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Discussion Starter #1
Yes, I found the thread as to whether one is needed or not. It appears as if there is a 'fuel plug' which means one is not required. Okay, I have not a clue what I'm talking about, but moving right along...

When I finally get to the point of installing my TS in an Alfetta GT, I'd like to install a sensor. The car might or might not get a catalytic convertor. If I do install one, I understand the sensor will protect it.

However my main reason for installing one is that I want to (also sooner or later) get a digital air/fuel ratio meter so an oxygen sensor would be required. The Innovate meter has been recommended to me.

If/when I get to that point, what model/type of sensor would work best? I gather the preheated oxygen sensor is the newest type and the best, but assuming I do insall a catalytic convertor, would it then work with the TS' Motronic engine management unit? Or must it be a specific sensor?

One more question. I suspect an engine management light is more of an annoying pain for most folks, but would adding one be a good idea? Obiously if the engine isn't running well one wouldn't need a light to tell them. However, if it 'goes off song' but still runs 'pretty well', it might be nice to have. Comments?

Biba
 

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L-jet and Motronic both use a narrow band O2 sensor.

Later in the 80's they all went to the heated version, though the unheated works just as well once warmed and provided you're not sitting and idling for extended periods. (they cool down at stoplights, but that's kind of a moot point as most EFI systems revert to a different mixture not based on stoich when idling)

Heated sensors cost more than unheated.

Narrow band are cheaper than wide band, wide band can be more accurate.

The A/F gauges are the same deal: narrow band is cheaper than wideband, by far. (we're talking close to $75-$100 difference in some cases)

An O2 sensor won't 'protect' your catylist, it'll only try to tell the ECU what mixture you're running. It's up to the ECU to try and correct mixture based on a great many variables and whether or not all your sensors and senders are in good order.
 

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Biba,

You can wire up a Check Engine Light from the Motronic ML4.1 ECU. Check the Twinspark Questions thread. I posted a link in one of the posts to a website that had a little bit of info on this.

Regards,
Lawrence
 

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Discussion Starter #4
Tifosi and Lawrence, thanks for this information. What especially confuses me is not only the different types but that it seems as if every model of every car has a very particular O2 sensor that must be used. However, I guess I'll cross that bridge...

Lawrence, could you give me a hint as to which Twinspark Questions thread it was you posted the link? There are about 35 or so threads when I plug in 'Twinspark Questions'.

Biba
 

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What especially confuses me is not only the different types but that it seems as if every model of every car has a very particular O2 sensor that must be used. However, I guess I'll cross that bridge...
It's not as confusing as you'd think actually.

Different cars use different part #'s simply because the auto manufactures can put a different part # on each one and then charge what they want for that part #.

Hit a parts store sometime and ask about a generic unheated (single wire) narrowband replacement one and they'll offer you one that will fit about every car on the road that uses a single wire unheated O2 sensor. (as in the same one that fits an L-jet Alfa will also fit a Ford, Chevy, Dodge, Renault, BMW, etc., etc.)


The big issues are wideband vs narrowband and whether it's unheated or heated with a 2 wire (which is actually 3 on the sensor) or 3 wire (which is actually 4 on the sensor) setup.


Narrowband are rated from .1 to .9 volts output (stoich being roughly .45 volts) while wideband are 1 to 5 volts.

That's it :shrug:

No special difference from vehicle to vehicle, no different fit, no different bung in the exhaust.

Simply a matter of output voltages and number of wires.
 

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Just looked up that Innovate system.

Looks like it's wideband only, (at least those that I looked at), so it won't work with your Motronic unless you don't actually hook it TO your Motronic. (ie: you use it to operate the A/F gauge alone and nothing else, though the datalogging may be of use, even if you can't tune the non-adjustable Motronic with it. If you want actual tunability, aftermarket programmable EFI is the only way to go)

Autometer has several narrowband A/F gauges that will tie right in with the Motronic O2 sensor (you just tap an extra wire from the sensor output to the gauge, hook up a + and a -, mount the gauge, drive....) and won't cost hundreds of dollars. (most I looked at were around $60-$70)
 

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Biba,

Here's the quote from the link I was referring to:

"The Motronic 4.1 system has a self-test capability that regularly examines the signals from engine sensors and internally logs a code in the event of a fault being present. This code can be extracted from the Motronic Serial Port by a suitable Fault Code Reader. When the ECU detects that a fault is present, it earths pin 17 and the warning lamp on the dash will light. The lamp will stay lit until the fault is no longer present. If the fault clears, the code will remain logged until wiped clean with a suitable FCR, or until the engine has been started for more than 20 times when the fault code is self initialising. An ECU that retains codes for faults of an intermittent nature is a valuable aid to fault diagnosis."

