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stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

hi
my 4wd as stopped working on my p4, no bangs or nasty noises its just stopped working, the 4x4 light still goes out but i cant here the click that it usually makes, any ideas?
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tvatavuk · Posted: Fri May 11, 2007 1:04 pm Post subject:

Ordered by price
- oxidated connector or wiring to el. coupling or toothmesh sensor
- fuse on 4x4 relay
- brake switches (both working?)
- tooth mesh sensor
...
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

i `ve had alook under the gaer selector while running and i can see the prop spinning from electro coupling to v coupling so if i am correct does that mean my vc is knackered also i still dont hear that ping on ignition from the electro coupling but if the prop is spinning from there doesnt that mean it is working?
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tvatavuk · Posted: Fri May 11, 2007 2:43 pm Post subject:

Only your first propshaft from el coupling to vc is rotating?
Whole porpshafts+vc will rotate even when el.coupling is not connected because rear diff is spinning propshaft Smile

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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

oh isee said the blind man! , the diff is rotaing the prop, now that makes sense so it probably is the electro - coupling or something to do with it.

do you know which relay it is - i am guessing it is one under the bonnet by the battery - i`ve had a look already at them, they seem ok ( not burnt or anything, 3 of the relays have fuses which i have checked also)like i said b4 the 4x4 light is working as it should, i have also looked at the wires going to e.c. and they look ok.

thanx for your help btw
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bobbber · Posted: Fri May 11, 2007 7:53 pm Post subject:

Steve,

You have the manuals for the 4x4 system??? If not - drop me an Email... and I'll send them over or something.

Bob
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Fiat Bravo 165 Sport

paulhide · Posted: Fri May 11, 2007 8:44 pm Post subject:

First make sure both brake pedal sensors are springing back out. Check tooth mesh sensor. They are sensitive Exclamation

Two wires go from gearbox through floor. One (big red) is for the electromagnetic couple. The other (black) from the back of the gearbox is from the sensor. It has two wires and a copper shielding wire behind the central console. (make sure you've got the right one as there is another three wire connector there) Check the two wires for resistance with a resistance meter. If no resistance then it has failed. Had this go on both my P4s and recently diagnosed and fixed this on a white London P4 which Peter Sharp now owns and it's not too hard and even had a garage phoning up asking for this information Exclamation

Owe this knowledge to Tino. (thanks). Fairly sure that you can still order these if this is the problem and I don't think they are too pricey either (maybe order two for safekeeping?) and they are not too hard to replace. Good luck.
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stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

thanx paul
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stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

i have got the manual on a cd somewhere but i was hoping to find out the usual causes like paul has said it probably the tooth mesh sensor
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stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

btw i can tell the difference in the handling between a p4 and a 16v , one loves to wheelspin the other doesnt
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mt · Posted: Wed May 16, 2007 11:01 am Post subject:

I'm asking this cos i don't know the answer, but wouldn't the absence of the 4x4 light coming back on indicate that it's not a failure in anything the ECU tests? Like the brake switches for example?

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

thats what i thought tbh
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paulhide · Posted: Wed May 16, 2007 4:15 pm Post subject:

Oh shit! Let me get this right. Are you saying that the 4WD warning light comes on at start-up and then goes out? Is that right? Yet you still have no 4WD? Question

With tooth mesh sensor failure or relay or brake sensor failure the light would go out briefly then return on.
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http://www.alfa-pages.co.uk/viewtopic.php?t=5188

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

yeah the light came on with the ignition and then went out 3 secs later like it should but today i have noticed the light on when driving.
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tvatavuk · Posted: Thu May 17, 2007 10:56 am Post subject:

That is good sign, that at least 4x4 ECU is working as it should.
Poorly adjusted brake switches or failure of brake switches can lead 4x4 ecu to think brake is ON meaning you get no click from el. coupling untill you release brake pedal. 4x4 light will stay off because it is way it meant to be working.
Similar thing will hapen when toothmesh sensor fails. Until 4x4 ecu don't check it later in driving, no 4x4 warrning light will came on.
You speedo is working? In case it is not 4x4 will disengage everytime you press brake.
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

yeah speedo is working, i have a feeling its that mesh sensor, anybody know the part no.
i am trying to sort out the fuel system at the mo - its short on top end for some reason - there is not much power high in the revs, i have just fitted some calibra red top injectors and i`ve got a fuel pump off a calibra too, i`ve just got to get a fse power boost regulator to ramp up the fuel pressure to 2.5 bar or 3 bar if i`m feeling brave, i was going to do these mods anyway because of airflow mods i have done ,ie porting the heads and an inlet valve mod. bobbber is sorting me out a new fuel filter aswell so basically the fuel system is totally being replaced.
then i will worry about fixing the 4wd, i am going to check the sensors with a multimeter to see if i can find which one is playing up.
thanx everybody for your replies - much appreciated.
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mt · Posted: Thu May 17, 2007 2:46 pm Post subject:

When my second brake switch wasn't working (as in it had been reomved by a garage for the MOT as it was causing the brake lights to stay on permanently and they weren't an Alfa specialist so didn't know what they were doing...) the 4x4 light used to stay off for anywhere between 10-20 minutes and then come on, but the 4WD didn't work. Apparantly the ECU checks the brake switches a number of times before declaring it defunct (can't remember the exact details but it's in the maunal Tino sent me)which can take a while.
Might want to check if this is happening to you?

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

hi mt
i usually do run on 95 ron but i have put the good stuff in now and again and i noticed the car was quicker, i can tell thats its not quite right, the revs are slow to rise and i struggled to overtake a ford galaxy the other day - hide my face in shame
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stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

ok
i,ve checked the brake switches and ive found the bottom one seems ok
off normally and on when brakes applied
the top brake switch however doesnt seem to be working on all the time, i am guessing but this switch should be on normally and off when braking is that correct?
and can i just order one from mangoletsi if so does anyone know the part number.
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tvatavuk · Posted: Fri May 18, 2007 3:16 pm Post subject:

That is correct.
One switch is ON/OFF
other is OFF/ON type Smile

Sorry no partnumber, I know when mine started playing up, I bought it in local car parts store by dimension and type of work it was fawcet or something similar unknown brand.
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

Scott Sander · Posted: Fri May 18, 2007 9:07 pm Post subject: