Mondial fluctuating idle

I would have a good look at the spark plug extensions, if you have the old style , the trangular clip is very close to the insulator,(piece that makes the connection to the top of your spark plug ) it tends to blow out there and short the plug out, making an erradic idle due to the shorting out, but cleans up when you accelerate.....this is a very common problem that is overlooked with these engines, the new style extensions will cure this blow out problem

Just my 2 cents

Ang

 

When I changed all the plug wires, I checked the extensions with my volt meter for continuity and they checked out fine unless this procedure I did is incorrect. I have been reading every thread I can and I think ,only one side of my engine is working. I have noticed from reviewing the videos I took when I was checking the o2 that when the car is running good the o2 is at range but when the car is running bad the o2 is in the mv, which means the car is running very lean. I think I am getting these lean o2 reading because of all the o2 flowing from the dead non fireing bank. The o2 is trying to adjust the mix but cant. I still have the car at the shop and they cant figure it out. I downloaded the 328 bulletin on how to check the microplex, I just need to pick it up the car check all the ignition system to rule out a bad coil.

 

Update, I thought I would test my theory today and check the coils for spark, so I headed out to pick up my car at the repair shop. As usual once the car warmed up I felt I was driving a boat, so I hit the accelerator and went WOT as to see if I can relieve the o2 from command and wow the car felt good. Well, after driving like a crazy teen from the repair shop I disconnected one of the coils and the engine started up but still fluctuating, and I tried the other side and the same result fluctuating at half the power. Well, if air is leaking in from the exhaust it must be from both manifolds or where they both meet or maybe, that new o2 sensor is dead and not creating any voltage. I’m going with the bad o2 so I ordered another and if that don’t work, I think I’m going to lose it, Chevy Chase style, lol. I know part of my problem is that I don’t know what the hell I’m doing, and as a hobby, is getting very expensive and not very relaxing. Well, all I can do now is wait for the new o2 to arrive, and hope for an ez button.LOL or CMC if your a latino.
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new o2 did not fix a thing.

Steve, when the car is at idle it runs lean because the air injection is on, and when I disconnect the tube from the air pump to the cut off valve the car goes rich (8.5) on volt meter( o2 disconnect (+) from sigle wire and ground) . That means the car can go rich and I dnt have an exhaust leak.
Somebody please, what else can I check, I have hit a dead end.
No fluctuation when FV is disconnected with very little power, and car runs well with o2 disconnected.
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Couple of questions:

1. Is this at warm idle (when the air injection should already be "off") or during cold idle? If at warm idle, that would definitely indicate a problem (there should be no vacuum present on the small vacuum line to the cutoff valve that you unplugged when the engine is warm so it should make no difference whether that vacuum line is plugged in or unplugged when warm) -- either bad electrovalve or something is wrongly "telling" the electrovalve to be "on" (like having the wrong logic coolant thermoswitch). The DC voltage between the two terminals on the electrovalve should be:

cold = +12V (which opens the electrovalve, and puts vacuum on the small line going to the cutoff valve)
warm = 0V (which leaves the electrovalve closed, and put no vacuum on the small line going to the cutoff valve)

2. "8.5" volts would be a very strange (too high) output from the unplugged O2 sensor -- did you mean 0.85 volts?

 

1.Yes, when the car is warm the vacuum is on all the time at idle

2. Sorry, .85 dcv, but when I disconnected the vacuum line the symptoms did not go away

what I need is a flow chart that I can follow, is there one out there. I think I need to rewind and start over step by step.

 

This is DEFINITELY wrong and needs to be resolved. Measure the voltage between the two terminals on the electrovalve (item 2 in the SPC jpeg you posted) when at warm idle -- if it is (wrongly) +12V, you most likely have the wrong logic coolant thermoswitch installed, or the coolant thermoswitch has failed and is just always stuck "closed". If it is 0V, and vacuum is still present on the small vacuum line going to the cutoff valve then the electrovalve itself has failed. Also confirm that the small vacuum lines are connected correctly to the electrovalve (as mixing these up can change the functional logic):

port 1 = the line going to the intake manifold (the vacuum source)

port 2 = connected to the cutoff valve

port 3 = left open to atmosphere (no line)

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Yes, that's better/reasonable voltage value I know that it seems disappointing that it didn't "fix" it, but if the last mechanic tried tweaking it up while the air injection was "on", the tweak could be way off. Also, if the coolant thermoswitch is bad (and was "closed" during the last tweak-up), same thing -- could make the whole tweak bogus because it would be "telling" the injection ECU "I'm cold". You need to make sure that the air injection is "off", the coolant thermoswitch is "open", and the O2 sensor is unplugged when you make the warm idle mixture tweak -- IMO this is "to rewind and start over ".

 

Is this the coolant thermoswitch?

I checked this switch and when cold there is continuity and when warm no continuity(closed)
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Yes (but you said that a little wrongly)

When cold, there should be continuity (i.e., closed) = 0 ohms (or a few ohms maximum)

When warm, there should be no continuity (i.e., open) = infinite ohms

If your coolant thermoswitch is OK, then you should confirm that the DC voltage between the two terminals on the electrovalve is 0V during warm idle. If vacuum is still present on the small vacuum line going to the cutoff valve during warm idle (when you have 0V between the two terminals on the electrovalve), then the electrovalve itself is bad, or it is hooked up incorrectly.

