Toyota Corolla T Spirit 2.0L diesel cold start problem.

does it have the right oil in it? Is the battery/charging system good? Have you checked the glow plugs?

Thank you for your message. It has the right oil according to Toyota spec. Always been serviced by Toyota, interim oil changes using oil supplied by Toyota agency. When the problem first occurred I changed the (original) battery for a new item of slightly higher a/h. Charging system has been checked and is good. Even on the original battery it cranked at a good rate. Glow/heater plugs checked & ok I have gone through all the basic tests and all appears good, but the problem persists. That's why I'm thinking that the problem is caused by a sensor throwing the towel in at zero or less degrees. Unfortunately I have no way of proving this. Nick.

then the next step will be to see if it has any stored fault codes. you could try giving it a whiff of easy start to see if it starts then, if it does and continues to run then the problem is probably heater plug related if it doesn't keep running then there is something much harder to find, like faulty electronics.

Thanks but no. I won't use easy start on it. We use this as a VERY last resort on industrial engines (cat, cummins, dorman, scania, volvo etc) and I have first hand knowledge of the damage ether causes. OTOH I have tried a blower heater under this Toyota for 20-30 mins and it then starts immediately.

I presume that finding any stored fault codes is a main agent job?

used as a diagnostic there is no danger at all. spraying it in for minutes at a time would be dangerous. if you are unhappy with easy start then spray in some wd40 it will give much the same effect.

Have you actually seen each and every glow plug actually glowing using the vehicle system?

The codes can be read using an ordinary code reader, most garages will have one, or get your own from ebay.

And if they only checked the resistance did they disconnect each electrical connector before checking? I've just gone through this myself with an astravan that was hard starting from cold. All plugs showed normal (less than 1ohm) but I forgot to remove each power lead from the plug. It was only after removing all GP's and testing individually that I found one was completely dead.

I have always been very suspect when people have told me that they have checked the resistance with them all connected, I know it 'should' work (perhaps under lab. conditions?), but in practice it doesn't work, you need to see that they can actually glow using the vehicle system to get a meaningful result. Also I have seen glow plug relays that will light a bulb, but won't when the glowplugs are connected (especially old escorts) where the relay contacts are burnt away. Likewise poor connections to the wire to the glow plugs again can give hours of confusion.

Mrcheerful

In message , Mrcheerful writes

You can be even more suspect than that! It can't work: not in theory, not in lab conditions, not in practice. (Kirchoffs laws, ISTR)

Any difference seen with the wiring connected (it connects them in parallel), is either measurement error or else the wiring is faulty (which would cause its own starting problems)

...

Regards

At the risk of thread merge you can do it, by measuring the current but you do need a DC clamp meter.

that should work I agree. You could also just power the whole lot through a suitable ampmeter (50 A range?) and a jumper cable. I wonder if exterior (of the glow plug) temperature rise would be measurable (on a cold engine ) or whether the head would be too much of a heat sink?