2.1TD cutting out when warm

[Xsarahdi]

Hello,

I have got a Peugeot 406 2.1TD with the EPIC pump. It's recently started cutting out when up to temperature, particularly when returning to idle (e.g. at junctions). I'm suspecting it is something to do with the pump or pump electronics, but I was wondering if there is anything else to rule out.

I recently replaced the fuel pipe all the way from the tank to the filter as I had noticed a few small air bubbles in the pipe from filter to pump. I know these pumps are sensitive to air. There is no longer air in the clear pipe from filter to pump. This didn't help solve the cutting out.

Symptoms:
- Runs fine cold and warming up, it's just when it gets up to temperature that it cuts out. Starts fine when cold too.
- The first time it cut out it restarted normally but I was pretty much home by this point so it was only driven for less than a minute after restarting
- The next day it cut out and when restarting it would run for only a couple of seconds before cutting out, but would rev a lot by itself in those couple of seconds. However, the rev counter stays at zero and other lights stay on on the dash, so it's like the car hasn't recognised it is running in those couple of seconds. It sounds awfully clattery in those couple of seconds, like the pump is going way too advanced.
- The only way I could get it to stay running after restarting several times was to have my foot slightly on the accelerator to hold the revs. After a short while of sounding awful, it would then run normally, but then when getting to the next junction and returning to idle it cut out again. If I keep my foot slightly on the accelerator at a junction then I can keep it running.
- For a few years now, when turning off the key, the engine carries on running for a few seconds, which I haven't addressed as it didn't really bother me.

Do these symptoms point to something in particular, or is there anything else I should do to rule anything out?

Thank you.

[mickthemaverick]

Just a quick thought based on a previous experience. My 2.8 TD in a Mitsubishi Delica developed similar symptoms which turned out to be air getting into the fuel rail feed via a tiny crack which opened as it warmed up!! Just a thought!

[PaulC5]

You could also check the crank shaft sensor.

[CitroJim]

You could also check the crank shaft sensor.

And also the Needle Lift Sensor. This can be found on the side of one of the injectors. There are not the most reliable of components. In case of failure, the pump electronics will use the crank sensor to establish timing and vice-versa.

The Needle Lift Sensor can be checked with a simple continuity check using a multimeter on its Ohms range. It should read in the region of around 100 Ohms.

Check cold and hot as the sensor may be OK when cold and then go open-circuit when hot.

Does the tacho become erratic when the problem is extant? This may point to a sensor problem.

The best check of all will be to run Peugeot PP2000 diagnostics over it... There are test routines to fully check the pump as part of those diagnostics...

Also, as these pumps age, its wiring can become very brittle and fragile, worth checking all looks sound and all soldered wiring connections around the pump are all good and secure. The wiring insulation can crack, flake off and cause short-circuits...

[Xsarahdi]

Just a quick thought based on a previous experience. My 2.8 TD in a Mitsubishi Delica developed similar symptoms which turned out to be air getting into the fuel rail feed via a tiny crack which opened as it warmed up!! Just a thought!

I had read that air can be especially problematic! Hopefully I've tackled that one unless it can be drawn directly into the pump somehow!

You could also check the crank shaft sensor.

How would I go about checking it?

You could also check the crank shaft sensor.

And also the Needle Lift Sensor. This can be found on the side of one of the injectors. There are not the most reliable of components. In case of failure, the pump electronics will use the crank sensor to establish timing and vice-versa.

The Needle Lift Sensor can be checked with a simple continuity check using a multimeter on its Ohms range. It should read in the region of around 100 Ohms.

Check cold and hot as the sensor may be OK when cold and then go open-circuit when hot.

Does the tacho become erratic when the problem is extant? This may point to a sensor problem.

The best check of all will be to run Peugeot PP2000 diagnostics over it... There are test routines to fully check the pump as part of those diagnostics...

Also, as these pumps age, its wiring can become very brittle and fragile, worth checking all looks sound and all soldered wiring connections around the pump are all good and secure. The wiring insulation can crack, flake off and cause short-circuits...

Thank you for lots of information. I will get the multimeter out and check the needle lift sensor.

Yes, upon restarting, the tacho stays at zero. If I can get the engine to stay running by keeping the accelerator slightly depressed, the tacho stays at zero whilst the engine sounds like a bag of spanners, only when it clears and runs normally again does the tacho return.

I do have PP2000, just not the older cable style that I dare say it will need.

Is this wiring under the black plastic cover on top of the pump?

Thanks

[CitroJim]

Is this wiring under the black plastic cover on top of the pump?

Yes, it is.

The crank sensor is best checked by substitution. That the tacho plays up is a good clue this or the Needle Lift Sensor is unhappy.

Keep us posted on progress...

[Xsarahdi]

Yes, it is.

The crank sensor is best checked by substitution. That the tacho plays up is a good clue this or the Needle Lift Sensor is unhappy.

Keep us posted on progress...

Thank you.

I checked the resistance of the needle lift sensor - 103 Ohms when cold and 123 when hot.

I had it running on the driveway for a fair while until it was up to temperature and couldn't provoke the issue, so the hot measurement wasn't at the point of it misbehaving if the sensor is likely to be erratic.

I did notice the engine hunting slightly as it got up to temperature.

[CitroJim]

The needle Lift Sensor would appear to be OK. One sure way to check is to disconnect it whilst the engine is idling. With it disconnected the engine note should change very significantly and the engine may even stop. If it does, that may indicate the crank/TDC sensor is unhappy - check its connector before condemning it.

[Peter.N.]

I know this sounds obvious but have you changed the fuel filter lately?

Peter