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High idle wnen cold

Discussion in 'Technical Q&A' started by Doc, Dec 22, 2003.

  1. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
    Full Name:
    Bill Van Dyne
    Now that the frigid weather is here, I noticed that the idle is excessively high on my '85 308--approx 3k until the motor begins to warm up. Upon warm-up, it's fine. Is there some way to adjust the cold idle to bring it down a bit?
     
  2. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    Hugh G. Rection
    I am told that is pretty normal for those years...the idle was designed to be quite high to heat up the cat faster, and reduce emmisions. The only may to "adjust" it would be to put some sort of obstruction in the aux air valve hose. People have done this, and you can probably find notes on it in the old F-chat archives.

    Here is some general info on the FI system http://www.auto-solve.com/mech_inj.htm, and the aux air valve specifically. Once you understand how the AAV works, you can see how a simple little obstruction will allow you to modify the cold idle to a degree.
     
  3. f355spider

    f355spider F1 World Champ
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    An example might be to install a plastic plug in the hose either before or after the AAV and hold it in place with a hose clamp. You could adjust the idle up by simple drilling a progessively larger hole in the plug.
     
  4. Eric308gtsiqv

    Eric308gtsiqv Formula 3

    Nov 26, 2001
    1,952
    Orange Park, Florida
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    Eric Eiland
    For what it's worth, Doc...my '85 308QV does the same thing...cold idle at 3k and drops down after warm-up...and this in on the "colder" days here in Florida :)
     
  5. f355spider

    f355spider F1 World Champ
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    BTW, on my 328 the cold idle is around 1700-1800rpm..not sure if that is the way it is supposed to be, or broke, but works for me..warm idle is around 1000rpm.

    I've always hear the FI 308's where set up much higher. Which I guess, means a larger orifice in the AAV. Wonder if a 328 AAV would slow it down some?
     
  6. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
    Full Name:
    Bill Van Dyne
    Thanks for the input, guys. I guess it's working as it should--just seemed rather high to me.

    Have a Happy Holiday, all!
     
  7. Eric308gtsiqv

    Eric308gtsiqv Formula 3

    Nov 26, 2001
    1,952
    Orange Park, Florida
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    Eric Eiland
    Yes, Doc, it does sort of make you cringe when you first crank the car and it climbs to 3k RPM and stays there for a minute or two! Like yourself, and others, I'm curious if this is the normal rev range on cold conditions as well.

    On the '85 Euro TR, with K-Jetronic, the RPM on initial start in cold weather is about 2k max, and quickly settles down between 1k and 1.5k.
     
  8. MRFOTOS

    MRFOTOS Karting

    May 26, 2003
    232
    Maui, Hi
    Just my 2 cents, my 80 308 GTSI Jumps up to 3K and holds for a few min.also,even with the Aux starter injector disconnected, it just doesnt seem right, but glad I am not the only one who cringes at the cold engine/hi-rev combo. Who is the Einsteininini (Italian for Einstein) who thought this is actually good for a V8 engine.Maybe its the same guy who says you need to take the engine out of the car for the 15K service, then charge you extra $$$ for a ring job due to extensive wear from hi-revs on a cold/ oil starved precision built motor.
    Hmmmmm
    Just my 2 cents
     
  9. f355spider

    f355spider F1 World Champ
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    Mrphotos, check the link I provided below, the cold start injector has nothing to do with the cold idle setting, the aux air valve does. Next time you start the car cold..find the aav, and there will be two hoses that attach to it. Try carefully pinching either hose with a pair of pliers (being careful not to damage the hose), and you will see the idle speed drop. That is how the idle speed is controlled. Thus, if you can put an obstruction in the hose, you could slow down the cold idle speed.

    Agreed, 3k cold idle is crazy, but apparently needed for emmisions reason to heat up the cat quickly.
     
  10. seschroeder

    seschroeder Formula Junior

    Apr 25, 2002
    251
    Alexandria, VA
    Full Name:
    Steve Schroeder
    For what it is worth my 82 GTSi starts at 1,200 RPM and slowly builds to approximately 3,000 RPM. At approximately 140 to 150 degrees (amber light goes out) it drops to a smooth 1,000 RPM idle. I had probems with the cold start system but cleaning the aux. air valve with carb cleaner and use of WD-40 fixed the problem.
     
  11. Eric308gtsiqv

    Eric308gtsiqv Formula 3

    Nov 26, 2001
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    Eric Eiland
    Yes...actually mine starts and behaves the same way as seschroeder's does...
     
  12. ROGER

    ROGER Karting

    Feb 9, 2002
    131
    Lake Havasu City, Az
    Full Name:
    Roger Blakeman
    I put a small ball bearing in the hose that solved my problem-Just disconnected the hose, installed bearing(slightly smaller than the hose I.D.), reconnected the hose and I was good to go. No more high idle speed.

    Merry Christmas, Roger B.
     
