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post #1 of 27 (permalink) Old 02-01-2013, 10:59 AM Thread Starter
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I'd like your thoughts...

I'm not real good at explaining but here goes. I've been chasing a weird running issue for a few months. Not serious, just annoying. Sometimes the car will stumble at lower revs under load, kinda like points being out of adjustment. Idles great. runs like a train at speed, great gas mileage. 2 things I notice. One the first cold start of the day, it pops mildly in the plenum and the exhaust smells rich.

New plugs, wires, coils, caps, rotors, (2 each as its a twinspark), coolant temp sensor. Car runs btter with each addition and the parts were original so no harm replacing. Tonite I was reading the owners book and noted the spark plug wires and compared to how mine are and got to thinking, maybe I have two switched. Bear in mind the car runs great. In the pic you can see the dizzy on the left feeds the plugs on the left of each cylinder. Except the 2nd and 3d ones from the left. I reversed them to better align with the illustration in the book. Car runs great in my driveway but I've not driven it as its foggy out tonite. In all'ya'll's (yes this is a word) collective thoughts, could this have been the source of my problem?
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post #2 of 27 (permalink) Old 02-01-2013, 11:34 AM
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Don't know a thing about the TS but something looks amiss (pun). Note cylinder #1 has 2 wires from the front cap and cyl #2 has 2 wires from the rear cap. This contradicts cyls 3 & 4 which have 1 wire from each cap.

Jim

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post #3 of 27 (permalink) Old 02-01-2013, 12:09 PM Thread Starter
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Mr Jamin Papa, those are the 2 wires I moved so left dizzy feeds the left plug in each cylinder and the right dizzy feeds the oppposite ones. Neither do I know enuff about the TS firing to surmise an opinion. sort hit and miss (pun 2). FWIW I switched the plug wires while the car was running and only when the 2 were disconnected at the same time, did it run notably ruffer. I'm pretty fastidious about these things and cant imagine I inadvertantly mixed these 2 back when I was pulling plugs to change them over.

My question is: would having them just off as I did, contribute to the odd running characteristic I've tried to describe? I'm anxious to put her on the road in the morning and see. And 2d question, think this could contribute to the first start manifold pop I get? We'll see. thanx and ciao 4 now. chris

Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #4 of 27 (permalink) Old 02-01-2013, 12:55 PM
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Quote:
Originally Posted by jc96 View Post
My question is: would having them just off as I did, contribute to the odd running characteristic I've tried to describe? And 2d question, think this could contribute to the first start manifold pop I get?
Yes and yes.
Fair bet that the firing order is off. Have zero info on the TS and can't really see all the wires in each cap. Can you post up the page from the book you used? Or, a pic of each dizzy cap from the 'top' showing where each wire goes?

Jim

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post #5 of 27 (permalink) Old 02-01-2013, 01:08 PM Thread Starter
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The book only shows wires coming from the cap covers, nothing specific. I rather doubt I've got the firing order off as the car runs so well. I've been looking and cant find any diagrams showing clearly what cap terminal feeds what cylinder. The manual indicates the second spark is mainly emmisions related thus my thinking it is wasted spark. Fires each plug twice during the 4 cycle sequence. This thing is weird and really fascinates me as I'm somewhat old skool in my training and the limited amount of info I'm able to find.

Am I on my way thinking that if one of the plugs of the 4 (two cylinders in question) is firing on an exhaust stroke, (by being actually supposed to fire the adjacent cylinder on the comp stroke) it is this that causes a pop in the plenum as the exhaust valve is open and vice versa? Wish the fog would clear so I could go ridng tonite but, better safe than impatient. ciao, chris

Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #6 of 27 (permalink) Old 02-01-2013, 01:15 PM Thread Starter
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just for grins, ciao, chris
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89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #7 of 27 (permalink) Old 02-01-2013, 01:25 PM
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WheW! This is as confusing as my GTA engine. On those one plug is set to fire 1 degree ahead of the other (intake first). This is not easy to set up, I do it with a Sun distributor machine. Should they fire at the same time, or backwards, it runs not badly, but oddly. If you loose either the intake plug bank or exhaust plug bank, power goes down, and the one time it happened, I had spark knock. These engines also had a tendency to fire both plugs at once at low rpm due to a lack of coil input isolation which gave crummy idle. Coils isolated with a diode isolator, a full race GTA engine will idle smoothly down to <900 rpm.
From my experience with this admittedly OLD technology, I would venture to guess that correct plug wire orientation on a twin spark would be critical to proper running, but as usual, this is just my opinion.
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post #8 of 27 (permalink) Old 02-01-2013, 01:40 PM Thread Starter
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bear in mind the first foto above is the way its been for months, I tonite reversed the wires in question. I'm thinking cyls 3 and 4 were firing as they should and 1 and 2 were firing as they should half the time and as they shuld, the other half the time but at the opposite time as they should have been. Hows that for explination?!!!!

