Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Hi, wonder if I can get some help.

The car is startiing badly, although cranking speed is excellent.

Over recent months, the glow plug indicator light has only been staying on for a very brief period of time and now it's not coming on at all.

It's now taking quite some time to start, and when it does, is quite smoky for a few seconds. I think the glow plugs are not heating up. I also had a fault cleared a few months ago that indicated "incorrect glow plug timing".

Can anyone help me with this ? Maybe the glow plug relay ?

Many thanks......ebt

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Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Just perfect now thanks. Starts like a new car :-)

All Replies

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Peter.N.

It could be although if its a common rail engine they usually start quite well without the glow plugs. You can check the circuit by connecting a meter between the glowplug feed and earth, it should read about 10-11 volts for the duration of the plug function i.e. about 10-15 seconds after you turn the switch to the glowplug position. No reading - the circuit is at fault, anything like 12 volts and one or more glow plugs need replacing.

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Thanks, will update with solution.....

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - dieselnut

Possibly coolant temp sensor is faulty & telling the ECU the engine is warm when actually it's cold, so giving a very short glow period.

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - unthrottled

A short in the coolant temperature sensor circuit would give a low resistance reading to the ECU-which would be interpreted as high temperature (voltage and resistance drop with increasing temperature).

Modern common rail engines use low compression ratios and do need glow plugs to start at temperatures much below freezing.

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Oh woe is me :( Seems the glow control regulator is working fine. I took it off, cleaned up the contacts and replaced.

I managed to get the connector off the left hand most glow plug (when looking from the front) and measured the voltage. A pretty solid 12v (no voltage drop from the other 3 connected, which surprised me a little). This voltage was applied for a good 5 seconds EVEN THOUGH the glow plug dash indicator lights still goes out after 1/5 second. (As an aside, I did this 3 times, so 3 x 5 seconds voltage applied to the plugs, and it still needed to crank far too long before starting).

So, I measured the resistance of the plug I could get to. 42 ohms ! I then managed to get the connector off the adjacent plug and that measured 45K ohms ! I assume there must be a current sensing device that is used to light the glow plug dash light (and also indicate to the ECU that all is working well).

So, after 160k miles, it seems I may have to replace the glow plugs, what does the forum think ? The main issue is that the turbo charge inlet pipe runs right across and needs to be removed and even then, access is not that good. Additionally I really don't want to snap any of them off. Any suggestions.

Any idea what size deep walled socket I need ?

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - piston power

Glow plugs always best to remove them and see how well they glow.

160k well you have done well what you buying genuine not cheap tosh?

Do also check no air is been dragged into fuel filter seals this can make poor starting but check plugs first.

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Yep, 160K not bad. It's ex-Thames Valley Police, so very well serviced.

Think I'll soak the plugs for a few days in some releasing oil before trying to get them out. Will get NGK if funds allow.....ebt

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

The NGK plugs were £10.90 + vat each, about 30% discount. Expensive but the best available.

Luckily enough, the left hand 2 plugs came out very easily. I got a 12mm deep walled socket and an extensoin bar that allows an angled connection as well as straight in. They undid really quite easily, so I can only assume that the engine maker, Isuzu, used copper grease or an equivalent.

So, I've luckily managed to change 2 already, but the right hand 2 required the removal of the turbo air charge pipe that comesfrom the air cleaner and goes right over the top of them.

For interests sake, one of them metered 44.8 ohms and the other 5.6k ohms. SO, both duff but in different ways.

Will update after changing the other 2, hopefully quite quickly.........ebt

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Railroad.

Most if not all modern diesel engines are Direct Injection, and they are not dependant on glow plugs for cold starting. In fact the glow plugs' primary purpose isn't even for cold starting. They're actually for noise reduction and for improving emissions when the engine is cold. However, they do switch on for pre-heating when the outside air temperature falls below 2 degrees Celcius.

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Now finished all four. I had to swing the air charge pipe from the air cleaner to the turbo out ot the way. 2 mounting bolts, 2 jubilee clips, 2 cable clips and 1 hand operated clip on the crank case breather. For interests sake, the third of them metered 112 ohms and the fourth 91.3 k ohms. SO, all plugs were duff, no wonder it cranked a bit before starting and issues blacl smoke from all the unburn fuel ! :LOL: Will last update tomorrow after a cold start to see what the glow plug indicator lamp does. THANKS all for support...........ebt

Vauxhall Astra H 1.7 CDTi - Slow starting, glow plug relay possibly ? - Englishbullterrier

Just perfect now thanks. Starts like a new car :-)

 

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