point of no return.......

Lawrence1973 · Unread post by **Lawrence1973** » 28 Mar 2009, 10:07

I recently posted a topic about swapping my fuel injection pump on 406 1.9 TD

All was perfect until it broke down the other day! On my first inspection, I thought it may have been the head gasket - the engine still runs but runs on what seems like 2 or 3 cylinders. A lot of shaking around as it runs (I guess due to the uneven ignition).
There has been no temperature increase/boiling and I can't detect any oil in the coolant. The dipstick and oil filler look ok and no obvious bubbles of coolant in the oil.

I have noticed quite a bit of oil inside the air flow pipe at the top of the engine (the fairly straight plastic one that connects to the short piece of hose near the top on the manifold) when i removed it the oil was resting in the bottom of the short pipe.
I am starting to think is that the there maybe some sort if injection problem. There is diesel getting to the injectors but I am wondering if the recent work might have finished off an injector or two?

Any Ideas? cheers

Unread post by **CitroJim** » 29 Mar 2009, 09:11

Hi Lawrence,

What were the symptoms of the breaksown? Did it happen suddenly or gradually come on? How does it start? Does it smoke now and if so, what colour?

Did you hear any funny noises before it happened?

Oil in the inlet tract is normal. No worries there...

There is nothing in the pump par-se that can give those symptoms and injectors don't fail like that. Pumps generally either work or they don't. Injectors normally fade out gently. A bad injector will make the engine knock heavily.

My betting is that it's related to the ECU and more likely the needle lift sensor on No.3 injector or the TDC sensor. If the signals from these fail the pump/ECU fails into limp-home and it does sound and run terribly when that happens, especially if the needle-lift signal is lost. Check the black conector from the injector and then check the resistance of the sensor. It should be around 109 ohms.

Massive air leaaks resulting in fuel starvation can also cause this, along with a blocked fuel filter. Don't give up just yet!

Lawrence1973 · Unread post by **Lawrence1973** » 29 Mar 2009, 22:37

Hello Saviour,
The lady was driving. It was fairly quick by all accounts.

Do injectors block? The reason I went down the injector fault route was perhaps a bit of dirt contaminated the pump outlets. When I first got to the car on the roadside, I noticed it was knocking pretty badly. Here is a thing, I noticed that the vacuum hose we talked about before (idle cable) was off, must have come off (would that knacker any electronic gadgets?)Any how, I put that back in place but it didn't rectify it (not that I expected it to really)

No smoke, It starts like a dream but doesn't ever run normally.

The cable to the injector looks sound enough.

When I got it home, I took off the union bolt on the injector nearest the fly wheel and there were small specks of dirt in the top of the injector.

I will check out the rest of the things soon. If any of the sensors have failed, is that integral with the ECU or can it be in the actual sensing devices?

I won't give up yet, I am thinking of acquiring a set of recon injectors - Do you know if the older injectors are compatible? obviously not the one with the sensor but if the Bar pressure is the same, I could try replacing the other 3.

Here is the email address [email protected]

Thanks Jim

Lawrence

Unread post by **myglaren** » 30 Mar 2009, 01:17

The small specks of dirt are likely unburned diesel combined with soot.
At my first service on the C5, one of the injectors was leaking and had deposited a small heap of what looked like coal, black, shiny and very hard.
It was, as said unburned diesel escaping through the gap where the washer had been. Completely burned away.

The injector was removed, cleaned up and a new washer fitted and all was fine untill just before it's last service (August 08) when All the injectors were leaking, only very slightly but still. All removed, new washers fitted and all fine again

Recently (since about Christmas) the idle, warm or cold, has been a bit rough.
Recently it has become very uneven. Starting from cold gives a puff of white smoke (unburned diesel) from the exhaust and it sounds a bit rough too. Always starts up quite happily though.
Looks like one of the injectors has gone bad.

It rattles along quite happily otherwise though. Fuel consumption is up a bit despite three tanks of Shell V-Power.

Going to the Doctors next week to get it seen to. Sonic screwdrivers can fix anything

Unread post by **CitroJim** » 30 Mar 2009, 12:38

Hi Lawrence,

If you saw small specks of dirt in wet diesel in the top of the injector union then it looks like the pump may have some contamination inside it. Has it ever ran without a fuel filter? Has it ran on veg at any time? I ask as veg will scour the tank and rapidly block the filter when you begin using veg and I'm wondering if this has happened in the past and someone ran without a filter as a "get you home" bodge.

generally, the filter does an excellent job of keeping muck out of the pump and injectors.

Small specks of muck and rubbish will certainly clog the fine passages in the injectors and upset running but the good news is that can be carefully stripped and cleaned.

Basically, remove them from the head, clamp the big hexagon in a vice and unscrew the body using a suitable tool on the flats at the top. Just be very careful of the needle lift sensor as it's easy to break it when disassembling. Be very careful to keep the springs and shims in strict order when disassembling injectors as these calibrate the injector. Also be careful to avoid damage to the pintle.

If the injectors are full of rubbish, the pump too must be stripped and cleaned as there'll be much and rubbish in the pump. If the pump is not 100% cleaned, the problem will just return. There is no sure-fire way of flushing the pump without a full strip.

They're not hard to strip but there are severe pitfalls and it's easy to break the HP pumping element if you're not careful.

Hope that helps Lawrence...

Lawrence1973 · Unread post by **Lawrence1973** » 30 Mar 2009, 20:59

Thank you for that info. I will see how it goes with the new injectors. I can't face another pump removal at the moment!

Cheers

Lawrence

Unread post by **CitroJim** » 30 Mar 2009, 21:26

No worries Lawrence,

I'll be interested to hear what you find...

Lawrence1973 · Unread post by **Lawrence1973** » 13 Apr 2009, 19:03

Hello Jim....

Took a reading of the sensor. Assuming I have done that correctly, I got a reading of 91.
I must admit, I wasn't entirely sure where to set the multi meter?

other readings on other settings measured 0.01

Any thoughts?

Unread post by **CitroJim** » 13 Apr 2009, 19:30

That'll be 91 ohms Lawrence. Usually they're around 110 ohms so that is most likely OK as they normally fail open-circuit.

Did you try some more injectors?

Lawrence1973 · Unread post by **Lawrence1973** » 13 Apr 2009, 19:47

Jolly good!

Getting to the end of my tether

Is there a chance I could speak to you on the phone?

I guess the other option is the TDC sensor? I am still not sure about ruling out the head gasket.

The injector thing was a silly move, I swapped 3 apart from the Needle lift injector and of course.....there was no change! I'm not even sure they are the correct injectors...they look identical but I smell a rat...

Thanks as always

Lawrence

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point of no return.......

point of no return.......

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