  13. f355spider

    f355spider F1 World Champ
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    Sounds like a good fix, but would be concerned about "retention", making sure it doesn't end up somewhere it shouldn't....for example, you wouldn't want to place it after the aav, where it might get sucked into the intake manifold. Before would be good, as long as it cannot pass the opening in the aav, and won't move backward.

    BTW, are you trying to "defeat" the cold idle or lower it? It serves a useful function of preventing the car from stalling or hestitating when cold. Lowering the speed would be fine, but defeating might cause some folks trouble, depending on the general state of tune and operation of the car.
     
  14. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
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    Bill Van Dyne
    Roger--exactly where did you install that ball bearing. I think i'd like to try it. Please be as specific as possible as I'm not a mechanic and am still feeling my way around this car.
     
  15. MRFOTOS

    MRFOTOS Karting

    May 26, 2003
    232
    Maui, Hi
    Thank you Davehanda for the idle Tip, ill give it a try in the spring when the snow is gone and it warms up a bit, but i didnt see the link you mentioned.

    Merry Christmas to all
    Mark
     
  16. wax

    wax Four Time F1 World Champ
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    Jul 20, 2003
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    {Maxwell Smart}Ah, the old ball bearing trick, aye?{/Maxwell Smart}
    Roger will have to fill you in on "exact" size and place, but it works.
    The only maintenance my Grandfather ever did with any car (always Chrysler New Yorkers) was just that when it got cold.
    {Grampa}IIIIIIII never channnnged the oooiiiilllll, fiiiilllllterrr or plugggggs - nuthin'! Just the ball bearin'! Harrumph!{/Grampa}
     
  17. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    I stopped the cold idle on my QV by jumpering the coolant temp sensor on the recovery tank. Not sure if this is the same for later QVs. Works fine when cold and stays at 1000rpm all of the time.
     
  18. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
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    Bill Van Dyne
    398GTS--when you say, jump the temp sensor connections, do you mean to just disconnect the wires from the sensor or do you connect the 2 wires together with another wire?

    Stupid Q here--is the auxilliary air valve the same as the warm-up regulator? If not, where is the aux air valve located. My manual refers to it in the text, but it's not labeled in the schematic.
     
  19. pete04222

    pete04222 Formula Junior

    Nov 1, 2003
    613
    Maine, USA
    Full Name:
    Peter Cyr
    Just my 2 cents worth but.............
    Ferrari engines just plain run higher than what I am used to. Think about the fact that the 308 engine doesn't start to make any real power until around 4,500-5,000 rpms. Wow! That is past the redline on most of the cars I've had. I took me a while to get used to driving the Ferrari. You really need to put it in one gear lower than what you think should be the correct one. I'm not talking about idling down Main street, I'm talking about the "get-up-and-go" driving. I was shifting it at around 5,000, which seemed high to me compared to the American muscle cars, now I let 'er rip up to 7k before upshifting. Oh yeah!!! Now we're talking Ferrari!

    The slow idle is around 1,000 so a high idle of 2,500 to 3,000 I don't think would bother me. Mine is the carb model so I don't have the same problem you do. My problem is keeping it running when cold.
     
  20. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,220
    TN
    On my 85' I don't see the AAV. My 83' QV has one but I don't see it on my 85'. The WUR is to the left of the airfilter box. It will have a vacuum connection on top of it and a Bosch harness electrical connection on the top. It is rectangular in shape and has 2 fuel lines connected to it. Please let me know if you find an AAV. On my 83' it is behind the WUR. I don't like 2000rpm high idle when cold. I prefer 1000 rpm. Like I said on my 83' jumpering the coolant temp sensor stops it but it doesn't stop it on my 85' QV. Yes you remove both wires and use a jumpered with spade connectors. Merry Christmas to all. HTHs.
     
  21. ROGER

    ROGER Karting

    Feb 9, 2002
    131
    Lake Havasu City, Az
    Full Name:
    Roger Blakeman
    Yeah, I love it. I knew I'd get a rise, thanks wax. Any way Doc the cold idle speed can be dropped by putting a bearing in the hose from the cold start air valve to the auxilliary air valve. The bearing size I used is about .56", just measure your hose I.D. as it may be different than mine and put in a slightly smaller bearing.

    davehanda's statement is correct. This defeats the purpose of the design and I recently removed the bearing from my car. I polled the forum and the consensus was that this was Ferrari's design of the system, not to worry. I still cringe when I do a cold start because that cold engine/oil at 2,300 rpms is disconcerting even though it is a high rpm engine. Also, he's correct in the possibility of stalling, etc. til it gets warmed up. I had the hose plugged last winter and I didn't find that a problem but then we all drive differently. Now that I think about this I may just reinstall the "bearing".

    Enough and Merry Christmas and Happy New Year!!! Roger B.
     
  22. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
    Full Name:
    Bill Van Dyne
    Would it be possibl to include a picture of the AAV for clarification? Thanks.
     
  23. f355spider

    f355spider F1 World Champ
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    Check the link I provided earlier in the thread for a description and photo of the aav.
     

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