Testing Cold Start Valve | FerrariChat

Testing Cold Start Valve

Discussion in 'Mondial' started by hnichols, Mar 3, 2021.

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  1. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Hello everyone,
    I have a cold start issue on my 3.2: basically takes alot of cranking to fire. Time is correlates closely to outside temp; in the summer it wasn't much of an issue. Warm starting is immediate.

    My hypothesis at this point is either the thermo-time switch (TTS) or the cold start valve (CSV) itself. I think it's confined to those two elements b/c it seems to be simply a matter of getting fuel to the cylinders. It's not like it fires right away and then dies.

    1. I believe I check the thermo-time switch by putting a voltmeter across the two terminals of the unplugged CSV connector while someone cranks the engine. It should read 12V for a few seconds and then go to zero. Is that right?

    2. To check the injector itself, I unscrew it from the plenum leaving the fuel line attached, bypass the thermo-time switch and have the injector spray (if it works!) into a jar.

    3. I think I bypass the TTS by plugging a spare connector into the CSV, attach one wire to the + terminal of one of coils and the other to ground. When the key is "on" I should be getting 12V to the injector -- is that right?

    4. Questions: to build fuel pressure, can I simply have the key in the on position for a few seconds to run the fuel pump?

    5. Where exactly is the + terminal on the coil -- do I unplug the connector with the yellow wires (see pic)? And do I have to remove one of the coils from the bracket so it's right-side up? Is there an easier way to test the injector?

    Thanks in advance! Image Unavailable, Please Login
     
  2. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    In order to build fuel pressure, the key would have to be in the run position, and the either the safety switch removed, or the air vane depressed. You will be able to hear the fuel pump running.

    I like the idea of removing the cold start injector from the plenum, and putting it in a jar to test. Make sure to plug the hole in the plenum.

    Any 12V source can energize the injector, like a small battery. You don't have to use a source from the car.

    The longer you let the car sit, the more cranking you will have to do to get it started. Make sure you have fresh fuel, and the fuel system is clean.

    Your problem could be that your cold control pressure is wrong for the ambient temperature. You adjust this by moving the pin in the WUR. There are factory specs you can go by. You will need the right gauge setup to measure this.
     
  3. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Thanks for this! So, just for clarification, to activate the fuel pump the key needs to be in the run position and air vane depressed? I was hoping that there would be enough residual fuel pressure to test the CSV if I've recently run the car (the accumulator maintaining pressure for a time).

    I really think it's temperature related more than anything else. Hopefully I won't have to mess with the WUR, esp. since things are fine once it turns over.
     
  4. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    The WUR is what sets the mixture for a given temperature. The colder the engine, the richer the mixture it's going to need to start. The WUR was probably adjusted at the factory to some average value.

    One other thing you could do is to leave the key set to off, remove the air box, press down on the air vane, and spray some starting fluid into the intake. I guarantee the engine will start right away.
     
  5. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    I removed the cold start valve and activated the fuel pump by depressing the air vane in the airbox. I plugged a spare connector to the valve attached to one of those tiny A23 12V batteries. Absolutely no indication that there was electricity energizing the injector. (A standard 9V likewise had no effect. I'm not terribly confident about my testing procedure (would one of those little batteries really have enough juice to do anything?), and so I haven't concluded that the injector is bad.

    When I cranked the motor I got a voltage reading between the contacts in the connector plug, but it wasn't really close to 12V. Again, I don't have much confidence in my testing procedure; my digital voltmeter went from 0 to a bunch of readings that changed so quickly I couldn't nail down a number in the 2 seconds I had available. I guess my question at this point is whether those injectors need the full 12V or nothing. Or should they show some sign of life even at a lower voltage.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #6 Steve Magnusson, Mar 7, 2021
    Last edited: Mar 7, 2021
    It's better IMO to unplug the safety switch on the airflow meter rather than depress the airflow plate to run the fuel pump. When you depress the airflow plate, you'll be spraying liquid fuel out the injectors; whereas, with the safety switch unplugged (and the airflow plate at the rest position), you won't.

    An A23 battery can hardly deliver 30 mA max -- the cold start injector will probably require several hundreds of mA to actuate.

    Perfectly normal for the battery voltage to droop down to ~10V when the starter motor is cranking and drawing 150~200A, and it won't be very constant so a good digital multi-meter is probably "too quick" to read its display. Better IMO to just connect a 12V bulb to the cold start injector harness and confirm visually that it glows fairly strongly for a couple/few seconds during initial cold cranking (and, by positioning it so that you can see it in the rear view mirror from the Driver's seat, you won't need an Assistant ;)). Can't say that I've ever come across a spec for the minimum voltage needed to actuate the cold start injector in the F documentation, but I'd bet it might be something like 6V (but it needs to have enough current, too).
     
  7. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Many thanks, Steve, for your reply. All very helpful info. The 12V bulb (or noid light?) is a great idea. Any suggestions for a good power source for the injector? I've seen videos where people check injectors with standard 9V smoke detector batteries. I know the voltage (and of course amperage) is too low, but I thought it might hum or buzz ever so faintly, but there's absolutely no indication that there's any current at all. My impression was that those CSVs are robust parts, but are they known to go completely dead like that?
     
