cylinder head sensors

[dandywarhol]

I'm feeling your pain Mondo - no answers to the fan problem but i'll have a look through the manual for posibilities - the glow plug thing could be down to inferior plugs - I always find NGKs to be reliable - blueprint not always so good.............

[rita]

Hello,, my issue rumbles on..,.

Just to recap, our bottom rad hose went on the motorway a month or two ago. Rapid (unnoticed) coolant loss led to overheating, causing a cracked head. Head replaced, 1 and 2 pin sensors on side of head replaced. Numerous hoses replaced (not broke but probably due to ...), coolant loss alarm fitted...

Our Bongo is now running but with a couple of minor niggling things which neither I and our regular mechanic seems ot to be able to figure...

Rad fans come on when ignition turned on.

One or two glow plugs seem to be down.

Now, we seem to have gone through more glow plugs than one might expect over the 5 or 6 years of our ownership. From what I have been able to gather on here, the ECU governs the operation of the glow plugs, also the rad fans, so I thought it could be that this overheating has damaged our ECU, or it was dodgy before (re glow plugs) or both.... so i managed to gat a 2nd hand ECU from a 'working' vehicle from a reputable bongo bit dealer.. Tried this out this morning and no difference whatsoever. Which I guess may be because this replacement unit has the same fault as our existing one, or may be because the current problems (rad fans, glow plugs) are not caused by the ECU. Question is, I can understand if the glow plugs got boiled with the engine, they can be replaced, but why are my rad fans on all the time ?

Also, low coolant alarm now seems to activating at unusual times for worrying lengths of time, since antifreeze was added (cold level is at max mark) ... !! Just to confuse me even further I guess.

Any advice deas or theories gratefully received,,one does like to solve a problem but my sanity is being a bit compromised (this is now the third cylinder head on our Bongo),, also if anyone is in need of a 2nd hand (but possibly working !) ECU and/or new, but not needed, engine compartment/scavenger fan sensor, well, I'm your man.

Hi,sorry to hear that you have not solved the problem, I noticed that you fitted a ECU from a known working vehicle.
There is a strong possibility that the wiring or another component was damaged when the engine overheated.
If that is the case you will just knacker any Ecu that you fit.
It might be a better option to fit YOUR old ECU to the known working vehicle,this should prove it.
Only a thought, hope you can solve it.

If

[MondoBongo]

oops...

Yes the intractable tale of our thermally compromised engine coughs and splutters on.. ..

(actually the thing's running ok, once started, but I wonder about the long term effects of having the fans on constantly. If its no more problem than needing to replace the fans prematurely.....)

Determined to get to the bottom of it though..

Well, logically you're right I guess..

I was told it was a known working ECU but I've no evidence of that assertion. I suppose if my overheating, or something else, caused a break in some circuit or other to do with the operation of the fans, then a fully working ECU wouldn't make them work either..

I wonder, would there be any risk to the vehicle that either my, or this other ECU, was fitted to for testing. If not I guess I could ask my acquaintance Nigel for a borrow of his Bongo while its parked up at our work car park.... Could even check the drivers window switch while at it. Unless of course a ddgy switch can blow the window motors, which it probably could.....

...Who knows, he might even be reading this (He's got a big BongoFury sticker in his windscreen)..

[dandywarhol]

You'd be best to check for continuity in the wiring from all the sensors to the ECU - if a break is in a wire then the ECU will probably default to fans on.

[MondoBongo]

Hello all

My issue rumbles on..as does my Bongo...

The mechanics have checked for continuity, and cannot find any breaks..

However on investigating the drivers side of the head, it appears that the 2 pin sensor, to the rear, had come adrift from itself.. ie the threaded part is still screwed into the head, the green plastic plug, with 2 small (broken) soldered connections in, was not connected to this but was hanging around still connected to its cable.

This seems a pretty sure bet to fail to operate the fan circuits correctly. Its a new part though, only fitted a month or two ago..

HAs anyone else enountered this ?

So, once its replaced again, if the problem persists, it seems we'll be going for the relays next.. (air con, maybe A.N.Other..)

[dandywarhol]

That surely has to be the cause - that sensor controls a lot more than the fans - glow plugs/ autobox lockup...............

[MondoBongo]

Well here I am again. For those who enjoy the partial solving of partial mysteries,... get this....

The harshest winter I can recall was not the best of times to have ones radiator fans blasting -5 degrees air onto a cold radiator every time the ignition was turned on. Took bloody hours to get the ice sheets from the windscreen (both sides) . Anyhow the mystery was solved by noticing that the wires to the 2 pin sensor (which had only been fitted, with the fitting of my new cylinder head, a few weeks prior).. were broken. Hence no continuity and fans on all the time. Now resolved by the fitting of yet another 2 pin sensor.

I am now the proud owner though of a second hand ECU, whch I believe to be fully workng,, and scavenger fan sensor (new) ,.. if any other brave bongonauts are in need of said items..

Cheers all

[MondoBongo]

Oh crikey. I'd forgotten I'd sent that last post.

what a

[mikeonb4c]

Well here I am again. For those who enjoy the partial solving of partial mysteries,... get this....

The harshest winter I can recall was not the best of times to have ones radiator fans blasting -5 degrees air onto a cold radiator every time the ignition was turned on. Took bloody hours to get the ice sheets from the windscreen (both sides) . Anyhow the mystery was solved by noticing that the wires to the 2 pin sensor (which had only been fitted, with the fitting of my new cylinder head, a few weeks prior).. were broken. Hence no continuity and fans on all the time. Now resolved by the fitting of yet another 2 pin sensor.

I am now the proud owner though of a second hand ECU, whch I believe to be fully workng,, and scavenger fan sensor (new) ,.. if any other brave bongonauts are in need of said items..

Cheers all

Great news - all sorted now then?