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Discussion Starter #1
Just purchased my first Alfa, so I'm definitely a newbie. The car starts fine, however, it idles rough. When I drive it, the rpms drop to the point I have to feather the gas pedal to keep it from stalling, even after it has warmed up. The plugs and wires are new, so I'm not sure where to go from here to smooth it out. If it was carbureted, would feel like a timing issue or air/fuel mixture. Any suggestions on what i can do to improve performance? No idea what adjustments are available on a FI Alfa.
 

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Are there specific places to check starting with the most common offenders? Is the best way to check to just let the car idle and listen for leaks?
 

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the Motroinic uses an electronic idle stabilizer. More then likely the valve inside has gotten sticky or it has gone bad.

But first go over every rubber hose on the intake system. Especially the plenum hose from the airbox to the center of the engine. It gets cracks and they are hard to find with out taking it off.
 

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Great....thanks. I'll start the search tomorrow. Is there a diagram of the Motroinic/electronic idle stabilizer? Where is it located?
 

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The silver thing bolted on the back of the intake plenum. Will have a small Bosch label on it and a wire connected to it.
 

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welcome to the board. A 1990 is a nice combination of the S3 spider body with the more modern S4 motronic engine.

with any first alfa you should have a few basics to hand:
a digital volt meter (DVM) to test resistance, volts etc....20/30 bucks buys one these days.
a good coloured wiring diagram (I will send you a pdf to your private conversations box)
a can of electrical contact spray (alfa electrics need care)
a can or two of brake cleaner spray (cleans things!)
a can of WD40 spray
and a few basic tools in metric sizes.

To your rough idle problem:
first off these cars hate 'false air', that is a small leak in any one of the rubber air or vacuum hoses on the engine, especially that big accordian hose over the top of the engine....check it has not come loose where it is attached, and that it has no small splits.

the IAV (Idle air valve):
remove it. The original hoses will have those 'clic-r' hose clamps, that are a pain to remove (unless you have the cheap 'clic-r' clamp removal tool), but generally a pair of needle nose pliers does it. The IAV itself is held on by that clamp and one allen head screw underneath (another idea for your tool kit...6, 8, 10 & 12mm allen head bits to fit onto a small socket wrench set)
once in your hands, spray it with the brake cleaner fluid and shake it around...make sure the vane inside moves easily with your finger. It fits into the intake with a big rubber bush....this bush can harden/shrink a little (another source of false air), So when putting it back apply some silicone grease all around the rubber, inside and out before refitting.....just to be sure.

you can test the IAV's resistance: with your (newly purchased DVM!)...you want to see about 7 to 11 ohms between the 2 pins.
iav.jpg

If none of the above improves things then we can move onto the OVS (oil vapour separator) and a few other things to work through little by little

Oh and last but not least..........post a photo or two of your new spider, engine etc:)
 

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welcome to the board. A 1990 is a nice combination of the S3 spider body with the more modern S4 motronic engine.

with any first alfa you should have a few basics to hand:
a digital volt meter (DVM) to test resistance, volts etc....20/30 bucks buys one these days.
a good coloured wiring diagram (I will send you a pdf to your private conversations box)
a can of electrical contact spray (alfa electrics need care)
a can or two of brake cleaner spray (cleans things!)
a can of WD40 spray
and a few basic tools in metric sizes.

To your rough idle problem:
first off these cars hate 'false air', that is a small leak in any one of the rubber air or vacuum hoses on the engine, especially that big accordian hose over the top of the engine....check it has not come loose where it is attached, and that it has no small splits.

the IAV (Idle air valve):
remove it. The original hoses will have those 'clic-r' hose clamps, that are a pain to remove (unless you have the cheap 'clic-r' clamp removal tool), but generally a pair of needle nose pliers does it. The IAV itself is held on by that clamp and one allen head screw underneath (another idea for your tool kit...6, 8, 10 & 12mm allen head bits to fit onto a small socket wrench set)
once in your hands, spray it with the brake cleaner fluid and shake it around...make sure the vane inside moves easily with your finger. It fits into the intake with a big rubber bush....this bush can harden/shrink a little (another source of false air), So when putting it back apply some silicone grease all around the rubber, inside and out before refitting.....just to be sure.

you can test the IAV's resistance: with your (newly purchased DVM!)...you want to see about 7 to 11 ohms between the 2 pins.
View attachment 1659204

If none of the above improves things then we can move onto the OVS (oil vapour separator) and a few other things to work through little by little

Oh and last but not least..........post a photo or two of your new spider, engine etc:)
Hey Dom,

Would you please send me a .pdf copy of the color wiring diagram for a 1990 Spider as well?

Thanks in advance!
 

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Discussion Starter #11
Great insights and very clear guidance, much appreciated! Fortunately I have all the basic tools and meters, the knowledge is what is needed the most😀 I guess a service manual should also be on the list.
A little more about the car. It’s a silver 90 Quadrifoglio with the hardtop, Has about 60k miles. Was garaged since new, so no rust. I will take pictures outside once the weather clears later today I wasn’t really sure which years were more desirable than others, but I really liked the features of the QF such as the ground effects, gray leather seats and red carpet. Very unique.
Couple of other general questions:
What US supplier has the most comprehensive parts available?
What is the paint code for silver Quadrifoglio?
Does anyone make the l/r hardtop hook access pane
What is recommended oil, brand/viscosity?

