88 Mondial 3.2 sudden power loss | FerrariChat

88 Mondial 3.2 sudden power loss

Discussion in 'Technical Q&A' started by copterjon, Feb 23, 2007.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    I'm a little perplexed by a sudden loss of power a stumbling running condition that comes and goes. This happened two weeks ago for the first time after a drive. I was on my way home from a car show When the car had a sudden partial loss of power. Fortunately I was two blocks from home. After doing a brief check of the plug wires and some misc. connections I decided to put it on my scope. I couldn't see anything that would indicate any ignition issues. While the car was Idiling It suddenly came back to life and has been fine since Well, at least until tonight. After driving it to the gas station and filling up I started her up and she started running terrible just like before. what should I be looking for now? Any insight into this problem is appreciated. I would like to be able to drive it this weekend with the local chapter of the FCA on their planned outing. However, at this point I'm not comfortable driving it around the block.
     
  2. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    Does it get real quiet and smooth when it loses power? It sounds electrical
    I think you may be intermittanly losing a coil pack - check the connections at both coils.

    Something else to check is the relay fuse in the back trunk on the K-jet board.

    I understand how you feel about being spooked to drive it (must be a pilot thing) - this is why I converted to a reliable single distributor and never looked back.

    Let us know!
     
  3. Ken

    Ken F1 World Champ

    Oct 19, 2001
    16,078
    Arlington Heights IL
    Full Name:
    Kenneth
    I would also bet it's electrical, but if that doesn't check out, it could be fuel delivery. Clogged fuel line or filter. Happened to me once and the car would come and go until I changed the line.

    One other thing that's not likely at all but also happened to me was a clog past the charcoal cannister in the emissions vacuum line and I was getting a vacuum in the fuel tanks. It started right after I filled them up with gas. Same symptoms: ran crappy, low power, would come and go.

    Ken
     
  4. ProCoach

    ProCoach F1 Veteran
    Owner

    Sep 15, 2004
    5,465
    VIR Raceway
    Full Name:
    Peter Krause
    Fuse box. Ignition rotor. RPM sensor. I'd check in that order.
     
  5. blmjumper

    blmjumper Formula Junior

    Jun 18, 2006
    341
    Boise
    Full Name:
    Ty
    It appears you've gone through the ignition....but this sounds identical to the symptoms I experienced when I had an ignition module go bad.

    Is it isolated to one bank of cylinders? Any indication of the "slow down" light?

    I also zip-tied the fuses on the ECU in the trunk as I've been told they tend to work themselves loose.
     
  6. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    I'm half tempted to replace both coil packs and see what happens. It sure sounds like thats what it could be based on talking with a few people this morning about it. I'm not a big fan of replacing half the system when I could redo both and know from this date that they are new. Every time I work on this thing I'm stunned at the quality of work, or lack thereof that was performed by the DPO. Thats Dreaded Previous Owner. I know it sounds frivolous to spend the money on these with out knowing for sure, but from now on I'll have peace of mind knowing that this part of the system is new.
    I have nothing in my records that indicate that one or both coils have been replaced. Caps, rotors,and wires/extenders all have about 4,500 miles on them.
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    If you are saying that you confirmed good spark on all cylinders during the bad running condition (i.e., you confirmed that it's not ignition related), another electrical thing to check is that you still have +12V power to run the "with Lambda" part of your K-Jet with Lambda system -- did you check/feel if the Frequency (Lambda) Valve was buzzing (+12V power present), or not buzzing (no +12V power), during the bad running condition? (This is related to Russ' suggestion about checking "the relay fuse in the back trunk on the K-jet board" -- but checks more than just the fuse).
     
  8. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    Steve, When I had it on the scope the rear bank was fine but the car was running poor. Just before shutting it down and checking the front bank it suddenly came back to life. We then checked the front bank on the scope and all things were fine there as well. Now, based on the car running poorly with the front bank showing good spark I kinda think maybe it's the coil for the rear bank that is operating intermittently. The one thing I know for sure is its going to be pricy.
     
  9. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
    2,655
    Boulder, CO
    Full Name:
    Mike

    What, coil packs being pricy? We're talking about ignition coils, right, one per bank, high voltage output, etc.? I replaced them in '02 on my old 308 for reasonable cost.
     
  10. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Can't say I follow that explanation (you checked the rear bank twice?), and realize it's tough when the problem is intermittent. In any case, if the bad running recurs, put a hand on the frequency valve to check (something you can do on the road without any tools).

    Please also comment on Russ' question -- during the bad running was it running:

    A. smoothly, but weakly, or

    B. rough and needed some throttle to stay running?
     
  11. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
    2,655
    Boulder, CO
    Full Name:
    Mike

    Right, and also whether or not the "Slow Down" (aka Catalytic Converter overhearting) light came on - and if not, can you verify that it works at all (should come on briefly during startup).
     
