1.6 HDI Electrical problem

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rob78
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1.6 HDI Electrical problem

Post by rob78 »

Hi Guys having a small problem with my 2008 xsara picasso and I think its the ignition circuit which is causing issues on cold starts, basically unburnt fuel and rough idle until the car has ran for 30 seconds or so. It drives perfect after this for rest of the day. After many hours searching various forums I think there should be a postheat cycle to aid startup and improve the cold idle, unless someone can tell me otherwise?

I have fitted refurbished injectors, blanked the egr, checked for vacuum leaks and only run on shell premium. My mpg is around 55 which I am happy with and the car is great to drive, minus the cloud of unburnt fuel at startup.

Being a newly (ish) qualified industrial sparky ive worked my way through the wiring as best I can and think I have a problem with the glow plug circuit. After finding out I have no output at the glowplug relay I have swapped this (tried 2 new ones) and the glow plugs themselves (all 4 without snapping) but still have the same problem.

I have around 1.2 ohms and 1.5 ohms on each plug when testing forward from the relay harness which tells me they are ok, and if I disconnect the temp sensors to fuel the ecu the glow plug relay is given around 10v but the plugs are drawing no current, where I would expect it to be around 40-50A at the relay output between the 4 plugs when read with a clamp meter.

If I disconnect the glowplug harness at the relay completely then I still get the dashboard glowplug light come on so I assume the ecu is seeing the relay and is happy?

The starter is pulling 50A ish and the car turns over fine, battery voltage is normal, I have pulled the bonnet fusebox up and found the "hidden" fuses for the glowplugs and checked continuity back to the relay and checked these 70A fuses havnt popped.

Lexia is giving no errors, and im starting to lose the will to live. Im sure its something daft that im missing but don't know what, if theres someone on here who is a whizz with French electronics I would be eternally grateful for their help.
wheeler
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Re: 1.6 HDI Electrical problem

Post by wheeler »

Does the engine start up straight away or does it take slightly longer than normal to fire up?
This engine shouldn’t need glow plugs to start normally unless it is really cold like around 0 degrees.
The post heating is really used for making the engine heat up faster to aid emissions.
You could always rule the glow plug thing out by applying 12v straight from the battery for a few seconds, use your amp clamp to confirm they are operating.
rob78
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Re: 1.6 HDI Electrical problem

Post by rob78 »

hello wheeler, thanks for your reply.

normal ambient temps it starts more or less it turns over two or three times then catches, with rough idle and unburnt smoke.

during this recent cold spell, around -2 here in Lincolnshire early in the morning, it takes longer. A couple of times its caught on third or fourth turnover of the starter, chugged a couple of times then cut out, but struck up ok on the second attempt, again on three or four turns of the starter motor, idled roughly and ploughed out unburnt diesel fumes then cleared after a few seconds. Smoke definitely worse the colder the external temperature.

its definitely harder to start the colder the ambient temperature is. It starts a little better if I stick some 2-EHN in the tank but still get the rough idle and smoking.

the sensors for external and engine coolant are giving the right readings on lexia as far as I can see, and initially I was hoping for a vacuum leak which I have checked for by spraying easy start round the hoses and manifolds with the engine running with no increase in idle speed so again it was back to the drawing board.

also the priming bulb stays solid overnight, and I should have mentioned before Ive changed the obvious things like filters and fluids. It has been suggested to be that the issue could be cylinder related but im loathe to pull the plugs out again and do a compression test as the problem is purely the first start of the day, rest of the day she runs perfectly (well as perfect as a 2008 Picasso can lol) with zero smoke on startup.
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Chris570
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Re: 1.6 HDI Electrical problem

Post by Chris570 »

I have a 2006 c3 1.6 HDi with exactly the symptoms you're describing. worse the colder it is, almost like it's running on 3 1/2 cylinders and then as it warms up the smoke clears and all is well.

To give you some info with what I've done,

EGR Blanked off
Glowplugs replaced (3 of the 4 were ok when bench tested)
fuel filter replaced
premium fuel used
injector cleaner used
chipped the ECU

No changes.

I put it down to a wonky injector as the smoke is certainly unburnt fuel in my case and I struggle to think of what else what only affect one cylinder.

Anyway just put this here incase it helps you with your diagnosis.

Oh and once the rough running/smokescreen clears it pulls like a train all day long and is smooth running.
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white exec
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Re: 1.6 HDI Electrical problem

Post by white exec »

Would go with that advice to try a start on a cold (near zero) morning, with GPs manually powered up.
As you say, expect about 10A apiece - ie 40-50A in all.
Jump straight from batt+ to GP rail (or (GP relay output).
Suggest pre-heat of 30secs, then start, then post-heat of 1 minute (given how cold it is now).

That should give a clean start.
If it doesn't, then suspect something else.
If OK, then investigate GP relay action.

Are the GPs BERU brand? If NGK or something unknown, replace them with BERU, which are known good.

