hi, wonder if any of you guys can help me with this, i know these cars pretty well but seem to have ran to a dead end. basically from fully cold ie. left overnight then the car is a pig to start and when it does it smokes heavily with grey fumes for 5 minutes or so. the glow plugs have been replaced yesterday and i can confirm they definately work by putting them across a battery and they glow brightly at the tip, one was dead so it now catches first turn of the key but you need to keep the accelerater pressed down then rev the car to get it to fire properly and settle to idle, it's like a massive flat spot when you first start it which makes me suspect it's suffer from fuel drain back overnight, priming the bulb doesn't make much difference and ive replaced the leak of pipes and fuel filter seal as they are the most common points of air ingress.
ive measured the glow plug feed whilst running and it stays more or less at 13.4 volts for circa 3 minutes then the relay switch's off so im ruling that out. having read the xantia thread that's running at the minute it could be exhaust valve clearences but id have thought this would affect more than just the very 1st start of the day, you can start the car leave it to idle for 5 minutes (thermostat still closed so don't really suspect you could say it's warmed up) stop it and it restarts fine with no smoke, the cold start waxstat is taught when cold and goes slack as it warms so suspect it works, ive also tried removing the waxstat wire and fully adjusting the arm on the bosch pump by levering with a screwdriver so it is definately in the cold start position and again it has no effect,
so now im at a loss to explain what's happening, so all help would be gratefully received.
cheers
chris
Edited by Dynamic Dave on 23/12/2007 at 18:23
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Assume you are running it on DERV and not veg oil?
Given that the plugs are known good, and you've still got rough start then I would say it's out with the feeler gauges and see what those exhaust valves are doing...
The usual symptom of air leak is no effort to fire followed by a clean start. Rough immediate start suggest either plugs or compression. You've got good plugs, so that only really leaves on thing.... You will of course need to check the EV clearances stone cold to make any sense of it.
--
RichardW
Is it illogical? It must be Citroen....
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no no veg oil in this one, really can't be bothered with valve clearences may just live with it then, not a big deal really just a problem on 1st start
chris
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Do your glow plugs actually have any voltage on them? Connect a meter between the terminals and earth and turn ignition to glow plug position, you should have 10-11 volts.
Peter.N.
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yes there's a good voltage at the plugs for the duration of the post heat which is circa 3 minutes
chris
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thought id bring this back to life, finally got round to measuring the valve clearences and they are as follows (from cambelt end 1st) the tolerances by book are inlet 0.15 and exhaust 0.30 both are +/- 0.05
Inlet 0.038
Exhaust 0.254 (in tolerance)
Exhaust 0.229 (out slightly)
Inlet 0.102 (in tolerance)
Inlet 0.152 (in tolerance)
Exhaust 0.254 (in tolerance)
Exhaust 0.229 (out slightly)
Inlet 0.152 (in tolerance)
the 1st inlet measurement im concerned about as i actually couldn't get the 0.038 feeler in and i don't have another smaller but this may be down to the awkwardness of access on that valve, but what effects would a wrongly shimmed inlet valve show?
so do we agree 2 closed exhaust valves will cause the above problems im suffering and what about the 1st inlet?
cheers
chris
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can anyone confirm the actual tolerances for me as ive just checked my autodata cd and they say +/- 0.07 on the above figures which would make the exhaust valves only very slightly out of tolerance and would that be the cause of the problem?
chris
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Chris
That inlet is virtually closed up - that's your first concern.
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id gathered that but what's the solution? i can take the cam out and measure the shim in there but i have no reference to measure up as i can't get a feeler gauge in. i could calculate it against 0.038 which is my smallest feeler, then get the shim for that from peugeot and hope with the +/- 0.05 it is within tolerance, if not then isn't ill at least have a proper measurement to calculate from
chris
Edited by thomp1983 on 08/01/2008 at 15:07
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Can you get anything through there - tinfoil; dental floss etc? That's a 1.5 thou feeler you've got there - some pro sets have a 1 thou [.0254 in silly-size.]
If you can establish that there isn't a negative gap, then you'll just have to estimate it - which given the tolerance, will still be OK.
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screwloose that would of been a great idea but ive dismantled the cam now so ill just work on a thou and guess from there, the shims are only a couple of quid and i can have the cam out in 15 minutes on these so not too much of a trial if im wrong.
the shim sizes as removed are (only removed the 3 that are out of tolerance),
inlet 1 3.05
exhaust 3 2.96
exhaust 7 2.88
so im off to peugeot now to get shims in the following size,
inlet 1 2.94
exhaust 3 3.03
exhaust 7 2.92
or as close as peugeot do to them
cheers
chris
Edited by thomp1983 on 08/01/2008 at 16:43
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well peugeot didn't have all 3 shims in, only the 2 exhaust ones, so ive fitted both them and put the original exhaust 3 shim in the 1st inlet so the new clearances are,
inlet 1 0.102
exhaust 3 0.254
exhaust 7 0.254
so all 3 are now within tolerances so just got to have some tea refit the belt covers and engine mount and fire it up and see what happens
cheers
chris
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well it's reassembled and still smokes from cold start, but it is alot better and acceptable and clears after the 1st 30 seconds and more than liveable with
thank you very much for all the help,
chris
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Chris
Glad to hear that it's improved. That inlet valve's sealing may well have suffered by not being on it's seat very much and a bit of running will help it reseat, so it may get better still.
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