Preliminary Idle adjustment (Spica) - Alfa Romeo Bulletin Board & Forums

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Old 05-06-2003, 08:32 PM
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Preliminary Idle adjustment (Spica)

My GTV is idling very high (1700rpm), and I've pulled the air cleaner-to-equalizer block hose (picture below), and tried screwing in the adjuster screw (picture below) to reduce speed. But it's not working, I have a feeling something is stripped in the equalizer, maybe some sord of washer. Anyways, when I clog the equalizer the idle drops to 900rpms. So I stuck a chrome tire vavle cover in the hose to clog it, and plugged it in, and the car seems to run fine.

Am I at harm clogging this hose?
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Old 05-06-2003, 09:21 PM
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Sniady-

NO NO NO!!!! Guilty of Alfa abuse. Sentence . . . 10 lashes . . . well laid on. Do not mess with the SPICA FI system unless you know what you're doing. It's not so complicated that you can't read for a couple of hours and understand it well. Get into the book.

There's a reason is running fast.

1. Check that the throttle cable is not holding the throttle off the idle stop when the engine is at running temp (170 minimum). If the knucklehead PO adjusted the idle cable tight with the engine cold, then it would not allow the throttle to go all the way to the idle stop when hot.

2. If the throttle cable is correct, on the back of the injection pump, check to ensure that the distance between the idle reference screw and the throttle arm is no more than .019" when the engine is hot.

3. If it's larger than that, then the thermostatic acutator is probably malfunctioning. The TA extends a piston in the injection pump as the engine heats up and commands the mixture to decrease in richness (pump throttle arm to go closer to the reference screw). The engine MUST get to at least 170 degrees. If it doesn't replace your coolant thermostat. If you suspect that the TA is bad, get the engine up to operating temp, carefully remove the center bracket of the thin brass tube, then remove the two small screws holding the actuator in the top of the pump. DO NOT KINK THE BRASS TUBE. There's a small chrome piston that should be protruding and it should be about 27-31mm from the end of the piston to the base of the flange plate, depending on the year of manufacture. You can also remove the whole TA and test it in a pan of heated water and a thermometer. If you need a rebuilt TA, they're about $200. The salient part here is that the "pump gap" (between the reference screw and throttle arm be no more than .019" when the engine is hot. UNDER NO CIRCUMSTANCES REMOVE THE PLASTIC CAP OR SAFETY WIRE, NOR CHANGE THE SETTING OF THE REFERENCE SCREW ON THE BACK OF THE PUMP. NEVER! NEVER! NEVER! NEVER!

At hot idle, the only air the engine should get should be through the idle circuit and that adjustable tube. There is a rubber O-ring behind the threaded pipe that is pinched. When it's pinched, it narrows the hole that the idle air must go through, thus changing the idle speed a small amount. Replacement O-rings are available from Centerline, et al for about $2. You may check to ensure that there actually IS an O-ring in there to begin with and that it's pliable and not hard/cracked. You never know what PO's did to the car. That idle speed adjuster is not going to get the engine up to 1700 rpms.

Last edited by Roadtrip; 05-06-2003 at 10:14 PM.
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Old 05-06-2003, 09:40 PM
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very good advice from roadtrip, it's always good to read before you experiment and can cause damage.
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Old 05-06-2003, 11:07 PM
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I doubled checked the throttle cable to, I actually tightened it up a little.

Also, can idleing high, have anything to do with the choke? My choke has been having a mind of it's own, and I think I'm running with it on.
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Old 05-07-2003, 12:49 AM
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Haha! That was me!! Tighten the cable when it was cold.

Quote:
Originally posted by Roadtrip
If the knucklehead PO adjusted the idle cable tight with the engine cold, then it would not allow the throttle to go all the way to the idle stop when hot.
Sniady, have u checked the butterfly when the engine is hot. Are they completely CLOSED? How about the short rod?
How about the HAND THROTTLE?

BTW, where is the choke on our GTV?
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Old 05-07-2003, 08:01 AM
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Yea, I know that was you Alfa_Chan. Before you told me about it, I hadn't thought about it. We'll . . . . I just "assumed" . . . . and you know what that means. Anyway, "throttle cable" is now an early step in my SPICA troubleshooting guide.

Sniady - There is no choke on an SPICA system. I think what you're refering to is the pull cable on the lower left rear of the center console. That's a "hand throttle." All it does is pull the throttle cable back a little so you can set a throttle position without pressing on the accelerator. It's ONLY function is to help keep the rpms up a little when the engine is cold and warming up. It is NOT a cruise control and should NEVER be used while the car is in motion. It DOES NOT release when you press the brake pedal like cruise control systems do.

To check to be sure it's not restricting the foot throttle, look where the cable goes through the firewall (center left side of the firewall, then goes through a loop on a tang attached to the throttle actuating bar (that's pivoted on the firewall). With the hand throttle pushed all the way in, it should be loose on the throttle bar and not preventing the manifold butterflys from going to full shut (engine hot). Since you say you've already checked the throttle cable (there should be just a bit of slack allowing the throttle bellcrank to go against the throttle stop screw), then the hand throttle is probably not set too tight either.

I think you're down to a grossly maladjusted idle stop screw (unlikely, but possible) or a bad T/A.

In a SPICA system, the Thermostatic Acutator acts as a choke would in a carb engine. However, it does NOT restrict airflow in the intake like a carb, but rather mechanically enriches the mixture as well as opens the throttle slightly to provide a higher cold idle. As the engine heats up, the TA piston retracts and the FI pump throttle arm returns to the reference position (.019" clearance). This also closes the throttle butterflys back to full closed so the ONLY air the engine is getting is through the idle system (small hose from air cleaner to manifold, then the 4 even smaller hoses to each cylinder barrel).