Yea, this thing has some electronic devices that verify phase and modify it to some degree and keep everything in check read from the rear cam (intake I believe). we'll see. It's little stuff like this that keeps me sane yet drives me nutz at the same time. ciao, chris

Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #9 of 27 (permalink) Old 02-01-2013, 01:42 PM
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The diagram shows that your firing order is indeed incorrect. The diagram shows both a C & D wire on each of the 4 cylinders. Your engine has C & C on cyl 1 and D & D on cyl 2.
Assuming that the C & D wires on cyls 3 and 4 are correct, I tried to ID some of the wires in the caps. The firing order is 1-3-4-2. Of important note, the firing order on the front dizzy will be clockwise as viewed looking over the right front fender. The rear dizzy will turn anti-clockwise as viewed looking over the left front fender. Please see attached pic.
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post #10 of 27 (permalink) Old 02-01-2013, 01:50 PM
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Quote:
Originally Posted by papajam View Post
The diagram shows that your firing order is indeed incorrect.
You are correct. The diagram clearly shows that each cylinder should have one plug fired by each distributor, never both by one dizi.

The fact that you have not altered 3 & 4 it should be easy to work out which wires are swapped, especially using Jim's post.
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post #11 of 27 (permalink) Old 02-01-2013, 01:57 PM
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WoW! At least I feel better! Took me a while to come-to-terms with the GTA engines, now I understand the twin spark, at least a little. Thanks Jim!


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post #12 of 27 (permalink) Old 02-01-2013, 02:01 PM Thread Starter
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Yessir, think we're using the same terms expressed different ways. Went down and fired it as I'm hopeful it is cold cold and no pop - so well see after an overnite cold soak. On your engine Mr Raymond, is that a points ignition? ciao, chris

Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #13 of 27 (permalink) Old 02-01-2013, 03:21 PM
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While there's no doubt that your leads were wrong and that would probably be the cause of your pop-on-starting, your mid-range hesitation could also be due to worn contacts in the AFM.
There's metal contacts that slide along a copper strip, and over time the strip wears in the mid-throttle area where the contacts do most of the movement (often around ~2500 rpm sort of range).
The effect of this is intermittant over/under fuelling at mid throttle.

And FYI on the distributors - there's no difference in the timing between the two, they both fire together. The engine will run quite well with only one plug per cylinder, and often if the leads are in the wrong position the engine still runs well enough anyway.
As long as there's one plug firing at the correct time in each cylinder then the out-of-phase firing has little effect (as long as it doesn't happen on the ingestion stroke).
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post #14 of 27 (permalink) Old 02-01-2013, 11:34 PM Thread Starter
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Thank you.. Wifes from Croyden. lots of friends in Five Dock. Of course its pouring rain down this morning so a good drive is not in the cards right now but will start her and see. I'm thinking (relative to proper running) that what I have is a 4 cylinder car running on 6 properly (timed) spark plugs!

Things like this are what keep me outta the bars and reminds me that mistresses can be fussy even if they aren't of the female persuasion. Ciao, chris

Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
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post #15 of 27 (permalink) Old 02-01-2013, 11:45 PM Thread Starter
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I've been looking at the AFM on a Spider thread and saw the video on that issue you speak of. Interesting. In this image, number 1 is whats called a sensore numero di giri e fase and number 2 is variatore di fase. In my limited italian means pretty much rotation timing and variable of the time.
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Maintaining my tenuous strain on reality.
89 164 2l Twin Spark, 2011 Tonka Dump

Recently added: an 89 75 (Milano) 1.6 litre w/44K on the klok.

Past loves:
79 Alfetta GTV w/Spica, my 1st Alfa

An 88 Graduate. Not really love but interesting nonetheless.

A 68 BMW 1602 - man do I regret letting that one go!

79 Scirroco, ex plowed into an illegally parked house with it...
jc96 is offline  
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