If you run a circuit like this

...+12V ==> lamp ==> pin 17...

it will give you a 'check engine light' of sorts. I've got an unused light on my GTV's dashboard that I was going to use for this.

Regards,
Lawrence
 

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Discussion Starter #8
Lawrence, thanks. I'm assuming either you've never felt the need for the warning light or else just haven't gotten around to hooking it up.

Is the wattage critical on the bulb used? I can't imagine it being a special light, but if so I gather one finds it at the usual sources (not in the US)?

How the heck does someone know that pin 17 is the one to use? Boggles my mind.

If I was installing the TS in my '75 Alfetta GT (rather than in another Alfetta) I'd use the SLOW DOWN catalytic converter warning light. I can't imagine how Alfa got by with that one but it was early on with the converters.

Biba
 

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G'Day Biba,

The bulb must not be bigger than 1.2 watts.

I have wired up both my TS and 164 and have never seen the lamp stay on (as a check engine lamp). Maybe the ECU requires a later 'chip' (mine are both early versions).

There is a diag document (in Italian) on my site (provided by JimK) which has some good pictorial descriptions of the test procedure and test lamp wiring.

Don't get too excited about being able to use a serial port fault code reader, there isn't one. We're stuck with the flashing lamp.

There is an eBay seller in the US selling O2 sensors for the Alfa 33 at a very good (starting) price ($24.79). These sensors have the Alfa connectors but the wiring is longer than a TS (or 164). The seller id is ufixitautoparts.

I got one for the $24.79 :D and one other didn't sell.
 

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Discussion Starter #11
Craig, thanks for this info. I'll go check out the O2 sensor. Price sounds More than reasonable.

Is it possible the bulb's wattage is Extremely critical and needs something (for instance) at exactly 1.0 watts to be effective? I also gather your 75 TS and 164's engines have never faltered? Meaning not running like crap, yet light refused to go on? A bit lazy, but I don't want to go to the trouble of wiring a lamp up and installing if it is merely 'decoration'.

Is the wiring diagram somewhere in the 'files' I downloaded of yours? Why oh why couldn't the headings be designated: Engine. Transmission. Wiring diagram? Obviously not your fault.

Biba
 

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Craig, thanks for this info. I'll go check out the O2 sensor. Price sounds More than reasonable.
I also see Milano O2 sensors which are the same (but shorter wires) for $100 more so yes the price is more than reasonable.

Is it possible the bulb's wattage is Extremely critical and needs something (for instance) at exactly 1.0 watts to be effective? I also gather your 75 TS and 164's engines have never faltered? Meaning not running like crap, yet light refused to go on? A bit lazy, but I don't want to go to the trouble of wiring a lamp up and installing if it is merely 'decoration'.
No, definitely not critical. However having the light (and switch) wired up so you can read the error codes does help with some problems.

Is the wiring diagram somewhere in the 'files' I downloaded of yours? Why oh why couldn't the headings be designated: Engine. Transmission. Wiring diagram? Obviously not your fault.
Actually it may not be in the manuals on my site. I do have information gleaned from other sites which does not appear on mine.
 

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I bought the O2 sensor for my TS from Centerline. They sell a functional equivalent, but it has a different tail on it. You would have to splice it into your TS injection harness, but I expect you would have to do that anyway. I think they said it came from a Taurus.

Regarding the Check Engine light, I'm still getting the engine ready to fire up for the first time, so this is a ways down on the list of things to do. BTW, the wiring harness diagrams on Craig's site are invaluable and I've pulled 90+% of what I've needed from there. I can't thank Craig enough for this resource.

There are a few sites on the Bosch Motronic system that have other good information. It was through this other reading that I pulled the quote from my previous post.

Regards,
Lawrence
 

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Discussion Starter #14
Again I want to thank you all for taking what is a pretty mundane topic and answering my questions in full. I'm of course a looong way off in needing all of this info but good to know I don't have to start entirely from scratch once I get it started.

Biba
 
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