Citroen Xsara 1.9D DW8 engine problems (misfire) | updated w

[markdeacon]

Hi everyone,

I recently brought a 2000 X reg Citroen Xsara 1.9lx D with a Bosch fuel pump.

Unfortunately I am having a slight problem with it at the moment and I was wondering if there are any experts on the DW8 engine that know what I should be checking.

Here is some info on the problem and what I have already done to try and fix it.

Firstly the car is running on 100% waste vegetable oil which has been properly filtered and is running fine in another car. I have also fitted a larger fuel filter and a flat plate heat exchanger to heat the fuel.

It starts fine from hot or cold but has a rough idle and jerkiness when pulling away once it has been running for a couple of minutes. If you hold the RPM at anything higher than 2000RPM it seems to be fine.

Also it idles fine for aprox 20 seconds every time I restart the engine then goes rough again.

What I have checked and done so far:

I have run it from a jerry can of diesel and it still had a rough idle.

I have checked the EGR valve and it looks like someone has disconnected the vacuum hose as I can't find it. However I don't think the EGR is causing the rough idle because I have looked at the position of the EGR valve while it is running rough and it is in the closed position.

I put a clear hose on the fuel return to see if there was any air and confirmed that it's pretty much clear, there was a couple of bubbles every now and then but it didn't seem to be related to the rough idle.

I run the car on a bottle of neat injector cleaner for 20 mins and I have noticed a small improvement with the running of the engine but it hasn't cured the rough idle problem.

Here is a youtube video that shows the problem.



Here are a couple of pictures for anyone that is interested in what I have done with the heat exchanger and filter:




Thanks in advance for any advice!

[markdeacon]

Just an update really, I've had the injectors out and tested at Automarine diesel in Shoreham today and they said they were fine. All opening at the same pressure with a good spray pattern.

Haven't refitted them yet as I'm waiting for my compression tester to arrive.

I belive the reason that it runs fine when the engine is restarted is because the glow plug post heating kicks in for an ammount of time up to 3 minutes depending on the throttle position microswitch and the coolant temprature sensor readings.

[markdeacon]

Inside the combustion chamber looks pretty dirty and could do with cleaning up, any ideas on best way of doing that?

[citroenxm]

Not sure if you know, the DW8 is an IDI engine, and is virtually the same as the XUD engine, infact if you remove the oil fillter top it still has the three bearing cap cam shaft.

Anyway, the fuel system is a little more updated - have you checked all vaccuum pipes etc? Do these later pump use a vaccuum to advance the timing or not? I dont really know.

All im trying to say is its not as complex as a HDi engine, so it cant be that much causing an issue.

[citroenxm]

Can you do a video IN THE engine bay, so we can hear what exactly the engine is dooing...

Does it emmit a puff of smoke when its rough??

[markdeacon]

Right here is where I am at now:

Engine still misfires when it is idling and is noticeable until approx 2000rpm

Engine has had new oil, filter, coolant and thermostat. Also had new injector seals.

Eliminated fuel system (apart from IP) by running it from a can
Eliminated injectors - had them tested by a automarine diesel in shoreham
Eliminated EGR valve as its disabled

Done a hot compression test and got

460psi 500psi 500psi 510psi

All cylinders build up at about the same speed which I think might be quite slow? Took quite a bit of cranking to get them up to those pressures.


Are those results bad enough to cause a misfire at idle?

The only other thing I can think of is an injector pump seal however I don't see why it would run fine while the glow plugs are post heating?

I am going to do another compression test hopefully and put it up on YouTube in the next few days.

[markdeacon]

[Lighty]

Could be worth checking the valve clearances, as they do closu up with mileage.

[evilally]

Worth checking valve clearances as said, but going by my recollection of XUD compression specifications, those numbers look very healthy. I had a strangely similar issue with my 406 last year:



The car would start when cold, but was a bugger to start hot. Car ran fine once moving.

The 406 is an XUD with the Bosch AS3, which I expect is somewhat similar to your car. In the end I swapped the fuel pump and that sorted it. What I did notice some time later was that on the pump I took off, the lock nut for the main fuel screw had come loose, and it looked as if the main fuel screw had unwound.

Has the engine been timed up to check that this isn't a timing issue?

[citroenxm]

An XUD wont run at all if the Belt Timing is one tooth out on the PUMP pully. It will if the valve timing is out, but it will be worse then that!

My advice now, I think, would be to try and source a late Bosch Pump like yours and do a swap, it might be hard though, as most DW8 engines had Lucas pumps on them. Im not sure if a very LATE Bosch pump from say a 1999 XUD will work.

[markdeacon]

Video of compression test

What you think?

[steelcityuk]

Hi,

I know you've said that the EGR is disabled but have you checked that it isn't actually leaking exhaust gasses back into the inlet manifold. From experience I can say that they do stick open so just disconnecting the actuator won't always work - assuming that is what you mean?



Apologies if I've misunderstood.

There should be data available of the expected cylinder pressures and what tolerance is acceptable. If one of the cylinders is out of tolerance slightly then maybe it could be masked by post heating of the glowplugs.

Steve.

[citroenxm]

Id say Fk all wrong with that, 500 psi on each cylinder!

Looks pretty good to me!

[markdeacon]

Hi,

I know you've said that the EGR is disabled but have you checked that it isn't actually leaking exhaust gasses back into the inlet manifold. From experience I can say that they do stick open so just disconnecting the actuator won't always work - assuming that is what you mean?



Apologies if I've misunderstood.

There should be data available of the expected cylinder pressures and what tolerance is acceptable. If one of the cylinders is out of tolerance slightly then maybe it could be masked by post heating of the glowplugs.

Steve.

Hi the vacuum pipe has been disconnected by someone before I owned the car, I have checked that it's in the closed position and observed it being closed while the engine is misfiring.

Haynes has data for the expected compression pressures:

Hot engine, at cranking speed

Normal - 363psi to 510psi
Maximum difference between any two cylinders - 73psi