Lucas Epic experts wanted!!

marty1979 · Post by **marty1979** » 06 Dec 2010, 14:27

Afternoon all! I come to this fine site after a recommendation from the 406 owners club. I have an unusual prob with my newly purchased 406 2.1 estate, great car by the way. The thing is, after about 30 min's at normal operating temp, under load the car will suddenly start knocking quite badly as though an injector has gone down, if I back off the throttle and just push enough to maintain current speed it's ok, but any amount of load will cause it to knock and smoke a bit, it also doesn't pull aswell when this happens, but it does still pull. It will do this for about a minute and then the car will return to normal, no noise, good power, but the noise can return any time and usually does. Today I noticed that if I pull away when this happens, I go through 1st all the way up to 4th, but when I drop into 5th the noise goes away and it drives as it should again, it makes no sense to me. I have checked the needle sensor resistence which is around 300, should be 100 from what I've read, but even with this disconnected it makes no difference to the way the car drives. I've also checked every electrical connection under the bonnet and all seems well, the only things I haven't checked is the timing of the pump, although it starts on the button every morning, and the leak off pipes as I had a thought that air could be entering an injector from a dodgy pipe. Any help on this matter is greatly appreciated. Take care. Martin

panason1c · Post by **panason1c** » 06 Dec 2010, 14:37

Sorry, i'm no expert but it sounds to me like a faulty injector.

Post by **CitroJim** » 06 Dec 2010, 16:57

That does sound odd... Indeed a duff injector could be the cause but my first suspect would be fuel starvation leading to an upset of hydraulic pressure in the pump. This pump is fully "fly by wire" and every function is critically dependent on the correct fuel pressure being maintained within the pump.

The first port of call is the fuel filter. For the reason stated above, these pumps need to have a spotlessly clean filter at all times and a bit of dirt will wreak havoc. If the filter is Ok then check the tank strainer; these often cause restricted flow when they get covered in muck.

If this does not bring about relief, a diagnostics session using a DIAG2000 or a Citroen Lexia fooled into believing the car is a Citroen Xantia with a P8C engine will be necessary. using these tools, a full set of tests can be made including full advance checks, a 3000 rpm check and also live data can be viewed to ensure the needle lift sensor is in fact giving a correct output and that the ECU is acting upon the signal properly. I've known EPIC lift sensors appear OK on a simple resistance check but giving little output when checked on the Lexia/DIAG. Also, a Lexia/DIAG will give you access to any stored faults in the ECU that may give a clue. Live data will also check all other sensors are working correctly.

The thing is, you need the diagnostics operator to know his/her stuff. These machines do not give answers on a plate and their output needs a high degree of understanding to interpret properly.

marty1979 · Post by **marty1979** » 06 Dec 2010, 17:54

I actually did check the strainer in the tank and it was spotless, and although the filter looked a bit black on the bottom half I didn't think it would be the cause of my problem, but maybe it could? Looking back through the service history it has been serviced every year at mot time, and anything else that needed doing was done regardless of expense. One thing I have noticed while driving with the radio off, is that as the car warms up it sounds more and more rattly, just like it's running a few degrees off or something? I the timing belt was done around 60,000 miles ago (I plan to change the entire kit this weekend with a new waterpump) so I would think that if the timing was off it would've occured a lot sooner than now, unless the static timing has drifted somehow, probably not. The green sensor screwed into the block, would that be suspect in your mind CitroJim?

Post by **CitroJim** » 06 Dec 2010, 18:11

Yes, the green sensor could be suspect Marty but the give-away here is that it also drives the temperature gauge via the ECU so if it was really duff then it might show on the gauge. Having said that, the gauge is damped so erratic signals from it might not show. The other sensor worthy of a look is the inlet air temperature sensor on the inlet pipe elbow.

Possibly also the MAP sensor down on the intercooler. This has a small rubber sense pipe on it that may have split and thus giving a duff boost signal to the ECU.

That the fuel filter is dark on part of it would be enough for me to swap it.

EPICs are very sensitive to static timing. Here is the official procedure for checking it and whilst doing the belt is an ideal time. It's easy enough.

EPIC Static Timing Page 1

EPIC Static Timing Page 2

A 2.1 should never sound clattery so it does sound as if there is a timing issue. They should run just about as sweetly as an HDi on anything above tickover.

I know my signature no longer attests to it but I ran a 2.1TD Xantia for a long while. The engine is a peach.