Wisdom seems to be that HDi engines don't much need pre-heating when the weather is not too cold, but do struggle when temp dips. XUD hopeless on starting without proper GP operation. HDi also seem to need (rely on, on some versions) a brisk cranking speed, which equates to a kind of pre-heating.
rob78
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Re: 1.6 HDI Electrical problem

Post by rob78 »

Gents... Many thanks for your input.

I had hoped for a wonky injector myself, so I purchased 4 second hand and had them refurbished and tested fully which I fitted with new washers et al but this made no difference (and luckily the mrs didn't see the invoice)

I will jury rig the plugs straight to the + rail tonight when it's a bit quieter here. I cant find a switch in the workshop which is big enough for the expected current so won't be able to do it properly but I should be able to knock up a quick and nasty harness of sorts to link the + terminal and the plugs and see how we go from there.
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Chris570
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Re: 1.6 HDI Electrical problem

Post by Chris570 »

I'm watching with great interest. Good luck!
RichardW
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Re: 1.6 HDI Electrical problem

Post by RichardW »

I wonder if a compression test might be informative... there was someone on here a while back dealing with a broken cambelt (can't remember if it was this engine) and it turned out the cam lobes were only pressed onto the shaft, and when the belt went some of the cams got knocked out of line. The symptoms you have are rather like those you get on an XUD when the exhaust valves have closed up - these have hydraulic lifters so it can't be that, but if one of the cams had slipped a bit you might be low on compression on 1 cylinder till things warm up a bit?
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Chris570
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Re: 1.6 HDI Electrical problem

Post by Chris570 »

I think that was the 8v engine and this is the 16v engine. I forgot to mention in the time of my symptoms I also did the cambelt so it's not a timing issue. Also the problem goes away after seconds, literally only the time for the combustion chamber to get hot.
rob78
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Re: 1.6 HDI Electrical problem

Post by rob78 »

gentlemen...thanks once agan for your musings.

after knocking up a harness with a switch and connectors etc to bypass the glowplug relay I can safely state that I still have around 0.13A draw rather that the 30-40A expected.

The fact that I can see around 1.5ohms at each plug when belled out from the plug at the bottom of the harness tells me that even though the plugs are there they don't seem to be doing anything so I would like to think the wiring to the plugs is ok and I was sold the wrong plugs that for some reason are just ornamental rather than functional.

the old relay was not stuck open so I don't think they have burnt out after they were fitted but process of deduction tells me that with a new relay, an intact wiring harness and plugs at the end then the plugs must be the wrong type, if that's possible?

ideally I would now like a second lowplug harness and connectors and a set of plugs (comment noted on beru) and see where we go from there.

I thought id cracked it last night and overthought it that the realy was switched via the BSI probably by a triac that had failed but this was not the case. I suppose if im taking the plugs out to replace then it would be a good time to test the cylinders for compression also.
rob78
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Re: 1.6 HDI Electrical problem

Post by rob78 »

out of interest I hooked up my Delphi software and interface this afternoon and did a live read of the parameters to see if that came up with anything, and it would seem there might be two problems rather than one and the glowplug issue may be separate and not related to the smoking / rough idle.

Cylinder 1 (which may be cylinder 4 I don't know if the Delphi numbers them the same was as Lexia, e.g. the gearbox end is 1 and cambelt end is 4) shows a large + spike on startup, up to around +15 whereas cylinders 2,3,and 4 are all about the same and only show a tiny + correction around 1-2. Such an increase in positive trim would be overfueling the cylinder and leading to the smoke one would assume? I can rule out injector problems as the original ones have already been swapped out and the problem has persisted.

Once you touch the accelerator the + trim on cylinder 1 drops down to same as the other 3. Again I have sprayed round the intake manifold and surrounding hoses with carb cleaner hoping it would be a simple vacuum leak or failed inet manifold gasket but nothing, so maybe as suggested this is something to do with the valves on cylinder 1, in which case it is probably financially unviable to repair.

At almost 146k I suppose these things happen, which sucks as the car drives beautifully and we wonder how we managed for so long with kids and dogs and not having an MPV.
Sharkie
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Re: 1.6 HDI Electrical problem

Post by Sharkie »

Do these injectors need their codes programmed into ecu ? If so, might be the cause.
Glowplugs fail in many ways, if they draw no current they are shot. They can fail partially and cause all sorts of issues. even the deposits on them cause issues. Warm the engine up before you remove them or you may break them off.
Injecting more fuel than needed can actually snuff the combustion out on cold engine. At this point, it may be anything. I would recommend you sort out the glow plugs (they are used even post start up for emissions control and smoother running) and after couple thousand miles compare the startup. Diesel may have washed the bores and made them glazed or scuffed which results in bad compression as well valves may be slightly out. Bad startup causes deposits that don't clear for a long time driving and just accumulate on.
Such things may be annoying, but as long as the car drives fine don't worry too much worry about it. Cylinders are uneven even new from factory, and with time and wear they deteriorate further. Nr.4 (closest to flywheel) is the hottest of them and receives the worst quality oil and low flow of it as well. If there's issues, it shows on that first.
Diesels aren't affected by vacuum leaks, well not as much as gassers anyway