Glow plugs on all the time

[mad o]

Evening all,just got in from trying to sort out my starting problems, think i have got it sorted(leaking fuel pipe).While trying to find the problem I've changed,ECU,Glow plugs,Both glow plug relays and 80 amp fuse.The only way to get it started was with a little misting of easy start and she would run fine.Just to make sure glow plugs where working as thay should I hooked a led light to the buzz bar,this is what happened,full power click of relay then half power as it should, now the thing is the light never went off even when up to temp, why would this happen?is it controlled by the resistor under the manifold or block temp sensor (which is all so new). Many thanks up front ....Mick

[surfenstein]

The cold start is a 2 stage voltage system. When you turn the key the light comes on when the glow plugs have 12 volts. When the light goes off the ecu timer leaves the glow plugs on 7 volts for up to two minutes depending on temperature.The timer on the 1kzte engine is part of the ecu, try changing the ecu over and see what happens.

[mad o]

Thanks for the reply,changed ecu,plugs still getting half power after dropping from full power,could this be down to the block temp sensor, maybe broken wire when I changed it.The only other thingi have done is replaced relay from a metal round one to the square plastic one.The wiring was different ,metal one was sealed wires in the bottom,plastic one had plug in bottom.If the two small wires where round the wrong way, could that be the fault. would it damage anything if I put them round the other way.Many thanks.... mick

[surfenstein]

Yep check your pin outs, its possible you have just melted the relay contacts together. Refit the metal relay. I have read somewhere that the glow plug circuit uses around 20 amps. So make sure the relays you use are capable of handling that amount of current.

[mad o]

Thanks Surfenstein was going to check tonight but way too cold,will try it tomorrow.thanks again...Mick

[mad o]

Evening all,just an update on my problems,put metal relay back on and still the same,(half glow all the time) As I was sorting out the relay, think I have found the problem with the no start after a couple of hours, fuel pump has a slight leak from the distributor head,this is allowing the fuel to run back from the injectors and get replaced with air.Going to order a seal kit from Roughtrax, I have another pump I'm going to reseal so come the weekend the change over should be straightforward , I hope. Hopefully that should sort the starting problem...Mick

[surfenstein]

How long are you leaving the engine running for before you are checking for voltage at the glow rail.

[mad o]

Hiya, ran it up too temp and then took it for a mile drive, led light that I hooked up to glow rail was still getting half power,now I think I have found the starting prob, I'm going to check the block temp sensor at the ecu tomorrow... Mick