Strange BX Glowplug problem

mat_fenwick · Unread post by **mat_fenwick** » 20 Jul 2005, 01:03

I have a '93 BX TZD turbo with a strange starting problem. During this summer and the previous one it will turn over for between 5 and 10 seconds (unless it has run in the last hour, when it will start fine) before starting, and then will start with a lot of grey smoke, presumably excess fuel. However, if you turn ignition off and back on again to give the glowplugs a second chance, it starts perfectly.
Now here's the strange bit - during last winter it would start fine with NO problems whatsoever. I was going to change the glowplugs at the end of last summer, but then winter came and the problem seemed to disappear.
My plan is to replace the glowplugs anyway (~40k miles and 3 years old) but I was wondering whether anybody had any other ideas. I just can't understand how what I suspect to be a glowplug problem should be worse in hot weather. It it generally in excellent mechanical condition, so I am not suspecting anything more serious.

jeremy · Unread post by **jeremy** » 20 Jul 2005, 01:21

If when it does start don't waste your money on new plugs. The generally fail one at a time in quick sucession so the starting would get lumpier and lumpier and steadily more difficult.
By all means chack them - take the lead off the top and connect a wire from the battery with a bulb in it to each in turn. If the light lights the plug is ok.
I wonder if the plugs are always working - ie an intermittent fault in the circuit - eg the relay. The timers seem to be temperature sensitive and it may be that this mechanism has failed. (My TD (89) seems to take much longer to heat when cold and there are probably at least 3 lengths of timing. I've never had to investigate but its quite noticeable.
jeremy

citronut · Unread post by **citronut** » 20 Jul 2005, 03:11

if i try to start my 1.9D as soon as glow plug lamp goes out it wont start strait away,but if i wait for the timer relay to click off it starts instantly,also if i dont start it for more than a day i have to pump the primer up as it must have an air leak in fuel system,i have never bothered to check where it is because it always firers up after priming regards malcolm

jeremy · Unread post by **jeremy** » 20 Jul 2005, 03:16

Having to prime the pump everyday is a bit tedious isn't it - I suppose you could expend its hoses so you can get at it from the outside though.
jeremy

Unread post by **CitroJim** » 20 Jul 2005, 03:20

My old 405TD does nearly exactly this. When it's stone cold and/or the weather is cold it starts instantly as soon as the glowplug light goes off. When the engine is warm and/or it's a hot day it needs a good few revouloutions to start but starts better if a few moments pass after the glowplug light goes off before attempting a start. My Xantia also does this to a lesser degree. Both have Bosch pumps.
Opinion from a Diesel specialist was that the modern ULS diesel is thinner when warm that the old DERV and this combined with a little pump wear is just enough to cause the problem. In the cold the fuel is a bit thicker so the problem does not occur. Sounds plausable enough...

Unread post by **Peter.N.** » 20 Jul 2005, 03:27

Sounds possible, I know that certain engines can suffer from poor starting when hot due to fuel pump wear but another possibility is, if the glow plug relay is temperature sensitive, it is not leaving the glow plugs on long enough, hence starting OK with a second dose. If it was me I would just give it two lots of heat and, as has been mentioned, dont turn the key until about 5 secs after the light has gone out.

citronut · Unread post by **citronut** » 20 Jul 2005, 03:35

jeremy if you read what i said i dont have to pump up the primer bulb every day,as 99% of the time i use the car every day,its only if i dont use it for more than one day i need to pump primer regards malcolm

dnsey · Unread post by **dnsey** » 20 Jul 2005, 04:00

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">I suppose you could expend its hoses so you can get at it from the outside though<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Why not do the job properly, and have the bulb inside the car[:D]

jeremy · Unread post by **jeremy** » 20 Jul 2005, 04:30

Still seems like hard work - I'm suspicious about the claimed pump wear - My 199,000 mile BX TD with the Roto diesel pump starts first time after a fortnight outside in extremely hot weather and I don't think this problem is common amongst high mileage cars.
jeremy

mat_fenwick · Unread post by **mat_fenwick** » 20 Jul 2005, 23:29

Many thanks for the ideas, I have a few things to check now, although it's not really a problem to use the glowplugs twice, I like everything to be spot on.