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Discussion Starter #1
Hi all,

As I wait to source a new motor for my beloved 2.0TS which chewed it's big-ends! Unheard off in that motor; Oh well.
Anyway in the mean-time I've joined the dark side and bought a '92 3.0 V6 :D:D!!

A few details:
1992, so Motronic.
Only two owners from new, first was an Alfa dealer, the second an enthusiast and genuine gent.
Best gear-change on any of the (to date) four 75s that I've owned: direct, mechanical and tactile. Lovely.
Koni dampers allround and Bilstein springs out back.
No cat and a full CSC exhaust front to back, manifolds and all.
My God! Is the gearbox optional on these motors ;), it pulls like a train from anywhere in any gear :D:D - oh, and sounds rather nice too.

Anyway, I've a few small queries that maybe someone can help me with.
I was underneath yesterday doing all the obvious Poly bushes when I noticed that the forward mounts of the rear cross member are held off the chassis proper by spacers of about 2cm ~ 1 inch. None of my TSs had this; Is it normal on the V6?
The cat is gone, as I say, but the Lambda sensor is still there and feeding back to the Motronic. This should be lowering my power slightly, yes? Should I just switch the Motronic fuel-type plug to non-cat? Will that cause it to simply ignore the Lambda?
When I start the engine first time the oil-pressure warning light stays on - oil pressure is fine though. If I switch off and restart within say, ten seconds - no warning light. Hardly an issue, but slightly inconvenient. Anyone ever had this?

Anyway, sorry about the length of the post and thanks in advance ;);)

Ed.
 

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Discussion Starter #5
Actually, I think you have a spare ARC control box, try swapping it (or with the one from the TS if you don't have a spare). I'm interested in seeing if the oil pressure sensor plays a part in this issue or if it's a problem in the box.
Will do. So the control box over the glovebox, rather than just the ARC itself which is simply a reporting tool?

Ed.
 

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The spacers are normal. All the V6's i've come across had them. It's important that you make sure they go back in when you ever work back there.

Why would the Lamda sensor give you less power? Am I missing something here? When you go to full throttle, Motronic should igonore the Lamda all together and just use the fuel map that is stored in the brain of the ECU.
 

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Discussion Starter #7
The spacers are normal. All the V6's i've come across had them. It's important that you make sure they go back in when you ever work back there.
Well, you learn something new everyday :)

Why would the Lamda sensor give you less power? Am I missing something here? When you go to full throttle, Motronic should igonore the Lamda all together and just use the fuel map that is stored in the brain of the ECU.
Sorry, now that I think of it I got that slightly backwards. It should give me slightly worse economy not less power. The logic being that the Motronic will stop it going to lean-burn on light throttle applications to protect the cat (it will keep it stociometric). Whereas with no cat it should allow ultra-lean.
If I take my foot off the gas :))))

Ed.
 

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Congrats! Sounds like a real gem - a 1992 75 Motronic is about as good as it gets. I still have a UK car magazine of the area where they tested the aging 1992 75 3.0 Motronic against (among others) the new BMW 3 series at the time. They definitely recognized some qualities in the 75.
Jes
 

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Dave, doesn't sound familiar. I'll try dig it up for a scan. Particular for Ed since it may be the exact model he has gotten his hands on.
Jes
 

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From what I remember ( I haven't worked as a mechanic for over ten years, and I worked mainly on T-S cars), the plug thing was mainly used to change the ignition map. This was in the days before knock sensors were commonplace in cars. The three levels of tune was for 92, 95 and 98 octane (the 98 octane setting being for markets where leaded fuel was still available, and, correct me if I am wrong, the oxygen sensor not being able to cope with lead was not used). I have a feeling that the 192 bhp that was quoted for these engines was for it running on 98 octane. So beware of setting it up that way if you are not feeding it that juice.

I used to set the aussie ones for 95 octane with cat. Gave them a bit more stick without risking the engine. As for the aussie T-S cars having 148 bhp on 92 octane..... phah!

I remember that CAR article. They raved about how involving the 75 was.
 

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When I start the engine first time the oil-pressure warning light stays on - oil pressure is fine though. If I switch off and restart within say, ten seconds - no warning light. Hardly an issue, but slightly inconvenient. Anyone ever had this?
That's not an uncommon problem on these cars. I never bothered to fix it on mine though I've been told the sending unit could be faulty. Other people here who actually have fixed it will be able to tell you exactly how.
 

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Discussion Starter #15
Steel manifolds cooking the coolant

Fixed this a while ago and meant to post about it as it seemed quite strange.
As noted earlier, my V6 has steel manifolds (CSC). Whenever I revved it hard (so +5K) for more than a couple of seconds, My nostrils would be assailed by a really really strong smell of burning rubber. Also the expansion bottle was blowing water outthe cap whenever this happened.
Turns out that it seems to have been the rubber coolant pipes running along the side of the engine bay were being cooked by the exhausts! They were well clear of them, but the radiated heat appears to have been sufficient to part-cook the rubber, and flash-boil the water therein, causing the overflow lid to vent under pressure.
I've now wrapped the coolant hoses in thermal shielding, and then covered them with some aluminium ducting, and both symptoms are now cured.
I must confess that I would not have expected the heat to be that extreme.

Ed.
 

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Congrats! Sounds like a real gem - a 1992 75 Motronic is about as good as it gets. I still have a UK car magazine of the area where they tested the aging 1992 75 3.0 Motronic against (among others) the new BMW 3 series at the time. They definitely recognized some qualities in the 75.
Jes
This is the one. From Car Magazine. I think that it really nails what the 75 3.0/Milano Verde is all about.

Sorry about the size, but like that it's readable











 
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