3.2 Can't Hold idle sounds like a cylinder missing

The fuel distributor head has a diaphragm in it which cracks with age, you can get a repair kit for about £50 and a diy job. A man i know had problems with a mondial cutting cylinders out and blackened plugs, rough running, backfiring etc. Once repair kit fitted it ran fine.
The idea of checking dip stick is to check if unburnt fuel going past pistons into sump oil- his was so bad sump was coming up. If its split it alters the equal fuel delivered to the injectors.
Look on e bay for kit as used on volvo, id plate on side of distributor head to get correct part. Its bosch so parts are about but not from ferrari

 

That does not prove that the protection relay is working -- even a "good" protection relay needs the correct signals coming into it to close properly. Did you measure the voltage between terminal 87 and terminal 31 at the protection relay with the protection relay plugged in and the engine running?:

If +12V = then the problem is elsewhere.

If not +12V = then you need to investigate the signals coming into the protection relay: the voltage between terminal 30 and terminal 31 should always be +12V (even with key "off"), and the voltage between terminal 15 and terminal 31 should be +12V when the key is "on".

 

I've had 1 cylinder drop from a bad plug wire. Smell of unburned fuel, but the motor idled pretty good. I've had 1 bank go out from a faulty coil assembly, but the motor ran pretty good. It essentially became a 4 cylinder. Drives okay, just down on power. It sounds like you've got a fault affecting more than 1 cylinder.

Do the starting fluid test. Isolate to ignition or injection. Then start looking at components.

Also, don't overlook the possibility of a vacuum leak. I had a hose come off the AAV once. Big vacuum leak = rough running.

 

I went through this very same thing, heard the same clunk sound then poor idle.......I am still not out of it.
What I do know is this:

Had good cylinder compression pressure and funny fuel pressure

1. we chased the distributor, wires, coils and ignition modules. All replaced, no change
2. we chased a bad fuse panel. Has it completely rebuilt and charred connections replaced, no change
3. we chased fouled plugs. All replaced, no change
4. we chased the over - voltage protection relay feeding the ecu. Replaced it, no change
5. we chased the ecu. Put a known working ecu in its place. No change
6. we chased the o2 sensors (sending the wrong voltage to the ecu) Replaced it, no change
7. we chased the frequency valve. Existing unit is buzzing. I bought a new unit off ebay but have not installed it.

At this point there was bad cylinder compression pressure and gas leaking out of the exhaust system and gas in the oil lube system. Obviously we tried running it too much and the unburnt gas made its way around the piston rings, washing the oil out and diluting the oil.

8. we are in the middle of having the engine completely rebuilt down to the block. All cams, heads, valves removed. We did a complete valve job with new valve seals, I had 8 custom made pistons made, being installed now. The old original pistons had black crusty carbon build-up on the surface.

I am in it too far now to turn back. The mistake we made was not having the fuel distributor and warm-up regulator re-built before jumping into No.8... I could not talk my mechanic into it. This would have removed the fuel pressure problem from the equation. (I had just replaced the fuel pump, fuel filter and accumulator a few months before)

I started to educate myself on the Bosch CIS fuel injection system and found many pdf on the web. From my understanding if the fuel pressure reading is low, then the CIS system will flood the engine. Opposite of what you would think. I think running engine cleaner / Sea Foam loosened up some ethanol buildup and clogged the system which puts the frequency valve into overdrive, flooding the engine. I may be wrong but I hope some of the variables can be ruled out from my experience.

9. If I could do this over I would have rebuilt the fuel distributor first. To my knowledge there are only 2 people that do this in the USA. Dont try to do this yourself. The fuel distributor is full of small diaphrams and springs. You need to call Larry Fletcher, CIS Flowtech in Mobile, AL. (251) 929-3771. The re-build cost is $550-$600

I will never know if this was the real problem. We have now sent my fuel distributor to Larry and it is ready to be installed in a completely rebuilt 1985 Ferrari Mondial 3.2

I have many supplier names and numbers for the items discussed if you want to short circuit the research element. Hope this helps.

 

the symptoms are also similar to those of a leaking cold start injector. As the pressure increases when you activate the fuel pomp, so does the leakage. It's a simple check. My 3.2 is also a Swiss KE3.

 

Te the overhaul of the fuel distributor head- only seen this done once but very simple diy job. Just let off the banjo bolts and fit the overhaul kit containing the diaphragm, springs etc. Or find yourself a Volvo engineer as used on their cars.

 

I don’t know whether the following will help, but —

My ‘83 QV had the little sample tubes until I had them removed and holes plugged 3 years ago. Recently, one of those plugs in a header came out - with resultant loud popping and severe loss of power. Limped home.

