Xantia Cold Start - Stalling on first start up.

Post by **Rhothgar** » 10 Dec 2011, 14:14

Hi guys,

With the onset of the cooler weather this last week, my Xant has been struggling to start.

As some of you may know I ran Bio from Jan to March and it developed a problem of smoking on start up. It turned out that the glow plug on Cylinder 4 (Furthest from Cambelt) was dead so I replaced all 3 (couldn't get to one behind pump so gave up). This was at the end of March.

I fitted NGK 3473 Y924-J which according to the NGK cross-referencing website are an identical match for the OEM part number.

Back on with it today and determined to get the one behind pump changed.

Did a basic test by disconnecting feed wire and touching feed wire on to end of glow plug and it was sparking which indicated glow plug to be OK... or did it?

So I then checked the resistance of the glow plug and the multimeter remained at OL. (whatever that means). I know it should read about 1 Ohm.

I also checked the one on Cylinder 3 as I didn't really want to strip everything down to access them all. It read anywhere between 4 and 25 Ohms. Does anyone know if this is overtly bad?

This makes me extremely tempted to fit Beru but I'd have to build it up and strip it down again next week which seems a waste of time.

So I took out the glow plug from Cylinder 1 and connected it to the battery with jump leads. It takes approx. 30 seconds to glow the full length of the plug which is about the same time as the new one which I never fitted.

It seems the smoking problem now lies elsewhere. All injectors are fine. Just wondering if it could be the wax thermostat thingy that runs from behind fuel filter to the diesel pump to advance the timing on cold start?

Any ideas appreciated.

Post by **CitroJim** » 10 Dec 2011, 15:32

NGK Glowplugs are a little suspect Roger, I've found that from personal experience.

One that's reading between 4 and 25 ohms is definitely toast. Your test on the other one that produced a spark is not a fully conclusive test as all it shows is that it's passing current.

The test is to CAREFULLY connect a glowplug across a battery and watch it glow. The tip will begin glowing first and glow to a nice bright orange/yellow and if left on a few seconds longer the whole lower end will glow similarly for a good three quarters of an inch in length... My method is to attach a length of stout wire terminating in a proper ring to the terminal and hold the glowplug body in a stout pair of pliers. Hold the pliers against the negative pole of the battery and touch the end of the wire to the positive battery terminal and observe the glow...

If you do this test, beware - a glowplug gets very hot and stays that way for a surprisingly long time and they can inflict a very nasty burn.

I'd be highly tempted to replace them all with BERU glowplugs. They're a good known quantity.

Once fitted, check they're receiving at least 11V and that the post-heating is correctly working as I've described in the past.

Once you have a known good set of plugs in there and they are working as they should then we can continue this problem if necessary

jgra1 · Post by **jgra1** » 10 Dec 2011, 16:19

Roger I have had many GP fails in the last year.. last weekend, during one of these periods, i spent a fraction moe time than usual on them

I got them all out, and got all of my spares (3 different makes) and tested them all for resistance and glowing..
2 failed on all counts and were binned..
the only scale i could resistance check and get a reading was the <20 Ohm scale (I think)
the newsest ones all seemed to start at around 2.2, but wnet lower as the day got cooler..
the older ones all were about 1.4

I battery tested them all too, and thought I could see slightly different brightness and glow tip lengths...
I also tested the 60C cut out, as i was wondering if mine were always on and dying prematurely.. it was fine

I put a tested set of the new ones in, and thank goodness the car is starting well.. ( I think one had failed and one was half dead, before I took them out)

I then made 4 fly leads of 15A cable, with an eye crimped onto each end, and ran the 4 cables to a commen large screw in terminal.. this should mean that i can resistance check them easily next time, and jsut remove the offending one..

I appreciate more now, that if I had brought a new set a long time ago it may have saved soo much time, and so many weeks of bad starting when I was not able to mess around chaging them

One more thing.,. on mine, the no1 (or 4) one is easy to get out, if you get a 12mm spanner behind the injection pipes.. you can turn it a couple of flats and it is soon finger tight.. really has made that one easy.

I cleaned all the gp threads well before refitting, so they should all be finger tight most of their way now
john

Post by **CitroJim** » 10 Dec 2011, 16:43

I think you very succinctly demonstrated that all four glowplugs really do have to be in tip-top condition and of good quality for reliable starting in the cold John

jgra1 · Post by **jgra1** » 10 Dec 2011, 17:12

many times Jim

Post by **Peter.N.** » 10 Dec 2011, 17:35

They should read one ohm or less but the problem is its difficult to make a good enough contact to measure that sort of resistance, the connections are likely to have a higher resistance than the glowplug. To get an accurate reading the test leads need to be clamped on tight and even then you may not get an accurate reading with a cheap meter. Another way is to connect an amp meter in series with them, it should read 10 + amps, probably nearer 15 amps.

Peter

Post by **Rhothgar** » 11 Dec 2011, 10:42

Many thanks for the many, full replies so far.

CitroJim wrote:NGK Glowplugs are a little suspect Roger, I've found that from personal experience.

Obviously, your experience extends beyond just simply your own cars so I would imagine you've changed a few in your time. Are they really that poor bearing in mind I've only had mine in since March this year.

CitroJim wrote:One that's reading between 4 and 25 ohms is definitely toast. Your test on the other one that produced a spark is not a fully conclusive test as all it shows is that it's passing current.

Let me explain how I tested them for the avoidance of doubt. I used my mate's professional multimeter so no worries there. Set to Ohms, one lead on bolt to wing of body and other directly on threads of glow plug terminal NOT body of glow plug. I assume this is correct.

Should they actually be tested out of the head?

CitroJim wrote:The test is to CAREFULLY connect a glowplug across a battery and watch it glow.

