40 replies to this topic

[dapleb]

The slug always starts. But has over the past few years run lumpy in cold weather for 20seconds or so on initial start up.

On my long list of tests for diagnosis is a compression test. Unlike a petrol enjun, I am wondering if compression testing through the glow plug holes, how can I stop the burger from running?

Don't want to cut fuel as it lubes the pump and dunno how to cut off ignition. I reckon this burger will start eventually even with no glow plugs in. Guess I could do a cylinder at a time with plenty of wait in-between tests.

How is it normally done? Any advice welcome. Ta.

Enjun is DW8 n/a.

[Snowbird]

Disconnect the wire on the injector pump and it shouldn't start but pump will still be full of fuel, just cranking over won't hurt it anyway.
I'm assuming 1.9 TDI not hdi.
Doh! Just twigged DW8, ignore me.

Edited by Snowbird, 29 December 2021 - 07:17 pm.

[dapleb]

Thanks SB. The ignition solenoid on these is armoured...built into the pump casing.....guess there is still a way to cut ignition somehow.

[Catteeclan]

I would test through the glow plug holes with them all removed, bitch won't start then.

Checked your valve clearances? They close up over time making starting difficult and lumpy.

[dapleb]

Brill ta Catte, will try that.

That's why I am gonna test compression as a slightly quicker way of checking valves than removing covers and using feelers..which I will probably end up doing anyways.

Have heard inlet valve clearances close up over time holding inlet valves open when enjun cold
...but coming back into tolerance when enjun warmed. At nearly 187,000 trouble free miles it has earnt some attention.

My guess is that it's this rather than glow plugs (already tested/replaced) since the issue developed or injectors or air in the fuel system, which also seems to be a common problem.

Also waxstat is not functioning correctly but it seems this just regulates cold start revs rather than oubt to do with timing. I can simulate correct operation and it just runs lumpy faster. (✷‿✷)

Thanks for input.

[Catteeclan]

Brill ta Catte, will try that.

That's why I am gonna test compression as a slightly quicker way of checking valves than removing covers and using feelers..which I will probably end up doing anyways.

Have heard inlet valve clearances close up over time holding inlet valves open when enjun cold
...but coming back into tolerance when enjun warmed. At nearly 187,000 trouble free miles it has earnt some attention.

My guess is that it's this rather than glow plugs (already tested/replaced) since the issue developed or injectors or air in the fuel system, which also seems to be a common problem.

Also waxstat is not functioning correctly but it seems this just regulates cold start revs rather than oubt to do with timing. I can simulate correct operation and it just runs lumpy faster. (✷‿✷)

Thanks for input.

 

You'll prob find you've still got some good compression, tight valves don't seem to show up like that.
I had an Isuzu engine in my astra. Always ran fine but winter starts were as yours and with good compression.

The garage I worked in at the time had a plaining table which was great for grinding down/skimming shims.

 

Yes normally inlets hammer their way into the head, when left they burn out just like someone took a cutting touch in there.
These old diesels, although polluting piles of shite will go on for ever. I've seen injectors drip rather than spray and the buggas still start and run fine.
 

 

[dapleb]

Ta Catte. Eeeks I'd best not leaf it any longer then as I don't fancy cremated valves!!!

I had assumed that if the valves are being held open then compression would be well below spec. But think oil just measure clearances as I will no doubt have to continue from the measuring to removing anyways.

I did wonder how easy it would be to find shims...already checked, they is not same dimensions as tdm shims but apparently are the same size as some Kawasaki juans. Also I suspect some of the gaps will be negative (ie valves held open) so getting accurate measurements could be fun.

Wonder if anyone does a tdm style shim exchange program. ʘ‿ʘ

[Catteeclan]

pug forum

[Snowbird]

I might have some somewhere if the same as the XUD9 ones, I'll have to have a hunt but may have ditched them when I got shot of the boat I fitted a pair of pugs to.

[dapleb]

Ok ta SB, I am certain they are the same as XUD. About 13.43mm diam I have heard That would be handy.

Think I will need to get the smallest size (or measure without shims) to get accurate gaps as I suspect there will be no gap to measure with existing shimeroos.

[Snowbird]

Back to cranking without starting, just leave ignition off and spin over with a screwdriver across the starter solenoid?

[dapleb]

Good plan. I think have given up with compression test now. Just gonna check clearances.

First all the other simpler checks...air in fuel. Have tried fuel tank above enjun height overnight (to stop air ingress if a leak) but didn't make a diff. But have a non return valve to fit and will check poipes (not hopeful). Got a new waxstat to fit (very not hopeful) and will recheck glow plugs (not a chance in hell it's this). (✷‿✷)

[Snowbird]

I've found a bag of 12 shims, 4 of which are 13.4mm dia. the rest are 13mm and I suspect kawasaki Z650 shims which would work but be a bit loose and liable to shuffling a bit, There's no markings so you'd need to measure them.

Let me know if you want them, I have no use for them.

[dapleb]

Yes please SB. If you def dont need em. The XUD and swapping what's in there might do the job and the Kawasaki Juan's might be useful for getting initial clearance values.

If you lettuce snow what ya want Ferrum and post oil paypoop ya or summat. Thank you.

[Snowbird]

Send me yer address as I lost it from last time.

[dapleb]

:thumbsup:

[Snowbird]

Chuck a squid or two in the local air ambulance or summat if you must, I have no use for them.

I'll chuck em in the post later.

[Snowbird]

A DW8 is not actually an HDI is it? (but I think a DW10 is HDI) So my comment about the wire on the injector pump should be right after all, another line of thought is when I put the pugs into a boat I used a normal lucas diesel ignition with manual pre-heat and if you moved to that postition once running it would run lumpy and revs would drop, your pug should have a timed pre-heat depending on engine temp so maybe it's keeping the heater plugs on too long after starting making it run rough.

I normally hold the heater plugs on on my volvo penta's for 20 seconds after starting to clear the smoke quicker but the heaters are in the inlet manifold on those not the head as it's an old school direct injection.

[dapleb]

Thank you very much SB.

Yes DW8 is non turbo old skoo enjun and dw10 is hdi enjun.

I started the sluggy this morning and had a good listen. It actually runs fine for 3seconds and THEN runs lumpy. Which I wouldn't have thought it would do if valves. More like air in fuel or as you say summat else interfering.

I am gonna start going through everything in a few days but have already checked power to glow plugs and the glow plug relay. It provides power to glow plugs for 37 seconds which suggests it has some post heat function too...or maybe that's a problem. It's hard to find correct info as enjun fitted to so many different vehicles with slightly diff systems and ages. Some have more ECU involvement than udders and some only designed to pre heat.

It's gonna be a nuisance to diagnose as after initial start up the symptoms can't be recreated until about 12hours later!!!

[Snowbird]

Maybe worth crack each injector nut for a few seconds while running to let any air out but they should self bleed through the leak off pipes for tiny amounts.

You could disconnect heat plugs and run a wire to do a manually controlled pre-heat as you start all from under the bonnet, a mechanical injector pump can't have much ecu stuff going on for basic running.

Is the wax stat sticking as it controls the fast idle, maybe a bit of engine vibration sorts it, should be a short pull cable to the injector pump that you could put a pn mark on when cold and see if it moves a few seconds after firing up, can't remember which way round they work.

Edited by Snowbird, 02 January 2022 - 02:38 pm.