Hope that helps Marty and welcome to the forum. Forgot to welcome you in my original reply, sorry

marty1979 · Post by **marty1979** » 06 Dec 2010, 18:28

That's great Jim, I really appreciate your help. I know how good this engine can be so I really hope I can sort it out. I'll be here for a while, and I'll keep updating as I go along. Take care. Martin

marty1979 · Post by **marty1979** » 08 Dec 2010, 21:52

Update!! On Monday I put a concentrated dose of injector cleaner into the filter bowl and the tank, and on Tuesday the car didn't get upset once, so I thought that maybe it was a dodgy injector, but today the problem returned so I went and bought a new green temp sensor and will see how that goes tomorrow. I'm still thinking that it's timing related so I will check the static timing when I do the timing belt, many thanks for the illustrations CitroJim, should help me out loads. I'm not convinced that it's a terminal pump problem as it drives as you would expect 90% of the time, and most people could probably live with it but I hate things like this and it needs to be sorted. Things on the to do list are leak off pipes, new filter, timing belt and adjustments if needed, bloody good hose down

Take care all.

marty1979 · Post by **marty1979** » 09 Dec 2010, 13:58

Update number II. Ok, so yesterday afternoon I installed a new green coolant temp sensor and disconnected the battery over night, hasn't solved the problem. So, there is only the needle sensor to go, which when disconnected makes no difference at all to the engine, so either the ECU is ignoring it or there's something else going on, I have no engine light on by the way. I thought about taking the cambelt cover off to check the timing just now but looking at it, it seems as though I may need an hour just to get at the bolts that hold it on, so going to attack it on the weekend when I don't need the car as I use it for my courier bussiness you see. I noticed something today, when I pull of and the noise hits and the lack of power attacks, if I rev to redline in neutral it makes it all better for about 5 min's, and then of course it returns. Further updates to come. Hope everyone is warm and well. Be safe everyone. Martin

Post by **CitroJim** » 09 Dec 2010, 16:50

Watching with interest Marty

Have you swapped the fuel filter?

marty1979 · Post by **marty1979** » 09 Dec 2010, 17:19

I'll pick up a filter tomorrow when I'm at Euro Car Parts collecting my belt kit and waterpump. I really do hope that I find something up with the timing, because although I'm not too concerned about the prospect of having to convert to a trusty Bosch unit, I would really like to keep everything as it was when the car left the factory. I had the top solenoids off the pump earlier to see if the seals where damaged or perished but they were fine. I would really love to remove the whole thing and have a good look at it but the only days I have to really work on it are on the weekend, and even then I have to ensure it's going to be reliable for work come Monday. I don't know if there is a "how to" on doing a timing belt change but I will take pic's as I go, not only as a guide for fellow 2.1 owners but it will be handy if I get stuck somewhere and I need reference pic's.

marty1979 · Post by **marty1979** » 11 Dec 2010, 13:27

Curious!! Thursday afternoon was quiet so I thought I'd spend an hour under the bonnet. I checked all the leak off pipes, and snipped 5mm off the ends and refitted them, they were all the same apart for the one that feeds back to the return line which was the braided type, and it seemed to be soaked in diesel. Anyway, friday morning I started up and drove off, and instantly it started with the diesel knock and clatter when under load, usually this wold only happen after 30 minutes driving, but this started first thing in the morning on a cold engine and it continued for 5 or so miles and suddenly stopped, and since then it's driven better than ever, super responsive and very smooth. So, I wonder if air was entering an injector through a leak off pipe and screwing it up? Also put a new filter in yesterday and all seems well, haven't had a chance to do the timing belt just yet as it's a bit wet out today. If that was the cause of the diesel knock then I'm happy as I now know the cause, we will see. Take care all. Martin

Post by **CitroJim** » 11 Dec 2010, 17:33

Let us hope this is the solution Marty

The leakoff pipes are a critical component on the EPIC pump and often the tiniest leak here causes problems, usually with erratic idle and hunting when cold.

It's normally the first thing I suggest checking when looking at an EPIC fault but yours did not show the classic symptoms of bad idle

Fingers crossed!

marty1979 · Post by **marty1979** » 11 Dec 2010, 19:04

Yes, my fingers are very much crossed. Air ingress never crossed my mind because it always starts so well, and the idle is very smooth, although I have on occasion felt a little bump at idle, very rarely though. Thanks for all of your help Jim, I appreciate it a lot, and although my problem "appears" to be sorted if it does return you have given me more than enough to go on, and I hope I can use this new found info to help someone else in the future. Have a good rest of the weekend Jim, take care. Martin

marty1979 · Post by **marty1979** » 21 Dec 2010, 22:22

Final update. I thought I'd come back and finish this thread off just incase someone in the future with the same problem stumbles across this page and needs help. After driving nearly 300 miles since replacing a leaky leak of pipe my car hasn't missed a beat, so very pleased indeed. Have a great Xmas everybody. Martin

Jameswithapug · Post by **Jameswithapug** » 18 Feb 2011, 16:06

Mine does exactly the same thing. I ave also just found my map sensor hanging down under the car though so will try plugging that back in first.Just got to find out where it goes.