I used BIG jump leads. However, I left them connected for 30 seconds approx. Whilst this would cause overheating of the plug, would that overheating damage it? I suppose not because they are supposed to post-heat for 3 minutes anyway BUT the post-heating is regulated according to BERU website.

I checked for 11V prior to changing the plug behind the pump. What I found was as soon as meter was connected, it read 10.4V and very gradually increased up to 11V over a period of 30 seconds or so. It does not seem to be giving an immediate 11V which seems strange.

It did start a little easier and didn't stall after I fitted the 'remaining' plug but still a little bit of hesitatation. I think the problem lies elsewhere but BERU plugs are going to be fitted in the week as I am running out of time before driving to Austria.

Post by **Rhothgar** » 11 Dec 2011, 10:49

jgra1 wrote:Roger I have had many GP fails in the last year.. last weekend, during one of these periods, i spent a fraction moe time than usual on them

Hi jgra1. Any particular brand of glow plugs that gave you problems. When you say many do you mean individual or sets?

I then made 4 fly leads of 15A cable, with an eye crimped onto each end, and ran the 4 cables to a commen large screw in terminal..

A photo of this would be useful for the forum in general, I feel.

Post by **Rhothgar** » 11 Dec 2011, 10:51

Peter.N. wrote:Another way is to connect an amp meter in series with them, it should read 10 + amps, probably nearer 15 amps.

Hi Peter. Thanks for the thoughts.

Educate me please! How do I actually do that?

Post by **Rhothgar** » 11 Dec 2011, 11:03

Another point of note which I neglected to mention and I am not sure if this can be linked in some way. Obviously, stalling is not just linked to the pre-heating and the glow plugs and the pre-heating does seem to be working correctly. I know Jim can tune diesels just by listening to them but my mate thought it smelled as if it was running a bit rich but he is used to working on modern HDi engines all day and he did say he couldn't remember what an 'old' diesel should smell like!!! Naturally, I told him it had just run in at 136,000 miles.

I filled up yesterday. £96+ for 70 litres. I monitor my mpg very carefully with Accufuel app for iPhone. Last 3 tanks, I have achieved 46 mpg as near as damn it which is as good as it gets with a 1.9TD SX for general mixed motoring.

Yesterday's fill-up recorded 37 mpg which is not far off the worst ever on this car. I achieved more with average speed of 73mph and a few brief stints of over 120mph (conditions permitting) coming back from Austria to Calais on the Autobahns earlier this year.

All filters were new around Feb/March this year. Can't think of anything else that would affect efficiency so markedly in a period of one month. Or can I? I had to repair the air hose from air filter housing to inlet manifold? as it had broken just in front of the breather valve.

Post by **Peter.N.** » 11 Dec 2011, 13:18

Rhothgar wrote:
Peter.N. wrote:Another way is to connect an amp meter in series with them, it should read 10 + amps, probably nearer 15 amps.
Hi Peter. Thanks for the thoughts.

Educate me please! How do I actually do that?

Disconnect the feed to the glow plug and connect it to one terminal of the amp meter and connect the other one to the plug. Most multimeters don't read above 10 amps but that will be OK for checking one plug at a time. An old car ammeter would be OK.

Peter

Post by **Rhothgar** » 11 Dec 2011, 17:46

Thanks for that, Peter. I went to Maplins today and couldn't find any meter that would measure more than 10A.

I am now almost 100% convinced that everything is fine in the GP department as I checked feed again today and it was on 11V increasing to 11.30V just prior to relays clicking off. My mate's meter must have been faulty as the voltage went from 10.4 up to 11V after about 30 seconds. Guy at Maplins reckoned it would change as the resistance of wire alters as it heats up.

Pre-heating today light stayed on for 6-8 seconds and total of 20 seconds before relay switched them off. Started fine but 7 degrees today not 1! Hesitated for 2-3 seconds so still not perfect. Went to my Mum's for a cuppa. Spent over an hour there and checked voltages again. All fine. I waited until I could hear relays switch off and immediately started car. Perfect - no hesitation!

Power came back on for GP's for approx. 3 minutes 20 secs at 13V before switching off and dropping to -0.45V.

Engine was not at 60 degrees on the dash by this stage but, of course, engine is not going to stall after 3 minutes of running. Some camps say 3 minutes of timed post-heating others including BoL state 60 degrees. What's correct or should I not be bothered too much about it.

-20 degrees in Austria will soon find any weakness.

I think part of the problem in my mind is that the car has performed faultless all year. Now that the temperatures have dropped, one cannot expect the system to perform faultlessly without the slightest hint of hesitation if you choose to turn the car over as soon as the light goes out. It is only natural that with the drop in temperatures you have to get more heat into the cylinders.

Post by **Peter.N.** » 11 Dec 2011, 18:47

The Maplin man could be right, as the temperature of the plug increases its resistance will increase thus lowering its current drain. If you could find a meter which would read 60 amps or more you could check all the glow plugs at the same time by inserting it in the main feed lead. If they are all working they should be drawing 60 amps +, each one that isnt will lower the reading by 10 - 15 amps - that doesn't tell which ones have gone of course, you still need to disconnect them to find that.

Peter

Post by **myglaren** » 11 Dec 2011, 20:02

Roger - you can use an accurate DVM to measure the current by introducing a shunt of known stable resistance into the circuit and measuring the voltage drop across the shunt.

One like this, for instance.

Here's a Wiki article (read down a bit, 8th heading, "Use in current measuring!")

There are some inexpensive meters on eBay - one example here.

It's a while since I worked with this stuff so that's about all I can say without giving possible inaccurate information but no doubt some of the others will have some info to expand on it.

Post by **Rhothgar** » 11 Dec 2011, 20:37

Cheers for that one, Steve.

Hope you're keeping well.

French Car Forum