PUG 205 GRD Severe Engine Vibration

[Tamlin]

Hello All - owned 205diesel since 1984, but this problem is driving me crazy, so any thoughts would be appreciated. 1991 205 diesel (210,00 miles), engine (1769cc) started to vibrate quite severely (but no misfire) about 5 months ago. Vibration is most severe at start-up and reduces as engine warms up. Glow plugs checked, but changed just in case. Engine 'chugs' slightly on start-up, but always starts first time. The 'chug' is different from the behaviour when glow plugs on way out.

Cambelt changed (by garage - just had hip replacement at time and so couldn't do it myself!) early last year, but don't think this is part of the problem. Changed all engine mountings (3) and dampers (2), but no improvement. Left thinking now that problem is either injectors or fuel pump. Two injectors are leaking (very slightly). Injectors are Lucas LCR6730705C and Rotodiesel pump. Just bought recon injectors with new fire seals and Cu washers. A little concerned about difficulty in removing old seals/washers and so not attempted this yet.

More clues: engine hesitates (ever so slightly) if I freewheel down a hill towards a roundabout and then start to climb a hill. Checked out for fuel air leaks, but OK. However - and sorry if this is a very poor technical description - the engine just feels lumpy and one doesn't sense the engine is producing similar power levels as each cylinder fires. Additionally, the vibration gets worse at about 35mph in third (Sorry no tacho.) and and 45 in 4th. Engine is OKish above 50mph, but still doesn't feel smooth. The vibration is worst in the area of the right hand engine mounting.

Sincere thanks for any thought or suggestions.

[spider]

Check or have checked the valve clearances. Checking is quite easy (just top cover off, three bolts etc) adjusting is quite a bit of a pain though.

The cold start advance solenoid was not fitted to N/A units with the Lucas pump, I did consider that could be jammed on if it was but it does not really advance it enough to do what you're describing and it would get worse at it got warm not less. hmm.

Might be worth having a compression check too.

I thought of air but you've said you've checked that, and I'd expect as you know it would probably be smoking and missing a little bit (or worse) if it was getting too much air in.

A can of decent (such as Forte) diesel fuel treatment would not be a bad idea though just to see if there is any improvement.

I think this is one of those issues that could be difficult to solve without seeing the car though.

EDIT... Just noticed you joined today so "Welcome!"

[Tamlin]

Check or have checked the valve clearances. Checking is quite easy (just top cover off, three bolts etc) adjusting is quite a bit of a pain though.

The cold start advance solenoid was not fitted to N/A units with the Lucas pump, I did consider that could be jammed on if it was but it does not really advance it enough to do what you're describing and it would get worse at it got warm not less. hmm.

Might be worth having a compression check too.

I thought of air but you've said you've checked that, and I'd expect as you know it would probably be smoking and missing a little bit (or worse) if it was getting too much air in.

A can of decent (such as Forte) diesel fuel treatment would not be a bad idea though just to see if there is any improvement.

I think this is one of those issues that could be difficult to solve without seeing the car though.

EDIT... Just noticed you joined today so "Welcome!"

Thanks for such a prompt response Spider - and the welcome. Yes, valve clearences were one of my suspicions - but couldn't figure out how this would give rise to such dreadful tickover vibration. I will, however, check them out. Car does smoke a little on start-up (blue - so not fuel related) - as you'll be aware this is normal for the 205 diesel. Oil level never shifts between each 5K oil change. Hence don't suspect compression probs. (and no actual problems starting) OK on the cold start for the Lucas pump.

Will report back......as investigation progresses.

[Pug_XUD_KeenAmateur]

I had compression problems on my 1905cc XUD non-turbo 405 (much the same engine), but it didn't touch a drop of oil. Run it at a fast idle with the oil filler removed. If there's a constant stream of vapour, you've likely got compression issues; a compression test 'd confirm it or not. (there should be no visible vapour)
Should think a replacement engine 'd be cheap as chips if you're of the mind to provide it with one if need be. Might even know of a source; South Oxon / North Wilts area.

[Tamlin]

I had compression problems on my 1905cc XUD non-turbo 405 (much the same engine), but it didn't touch a drop of oil. Run it at a fast idle with the oil filler removed. If there's a constant stream of vapour, you've likely got compression issues; a compression test 'd confirm it or not. (there should be no visible vapour)
Should think a replacement engine 'd be cheap as chips if you're of the mind to provide it with one if need be. Might even know of a source; South Oxon / North Wilts area.

