Mk 5 Transit 2.5 TD – Limp Mode Problems

[Alistairnz]

Sorry – this is going to be a bit long!

Our Transit is a 1998 AutoSleeper Duetto motorhome with 98,000 miles recorded. We are currently in Italy, and until 10 days ago, it has run flawlessly. While we were sitting with the engine idling, the red light came on and the engine became (even) noisier than usual. I couldn’t get rid of the problem and we drove on to a camping ground. The van lacked power but would manage 50mph OK. I naturally thought that the Epic fuel pump had failed. I started and stopped it a couple of times on the way, but the problem persisted. When I next tried to start it, the starter solenoid chattered. Low voltage. I found that one of the battery terminals was quite loose. I cleaned and retightened them, and the problem had gone. No problem next day, but the morning after that, it happened again. After a few restarts, it went away for the day. That has been the pattern ever since. It starts fine, runs for a few seconds, and the light comes on. If I drive off, it’s sluggish and noisy. But, after a few minutes’ running, a restart, or maybe two, will see it run perfectly for some hours. Sometimes it won’t happen again until next morning, but other days, it will play up a few times, but always come right with a stop and restart or two or three. I’ve tried disconnecting the battery for a minute or so, and also stalling it to stop it, but the result is the same as using the key.

The only “pattern” I’ve worked out is that once it has come right, it doesn’t seem to fail while driving at open road speeds. Most failures happen when driving very slowly, say in traffic or in a camping ground. The engine starts very well, and stops as soon as the key is turned off, so the fuel shut-off system seems to be OK, and as it runs perfectly when the fault has disappeared, it appears that there is unlikely to be a najor mechanical fault.

As it runs so well when the fault has gone, I feel it’s likely that we’ll get back to the UK OK even if the problem persists. I doubt that I could find anyone in Italy who could read the fault codes, and there is the language barrier. I wonder if the low battery voltage from the loose terminal could have damaged something electrical. I presume it would have generated fault codes and would have sent it into limp mode on that first occasion. But I am at a loss as to why the problem keeps coming back.

I would appreciate any comments and advice.

Thanks.

Alistair

[marcrbarker]

Hi I'm not a regular established member of the forum but let me say on behalf a warm welcome.
Sparking loose battery terminal I wouldn't expect break anything.
I've got a suspicion could be just a pin inside the EPIC round connector has shaken disconnected. When idling long period the engine may be shaking around. The engine could make a loud clacking noise that comes and goes with loose connections. It's an easy one to rule out, to unplug you turn the round wheel thing 1/4 turn and unplug the harness. Then with a mirror and torch check the back to see if all the pins are all protuding. You can gently prod pins with fingertip to see if they're all locked in place.

[MinorMatt]

Hi Alistair

The loose terminal could well be responsible for your initial issues. However its unlikely to be causing issues now (unless you have managed to damage a connection.

The EPIC wiring loom takes the live and the earth directly from the battery terminal so its probably worth checking that the connections on the terminals themselves look good.

However, I suspect your issue is more likelty to be a sticky timing cam inside the pump itself

[marcrbarker]

I can add a bit. Pins on round connector I mentioned shaking loose during a rough idle, would be more likely if that round connector was often disturbed in the past.

Sticking advance/retard mechanism inside, when engine's at constant rpm ie idling the valve doesn't get to move. But it does get an end-to-end workout while starting that's more likely to break free any stiction. If that I'd expect a few start-stops-starts would be discovered the most effective to get rid of the red light and clacking noise.

[marcrbarker]

However, I suspect your issue is more likelty to be a sticky timing cam inside the pump itself

I'm with what MinorMatt suspects, cam inside suffering from stiction.

If so I would expect it to go on the blink more often when cold and idling when RPM is steady. I'd expect the first clacking and warning light is just after blipped the pedal RPM, then when revs drops back to idle the engine sounds clacky + warning light + limp mode. Then once it's all loosened up warm and restarted a couple 3 times no trouble until the next day when cold.

MinorMatt? I wonder if adding a litre of 2-stroke oil into the fuel would help?

[MinorMatt]

MinorMatt? I wonder if adding a litre of 2-stroke oil into the fuel would help?

Yes it might

[Alistairnz]

Thanks for the suggestions. The big round connector on the back of the pump has never been disturbed in our 16 years of ownership. I’ve had a look at the wiring connected directly to the battery. It all seems sound and tight, but I’ll detach it and clean everything to make sure the contact is good. The comments about timing cam sound logical, but also sound expensive to repair! The current tankful of diesel has about 300ml of 2 stroke oil in it. I hadn’t been able to find mineral oil in Italy for a few weeks, so this was the first does for a while. AT\t the same time as this, I had disconnected the battery for two hours in the hope that something would reset. I then had about 1.99 days of smooth running, and then the fault arrived again. This was after about 100 miles of running in the day, and happened when we were driving slowly through a town. Very disappointing! I’ll try an increased dose of two stroke oil.

[marcrbarker]

The big round connector on the back of the pump has never been disturbed in our 16 years of ownership.

I'd be inclined not to disturb it. I didn't explain well earlier was ťrying to say pins seem go loose after disturbing it a few times.

I hadn’t been able to find mineral oil in Italy for a few weeks, so this was the first does for a while.

My money's on that as contributory factor.
I don't think any amount of cleaning electrical terminals anywhere would make any difference if it's a sticking m3chanism inside IP

If a sticking mechanism that can be successfully kept at bay by adding 2T (dos tiempos) oíl then hey look on the bright side!, they say it's a good idea add twostroke anyway with the EPIC IP, now you have a reason why when anyone asks!