  8. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Yes, I'd agree that they are fairly robust, and I can't recall a single reported failure reported here (there may have been some, but it certainly isn't a commonly reported problem). I'm not following why you need to manually energize the cold start injector -- if you remove it from the intake manifold, and put it in a jar with the fuel line and electrical still connected, then cold crank the starter, you should be able to determine if any fuel is squirting out -- no?
     
  9. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Ah, yes, well I wanted to bypass the thermo-time switch in order to isolate the component that's faulty. I've been assuming that no fuel is being shot into the intake -- that's the issue. But if I determine that I'm getting voltage to the connector, then it wouldn't hurt to do the test you suggest. I shouldn't assume anything!
     
  10. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    You can energize the cold start injector with an old motorcycle battery.
     
  11. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Thanks for the suggestion. The amperage of the cycle battery wouldn't overload the injector the delicate wires of the connector? I'm assuming a 12V car battery would.
     
  12. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    Car battery would work, but kind of big and bulky.
     
  13. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    So how would that work -- just touch the two wires from the connector to the terminals of the battery? I would think the amperage would be too high. But, as you can probably surmise, I'm a bit weak on matters electrical.
     
    Horseman55 likes this.
  14. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    No, the maximum current passing thru the cold start injector is only dependent on the voltage applied -- when in use in the car, it effectively is connected to the car's battery (alternator).
     
  15. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    For reference, the current would be dependent upon the voltage applied, divided by the resistance of the injector coil. E.g. if the battery voltage was 12 volts, and the injector coil resistance was 12 ohms, the current through the injector coil would be 1 amp.

    I=E/R
     
    Horseman55 likes this.
  16. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Thanks to both of you guys. So, just to confirm, I can connect one wire of the connector to the + terminal of a car battery and touch the - terminal with the other connector wire without frying anything? That is, I don't need to put a resistor in series with the circuit to increase resistance and lower amperage. The battery I would use, by the way, is not the one in the car, but one that I removed from another car in storage.
     
  17. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    That should work. I wouldn't leave the battery connected for a long period of time. Will try to get you a resistance reading on my 3.2 cold start injector later.
     
  18. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Thanks for all the good advice. Connecting the injector with the battery worked like a charm: a nice spray of gas into the pickle jar. A 12V light plugged into the connector didn't even flicker when the car was being cranked. So I might go ahead an order a new Bosch TTS. The next task with be accessing the switch with a minimum of engine bay disruptions ...
     
  19. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Anybody know where a good place to find the Thermo-time switch, Bosch part 0 280 130 217, without paying the Ferrari tax? Not much luck with a casual internet search. This part must have been used on other European cars of the time. Thanks!
     
  20. tstuli

    tstuli Formula Junior

    Jun 12, 2018
    370
    NC
    Check SAAB 8361362

    Sent from my SM-A515W using Tapatalk
     
  21. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Yes, not a good sign -- but before buying a new TTS, have you confirmed that the cold start electrovalve fuse (7.5A) is OK? (It not only supplies +12V to the TTS when cranking, it is also involved in running the relays controlling the fuel pump during cranking.)
     
  22. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    I believe the thermo time switch provides a ground connection for the cold start injector. So instead of hooking your light into the connector, hook one end into the connector, and the other end to some chassis ground. See if it lights up then. It would be better if you had a volt meter.

    Also, it looks like that thermo time switch is no longer available according to Ricambi, and some Saab parts outlets. I guess we can add this to a long list of NLA parts for the cars.

    You could try and grab this one:

    https://www.ebay.com/itm/Thermo-time-switch-FERRARI-328-mondial-3-2-Temperaturschalter-121778/263390677508?

    What else comes to mind is that you could run a ground wire to a toggle switch under the dash.
     
  23. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Dumb question, but do I check the fuse simply by removing it eyeballing it? And if this fuse is involved in running the fuel pump during cranking, wouldn't I have issues with warm starting too (I don't)?
    Does it matter which of the two contacts I connect to one of the wires to the light bulb? I don't think one of them is marked as ground.
    I thought I saw one for $119 on one of the Saab sites. I'd feel sorry for the Saab guys if they end up having to get their parts in the little yellow box with the prancing pony.
     
  24. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #24 Steve Magnusson, Mar 14, 2021
    Last edited: Mar 14, 2021
    Yes, that's usually sufficient.

    Yes, that's a sign that the fuse isn't a problem, but it's super easy to check the fuse before spending the $s for a new TTS. The way those relays controlling the fuel pump work during starting is that they have two different modes when starting depending on how much air is being drawn in by the engine -- and the warm-cranking RPM can be faster than the cold-cranking RPM (this is also why, when one mode is mucked up, it can help to push the acc pedal down during starting, which lets in more air, and puts the system in the other mode). Most likely you'll need a new TTS (or have some other horrible Gremlin), but is checking a fuse, first, too hard? ;)
     
  25. hnichols

    hnichols Karting

    Apr 15, 2020
    191
    Chicago IL
    Full Name:
    Hugh Nicholson
    Indeed! And it's good to familiarize myself with the fusebox on my new (to me) car. I have a feeling it won't be the last time I need to go in there.
     

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