Unusual Starting problem.

[Winniebongo]

Hi, We have a 96 2.5 Td Bongo which we have owned for about 10 year and is well maintained and cared for. It started off with what I thought was a Glow plug relay issue, it was in a local Garage for another thing and they actually diagnosed, through the vehicle diagnostics that it needed a new relay, so we changed it for a second hand one and it was fine for about 6 months then the problem recurred. We decided to go for a brand new genuine Mazda relay, fitted that and it was fine for a few weeks but it's now back with a similar issue, the only difference being, I think the relay is better, so less clunky and a sharper clicking sound.
The van was professionally fitted with an immobilizer about 6 or 7 years ago, so when you go into the van there is a fob on the keys which you press onto a black plastic part next to the ignition switch, the light on there goes steady and you can start with the key as normal. I am mentioning this as I am now wondering if it may be an immobilizer fault?
Batteries (we have factory 2 fitted) are virtually new (Yuasa) and as I said, so is the Glow plug relay. Before fitting the latter I checked all the circuits, fuse link to the battery etc and all was fine. What is happening just now is that when I turn the keys all the lights come on, on the dash as normal, except the glow plug one, before anything else happens the electric fans come on. Now my understanding of this is that they shouldn't come on at this stage and usually if the glow plug light comes on, the fans don't and it will start as normal, so there may be something there I should look at. So generally, if the GP light doesn't come I will have constant fans on, it will turn over but not start unless with a lot of difficulty, Glow Plug light on, no fans = normal start.
If I keep turning it over it will eventually fire, if I can catch it (Difficult) on the throttle it will go but with loads of smoke and rough running till it heats up. Now this to me means if the Glow Plugs aren't coming on, hard start, if they do, light on, normal start.
To make matters worse, Ii I complete the rough start process the GP light will then come on, with the engine running, intermittently and the relay clicking on and off again intermittently and I am now worried I may actually damage the new relay by doing this.
I am going to have a look next time the weather permits but in the back of my mind I am thinking more than likely I need an Auto-Electrician but just thought I would try you guys first in case anyone has experienced similar

[g8dhe]

Certainly sounds like the glowplugs aren't getting power. The fans coming on can be the Air Con is switched on of course, which turns the fans on.

[willow2u]

Does the glow plug relay operate every time on a bongo or is there a temperature based sensor that turns relay on if it is temperature reliant this could be the issue

[g8dhe]

Just wondering if when they changed the glowplugs they changed them for short ones and now the busbar is shorting out and has caused the fusible link to blow, hence you hear the relay but no power ? Fusible link is connected directly to the battery terminal arm and feeds the contacts of the relay.

[Winniebongo]

Thanks for the replies. So it was wet yesterday and today mild and dry, so I thought, ideal time to have a look at the van. So I went out and it started first time, perfectly! I took it a run as yesterday's carry on had no doubt depleted the battery and every time I stopped, it re-started perfectly and in fact it continued to do this all day. I shouldn't complain but you know I kind of wanted to see the fault, diagnose and repair it, so much far that.
I checked the fans, Air-con was not on and today neither were they. I remember when we had cooling system issues, I was sent the wrong temp sensor (rear one) and the result of that was the same fans were on all the time. With the sensor replaced though, they only usually come on when the engine's hotter than normal. I think with the Glow Plug system issue I seem to have, the temp sensor must be getting fooled into thinking the engine is hot, why I have no idea.
I had a look at the immobilizer, there are 2 wires which I traced to the loom and through the bulkhead, I imagined it would splice into the ignition switch wiring but it doesn't go anywhere near. I took the cowlings off round the steering column and the bottom section of the dash. There's a mess of wires in there but nothing much looks damaged. Except for a tiny bit of white plastic with copper metal attached, which fell out and onto the floor. I had great difficulty finding where it came from but when sitting in the passenger's seat it's the right side of the ignition switch where 2 wires are attached. Whenever I pushed it in, it kind of pops in and out on a spring and makes/breaks connection of the 2 wires. It also sets off a beeping noise.I haven't heard for some time, I think it's just telling me the keys are in the ignition but there must be something missing, which should hold it in all place, so I have removed it again. At any rte it made no difference to the starting or Glow plug system, so not sure it's relevant.
I had a check at the connections to the Glow Plug relay and noted which were lives and which earths, all seemed fine so put it back together and it all seemed fine , again!
So that's basically as far as I got. Someone asked if the glow pugs had been changed, they haven't and so long as the dash-board light comes on I do have a fully functioning glow plug system, which will start the car with ease. It's only when i get no or intermittent light I have an issue. If anyone has a picture or diagram of what the right side of the ignition switch should look like, that would be handy, otherwise at this stage I think it's 'wait and see'.

