2.1 intermittent misfire/knocking

[marty1979]

Afternoon all, great site you have here, I hope someone can point me in the right direction with this slight problem I'm having. I bought my first 406 2 days ago, 2.1td executive estate, nice car, but occassionaly it goes a bit weird and starts to knock/rattle when you put your foot down, when this happens there is no accelaeration, it doesn't pick up as it should. This can happen anytime, hot or cold, but just as soon as it starts, it goes away and start behaving like normal again. I know that the pumps on these aren't the most reliable but I'm sure that this problem is not down to the pump, I'm wondering if it's a timing thing as when I disconnect the plug for the needle lift sensor nothing happens, no engine tone change or anything, I believe something should happen if I do this? Either that or the temp sensor, or maybe even the strainer in the tank is partially blocked causing a fuel restriction, I had a look at removing the sender today but I couldn't see how it can come out through the hole under the back seats. Any help very much appreciated in advance. Take care. Martin

[teamster1975]

Welcome in Martin!
I would have thought timing although it would be happening all the time.
I don't know anything about the diesels but chaps in the know will be along!

[marty1979]

Thanks Teamster, I've had a good look through this site and indeed there are some very clued up beings within. I look forward to hearing what has to be said about my problem. Thanks again. Martin

[poddack]

viewtopic.php?f=1&t=7355&p=73031&hilit= ... ter#p73031

You could give her a dose of Forte fuel system cleaner and a good service, is the engine warning light on?

[steve_earwig]

Did you try driving it with the lift sensor disconnected? Mine didn't misfire but maybe it's not failed in the same way.

[Captain Jack]

When my needle lift sensor was knackered, it did sometimes judder at higher speeds and once cut out completely at 70(ish)mph. It was also down on power but I didn't know it! Drove it like that for two years.

Of course, it could be something else. Run a cleaner through the engine - should help.

[mark21TD]

Hi Marty
Just to give you some background on the Lucas EPIC pump,
The timing is controled by the ECU so can't be setup manualy,
the ECU takes signals from a coolent sensor, needle lift sensor in an injector and (for some reason) two sensors for boost pressure,
inside the pump are some electronic valves, these are known for sticking / blocking up.
it will most likely need to be plugged in to a lexia computer for a full test.

There's a guy on frenchcarforum called citrojim, he knows a lot about these pumps and the 2.1td, maybe he could shed some light on your problems.

Personaly I'd be looking for a lose electrical conection somewhere.

Or you could change the pump for one off a 1.9td, myself and a few others have done this and it works well.
have a read of this if you fancy the pump swap
http://www.frenchcarforum.co.uk/forum/v ... hp?t=27900

[marty1979]

Thanks for the input guys. I've just had a browse through the paperwork that I was given with the car, it's been very well maintained I must say, but I found a couple of sheets of paper that appear to be a print out of a diagnostic test, and it does actually show a fault code: needle lift lost - intermittent, so that would tell me either the wiring or the actual injector itself is faulty. What do you fella's?

[steve_earwig]

I'm not sure if you can get one without the injector (Pug seem to sell them together for silly money). I had mine changed with the injectors by an independent injection place, I can't remember it being too expensive over just the injectors.

[poddack]

I've never run the car without the needle sensor although I disconnected it once whilst idling, nothing happened, no engine light or change in engine noise.
I recently bought some new injectors which have tested fine (thanks Omega) but haven't fitted yet but that's to stop a smoking problem.
The guy who checked them told me you can't repair the fourth injector or replace the sensor, you have to replace it.

Have you tried some Redex or Forte in the filter bowl?

[marty1979]

Yesterday afternoon I took the sender unit out from the tank, the strainer was spotless, I then moved up to the engine bay and unclipped and reclipped all the sensor connections I could get my hands on, haven't driven it yet as the roads were very icy. I will throw some redex in with the filter later on today and see how it goes. Stay safe everyone. Martin

[marty1979]

Update: I put half a bottle of redex in the filter bowl, and the other half in the tank, will wait for atleast 100 miles before I decide if that has done anything. Anyway, this morning I drove with the radio off for a bit, and I noticed that as the car warmed up it got more and more rattly as the temp increased, then at some point the temp needle rose to around 100 on the gauge and then the noise and lack of power kicked in, it sounds and feels as though an injector has gone down at this point, it also seems that resting at traffic lights for a minute or so relieves the problem for a few seconds but then it returns not long after setting off again. I'm leaning toward the temp sensor now as it appears to be temp related, I just took it around the block after 30 min's of cooling down and it sounds and goes fine again. Interesting.

[Bailes1992]

In terms of tempreture, drain the coolent, get some premixed anti freeze and a bottle of Wetter water! Put the bottle of wetter water in the tank and then fill it up with the antifreeze and bleed the system! I had this in my TD for 8 months and temp was always 70 to 80 degrees!
Also take it for a bloody good thrash! Stick your footdown and wind it upto 4750 a few times! Will do it the world of good!

[Gary406]

100 degrees. it shouldnt go that high , have you changed the thermostat ? or as it been changed recently, could be a dodgy thermostat thats making it overheat, or an airlock

[marty1979]

I should've mentioned that the temp only rises to around 100 when I'm in traffic for 10 minutes or so. I have a feeling that the fans aren't cutting in when they should, although the temp never rises any higher than 100 at the most whilst in traffic, the needle sits around 75-80 in normal driving conditions. Thanks for your input guys, I'm loving the car more and more each day, and when I get to the bottom of the little prob's it has, I'll love it even more I'm sure. Stay safe out there everyone. Martin