the mechanical pump, these can suffer from a failed diapragm, which will allow air into the system..........

In the past, I have repaired mechanical lift pumps by changing the diaphragm, but due to design changes, this is probably no longer possible.

If I am wrong, which is quite possible, I would expect you to have heard an electric pump running whenever you turned the key.

https://www.mister-auto.co.uk/fuel-pump/fiat/ducato/ducato-box-230-2-5-tdi-109hp-1994-2002/

 

[Kveite]

Hi Communicator and thank you for the reply.

I looked up the Iveco engine you listed online and compared it with mine where it seems like I do not have the mechanical lift pump as mine is just blanked off there. I decided to make a mess and pull up the fuel sender / possible pump from the tank and it showed that I also don’t have a low pressure pump in the tank so now I am a bit bewildered. I took a photo where it shows no mechanical lift pump I think, and I’ve put an arrow where the pipe from the filter goes into what I at least think is the high pressure pump. The fuel line/pipe goes straight from the tank to the filter and straight from the filter to this shown in the photo. Could mine just only rely on the suction of the main pump without a lifter/primer?

I will try to run the starter for a while to see if any fuel moves now that I know the pressure is not coming from the tank at least. I am starting to think maybe fuel is not my issue and I should check timing instead in case the belt has jumped a tooth or two again. It did that on me a year ago, but had a garage fit a new one for me so didn’t expect it to go again so quickly

 

[Kveite]

Anyone knows what this does? It is connected to my fuel return line it seems.

 

[Communicator]

Anyone knows what this does? It is connected to my fuel return line it seems.

Hi,

I cannot see all of the pipework, and electrical connections, but I will suggest that it is the electrically operated control valve for the (cold) flame start device.

A flame start device is fitted to my 2006 2.8 JTD, which is derived from the 2.5 TDI.

For a descrption see the following link which I found informative, as I was puzzled by a similar looking device on the inlet manifold of my vehicle.

Also I am attaching a pdf copy of the eLearn description of the cold start device for the 2.8 JTD. If I am correct, the principles will be similar.


https://motor-roam.co.uk/ducato-cold-start-flame-start-system-explained

 

[Kveite]

Ah, that makes sense. Thank you for the explanation. As it’s summer time it should not have anything to do with my issue, but nice to know what I am looking at. I am learning as I go here, but still no idea why the engine had the sudden change of heart and just does not want to ignite. I hope someone has a good idea while I continue a bit on my own ?

 

[Kveite]

It seems like the engine is pulling fuel. Ran it on the starter a few times before coming up with the plan of attaching a vacuum pump on the outlet of the filter which resulted in a few pumps gurgling some diesel and air, but certainly not a filter full so something must have happened. Tried to put the vacuum on to the outlet of the injectors, but was not allowed to pull anything through that part of the system which makes sense I guess. Had a cup under the same outlet to see if anything came out after turning the engine on the starter for a while a few times, but not more than a few drops I would say. We’re back to a point where there is a lot of white smoke out of the exhaust again though which lets me to believe fuel if going through, but weird I am not seeing any or more on the return line.

Does anyone know for sure how to know if fuel is going through as should? That the immobilizer, crash cutoff or anything else is not stopping the fuel, and the pump being fully primed?

If I can be certain fuel is going as should then I think I am down to the timing and the belt jumping a few teeth on either the pump or cam - unless there are more ideas flying around.

 

[Communicator]

Hi Communicator and thank you for the reply.

I looked up the Iveco engine you listed online and compared it with mine where it seems like I do not have the mechanical lift pump as mine is just blanked off there. I decided to make a mess and pull up the fuel sender / possible pump from the tank and it showed that I also don’t have a low pressure pump in the tank so now I am a bit bewildered. I took a photo where it shows no mechanical lift pump I think, and I’ve put an arrow where the pipe from the filter goes into what I at least think is the high pressure pump. The fuel line/pipe goes straight from the tank to the filter and straight from the filter to this shown in the photo. Could mine just only rely on the suction of the main pump without a lifter/primer?