Mark
 

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Great insights and very clear guidance, much appreciated! Fortunately I have all the basic tools and meters, the knowledge is what is needed the most😀 I guess a service manual should also be on the list.
A little more about the car. It’s a silver 90 Quadrifoglio with the hardtop, Has about 60k miles. Was garaged since new, so no rust. I will take pictures outside once the weather clears later today I wasn’t really sure which years were more desirable than others, but I really liked the features of the QF such as the ground effects, gray leather seats and red carpet. Very unique.
Couple of other general questions:
What US supplier has the most comprehensive parts available?
What is the paint code for silver Quadrifoglio?
Does anyone make the l/r hardtop hook access pane
What is recommended oil, brand/viscosity?

Mark
Greetings Mark and congratulations on your acquisition!

From my experience, not sure the word 'comprehensive' applies to Alfa parts suppliers anywhere. In the U.S., I've purchased parts from Centerline International, Vick Autosports, and Mr. Fiat. If you care to shop 'across the pond', I've found Classic Alfa and Alphaholics to have a good selection of parts, although the shipping can get pricey. Good luck with your Spider!
 

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Hello Mark and welcome to Alfa BB
Congratulations on getting a 1990 with Motronic injection. My favorite combination of S3 body style with S4 injection.
I have a white 1990 I concur with what Jim G and Dom have mentioned. THat idle air stabilizer is a very likely supect.
Where in the USA are you located?
 

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Discussion Starter #15
Always nice to hear unprejudiced choice of favorite model year😀. My logic to buy an Alfa was that even though it’s a “classic” car, it has some modern amenities like power windows, AC etc. love the added features of the Quadrifoglio.
Seems like a top notch forum that doesn’t look down on newbies asking very basic questions. I have just enough basic mechanical/electrical knowledge to be dangerous. Fortunately I have a great mechanic nearby who can fix all my binders.

I live in beautiful Wilmington DE. 😩
 

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Always nice to hear unprejudiced choice of favorite model year😀. My logic to buy an Alfa was that even though it’s a “classic” car, it has some modern amenities like power windows, AC etc. love the added features of the Quadrifoglio.
Seems like a top notch forum that doesn’t look down on newbies asking very basic questions. I have just enough basic mechanical/electrical knowledge to be dangerous. Fortunately I have a great mechanic nearby who can fix all my binders.

I live in beautiful Wilmington DE. 😩
I don't think anyone has ever given a "newbie" a hard time. Jim G is a very solid source as is Dom.
Both can answer most questions on S3 and S4 cars and I think Jim G can probably answer most any Alfa question. Don't know Dom that well but maybe he can also.
As far as performance upgrades which you asked about, Squadra makes a chip for the Motronic cars like yours. I have one in my 1990. FYI, 1990 cars are generally a little faster than 1982 through 1989 cars.
L-Jetronic cars do not have anything that I know of like that. See link.

 

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What is the paint code for silver Quadrifoglio?
Does anyone make the l/r hardtop hook access pane
What is recommended oil, brand/viscosity?

Mark
paint: there should be a paint sticker under the trunk lid...is it missing?
like this (this could be the correct code too for your MY90 as it is from an 87 factory silver spider)
argento code.jpg
hardtop: you mean the plastic covers for the side "J" hooks?
hardtop j hook cover.jpg
...no. nobody does those. Make a note of the PN and keep a search going...I found a NOS set on fleabay for about 30 bucks in original alfa bags (photo)
oil: any decent quality 20W/50 oil. I use Valvoline VR1 20/50. If you live in a really cold country/state then go a grade thinner.
 

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paint: there should be a paint sticker under the trunk lid...is it missing?
like this (this could be the correct code too for your MY90 as it is from an 87 factory silver spider)
View attachment 1659273
hardtop: you mean the plastic covers for the side "J" hooks?
View attachment 1659267
...no. nobody does those. Make a note of the PN and keep a search going...I found a NOS set on fleabay for about 30 bucks in original alfa bags (photo)
oil: any decent quality 20W/50 oil. I use Valvoline VR1 20/50. If you live in a really cold country/state then go a grade thinner.
Maybe i should not give away my secrets but you seem like you are nice guys. I bought 4 sets last year. Not cheap.

 

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Ghia, you'll find the Alfa BB very informative and entertaining at times, too. The occasional humor is free. ;)
Sounds like you have a solid Series 3.5 Spider there, as some folks call the 1990 model. I can vouch for the aftermarket ECU perfomance chips, I have a Ricambi chip in my S4, but the feel is the same with the Squadra chip. Nice improvement in idle and initial throttle tip-in response, a detectable mid-range acceleration improvement too.

Some other items I suggest to add to your wish list:
---a chassis stiffener, designed to bolt on, improves steering response and ride (IMO), somewhat lessens cowl shake and I think aids in suspension response because there's a bit less twist front to rear.
---headlight relays, which will brighten your headlights and prolong the life of your switch contacts.

I think it's fair to say the general consensus here on oil is don't use anything lighter than 10W-40, with many owners favoring 20W-40 or 20W-50 for the usual road use. But be aware that oil and tires are two topics here on the BB that generate a ton of comments and opinions! I would want to know what the PO used in the engine, frankly, and if that's within spec maybe continue using that oil.
 
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