[g8dhe]

The dashboard glowplug light is merely a timer light, it doesn't tell you anything about the state or power to the glowplugs at all.

[Winniebongo]

When the light comes on though, so do the heater plugs and the van starts easily, when it doesn't it really doesn't want to start which suggests no glow plugs. Granted I haven't checked but is it really worth it, when it seems obvious?

[Winniebongo]

Next chapter in the sorry saga; Next time I went to start the van I got the issue again, fans on immediately, no glow plug light but it did start to flicker and click quicker than the last time. I am concerned this may damage the new relay so didn't let it do that, checked connections and everything seemed fine. Tried to start again and it was perfect and also perfect for the rest of the day.
I am wondering if it depends on how long it sits, we don't use the van every day and it seems worse if it has sat a few days, particularly if it's cold and damp, does this make any sense t anyone?

[Northern Bongolow]

The fans come on when the battery is low, if there is not enough juice,
I would get the starter battery checked professionally.

[Winniebongo]

We have 2 starter batteries and they are both about a year old, so should be OK. I had the van running today and everything was fine. I noted a post on here where someone had issues with the under bonnet electrics, so I did a check on them but nothing obvious. Once it's sat for a couple of days I will look at the batteries with a multi-metre and see if they are losing power. There is something about the rear temperature sensor putting on the fans though and I think that's what's causing it, maybe not getting the correct current, making it think the engine is hot when it isn't?

[Winniebongo]

I was on here yesterday and read about a guy who's Bongo wouldn't start, there were a couple of things I picked up on and also I wanted to check the situation with the batteries, left for a few days as above.
At first the problem was present, fans on straight after turning the key, glow plug light flashing and clicking intermittently. I probably shouldn't have tried to start it before checking the batteries but when I did they were both at 12.34, so not bad considering.
I checked the fused link next to the battery, it seemed fine but I removed it, cleaned the terminals and re-fitted.
I checked the voltage to the Glow plugs, possibly my multi-meter is a bit slow on the uptake but what I think I was seeing was a lower voltage, then when the relay clicked off 11.97. Would this be due to the current feeding the plugs then when they switch off I am getting slightly less than 12v, should I be concerned about this?
I read about someone who had the longer heater plugs fitted and he found a short via one of the return diesel pipes. I have never changed the heater plugs but it dawned on me they may have been changed when the cylinder head was done about a year ago. I wouldn't know if they were wrong or not but I did think No. 3 was a bit close to the bracket in front of it and as it is hidden from view, I removed the bracket but still couldn't see properly, so I had 2 ideas, either put some kind of cap on the plug to insulate it or cable tie the adjacent pipes out of the way, I ended up doing both, so belt and braces. The rest, 1,2 and 4 seem fine and are no-where near anything else.
So I then tried again to start the van and it started perfectly, now I am left not sure if it is anything I have done or if ot may be just as bad next tiem I try to start it for the first time in a day but time will tell.
Appreciate any comments/advice anyone may be able to offer

[rita]

The voltage at the glow plugs is ok they are 11V rated, you could be correct about the ETC sensor it might just need the connections on the sensor and the extension cleaned. good luck.

[Winniebongo]

HI Rita, Sorry to be stupid but what is an ETC sensor?

[Ian]

Engine Coolant Temperature sensor

[Winniebongo]

Thank you, I did a Google search and got "Electronic Throttle Control", Whaat, on a Bongo, don't think so!
So this morning, van not interested in starting. So I left it till afternoon, till I had time to have a look. I really wanted to test the voltage to the glow plugs when the issue is happening but when I went to it in the afternoon, no issue!
So I had a bit of a poke about the engine, removed the Glow plug relay, checked all connections and tightened them but didn't find anything of concern. What I did notice.in relation to the rear temp sensor is when the ignition turned on, the GP relay clicks but so too does the temp sensor. If you unplug the sensor with the ignition on the fans come straight on. So I am thinking; if the temp sensor were to intermittently not click, could that be the root of the problem I have?
I really don't want to change the temp sensor due to all the issues we had with the cylinder head and so on but if it is the problem, it may still be warranted, so could maybe take it back to the garage.