  12. hank sound

    hank sound F1 Veteran

    Jan 31, 2004
    5,953
    Burbank, CA
    Full Name:
    Hank Garfield
    I switched coil pacs on Rachel, with a friend's pac off his 348. Voila!!! Got a used replacement board (pac) from T. Rutlands and all is well. When those things "go", they seem "come & go" for quite a while.

    Cheers, Hank
     
  13. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    Thanks for all the input guys. As for the question posted by Russ, It is still running smoothly but definately quieter. The "slow down" light has not come on during these episodes. It does come on for a moment during start up.
    Both banks have been checked the first time around. The rear (the one closest to the back of the car) was first to be checked while it was running bad. I have not had the opprotunity to check the front bank with it running bad because it seemed to rectify itself before I could. Fortunately each time it has messed up I've been very close to home.
     
  14. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    I messed up that explanation, Sorry. I'm trying to do 10 things at once here at work.
     
  15. blmjumper

    blmjumper Formula Junior

    Jun 18, 2006
    341
    Boise
    Full Name:
    Ty
  16. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    No trouble -- thought that you may have misspoke.

    For "running smoothly", you're chasing the right likely suspect -- ignition (since your injection architecture doesn't really have a failure mode that can take out just one bank. But put a finger or two on the frequency valve to calibrate yourself -- it's something that you can do in a tux on a date in an emergency ;)).
     
  17. eurogt4

    eurogt4 Karting

    Apr 15, 2006
    243
    Sacramento, CA
    Full Name:
    Mike
    check the connectors to the ignition modules, under the car on the lower lower left I think. I have seen bad connections there, will kill one bank . Mike
     
  18. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    At the risk of sounding dumb What and where is the frequency valve?
     
  19. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    it is next to the fuel distributor that looks like an electric fuel injector (because that is what it is) and as a cable plugged into it.
     
  20. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #20 Steve Magnusson, Feb 24, 2007
    Last edited by a moderator: Sep 7, 2017
    See Fig 57 on page 66 in your 481/87 OM (frequency valve = Lambda valve = metering valve). The frequency valve is driven by a PWM (rectangular wave) electrical signal from the injection ECU, and it acts in series with the fuel distributor to add or subtract fuel. When cold, the PWM signal is set to a fixed (default) duty cycle (which adds a fixed amount of fuel) and the system runs like a "dumb" K-Jet. When warm, the injection ECU looks at the signal coming from the O2 sensor and slightly changes the duty cycle of the PWM signal going to the the frequency valve (which slightly changes the amount of fuel being delivered) to try to keep the O2 sensor output at 0.5V (average).

    The PWM signal (a current rapidly switching "on" and "off") causes the frequency valve to vibrate/buzz (whether cold or warm) -- consequently, a "dead" (non-vibrating) frequency valve is a clear sign of a problem (whether cold or warm) on a K-Jet with Lambda system like yours.
    Image Unavailable, Please Login
     
  21. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    I put a new coil pack on the rear bank and voila!! the car started right up running smooth just like normal. I took it for a test drive and within 10 min. it started running like crap again. This time it's low on power, sputtering and popping through the air box. That was last night. This morning I checked the frequency valve after determining what part it actually is...thanks Russ and Steve.
    Well, It appears that I have a non vibrating frequency valve. I also checked on the relay for the K-jet and when I shake it I hear something bouncing around inside. If the relay is bad is that what's causing the whole problem? or am I in for some more surprises.
     
  22. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    You will need to replace the entire relay if something is bouncing around inside - that happened to me as well. It is probably the fairly common O2 protection relay. Take it to a Bosch place or use the number on the relay to replace it. When you replace this relay, all should be well.

    It is always possible that you had two things going on.

    Let us know.
     
  23. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Loose bits are never a good sign ;), but, if you want to be absolutely sure, the way the protection relay should work is (when the engine is running):

    terminal 30 should be at +12V
    terminal 15 should be at +12V
    terminal 31 should be ground

    when these conditions are met, the contact points inside the protection relay "close" and terminal 87 is connected to terminal 30 -- so terminal 87 is at +12V also (and this is the +12V power that goes to run the injection ECU which subsequently runs the frequency valve).

    If you confirm the three conditions above are met, but terminal 87 is not at +12V, you can be sure the protection relay needs replacement.

    99% likely that the protection relay itself is bad (with your report of loose bits and a dead frequency valve), but I just wanted to let you know how to be sure before buying.
     
  24. copterjon

    copterjon Formula 3
    Silver Subscribed

    Nov 11, 2005
    1,541
    Mesa, Az.
    I checked the relay per Steves instructions and sure enough terminal 87 is dead. I used a jumper from terminal 30 to terminal 87 and like magic the frequency valve had a pulse and the car ran like it should. With that being said I ordered a new relay this morning and should have her back together and running for some weekend fun. Thank you to everyone who chimed in on this thread you really helped me out. Oh yeah, I rigged the old relay so It could be used as a tester in the future. Even though this was annoying I feel good that I now understand more about my car and can help someone else out in the future that may experience the same problem.
     

Share This Page