Technical Funny glow plug behaviour - 2.0 jtd/hdi

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Technical Funny glow plug behaviour - 2.0 jtd/hdi

mabbs

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Hi

Hoping someone can point me in the right direction to an odd problem I have with a 2003 Peugeot Boxer 2.0 hdi (same engine as the Fiat JTD version as I have 2005 van with the same engine...) I have poor cold starting performance engine turns over quickly but won't fire when cold - glow plugs only have 8 volts going to them, and then once started run continuously even after a fast road run at 10 volts. I have replaced the glow plug relay thinking it was this but still the same behaviour, I have 12 volts supplied to the input side of the relay, so it must be an engine management / timer problem.......

I even took the van to an ex-Peugeot they said no faults in the ecu and its a deeper problem with the wiring somewhere, but suggested replacing the starter as an alternative to paying for hours of their labour as they said the plugs are only really needed in a Norwegian winter, but the engine turns over quickly when cold, just doesn't fire. Hot starts are no problem, has anyone got any suggestions of where to look next? I am but a simple poor farmer used to low tech tractor engines....
 
Glow plugs not needed as they said. Probably fuel pressure too low. Injectors won't be fired until pressure reaches somewhere between 200 and 300 bar.
 
Thanks for advice, found that by swapping the battery over from another van she spins over much faster but takes 15 secs of cranking when cold to fire. Oddly enough when I bypassed the hot start control system and for the glow plugs to work she fires instantly and turns over a bit quicker, so perhaps they are needed when everything else starts to get worn on a 13 year old van, even with the wonders of hdi tech. Think I'll wire in a manual switch in the cab to the relay to operate the plugs rather than trying to track down the problem.
 
Hi Mabbs, I have a 1996 1.9td. When starting, hot or cold, I turn on ignition, wait for the glowplug light to go out then turn off ignition. immediately turn on again, wait about 5 seconds and the fire her up. Starts every time on second or third crank. Give it a try before spending any time or money as I know how poor you farmers are. All the Best, Ian.
 
Thanks for advice, found that by swapping the battery over from another van she spins over much faster but takes 15 secs of cranking when cold to fire. Oddly enough when I bypassed the hot start control system and for the glow plugs to work she fires instantly and turns over a bit quicker, so perhaps they are needed when everything else starts to get worn on a 13 year old van, even with the wonders of hdi tech. Think I'll wire in a manual switch in the cab to the relay to operate the plugs rather than trying to track down the problem.

If it starts immediately with glow plugs then the pressure must be ok. If it needs the glow plugs in this weather then I suspect the compression is pretty low.
 
Thought I'd pick up on this thread again as I'm still having the same problem, having changed a set of glow plugs it fires up first time when it is -5oC, so whether in theory or not its meant to operate without glow plugs I need to get to the bottom of the problem because my engine doesn't fire without them and I need a reliable van!!!!

Does anybody know which sensors control/send a signal to the ECU to fire up the glow plugs? They run continuously at the moment (even when the van has been on a motorway run) with the consequence that it burnt the last set out and an alternator failed prematurely. Once started I disconnect the feed from the relay to save the glow plugs at the moment. I know when the speed sensor failed she wouldn't fuel up properly, so am hoping it is a simple sensor to change.
 
Does anybody know which sensors control/send a signal to the ECU to fire up the glow plugs?

I'm not familiar with the 2.0 JTD engine, but it's probably the same principle as the 1.9 JTD, and most other electronically controlled diesel engines.

In which case, the only sensor involved is the engine water temperature sensor. It sends a signal to the engine Management ECU, which then sends a signal to the glow plug control unit. If the engine temperature display is working correctly then the temperature sensor must also be working.
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Thought I'd pick up on this thread again as I'm still having the same problem, having changed a set of glow plugs it fires up first time when it is -5oC, so whether in theory or not its meant to operate without glow plugs I need to get to the bottom of the problem because my engine doesn't fire without them and I need a reliable van!!!!

Using a switch to control the glow plugs can be very expensive. The least you should do is add a loud buzzer to prevent the plugs burning out when you are distracted.

I do not know whether or not there is a special temperature sensor for the glow plug circuit in your vehicle. The ECU gets temperature info from a sensor that is part of the MAP (manifold absolute pressure) sensor; from temperature and pressure it calculates the air density and determines how much fuel can be injected.
The temperature information is not very precise. My van starts well without glowing at temps down to +5 C. Between +5 and 2 C. starting takes 2 or 3 attempts, below that the glow plugs do their job and the van starts at the 1th attempt. I.m.h.o that is caused by a poorly calibrated sensor, but I've learned to live with that.
 
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