I will try to run the starter for a while to see if any fuel moves now that I know the pressure is not coming from the tank at least. I am starting to think maybe fuel is not my issue and I should check timing instead in case the belt has jumped a tooth or two again. It did that on me a year ago, but had a garage fit a new one for me so didn’t expect it to go again so quickly

Keveite,

Your idtd will not use the injection pressures that are as high as those of common rail engines. Hence no requirment to fit new injector pipes if disturbed. So why not loosen an injector pipe and observe for fuel leaking when the engine is turned over? That should answer the fuel question.

Back to basics, in order to start, a diesel engine needs fuel, air, and a cranking speed of about 150 rpm.

So to continue, is your vehicle stored outside? Is there any possibility that mice have nested in the air filter, and blocked the airflow?

I am still puzzled as to the missing lift pump. Many years ago, my first vehicle was a diesel Landrover. It had a mechanical lift pump, and the injection pump (CAV) contained a transfer pump before the final injection stage. As far as I can remember, several other diesel cars owned by me had lift pumps.

 

[Kveite]

Hi again,

Time goes unfortunately. It is sitting outside so between the rain showers, other tasks and me getting someone who can help me turn the key I have now finally gotten some new tests done. I cannot see any clogging in the air-inlet, but ran it without the top of the air filter just in case to no help.

Loosened the pipes to the injectors, or the two I could easily loosen with the spanner I had and they were squirting fuel just at I would call normal. Then with the basics in mind I think I am down to the timing being wrong, if the belt has jumped a few teeth now possibly opening the exhaust valve a bit early not letting the compression build up as it should.

I will see when I can get to checking that.

Very odd with the no lift pump design. I am also used to there being one and also why I spent so much time and effort seeking out what I thought without question had to be the pump and then tearing out everything I could and going through every wiring diagram I could find to figure out where it would be fed from

 

[Torq]

My 2.8idtd (8140.43) does not have a mechanical lift pump or electric in tank lift pump, only the high pressure pump itself.
The only electrics on the pump are the 3 wires going to the fuel cut off solenoid where the injector pipes come out. Get someone to sit in the cab and turn on the ignition, if you hear the solenoid click then it's not the issue.

If you want to check your timing, these are the marks. crank, camshaft and injector pump. On the camshaft pulley there are 2 marks, a big v and a small notch, it's the small notch that you use.

T

 

[Kveite]

Thank you for all the replies. I was just on a little holiday, unfortunately not with this van but still had fun.

Had a quick check around the timing belt and was missing the 36mm socket so have to get one at the store tomorrow, but the belt is very loose so it’s evident to me it could have gone a lot worse ? Must be the tensioner that’s gone bad and probably not replaced by the garage that actually did a poor job on other parts of my van last time I had it in when they also were to replace the belt. I’ll order a new belt kit with tensioner to redo this job I think, and will check the timing points when I get the socket.

One thing that raised a question though is this sensor or solenoid on the fuel pump that I’m not getting any voltage or connection to earth through (open/eternal). Anyone knows what it is and how it should act? Is it a fuel cut off?

 

[Communicator]

Hi Kviete,

The part outlined in your photo looks very like a stop, or fuel cut off solenoid. It should be supplied at 12 V when ignition is on, and you should be able to measure a resistance through the coil to earth when disconnected from the supply wire.

You should not get any fuel to the injectors if it is not energised and working OK.

See part 240 on attached link, which is I think applicable to a 2.8 idTD, but probably similar.


https://injectionpumps.co.uk/interactive/interactive-bosch-ve-parts-diagram.htm

 

[Kveite]

It lives! I finally got to do some wrenching again and found it had skipped a tooth on the fuel pump so its timing was off. The root cause is the tensioner being shot on the timing belt. I’ve ordered a new kit with belt, wheels, tensioner, water pump and alternator belt so hopefully next weekend I’ll be back on the road.

Thank you for all the support and helpful information and tips here! I will certainly stay active on this forum both for keeping the old lady on the road as well as hopefully returning the favor one day.

Never did another measurement on that solenoid, but it must be okay and maybe I just needed an extra set of hands to start the engine or something while doing the readings, or my multimeter should go in the bin.

 

[Communicator]

I refer to my post #12 on this threadin reply to post #11 .

I have re-exmined the photos attached to post #11 , and changed my opinion. I now think that the device in question may be automatic injection advance device for cold starting.

For further information please see the link to an informative article on the motor-roam website.

https://motor-roam.co.uk/ducato-cold-start-flame-start-system-explained