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Hot (No Start) Issue - Need A New Direction

Discussion in '308/328' started by BrockBenson, Jun 29, 2019.

  1. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Thanks everyone for your responses. Steve as usual you are right, that pipe is upstream at the intake. I made the assumption pipe going to intake = vacuum :)Now with the WUR appearing to be within specs, I'll pull the injectors and bench test them for opening pressure, leaking and spray pattern.

    If I have to replace the injectors I believe that Bosch 0 437 502 047 is the correct one? Would anyone have the Bosch part number for the fat o rings that fit on the injectors? I don't think I'll pull the injector inserts out at this stage. I don't need more hassles. I just want to fix the current issue.

    Cheers, BB
     
  2. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Steve, I'd like to get a copy of the full section D of the 328 manual (for future reference). Is there a link anywhere on the WWW that it might be posted to? I tried the ones I've previously found, but that sections has been missing.

    Cheers, BB
     
  3. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,244
    Texas
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    Steve Magnusson
    #53 Steve Magnusson, Jul 14, 2019
    Last edited: Jul 14, 2019
    This link should get you the US 328 FNA publication that has that ...132 WUR information:

    http://ferrari.cdyn.com/ferrari_docs/328_technical_specs.pdf

    This link should get you Service Bulletin 80-29:

    https://www.dropbox.com/s/7qkumrcbwmz30t8/Service Bulletin 80-29 K-Jet with Lambda.pdf?dl=0

    And this link Service Bulletin 10-13:

    https://www.dropbox.com/s/hk5gupwre678a5q/Service%20Bulletin%2010-13%20Bosch%20K-Jet%20with%20Lambda.pdf?dl=0

    Those might be useful if you need to dig deeper (one thing I'd do is confirm/deny the function of the throttle microswitch -- if it was tweaked up with the idle portion of the throttle microswitch not closed at idle = that could maybe give you some weirdness.)
     
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  4. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,244
    Texas
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    Steve Magnusson
    Actually, after reviewing SB 10-13, if you have "surging at idle" = the throttle microswitch being closed at idle should be checked (I wrongly was thinking that it might be controlling the ignition advance of the DigiPlex ECUs, but doesn't seem to be any connection).
     
  5. BillyD

    BillyD Formula 3
    Silver Subscribed

    Feb 28, 2004
    1,328
    Pacific Northwest
    Full Name:
    Bill
    I'm relieved to see that people are talking about leaking injectors as the cause of a hot start problem. I too have a long crank time and a need for 1/2 throttle to get my QV started when warm. It can be 0 degrees outside and it'll start the second you turn the key, but no way warm. I did all the pressure tests without conclusive results. I never considered the injectors as I have a receipt from the previous owner for new injectors when the car was brought out of long term storage a couple years back. It always seemed to me the car was too rich on warm start and the easy cold start also is a telltale sign of lots of fuel in the manifold. Anyway I took my magnet out to the car expecting to have it to not stick to the injectors since they should be brass right? But it did stick! The invoice shows 8 injectors at $64 a piece with part number 0 437 502 047, problem is this is the newer brass part number according to my research. So my guess is the previous owner got charged for something not received. They don't look fresh like the accumulator or filter or other items replaced on the invoice. Goes to show you need to verify what you pay for or been told.
     
  6. yelcab

    yelcab F1 Veteran
    Consultant

    Nov 29, 2001
    9,107
    San Carlos, CA
    Full Name:
    Mitchell Le
    [QUOTE="BillyD, post: 146714658, member: 5354"... So my guess is the previous owner got charged for something not received. They don't look fresh like the accumulator or filter or other items replaced on the invoice. Goes to show you need to verify what you pay for or been told.[/QUOTE]
    I have seen that several times from known "good" mechanics.
     
  7. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    yes, that is pretty poor form! It takes longer, but if you've got the time and patience your always better off doing the work yourself. No one is going to take as much care and pride in your car as you do. At least that's my experience :)
     
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  8. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Well, its been a very frustrating few weeks. After lots of troubleshooting and parts replacement I am no better off. The hot start issue continues! So to recap what I've done in this order:
    1. replaced accumulator
    2. replaced fuel pump check valve
    3. replaced fuel filter (un-related)
    4. pressure tested K Jet system
    5. tested cold start injector (nil leakage)
    6. tested WUR and was within specs
    7. tested coolant sensor okay
    8. tested throttle switch okay
    9. replaced all injectors
    10. tested each cylinder for spark using induction timing light
    None of this has made any difference. She starts instantly when cold, drives great, but once warm will not start. I think I've tried everything that was posted here? I'm out of ideas ...... I've owned a few old cars and this has been one of the most difficult issues to solve! Does anyone have any fresh ideas before I throw in the towel :(

    BB
     
  9. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    744
    California SF area
    Full Name:
    Paul
    Just to state the obvious - you need to do all of this testing on a warm engine that will not start. If you are doing it on a cold engine that starts fine well, of course you're not going to find anything wrong. I assume you have tried flooring the accelerator while cranking, you could also introduce a false air leak by disconnecting the brake booster line from the plenum. If this causes it to start or even kick as if it wants to start you'll know your problem is too much fuel. Have you looked at a plug during this no start condition to see if it's wet? I think you said you already did that.