Do not go and start "adjusting" anything like idle stop screws, etc. What we're doing right now is just checking the operational integrity of the most likely suspects in your high idle problem.

If the TA checks out good, then a complete reset and tune of the SPICA system is probably in order. That's going to require a lot of reading and understanding and a nice Saturday afternoon . . . no beer until job is finished.

Last edited by Roadtrip; 05-07-2003 at 09:05 AM.
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Old 05-07-2003, 07:53 PM
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I checked the butterflies, relay crank to throttle & control unit rods, and the idle limit stop screw. It all seems to be intact.

I think it's the equalizer, one of the o-ring's is missing. So I built a little contraption, which let's in less air into the equalizer intake's, and it run's at 800 rpm.
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Old 05-07-2003, 07:56 PM
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RT thanks for the info. And I do think the spica need's a good tuning. So my contraption should work temporarly, I don't want to dish out money into it.

I going to try and equip some webers in a month.
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Old 05-07-2003, 09:05 PM
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The rubber O-ring in the equalizer only costs about $2 and are available through Centerline or IAP, I think.

If you convert to carbs, don't toss ANY part of the SPICA system . . . and be very careful when you dismantle it NOT to break anything, especially the TA.

I guess I'm a purist, but I generally like to keep them in original condition, including the SPICA system. Design-wise, it's a work of art and machining-wise, it's difficult to find something as finely made as a SPICA injection pump.

Someday I'd like to get a Spider and do a high performance street mod to it. Unfortunately, I'm out of garage space and I'm not sure my wife would take kindly to having her car evicted from the garage by ANOTHER Alfa. On the other hand, it may be worth just doing and appologizing afterwards. . . . . . . .
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Old 05-07-2003, 10:24 PM
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Quote:
Originally posted by Roadtrip
I guess I'm a purist, but I generally like to keep them in original condition, including the SPICA system. Design-wise, it's a work of art and machining-wise, it's difficult to find something as finely made as a SPICA injection pump.
I can say I'm the same way, only un-orginal thing on my Alfa are the panasports(for now).

I guess it's not orginal if I throw weber's on the motor, but in europe they did make 2 liters with webers, that's where I trick myself into carbs(So I have a good reason to trick my brain). I love carbs. But I also love when people say 'what the heck is that', it's a spica! 'what?' mechanical FI!'how does it work', it's mechanical! I dont know!

I want to keep my car orginal, but there's a few thing's that bug me. Like the seat's. I'm to tall for those sucker's, and I get bad back pain from them. So I'm throwing in some momo seats in the future. Also, there are so many day's that I look at my car and would like to throw back some steel's on it. I know it would look nice lowered with stock rims.

Me and my car have heavy issue's. We can never make up our mind's.
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Old 05-30-2003, 12:08 PM
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Okay, I'm a late comer here but back to the idle issue:

If you remove the idle air adjuster screw completely you'll know weather or not you've got an o-ring and washer in there. If you put your thumb over the hole and the engine dies then it's a good bet that the rest of the system is set up okay (assuming it runs good, has good drivability, smooth acceleration and gets about 27 mpg and the idle speed is your only issue).

You can get an o-ring at Ace hardware actually and I've used a short piece of vacuum line before - anything to restrict the amount of air that can get through that main orfice so you can get the correct idle mixture for a good smooth idle around 700 rpm or so. But the OEM o-ring and washer work the best, have the best adjustment "quality" and maintain the setting longer than any jury-rigged setup so eventually you'll want to go that route.
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Old 05-30-2003, 07:05 PM
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Welcome to the board Kcabpilot.

So I stuck my finger over the hole, and my engine did not die, the revs dropped, but did not die.

What do you think?
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Old 05-30-2003, 07:09 PM
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Check to ensure that all the throttle plates are "just" closed with the throttle at idle.
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Old 06-01-2003, 07:39 PM
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Quote:
Originally posted by Sniady

So I stuck my finger over the hole, and my engine did not die, the revs dropped, but did not die.

What do you think?
Probably means your throttles aren't closed. Start by disconnecting the long rod then disconnect the short rod at the bellcrank. It should line up perfectly with the throttles closed and the bellcrank at the idle stop. If it's too long either your bellcrank stop is out of adjustment or the short rod is out of adjustment. If it lines up good then something else is out of adjustment. Could be the long rod, could be the thermostatic actuator is not giving enough extension. The only real fix for that is replacement and they ain't real cheap. The way to check it is get the engine up to operating temp, shut it off and pull the actuator end off the pump (being careful not to abuse the tube) then measure the extension. Should be around 31 mm or so from base to tip.

Another thing to check is the idle air line to the vapor seperator. If it's disconnected or broken it could be letting enough air in to cause your problem. I'm not sure but it might do that also if it's hooked up to the wrong port on the canister.

Other than that, you need to go through the entire setup procedure from step 1 to ensure that everything's adjusted correctly.

Good luck
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Old 06-08-2003, 10:49 PM
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Spica

Geez...when I read your posts and advice, roadtrip, I can practically hear Wes Ingram's voice in my head quoting the same procedures. Good for you! Sounds like you thoroughly understand the Spica setup procedure. Hey, Sniady, why don't you have Wes set you up a Spica pump specifically for your car? Some of the guys here run Spica on their race cars and kick butt, and you can't BEAT it for streetabilty when set up properly. I love the easy starting and steady idle my pumps give me. Totally reliable, too.
(Hope I didn't just jinx myself, there).
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