Alfa Wiring Diagram Needed - Urgently

[Guy Mayers]

Hi all, I need a wiring diagram for the UK Market 1992 164 Cloverleaf with the Bosch Motronic ECU part number 0 261 200 130.

I've spent a week looking for a fault that's causing a no spark at the plugs and haven't managed to find anything yet.

I't almost at the point where I'm going to rip the entire loom out and start again and write another year of use of the car off.

If there is anyone out there with a car that's up and running with this ECU fitted I might well come visit with the current ECU to see if it fits & runs!

Guy

[Guy Mayers]

I found this diagram online this afternoon and I think it matches the loom I pulled from the donor car but there's a sensor I don't recognise yet. It's the third one from the left on the top line, annotated "M15" - does anyone know what this little bugger is? Or if I need it?

Cheers

Guy

[Marcolino]

Hi Guy,

found it in my alfa repair manual. Motronic 3.0 V6 Scheme. M15 is called "Verdampfungs Elektroventil" => Vaporizer electrovalve ?!

Think it is used to keep petrol fumes back in the fuel system ...? Excuse the translatio ...

[Guy Mayers]

Thanks! I'll have to check the remains of the donor car and see if it's still there. I wonder if the engine will fail to run without this little item?

Andrea agrees with your translation by the way!

Guy

[Cadami]

I asked the same question when rewiring my 24V Guy. Seems it's ok to cut it out..

[Strat Fan]

It wouldn't affect the running I'm sure.
It will be the solenoid valve on the vapour recovery canister which seals the tank when the engine is switched off & opens the canister to the plenum chamber when the engine is running.

[Cadami]

I'm assuming you're using a differencet ECU supplied with the engine? Does the fuel pump prime when you switch on the ignition?Have you cut down the original loom Guy? Maybe a faulty crank sensor or the wires are crossed?

[Guy Mayers]

Now I'm really really really really worried. Rechecked all the connections twice this afternoon. Reconnected the ECU to the loom and now there is a spark on each plug. The test light on the fuel pump also glows so the jobs for tomorrow are to lift her up and trace the source of the very slight fuel vapour smell, it's either a weep on a tank or one of the four clamps on the balance pipe. There are a couple of water leaks to close off too then I'll crank the engine for oil pressure, remote prime the fuel system to check for high pressure circuit leaks, fit the plugs and see if she'll fire up.
So, have I got an intermittent connection? The only difference I can see is that the ECU is sat on the floor of the car and not on it's mounting bobbins. If it doesn't fire with the ECU in place I guess it's that the ECU case might need earthing....

Guy

[Guy Mayers]

I'm assuming you're using a differencet ECU supplied with the engine?

Yes Allen, I actually got two with the donor, a standard one and one marie "Chipped" which I'll try once the engine is run in.

Does the fuel pump prime when you switch on the ignition?

Pump isn't connected yet Allen but the test light comes on with cranking on the starter. That circuit dies once the starter is disengaged but there's a second power supply in the ECU/Relay circuitry to supply power once there is oil pressure.


Have you cut down the original loom Guy?

I compared the original loom in the Stratos with the donor on the workbench. There were significant changes between the two but it was still easier to disconnect the redundant wires, plumb in new ones where needed (Lambda) and re-order connections in multiplugs as needed on the AFM to match the donor loom than remove the entire loom and replace with a cut down one from the donor.

Maybe a faulty crank sensor or the wires are crossed?

Definately not! checked, double checked and once again just to be sure! Plus new crank sensor fitted as the old one showed a very slight nip!

Guy

[mel lewis]

Have you got "Home Start" ?

[Guy Mayers]

Yes Mel, hopefully later today. I'm putting the plugs in this afternoon, priming the fuel circuit to test for leaks and should have it Started at Home later on!
Guy

[Guy Mayers]

Finally made use of that nice Halfords tool kit. The 14mm Spark Pug socket fits down into the heads a treat and really holds onto the plugs nicely, keeps them straight and should really reduce the risk of cross threading. I even managed to get the rear bank in without removing the plenum which is a first for me (the old plug spanner wouldn't fit without removing it).

Primed the fuel circuit remotely, straight up to a healthy, steady 6 Bar with nothing spraying out of any connections (probably only because I had the fire extinguisher handy. Reconnected the Motronic fuel lead and had one last check around.

Then started it on the key first time. Happy days!

Guy

[Cadami]

Excellent news Guy :-) I wonder what the issue was?

[turbonutter]

Primed the fuel circuit remotely, straight up to a healthy, steady 6 Bar with nothing spraying out of any connections (probably only because I had the fire extinguisher handy. Reconnected the Motronic fuel lead and had one last check around.

Then started it on the key first time. Happy days!

Guy

Good news on getting it running! I think I would be a bit concerned though unless you found a fault, as an intermittent connection will always come back at some point:(

6 bar is a good pressure for testing the fuel system for leaks, but if the regulator is in circuit, I am sure it should only be 3 or 3.5 bar......

[Guy Mayers]

Thanks Neil, I think I need to do some research to see what it should be running and back the regulator off a little. The motor was "rebuilt and uprated" before I got it but needed a proper strip and reassembly due to excessive oil consumption and lack of compression. It's a Cloverleaf with slightly raised compression and C&B cams so I'm not sure if there was a need for more fuelling or if this would be achieved from higher pressure? Any further advice on recommended pressure gratefully accepted!