I know your car doesn’t have the sample tubes - but my guess is that if you have a cracked head or some small leak in it - even though you haven’t got all the noise - perhaps that is the problem.

I’ll leave it to others to say whether that could be it, or not. Best wishes, SG


Sent from my iPhone using FerrariChat

 

I forgot to mention the crankcase sensors. We replaced both. The crankcase and the TDC sensor. The mounting plate doesnt fit anymore and we had to machine them to fit. Same Maranelli SEN8D. No change in my motor......If thats the issue, you are lucky!

 

Put a meter on the connections and give it a tap on the work bench, see if the meter changes re bad connection

 

That's OK (if you mean you measured the protection relay output 87-to-31 or the red wire at the anti-evaporation valve -to- ground). Whenever I say "+12V", I really mean "whatever the voltage is at the battery is doing" -- so a good result could be as low as about +10V during starter motor cranking or as high as +14.5V if running with the alternator spinning well.

Have you removed the cold start injector to confirm that it is not wrongly always spraying a lot of extra fuel into the intake plenum? It can do this with either an electrical fault causing it to wrongly stay open or a physical fault inside the cold start injector itself. First test would be to just unplug the electrical connector of the cold start injector -- if no change in the bad behavior, then you'd need to unbolt the cold start injector from the intake plenum (and place it to spray into a jar while blocking the open hole in the intake plenum with some tape) so that you can visually verify whether any fuel is leaking out the end or not. Fuel should only come out during the first second, or two, of starter motor cranking.

 

I would still do the starting fluid test. This will quickly eliminate the ignition system as faulty, if you can get a good idle.

If you think the fuel mixture is off, you can compensate by moving the air vane with you fingers. E.g. if you had rough running from a vacuum leak, pressing down slightly on the air vane will compensate and return a smooth idle. Pulling up slightly on the air vane will compensate for an overly rich mixture. This is not a permanent fix of course, but helps point you in the right direction.

 

Air vane is the plate in the mixture control unit (fuel distributor). You access it by taking off the air filter box. If the car stalls pressing down, you likely don't have any vacuum leaks.

Lack of spark would definitely cause the rough running and fuel smell. Usually it's just one bank though, and you can swap the coil assemblies to test.

The coil assemblies have a little black electronic module on them that go bad. It would be odd for both to go out at the same time. The common component would be the Microplex. You would have to swap this to test it.

Intermittent problems a lot of times are from bad electrical connections. Try and remove all of the ignition system connectors and spray contact cleaner.

I got replacement distributor caps from Superformance, and the holes for the plug wires were not deep enough for the pins to make contact. Had to drill them out a bit. Make sure the caps don't have any hairline cracks, or evidence of arcing. If some wires fire consistently, and others do not, I would think the problem is right there.

My Ferrari crank sensors are stock from new. Never had a problem with them.

I had a problem with a Ford 4.6 Mustang where it would intermittently lose power, and stall. Cleaning the crank sensor connector fixed the problem. This is a common problem on that motor according to some owners.

 

You seem to be sort of wishy-washy on this. Confirming if you really do, or don't, have proper spark at each cylinder needs to be determined before worrying about anything else.

This attached pdf file of Service Bulletin 80-28 describes the electrical measurements to confirm/deny if the Microplex ignition ECU is working correctly on a Mondial 3.2 (and testarossa), but it requires a special interconnection test box to be able to make the measurements with everything plugged in, or you have to dig in to the Microplex harness connector to get to the backside of the pins:

 

Yes, not much involvement of the fuse-relay panel with the ignition except supplying +12V to terminal 15 of the coils and to run the Microplex ECU.

When you say "I have changed out one of the coils with a known good one" do you mean a different coil with a different power module, too?

 

Remove one of the misfiring wires at the plug. Attach a new plug to that wire, and lay the plug on a metal engine part so it's grounded. This way you can see what the spark looks like at the plug.

 

Did you not read my post? I am telling you that my 3.2 went through the very same thing. Look at my list ......I spent the money chasing every electrical issue, every sensor, computer, o2 sensor, coils, ignition sensors, new distributors etc, etc.

At this point, Your engine almost feels like it has a timing issue, with misfires, right?.

First, You need to change the oil in the engine because at this point you have washed out the oil at the rings and gas is entering the oil sump. The gas will dilute the oil and thin the viscosity and you will get bad wear on the valves and piston rings.

You also need to be careful burning up your catalytic converter. While the car is running, look and you will see it may be glowing red.

You need to have the fuel distributor rebuilt. Its clogged with ethanol debris or one of the rubber diaphragms has a split in it. I included the name and number of the best CIS mechanic in the USA. Unless you want to have the entire motor rebuilt, like I did, Here is my show & tell!.

I have uploaded a CIS manual that I found online


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