Thanks for taking the time to reply Pug_XUD_KeenAmateurPug and thoughts are appreciated.
Thing that baffles me is this issue of slight (extremely transient) hesitation and immediate pick-up if I slow down and start to pick up speed again. This was why I suspected the pump or injectors. If this is a valve issue (which is what I also suspected initially), then why should it exhibit this behaviour? Also, no deterioration in performance in terms of acceleration or max speed and I still average 69mpg and smoke test result was excellent at last MOT. However I know the behaviour of the XUD7 so well (usually extremely smooth) that I can tell that something is amiss with the engine’s performance. If compression is low, then why don’t I detect any problem starting and why aren’t I burning any oil or noticing any reduction in performance? I do, however, agree that if each piston isn’t developing similar level’s of power on the firing stroke – at the appropriate time - then the engine would exhibit vibration.

The vibration definitely reduces as the engine warms up, but is still noticeable on tickover. I’m using the dipstick as my vibration reference and can see the reduction in oscillation amplitude as the engine warms up – but I can always detect the vibration in the car when I hit a specific rpm (as described in original posting). I even disconnected the lower engine mounting (with the car in-situ!) to try to get a better idea of the vibration amplitude and one can see the engine (whilst pivoted on the LH and RH engine mountings) oscillating, but the amplitude looks relatively small.

Apologies for taking up bandwidth with my query, but I did put the car into a supposed diesel specialist some months back – and wasted £150, which is why I am determined to solve the problem myself. I have inserted every possible combination of 205, diesel XUD7, 1769cc into ‘Google’, ……..and approached Alan Turing (RIP) levels of logic in my search for someone who’d experienced a similar problem. Needless to say, haven’t come across one posting which describes this phenomenon. I have even been viewing vids on youtube to see if anyone is running an XUD7 and - hee-hee - monitored their dipstick very closely! This engine is – arguably – one of the strongest diesel engines of all time and so I would be surprised (but not doubting) if it is an issue of compression.

Will try to find time this weekend to measure the valve clearances and oil film.

[spider]

Hmm. Its an interesting one.

Without trying to teach you to suck eggs, do you think the idle speed is high enough when its stone cold ?

I only ask as a faulty cold wax-stat can cause it to run too slow when cold. Unsure if you are aware of this or not, I expect you are but anyway without the 'stat pulling at the idle arm a little bit when cold it will try to idle at about 500rpm and likely stall on sharp deceleration as well, at least for the first minute or two until the engine gets a little bit of warmth. Had this on my 205TD when the end fitting popped off the 'fast idle' cable hehe. ,

I actually used a Renault unit (straight swap same threads etc) as it acts much faster than the PSA units and cuts off quicker. The cable is not quite long enough though so some extra thought was needed but that's a story for another time.

I'm still 50 / 50 on the valve issue but I think its worth popping a feeler gauge in to at least see where they are at. , The XUX7 tends to tighten them a bit (resulting in poor / dreadful warm starting but OK cold) if it gets a bit warm. I actually think the reason only the XUD7 does this (and it seems only in the Visa/205) is (1) In most specs neither have a temp gauge and (2) neither have an oil cooler fitted. I can't see them being too tight though as you'd have hot start concerns. If they were too lose you'd have noises or potentially burned valves I think, I'm not 100% on that however. Still as I say I think its worth popping a feeler gauge in to see and maybe if you want a can of decent fuel treatment might not go amiss, no harm in trying either of these.

[RichardW]

I'd be inclined to check the cam belt timing. This sort of behaviour is indicative of the timing being a tooth out. If the pin timing checks out, then I would get the actual timing of the pump checked with a dial indicator.

[Peter.N.]

I have had rough running cause by out of calibration injectors although not on an XUD, they are usually bombproof. If the valve clearances are far out you will get low compression on that cylinder/s. A compression test will help you in the right direction.

Peter

[Tamlin]

Hmm. Its an interesting one.

Without trying to teach you to suck eggs, do you think the idle speed is high enough when its stone cold ?

I only ask as a faulty cold wax-stat can cause it to run too slow when cold. Unsure if you are aware of this or not, I expect you are but anyway without the 'stat pulling at the idle arm a little bit when cold it will try to idle at about 500rpm and likely stall on sharp deceleration as well, at least for the first minute or two until the engine gets a little bit of warmth. Had this on my 205TD when the end fitting popped off the 'fast idle' cable hehe. ,

I actually used a Renault unit (straight swap same threads etc) as it acts much faster than the PSA units and cuts off quicker. The cable is not quite long enough though so some extra thought was needed but that's a story for another time.

I'm still 50 / 50 on the valve issue but I think its worth popping a feeler gauge in to at least see where they are at. , The XUX7 tends to tighten them a bit (resulting in poor / dreadful warm starting but OK cold) if it gets a bit warm. I actually think the reason only the XUD7 does this (and it seems only in the Visa/205) is (1) In most specs neither have a temp gauge and (2) neither have an oil cooler fitted. I can't see them being too tight though as you'd have hot start concerns. If they were too lose you'd have noises or potentially burned valves I think, I'm not 100% on that however. Still as I say I think its worth popping a feeler gauge in to see and maybe if you want a can of decent fuel treatment might not go amiss, no harm in trying either of these.