As to what the fault was I can only put it down to a bad connection somewhere. I did have the impression that the earth terminal on the Motronic Relay block was loose the first time I pushed the test wire into it and that it "clicked" when I pulled the spade connector out of it. Other than that I suspect there must be an intermittent contact somewhere and that it's going to come back to haunt me sometime!

Time will tell but at least I know that it runs with the loom set up as is so if I do end up rewiring from front to back at Christmas it's based on a sound diagram!

Jobs for this afternoon are to drive it in and out of the garage to ensure the clutch is still working as it should and bleed the coolant system, tightening or replacing any clamps as necessary, find the wiper fault and fix that, check the brake lights and see if the new gearbox has cured the lack of reversing lights I've suffered for the last couple of years. Or I could just check the bulbs having got a stash of spares in the Alfa donor.

Once all is well I'll scrap the donor and list the engine crane and engine stand on eVilbay to make some space in the garage again!

Guy

[turbonutter]

I am not sure of your engine, but pretty sure most engines are around 3.5 bar - with the vaccuum hose disconnected... it may have been tweaked slightly, but i doubt more than 4bar. Asking 6 bar from the pump will seriously affect its capacity.....

I did have a manual with the settings, but cant find it at the moment - all i can find is for teh 2.0 twin spark which is 3.3-3.7 bar... I am sure someone else will know the stock alfa setting.....

[Monte76]

Good news on getting your engine going Guy, I agree 6 Bar is high, you should really be looking at 3.5 Bar max with the vacuum hose disconnected.

Vince.

[Sando]

3 bar is what it needs to be set at as standard Guy. The ECU then opens the injector for longer when it needs to be richer.
The standard injectors flow enough unless you have any more serious mods. The pump would also be matched to this. It may well supply higher pressure but is not designed to and may not last long doing it.

Higher pressure will make it run richer throughout and probably wash the bores with unburnt fuel.
There have been a few people on here that have had their fingers burnt listening to some of the bull onforums, trying to get more power with bigger injectors or higher fuel pressures. Unless the engine needs it it and flows the additional air to match, it will only wash the bores and wear the engine out in no time. If that's what the previous owner was running it like, then that'll have been a significant factor in it needing a rebuild. Keep it standard and it will be fine.
Hope that helps
Rob

[Guy Mayers]

Thanks for the valuable insights Rob! Whilst I'm running in the newly rebuilt engine I've set it run at 3.1 kg/cm2 (my eyesight isn't as good as it was, the gauge doesn't read in bar!). There's a chipped ECU that came with the donor but that can stay out until later when I'm happy with the state of the engine and can do a full compression test after the running in or get it on a rolling road to check it over.

Cheers

Guy

[Guy Mayers]

More progress this afternoon, DROVE the car out of the garage and let it sit on the driveway ticking over to get the water temperature up and bleed the system fully. One water leak found that took a little tracing as it was dripping off the front of the gearbox. Turned out to be from the cylinder head outlet next to the oil pressure sender, couple of turns and that cured that but I'll have to keep an eye on all of them for a while. Once up to temperature the thermostat worked properly and the radiator heated up plus the cabin heater too, it chucked a little water out before I got the radiator cap on but not much. Needle got up to a fairly steady 90 and then switching on the radiator fans brought it down nicely. Decent oil pressure on tickover too. And for the first time in 20 years I've got a functioning oil temperature gauge!

Half an hour of annoying the neighbours I DROVE the car back into the garage. Wipers sorted, loose connection. Reversing light sorted (new gearbox) plus one earth iffy. All other electrics working properly bar the horns which are a pathetic parp. New ones on order, the donor Alfa ones are rusted and not much better!

I'm letting it cool down for a couple of hours and will then go round the hose clamps for a quick check. Remaining jobs are refitting the side ducting plates to the front of the radiator and checking the suspension geometry. I may leave that until next weekend. I also need to source a 3/8UNF bleed screw.... The brake banjo I tried needed two sealing washers and still didn't seal properly and a bolt/washer isn't ideal when hot water is pouring out as you try to relocate the first threads!

Only other query is fuel pressure again. The gauge on the regulator (connected to the plenum) is now reading 2 - 2.5 kg/cm2 on tickover, rising slightly with revs. Is that too low now?

MOT next week perhaps?

Guy

[Sando]

Be careful Guy or you could go too far the other way with just as drastic results. 3.1kg/cm2 this is a smidge over 3 bar which is 43.5 PSI. loads of converters on the web. This would be without the vacuum pipe connected I would expect. When connected it will then vary this when the engine is running and under load or sudden throttle opening. Rolling road and a way of measuring your exhaust gasses with an analyser or wideband lambda is the only sure way of getting this mixture right. Generally a standard ECU will cope with minor performance changes, however there is a lot of discussions about 12v injectors being near their limits hence people upping fuel pressure to richen mixtures or swapping injectors but often ending in tears, only a rolling road session will confirm what the engine needs. Until you confirm this I'd not do any high speed runs a running lean will have just as dire consequences

[Guy Mayers]

Thanks Rob, I'll have another look at it when it's cooled down somewhat and see what the pressure is with the vacuum tube disconnected and adjust it up a tad.

Guy

[][\/][ajor]

Great news to hear you've got it running Guy and thanks for sorting Donna today. Chuffed to bits with the lights. I'll see you at Stoneleigh for beer or three and with a bit of luck and hard graft, I'll be in the yellow peril. :)