    Don't give up. Every time you perform a test and find nothing wrong you have at least eliminated one possibility which narrows your scope. Sonner or later you'll find the smoking gun.
     
  10. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Yes the testing has been done on a warm engine except for WUR cold pressure test and maybe the cold start injector test (but I cannot see how it would change on a warm engine?) Flooring the accelerator has worked on occasion but it takes a long time (many repeated attempts taking up to 2 minutes). When the engine did start like this is ran rough for a while before clearing and had a strong fuel odour. Yes, during non warm start the plugs were black and sooted. I'll try the false air leak test and see what happens? Thinking about the air leak test, I've never tested the aux air valve, I wonder if that could cause this?
     
  11. kiwiokie

    kiwiokie Formula Junior

    Aug 19, 2013
    663
    Tulsa, OK
    Brock I thought the WUR tested as low control pressure? 2.0 vs 2.5-2.9 or did you retest and get inside the factory range?
     
  12. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    744
    California SF area
    Full Name:
    Paul
    It sounds as, even though it starts fine cold, you are too rich overall. I just put my partially rebuilt engine back in and I'm working through my own K-Jetronic learning curve trying to solve a rough idle but in my case (1983) I have no Lambda circuit. For you I think it's possible to monitor your O2 sensor output to get a sense of where the mixture is at. I ran a test on my injectors by putting all of them in water bottles and observing them and found two of them clogged to a point that they just dribbled until I pressed the sensor plate down 3/8 to 1/2 inch. Also three of them continued to drip when they should have been closed. Prior to this I also had a warm start issue on occasion but it always started if I opened the throttle while cranking. I'm pretty sure this was caused by the leaking injectors. I have a new set on the way but I'll probably do this same test on them before installing.

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  13. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
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    Have you confirmed that your frequency valve is buzzing/vibrating whenever the fuel pump is running? I think you are to the point where you need to confirm/deny if the mixture setting is reasonable, but the frequency valve needs to be working during that adjustment. (The frequency valve is used to add a little enrichment during warm restarts, and it won't work at all if the protection relay is not working.)
     
  14. mike32

    mike32 Formula 3

    May 13, 2016
    2,047
    Uk
    Have you fitted a repair kit to the fuel distributor head- about £50 on e bay. If the diaphragm is cracked it will alter the fuel delivery to each injector, if it delivers any at all. You can get overfuel to 1 unit and it leaks past the piston into the sump
     
  15. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Once Steve Magnusson pointed me in the right direction for the specs of my WUR (my 308 is a late model so closer to early 328 setup). I tested the WUR again and it fell within spec both cold and warm. See attached results (red dot on charts) and numbers below. So I have ruled out the WUR - but happy to be proven wrong.

    Yes the frequency valve is buzzing, its loud. I also unplugged it just to make sure that was what I could hear. I used to have a Edelbrock air/fuel meter that would show mixture ratio 10:1 to 15:1. But it stopped working some time ago. I might try see if I can get it going again that might give some idea of mixture?

    Steve, I had mentioned earlier in the post that I have an aftermarket muffler. So the oxygen sensor is not connected and the temp sensor is just stowed in the engine compartment. From my understanding of Ferrari SB 10-13 which explains the closed loop lambda system, with no signal from the oxygen sensor the system should just default to open loop. This was how I got the car. Could something else here have been tampered with causing the issue?

    Thx.
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  16. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
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    That's correct -- with the O2 sensor unplugged, the system runs open loop, but it should still start OK cold or warm. The O2 sensor is actually mounted in the catalytic converter outlet so I'm guessing that you don't have a cat either? When a cat is present, this effectively prevents the system from being set way too rich -- as you'll catch the surrounding coachwork on fire ;). Without a cat, it could be set way rich (although not sure that's what's causing your trouble - but something to check).
     
