Glow Plugs or what?!

[timpug]

Good morning guys,

I am pretty sure this has been asked 100 times but I dont understand fully.

Ok so this is the situation:
- Changed the glow plug relay
- Changed the glow plugs themselves

This is what I tested so far:
- All glow plugs have the same resistance or so (when crossing the negative and positive terminal of the glow plug
- Voltage when the key is turned escalated from 11v to 12.*v.
- After 12 secs or whatever, the voltage on the glow plugs is zero (when the relay kicks in)

Issue experienced:
When trying to start the car initially, you cant just turn the key once and turn the engine over. I have to turn the key once, leave it for 10 secs, turn the key off, and turn the key on again and let it heat up for a further 6-10 secs and then when I turn the key over it works perfectly everytime!

What I have read:
1. It could be air in the pump/fuel system
2. Issue with plugs themselves
3. Issue with the plug relay

I dont see how it can be #1, if its this, no matter how many times I heat the glow plugs it should remain constant.
No 2. and 3. I checked with the voltmeter.

Please can someone give me an explanation. Is my battery not outputting enough amps or something? What should the amps be when the key is turned on?

Thank you experts

[r3k1355]

What plugs did you use when you changed them?
It could be a battery on it's last legs, have you got one you could swap it with?

[timpug]

I got my hands on AC Delco which I read/heard are not bad at all. I compared the size and they are bigger than what I took out (it had NGK if Im not mistaken).

I havent tested the alternator/battery in terms of amperage or voltage really. You may very well be correct actually

I dont have a space sadly but will try see if a mate can help me out maybe.

Thank you for the suggestion, very valid!

[Danny Wideboy]

How quick does the starter motor turn?
If that is a bit lazy it will struggle to start first thing in the morning.

[DarkInferno]

what was the resistance you saw when you measured them?

You did remove the cable before measuring them didn't you?

"What should the amps be when the key is turned on? "  Lots... erm...

Back of fag packet: glowplugs can go down to 0R2... sooo...anything up to 240A?

I'd assume something wrong with the glowplugs/relay/battery as well.... Personally, I'd double check those plugs.

[zx_volcane]

Is he changing his glowplugs or what? #unhelpfulpost

[Piggy]

That voltage sounds too low imho.

Usually be above 12v even when not running.

...battery sounds tired. BUT could also easily be air ingress

[timpug]

How quick does the starter motor turn?
If that is a bit lazy it will struggle to start first thing in the morning.

Hey man, thats a very valid point you have mentioned. It has definitely sounded like its slowing down (struggling) a lil. It used to turn over fast, now its a bit lazy.

So you reckon its most likely the battery? Considering i have a different relay and different plugs, Im positive its that battery or even maybe the alternator.

What I have noticed which is probably linked to this, if I have my radio/lights/whatever else on and then open the door, the interior light flickers a lil as the motor turns over. I would reckon the alternator is maybe not giving enough juice to the battery. How can I test that and be sure? Access to the alternator a bit tricky to be honest as well

Thanks for all the replies guys.