Forum:
Hi guys.1st post. Thought I'd start with something simple .... (& then in another you can all tell me how to rescue my Fourtrak TDS from where I got it wedged yesterday 
)
T'other day it started on 3 cyls & blew smoke out for a while. Simple, duff glowplug. It was No4. So I thought I'd take them all out to make sure they do all come out. I put the duff one in the No1 hole just to save my back a bit & next day the car wouldn't start...no heat. Swopped 1&4 so duff plug was into No4 where it belonged & we started on 3 cyls again!
Now correct me if I'm wrong but the darned things are wired in parallel, so it shouldn't make any difference; so wtf is going on???? ............. & BTW:- any idea what those two blade terminal connections on the wiggly bar are for? 
I have an F70. The 'wiggly'
I have an F70.
The 'wiggly' bar is the current sense shunt for the variable delay type glow plug controller - so two wires should go off to the controller RHS footwell.
Interestingly, and I'm not sure the cylinder order, the one glow plug bypasses the current sense, the other three glow plugs are wired in parallel, but are in series with the current sense shunt.
I wonder if the current sense shunt has gone open circuit, and you are actually trying to start with 1x glow plug functioning (the one that bypasses the current sense shunt)?
I can email you the schematic if you want.
1985 Veg oil burning Fourtrak "Rocky".
1985 Veg oil burning Fourtrak "Rocky".
Thxs svo, very interesting.
Thxs svo, very interesting. Yes i would like the schematic please
- (Still working thru the oddball software for this site so I'm hoping my email is open for you?) ......... Just a thought, is the main current feed for the glowplugs supposed to go via No4 or No3? .... I'm more used to Bosch glowplug control, so the Jap way takes some adjusting to!
Shunting
I've sent you a PM (private message).
I haven't a clue as to why the Japs do glow plug control this way!!!!
On our F70, the main feed for the glow plugs connects at the back of the engine (next to bulk head). Between the back glow plug, and the front 3 is the wiggly bar, with two wires coming from it.
So going by what you say, I think the main current feed should probably connect to plug 4 (at the back of the engine).
I guess they did it this way as they needed to physically mount the shunt, so why not suspend it between two glow plugs? Only guessing.
BTW Some models were also fitted with a 'simple' timer, called a Fixed Delay Type, and this does not use a shunt.
1985 Veg oil burning Fourtrak "Rocky".
1985 Veg oil burning Fourtrak "Rocky".
Thxs guys I did notice
Thxs guys
I did notice the plugs were 7volt, & I thought hello hello, as u do,......tis neither series or parallel?! - or both! -- It's barmy. The plus point of parallel wiring (rapid heating apart) is that one duff plug doesn't kill the system (a la ancient Mercedes).....but then along comes japan plc. Though one good point is the lack of elechronics in a control box.
thxs to you guys I've now got my head (almost) around it .............. it's just a pity the truck is still in a ditch
---- axle diff locks anyone?
((I replied svo
))
Oh there is electronics - in
Oh there is electronics - in the control box drivers side (RHS) footwell.
The electronics monitor the current flow through the shunt!
I'll send the schematics, just to confuse you!
1985 Veg oil burning Fourtrak "Rocky".
1985 Veg oil burning Fourtrak "Rocky".
That's it. I'm selling
That's it. I'm selling it..............elechronics & only 2WD ..............total rubbish
Why did I believe folk when they told me the Fourtrak was the best
Curious
'92 Fourtrak 2,8 TDX
Interesting comment . So your selling it, due to electronics and only 2 wheel drive?????, total rubbish. How long have you owned this truck, have you ever checked that the 4x4 system works, that the auto hubs engage, or that you have locked in the manual hubs before engaging 4x4 drive to the front axle.
Reason I purchase my truck WAS because of its lack of electronic gizmos, Yes the Auto Hubs can be a problem with age/lack of maintainance, manual huds require ,as I have now fitted require a little forthought(lock them in before you get to the situation where you need them.) When I had a starting problem due to the heater plugs I renewed as a set. Yes, the designers of the wiring on Fourtraks have made some quirks, that cause problems, the lighting circuit is known for that. Due to the types of owners these trucks have had ( 4x4 owners are notorius for modifing there trucks) made alterations to wiring circuits, not always for the better.
The Fourtrak was built for a global market, that includes third world countries, where sevicing is limited, if ever carried out, it has stoud the test of time. You would find it difficult to find a truck of the era that the Fourtrak was manufactured that would exeed the it capabilities and long life. With any older truck lots of TLC is required as what one does not know what the previous owners have done to it or how they have used/abused it.
Take the time to read the fourums, lots of info available, and people to help. The Fourtrak is the best truck of the the era in which it was produced, and many modern trucks fail along side it, both for maintaince requirements,reliability and capability.
I have a disabled partner, a tetrapigic (4 Limbs) and we trust our Fourtrak, both for motorway and offroad driving, and we do a lot of both, it might be old but it gets where we need to go and its reliable.
Belive me there are there are few ,if any 4x4's out there that can stand up to the reliabitly and performance offroad that a Fourtrak can cope with,as regards the design of suspension, in my case leaf sprung truck.
Edward (ews) '92 Fourtrak 2.8 TDX
S o r r y
Apologies ews, my 'selling it' comment was tongue-in-cheek. I do know my way around a vehicle which is why I chose a Fourtrak Indy. I like the way they are engineered......... Only G wagon could replace it, but I've yet to see a 14 yr old totally unrusty turbo diesel one for £550!!!
......... but yes I do wish I could lock the diffs each end at times..........who doesn't?
The behaviour you describe
The behaviour you describe is normal for the quick heat variable delay system. SVO is right - the wiggly bar is a current sensor and only plugs 1,2 and 3 draw through this. The system is designed such that 12v is applied through 7v plugs in short bursts. If 12v were applied continually, the plugs would quickly burn up. The current sensor detects the drop in current as the plugs reach the desired temperature (due to the increase in their resistance with rising temperature). Thus when the current falls below a preset value, the main relay opens for 4 seconds or so to prevent the plugs from overheating. The plugs are typically energised for a few seconds on the initial heating cycle, a second or so thereafter until post-heating terminates. One issue with this design is that if any of plugs 1,2 or 3 go open circuit (ie typical plug failure), the total current draw throught the sensor is lower than normal and causes the preheat burst to end immediately to all 4 plugs. Hence the engine won't start, despite the plugs being wired in parallel. However if just plug 4 fails, the current through the sensor remains normal so the other 3 plugs function as they should. The result is that the engine will start but on 3 cyls initially and plenty of smoke. A plug failure in 1, 2 or 3 is often misdiagnosed as failure of the preheat timer.
Ah, I see i can confuse
Ah, I see i can confuse things by splicing a reply in anywhere..........so it's edit to the bottom time
Design
Thanks for explaining the design!
1985 Veg oil burning Fourtrak "Rocky".
1985 Veg oil burning Fourtrak "Rocky".
To add to the glow plug controversy
When I put the 2.8TD engine into my F20 I didn't have any of the glow plug wiring or controller relay etc so I did away with the whole lot altogether. I bought some 11V glowplugs (Wellman W572 - I'll double check if anyone needs to be sure) from evil bay, made my own bus bar from a length of aluminium flat bar and wired them in parallel through a heavy duty relay and a momentary switch on the dash. From cold, 10 seconds of glow and then it starts straight away without smoke or fuss. Use your brain as a timer and temperature sensor - it won't let you down unless you're in such a state that you shouldn't be driving anyway! If you can find your way around some simple wiring then I'd recommend this mod to anyone with a duff glow plug set up.