 

Thank you Steve, sorry there is no continuity, it is open when warm

And yes the connection to the electrovalve was incorrect. I unplugged them when I was installing the check valves and plugged it back incorrectly. Now when warm, there is no vacuum, but the bad idle did not go away but it is not as pronounced. Thanks once again Steve for teaching me, it feels good to know I’m learning more about my car.

 

So, I guess my next step is to tweak the mixture again, and
how would I go about, makeing this adjustments?
If I disconnect the o2 sensor and get the single wire(+) and ground, what readings should I be looking for?

 

(Lacking a gas analyzer) you could try something like 0.6~0.7V at warm idle (O2 sensor unplugged), but just being able to successfully change it from ~0.1V to to ~0.9V, by using the mixture adjustment screw (and then blocking the access hole) while the engine still quasi-idled OK, would be a good sign.

 

Update, today I set the mixture as per Steve's instructions and was able to have the voltage at between .5 - .7 dcv from the o2 sensor. The fluctuation has disappeared completely and the car is driving strong. This is the best the car has ever felt since I have owned it, and I have noticed the car is running very quiet now. Before, this car was very loud, I thought well, it’s a Ferrari it must be loud, so I wouldn’t even bother turning on the radio. I am still in disbelief, so before I get any more excited I will wait a few days to confirm fix.
Steve, thank you again for your help and wisdom, I hope this is it.

 

Update, my excitement was short lived to find out the erratic idle has come back.
So, I thought I would do the test again

1. FV. Warm idle acv between 2- 6.5 acv swinging up and down in sync with idle ( I think this should be about 5.3 – 6.3 closed loop. What does it mean when acv goes below 5.3 and what’s making it swing?)
2. o2 disconnected warm idle, volts from single wire and ground between .6 - .85 dcv
3. o2 connected warm idle, can’t really get a fix reading but between 56 mv - .8 v swinging as well in sync with erratic idle

I don’t understand why I get different numbers when o2 is connected and disconnected. It’s like when the o2 is connected it making the car go lean and when I disconnect the o2 the readings go quickly from the mv(super lean) to .85v(rich) and adjust between .6-.7 dcv.
Ok, I’m confused now, I guess where do we go from here?

 

From my last post test 1. Is this duty cycle for the FV or Im I inncorect by saying this.

I have also noticed when car is cold I get a reading of 4.3 avc when I think it should be 7.4 acv.
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Service Bulletin test no. 7
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Sorry to hear that it wasn't really improved. You seem to have the same "problem" as reported in this thread -- i.e., FV duty cycle not being 50%, or 6.4 VAC, with O2 sensor unplugged during warm idle (they made a typo in SB 80-29 -- that should say water temp greater than 57 deg C and oil temp greater than 25 deg C for the 50% open loop duty cycle):

http://ferrarichat.com/forum/showthread.php?t=257920

Unfortunately, he never gave a final resolution/status/solution (and I'm out of ideas beyond what's there -- i.e., check the oil thermoswitch operation )

 

It looks like everything is working fine, except for the missing 3 volts.

 

How do I check it and where is it located?

 

If this is the oil temp switch, it is open and being I live in Texas I think I should be open even if the car is cold, unless we get very cold weather. Is this correct?
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I guess it must be the ECU, anybody know any good ECU repair shop?

 

I am afraid that in my quest for a stable idle is coming to an end with no resolution. Unfortunately I am not alone and have pm other Fchatters with similar problems SeattleM5 and Alehholy to see if they were able to resolve their car as well. I am sorry to report that my fellow Fchatters have not found a solution for their off idle problem. I think I have a bad ecu, but I think, is not going to fix it. I have poured too much time and money, only to be disappointed yet again, so I am cutting my loses short. It is time to bring in the big guns and have called Nick from Nick Forza for help. I did not want to go this road, and would have much rather have a car correct for its year, but having a car true to its year in the garage broken is worst. So I am looking at my options and decided to give Nick a try, hopefuly he can come up with an attractive price and get this baby back on the road. I am thinking of pulling out the engine and send it off so he can do his magic with modern technology and reliability. I am also thinking this is a mondial and these cars have taken a hit and if it is even worth investing any more money. I have always loved the mondial since I was a kid, and was one of my dream cars. I remember first seeing the car in the movie Weird Science and I said to myself one day I will get that car. I feel this childhood dream is becoming an adulthood nightmare and I just can’t have that, but yet again, I do have a family, four little ones, and diapers, milk, and daycare isn’t cheap. All I can do now is wait and hope Nick can come up with a great solution for my desperate Mondial. I want to give lots of thanks to Steve Magnusson for helping and guiding me in my quest, I have learned a lot about k jet and o2 sensors, Thank you Steve.
Now where do I go from here, Mtv please pimp my ride. Lol

 

Was the problem ever resolved?

 

+1

 

The problem with the car is the idle is fluctuating when parked; rpms are at 900 to 1000 swinging up and down. The experiences I fell while driving, is a tug and pull, as if I were learning to drive stick shift for the very first time.