Can anyone identify this part?

mrbump · Post by **mrbump** » 20 Apr 2004, 02:08

Hi,
I know that this is off-topic, but hopefully someone could help:
I have just done an engine swap from one 405 1.9td glx 1995 saloon into another 405 1.9td glx 1995 (estate). Having some problems now that the engine is installed.
The fans come on straight away at full speed when power is applied to the starter motor (from ignition), but not when directly applied to the starter from battery. All connections seem correct including temp switch at bottom of rad, other temp sensors etc. There is also sometimes clicking from the glow plug relay/timer box when the ignition is switched to 'on' and the dash lights flicker (but not always).
After following wires and reading Haynes (which does not correlate to the wire numbers or colours correctly by the way, which is helpful[}:)]) from the fan relays, I have traced the problem to a little black box which sits under the passenger side headlight. It has a 12 pin multiplug. When this is disconnected engine will run and glowplugs still work, and fans do not come on anymore. Does anybody know what this unit does or what it is called? - My zx td doent have anything like it. Is it only fitted to certain 405 models? can it just be removed (bridge the fan relay connections which just seem to loop inside the box anyway)? Also, how many spare plugs should there be on the engine loom for this car (with a/c)? I have two spare (redundant) plugs, one black two pin and one green/brown two pin.
A friend of mine who is an auto electrician has spent a good couple of hours tonight tracing and checking the other sensor connections and all seems to be as it should, but the problem persists. I think we can only progress when we know what the control box under the headlight is trying to do.
Another (related maybe somehow?) problem: the engine will start and idle 100% from anytime hot or cold, however using the throttle does not affect the engine revs. Pulling the throttle arm at the pump its full travel only sees the revs raise by 100rpm[:(!] The engine was running absolutely fine before it was removed from the donor vehicle, this is why I hoped it might be related the the electrical prob. I cannot find any air leaks anywhere and bleeding the system at various points only produces clean diesel. Is it possible that the stop solenoid is faulty and sticking partially shut? Can theese units fail due to electrical damage? Or is it as I fear that the pump internals have become worn, or that the injector rotor head thing has become seized? I would like to think that there was an easier solution than chaging the whole pump if poss.
Oh, one other thing, if I was to change the injector pump, how the heck do you get to the bottom one of the three 13mm nuts that hold the pump onto its mouting bracket!!??[?] Please dont tell me that you have to remove the complete alternator/steering pump/ac compressor assembly and brackets to get a spanner in do you???
Sorry, a very long post I know but I dont know who else to ask all these questions to.
Any ideas at all would be appreciated.
TIA
[:)]

Post by **philhoward** » 20 Apr 2004, 02:22

Firstly, dropped you an answer on the fans on the Peugeot site...basically sounds like the infamous Bitron unit and it's temperature sensors.
As for the pump; you have connected the throttle cable to the throttle, not the cold start lever instead, haven't you? Daft question, I know..(awaits flames)

Dave Burns · Post by **Dave Burns** » 20 Apr 2004, 02:35

That sounds like the Bitron control unit for the aircon under the headlight, thats exactly the same place it is found on the xantia, it Also controls the engine cooling system aswell as the main fans for the aircon condenser.
There should be a bitron (brown) sender unit on the thermostat housing, if this is not plugged in the fans will run full time.
How long has the engine been sat idle, the pump can go rusty inside, even if the pipework is still intact and sealed, and if any of the pipes have been left off they go bad fairly qiuckly.
Check that the manual stop lever is not partially siezed towards the stop position, unlikely to be the stop solenoid but try all the possible problem areas before condeming it.
If it comes to changing the pump over. the bottom nut can be got at using either a crescent or an S bend obstruction spanner, you need a good quality slim (around the ring end) one, not one of those crummy sealey/draper types.

mrbump · Post by **mrbump** » 20 Apr 2004, 02:48

Hi,
Yes it does seem to be the bitron unit. I will try swapping the old sensors over tommorow and check that the brown plug is on the sender at the thermo. By the way, what colour plug should be the redundant one?
Will also check that the fuel stop lever etc are free and in correct positions. And yes, the throttle cable is connected to the other throttely bit![;)]
The engine and pump had sat for around 4 months only since the last time I had the car running, and they were also still in the engine bay, not exposed. Heres hoping that one of the levers is seized and i wont have to change the pump!!!!
Tkanks very much for the replies, i'll let you know how it goes[:)]
Cheers

mrbump · Post by **mrbump** » 21 Apr 2004, 04:25

Well, I tried swapping over the sensors from the old t-stat housing, tried playing with the fueol pump and problem is still there.
Does anybody have a relevant wiring diagram showing the bitron unit on it?
Pleeeeese!!![:0]
Cheers

mrbump · Post by **mrbump** » 22 Apr 2004, 05:06

Hi,
Problem now sorted. As such I now have 2 spare fully tested and healthy Bitron units that I dont need!
If anyone needs one let me know, they are nearly £50 from citroen, so it might be worth getting one of these ones to rule out a faulty unit before taking the plunge! Oh, and the citroen ones are non-returnable!![;)]
Cheers

wotsupnow · Post by **wotsupnow** » 01 Jun 2004, 15:26

Mr Bump, do you still have a spare bitron ? how much do you want for it ?
Pete