TD Zx - Lumpy starter when cold

AthlonZX · Unread post by **AthlonZX** » 30 Jan 2003, 23:18

Hello everyone,
I recently bought my first citroen, a 1993 Turbo diesel Zx Aura <img src=icon_smile.gif border=0 align=middle> , with 113000 miles on the clock.
When I start the car from cold (first thing in the morning), it fires up straight away, runs smoothly for about a second, and then becomes lumpy (misfiring?), at the same time it kicks out blue/white smoke. This clears after about 5-10 seconds and then the engine runs normally. I can stop and start the car for the rest of the day afterwards with no more smoke or misfiring. It doesnt smoke while it drives either. I am contemplating new glow plugs.
Additionally I feel the engine is a little unrefined at between 1100 to 1700 rpm, with allot of vibration coming into the cabin (though it feels fine at tickover, and after 1700 rpm). Could this be a deteriorating engine mount?
As it is my first diesel I dont know how much of this is normal behavior. I love the car to bits already and just wondered what I need to do if this is a damaging problem
Thanks in advance
David Carroll
Midlands UK
[email protected]

Unread post by **Jon** » 30 Jan 2003, 23:23

As for the cold running, I'd definately start with changing the Glow plugs. Make sure that you only fit Beru or Bosch, the OE plugs as various people have had trouble with cheaper brands. You'll have to remove the intercooler to change the glowplugs unless you have the hands of a 2 year old and the tool kit of an F1 team.
Also check that the cold start cable is working. This is the cable that runs between the thermostat housing and the back of the diesel pump. When the engine is cold this cable should be tight.
Not so sure about your other problem!
Jon Wood
Forum Admin
<img src="http://www.andyspares.com/images/2cv.jpg" border=0>

Dave Burns · Unread post by **Dave Burns** » 31 Jan 2003, 02:11

Hmmm.....could well be the glow plugs, but why would it start smoothly and then go rough for a few seconds, if it were the plugs it ought to be lumpy from the start, unless the relay is switching off too early.
Has it got a Bosch injection pump.
Dave

pwatson · Unread post by **pwatson** » 31 Jan 2003, 02:31

Could it be an air leak? Starts on the fuel in pump and then is dragging in air from leaky fuel filter or pipe or because fuel has drained "downhill" due to leak? Just guessing since I don't know whether it could start on fuel in the pump but my BX had an air leak(well 2 actually) from the filter and from the fuel heater behind the engine and gave similar symptoms. Test with transparent fuel pipe from filter to pump. Can you see air bubbles? Others will no doubt have opinions on this suggestion! (Don't be too rude!!)
PhilW
Phil

AthlonZX · Unread post by **AthlonZX** » 31 Jan 2003, 15:13

Thankyou everyone for you suggestions <img src=icon_smile.gif border=0 align=middle>. I think I'll have a bash at fitting some new glow plugs, and I'll check the cold start wire. Could it be water in the fuel filter? How often do I have to drain them? I'm not sure if it has a bosch injection pump but I'm going to have a nose when I'm cleaning her this afternoon.
My dad has suggested it could be a valve stem seal that is failing, but wouldnt that cause the car to smoke constantly?
Thanks
David Carroll(Athlon ZX)

jeremy · Unread post by **jeremy** » 31 Jan 2003, 20:12

Hi,
I don't think the smoke is a valve seal as I dont think it has any. I seem to recall someone saying the guides are bronze.
I have similar albeit mild misfiring on my BX and think its the minor air leak problem and keep meaning to have a look. I had the fuel heater replaced (on a BX TD its at the back of the engine above the waterpump) and it started doing it afterwards. Your ZX has a different arrangement and does not have this heater, relying on water heating of the filter bowl. You could try operating the proiming bulb before starting and see if this makes any difference, otherwise the best way is the clear pipe route and look for ANY bubbles.
The cold start unit on the pump is to be found at the end of the bowden cable leading from the thermostat housing. If you have the Roto-diesel pump it alters the timing electrically and produces an increase in idling which should be noticeable on the rev counter. If the thermostat operating it fails the cable will not tighten as the engine cools. The thermostat device is not very expensive (£20 from Citroen about 2 years ago)
Rather than remove your glowplugs on spec why not test their resistance - take off the wire on the top and test them. If you haven't a meter use a bulb. They should have an extremely small resistance as they pass something like 14 amps each when operated.
let us know how you get along.
Jeremy

someplace-else · Unread post by **someplace-else** » 01 Feb 2003, 01:15

I have run a BX to 200k, and about 6 years ago it suffered from a "surge" in power which I was advised was probably due to an air leak in the fuel supply. The easiest way I found to locate same was to apply air pressure to the fuel supply pipe at the tank end. I used a small 12v tyre inflator. It took seconds to locate the "hissing" leak.

sooty · Unread post by **sooty** » 01 Feb 2003, 01:22

I have a ZX td and have changed my heater plugs fairly easy.
Can someone tell why the Inter-cooler has to be removed, where this at the top the engine and the heater plugs are at the front of the cly. head facing you from the front of the car. I've seen this mentioned on several replies to Members.
I use a 1/4 drive socket and combination spanner for the wire connections, a deep 3/8 drive socket and combination spanner for the Heater plugs. Not having to remove anything, not even the injector pipes.
I don't see whats the problem is in changing heater plugs on a ZX.
Sooty

Dave Burns · Unread post by **Dave Burns** » 01 Feb 2003, 02:12

Sooty, you obviousely have a lucas injection pump fitted to your engine, try it on a Bosch equiped td, there isn't a prayer as the pump is much larger, and when the intercooler is off you can only get a socket on the two plugs at the flywheel end, the two behind the pump are ring spanner only.
David, I would take Phil's advice on looking for air leaks in the pipes on the supply side, knowing the layout of the inside of the Bosch pump and the symptoms you describe, this behaviour is exactly what I would expect, which is why I asked if it had one fitted, I'd put money on it that it has.
Dave