  17. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Steve, looks like I was mistaken. So the aftermarket exhaust that came with the car has a large single muffler and no cat. But the oxygen sensor is there, mounted in a bung just before the muffler inlet (rather than in the original cat). It was tucked away and hard to see from below! I followed the wires and they are still connected. The wiring and plugs all look original, so I assume its the original oxygen sensor just relocated. Do you think its operation would be affected being in the muffler inlet pipe rather than the cat? Or more importantly would that be causing the hot starts issue? I was thinking of un-plugging the oxygen sensor to allow the system to operate open loop and see if it makes a difference? Also, only the temp probe is not inserted in the exhaust. But that is only for the dash indicator isn't it?
    Some pics below.
    BB
     

    Attached Files:

  18. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
    18,244
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    No, that is the correct location for it (as close to the engine as possible where it "sees" all of the exhaust gases).

    Don't see how it would have any effect on warm restarting whether plugged in or unplugged, but no harm in trying that. One other thing you could do is measure the voltage on the single unplugged signal wire of the O2 sensor relative to ground at warm idle -- if it's pegged up at 0.95~1 VDC that would indicate the idle mixture is set rich.

    Correct. The thermocouple only sends a signal to the dash warning light ECU (not to the engine management system), and with no catalytic element present in the exhaust stream there is no reason to place it in the exhaust stream.
     
  19. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    280
    Good afternoon,
    I had the same problem with my 328 US specs. Your WUR belongs to a 328 US specs. I finally corrected the problem adjusting the air/fuel mixture when worm.
    That WUR uses two bimetal strips and two heaters, plus a barometric "plate" which affects the fuel pressure.
    Below are the fuel pressure adjustments.

    John.

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  20. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    280
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  21. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Thanks Hinecker, Steve Magnusson provided those specifications for me, I didn’t realise at the time that late 308s had the early 328 setup. I checked the control pressure and it fell within specifications both cold and hot – though on the lower range. You can see my results at posting #65 above. Something you mentioned though about fixing your 328 by adjusting the warm mixture got me thinking.

    When I bought the car earlier this year it came from a city that is at 1365 feet elevation - I’m at only 92 feet elevation (above sea level). I know the WUR is altitude compensating, and I tested that function by putting a vacuum on the atmosphere port on the WUR.

    But considering I’ve eliminated all the usual suspects, could it be as simple as the car is just at the wrong mixture (lean or rich) when warm. And more importantly, how can I test this theory?

    Cheers, BB
     
  22. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    280
    Morning,
    The heat probe is only for the dash light. The oxygen sensor must be mounted before the muffler if it doesn't have the cat, it will give a proper reading.
    Keep in mind that this sensor does not affect the starting of the engine, you can start the engine with the sensor unplugged, because the metering valve will operate at a constant duty cycle if no feedback is coming from the sensor.
    Also to mention is that the ECU only takes into account the signal coming from the oxygen sensor at idle and when the throttle is held at a fixed position and only when worm.
    I would check the oxygen sensor... when hot and engine idling unplug the black wire terminal coming from the sensor and test with a volt tester switched on DC volts. Negative of the tester would go to ground and positive to the back terminal. Voltage should oscillate from 0.2 to 0.9 constantly, if not or the sensor is bad or the air/fuel mixture is off.

    Hope this helps.

    John.

    BTW, Don't try to adjust the fuel mixture relying on the feedback from the sensor, this is a narrow band sensor and only operates correctly when air /fuel mixture is very close to 14.7 to 1... goes crazy out of that ratio, and you end up chasing the numbers. I learned this the hard way.
     
  23. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    280
    Morning,
    Yes, I fought with that problem just like you with no end results... The cure was the mixture.
    If you need to adjust it, I can show you an accurate, affordable way.

    John.
     
  24. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    280
    Couple of things you must keep in mind, the WUR can be adjusted in every way, but, if you're not familiar with adjusting it, don't even try...it'll drive you nuts.
    Last, the mixture, although adjusted at idle, affects the whole power band, that's why it's very important to have it properly adjusted.

    John.
     
  25. BrockBenson

    BrockBenson Karting

    Oct 18, 2018
    68
    Australia
    Hi John, I'm interest to hear how you adjusted the mixture to fix your warm start issue? I wasn't going to play with the WUR. The cold and warm pressures are within spec. I was going to try the MIXTURE ADJUSTER SCREW - which changes the relative position of the metering vane relative to the control plunger. The adjustment is carried out at idle but I understand its effect is felt throughout the engine's operating envelope. So I was going to mark the starting position, then adjust it a small amount in either direction to see if it solves the warm start? At least then I can return it back to if it doesn't work. Also going to do some measurements off the oxygen sensor when the car is running cold and warm and see what it tells me.
    BB
     

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