Sorry for the delay in replying Spider – checked valve clearances (very close to minimum values - but as stated before, no problem, whatsoever, starting). I will re-set them. Silly question, but do you know where I can procure the shims for the 1769cc?

On the comments relating to the pump (mine’s the Roto-diesel), I have only had one occasion after I had changed a timing belt when I was 1 tooth out – and the ‘cammy acoustics’ of the engine let me know, so doubt if this could have occurred. If this were the case, then the engine would be difficult (ish) to start (?) I mentioned that a garage had changed my last belt (including new rollers etc) and it was OK then. Never heard of a tooth jump during routine driving. On pump timing, I can’t see how this would have changed, since the camshaft and the pump are locked during cambelt change.

Not an expert on the Lucas injectors for the 205 diesel and so not aware if/how this could cause this vibration problem. I’ll be honest and say that I am baffled as to what is happening when I detect this vibration resonance (i.e. amplitude of vibration increases markedly) at around 35mph in 4th. (repeated at same rpm in 5th) – and then drops off.

Determined to solve this problem myself and so will purchase a (diesel) compression tester. I gather from all the reading I’ve conducted in this area that I need to ensure that all pistons exhibit similar readings (which obviously makes sense). I’m hoping that it actually is a compression problem, although my last 205 had knocked up 275 Kmiles without any problems and I’ve read of the XUD7 achieving well over 300Kmiles. I’ve rebuilt the rear axle on this car and its bodywork is v.good and so I want to keep it.

Will report back when/if problem solved!

Many thanks to RichardW and Peter.N. for replying - genuinely appreciated.

P.S. No, idle rpm is fine

[spider]

Let us know how you get on.

You're right it would be a £$"£$"£$ to start in most cases if it was out. It may be worth pulling the top covers off (clip on on your type I think) and just checking when the crank TDC pin is in, the cam and pump are where they should be.

I would think with some care 500K would be possible.

Body are usually excellent on most of these, signs of bad rust can be accident damage etc, there was very little if any rot on mine at all. Seemed almost indestructible It put the (nine years newer) 106D to shame in terms of the 'tin worm' . The 106 was starting to rot in some very odd places like the inside of the front bumper mountings, the 205 appeared almost as the factory intended it to be ie honest and not rusty.

[Peter.N.]

If this vibration is present all the time it could at least in part have a mechanical cause, what happens if you declutch when the vibration is present or even more drastic, switch the ignition off?

Peter

[Tamlin]

If this vibration is present all the time it could at least in part have a mechanical cause, what happens if you declutch when the vibration is present or even more drastic, switch the ignition off?

Peter

Hello Peter
Funny you should mention this because I tried this avenue earlier on - but no luck. One major dead end that I followed related to engine mountings. MOT chap had mentioned at my last MOT that the lower engine mounting was on the way out and so I became convinced (big mistake!) that the vibration was related to my engine mountings This will make you smile, but I bought a complete lower engine mounting (bush and bracket) from a 205 GTI (in very good nick) from ebay…….but, uh oh, it contained a solid bush! The car sounded like a tractor inside after fitting. Anyway, bought a new standard bush and got it pressed in correctly and ensured the bush was at 90 degrees to the fork.

I mentioned before that if I released the lower engine mounting and simply observed the engine (pivoted on the two top mountings) running, then I could observe the block gently oscillating. The vibration is now starting to sound serious and I am even beginning to wonder if it could be the crankshaft bearing? It sounds as though it is focussed on the RHS – i.e. pulley/ cambelt side. It is at its loudest when I start the engine and reduces slightly as the engine warms up. Checked tonight on my drive home from work – at a guess this vibration occurs around 1200rpm. The plastic panel on the top of the facial actually rattles as I traverse through 1200rpm. It only behaves like this under load. One can rev it in neutral and it’s OK. If I put my hand on the R.H. engine mounting bracket, then I can feel the vibration. I could even induce oscillations in my trolley jack if I placed it underneath the sump!

[Peter.N.]

Have you checked the crankshaft pulley?

[Tamlin]

Have you checked the crankshaft pulley?

Hello Peter

Sorry for late reply. Coincidentally - out of desperation - ordered a new pulley this week (not arrived yet), since I had run out of ideas - compression tests didn't reveal anything (all pressures reasonably balanced). I thought pulleys were supposed to rattle when on the way out - which mine doesn't, but not had time to inspect in detail. I guess a a dodgy pulley would explain the resonance, but short of cracking cannot see how this can 'fail'. Problem is that I cannot hear the vibration outside the car and just observe the vibrating engine.

[Peter.N.]

You will usually see some evidence of the rubber section of the pully failing which of course allows it to run out of true which will set up a vibration. I had one completely fall apart on an XM - but it had done about 250k miles!

Peter