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TR starting circuit Problem!!

Discussion in 'Technical Q&A' started by REM9, Dec 22, 2003.

  1. REM9

    REM9 Karting

    Jun 17, 2001
    173
    Finger Lakes NY, USA
    Full Name:
    rem9
    I have a 1986 TR which has run flawlessly and did so when parked 2 weeks ago. It now will not start. Engine cranks over strongly and sounds like it is starting to fire then dies when the key is released. Ignition circuits all seem active and testing indicated that's likely not the problem. I have checked fuses and note that with the ignition on, there is no power on either side of the fuse that controls the starting injectors. Has anyone dealt with this problem before or are there links back to this as an earlier topic. Are the thermal switches NO or NC at ambient temperatures?
    Any assistance would be appreciated.

    Thanks
    Russ
     
  2. PSP

    PSP Formula Junior

    Mar 31, 2001
    603
    Lake Forest, CA USA
    Full Name:
    Patrick S. Perry
    Do you hear the fuel pumps running? Are the coils original?

    Mine did something similar about a year ago (except I was on the freeway at the time). There is circuitry running through the chip on one of the coils that powers the fuel pumps - if the coil goes bad, it shuts off the fuel supply. The car will crank and sound like it will start but doesn't. If this is the problem and you swap the left and right coils, the car will start and run on one bank.
     
  3. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
    UK
    Full Name:
    Malcolm W
    May or may be fuel related but the obvious areas to look into are :-

    * Vacuum system leaking
    * Air flow senor lever and / or control plunger not moving smoothly
    * Auxillary-air device not opening
    * Fuel pump defective
    * Cold-start system defective
    * Cold control pressure outside tolerance

    There are several versions of the thermo time-switch, the temperature range is stamped on the side of your switch so I have listed below the data for all versions of the switch.

    Just a thought, does your car have an immobiliser / alarm system installed, these are usually (depending on the make) wired into the ignition / fuel system, if so there could be a fault there which prevents the car from starting.


    MW
     
  4. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,167
    Texas
    Full Name:
    Steve Magnusson
    Russ -- KE-Jetronic with Lambda (US version) or something else (K-Jetronic, KE-Jetronic sans Lambda)? My (foggy) recollection is that +12V power is present on the cold-starting injector fuses only during actual starter cranking, but I'll check the TR wiring diagram(s) in a few hours and let you know (but it would be helpful if you'd confirm version).
    There are several places in the white connectors (at the bottom of the fusepanel) to confirm/deny the presence of +12V associated with the whole injection ECU/fuel pump/tachometric interaction so if PSP's coil swap test doesn't locate the problem let me know and I'll find/post the diagram.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,167
    Texas
    Full Name:
    Steve Magnusson
    Russ -- my recollection was OK -- there will only be +12V power on the starting injector's fuse during actual starter cranking (not with just the key "on" nor with the engine running). If swapping the coils doesn't get it going on 1 bank other things to check are:

    1. Find the water temp switch pointing out the LH side of the thermostat housing (it is not either of the gizmos on top of the thermostat housing with the molded connectors). It will have 2 separate spade-type connectors -- one red wire and one orange/black wire. The red wire is the main +12V supply from the relay "C" in the black triangular box to run the injection system. This wire should be +12V during starter cranking and during engine running.

    The attached diagram shows the 4 white horizontal connectors at the bottom of the fusepanel (and you should be able to probe the wire connectors with everything plugged in):

    2. The violet wire in 5th from right position of the "x" connector is the +12V output from the tachometric relay and should go +12V during starter cranking or engine-running.

    3. The two white/blue wires in the 2nd position from the left on the "y" connector are the output from the starter solenoid and should go +12V during starter cranking only.

    4. The 4th (beige wire) and 5th (beige/black wire) from the right on the "y" connector are the fuel pumps -- should go +12V during starter cranking and engine-running.

    Anyway just some things to check/verify if it isn't a coil pack problem...
     
  6. REM9

    REM9 Karting

    Jun 17, 2001
    173
    Finger Lakes NY, USA
    Full Name:
    rem9
    I will attend this problem this evening armed with my voltage ohm meter. I appreciate the time you folks spent to give me these leads. I'll keep you informed of progress (or failures).

    Thanks
    Russ
     
  7. philvecc

    philvecc Formula Junior
    Silver Subscribed

    Nov 3, 2003
    692
    Longmeadow, MA
    Full Name:
    Philip Vecchiarelli
    Had the same problem with my '89 TR last summer. Turned out to be the tach sensor.
     
  8. REM9

    REM9 Karting

    Jun 17, 2001
    173
    Finger Lakes NY, USA
    Full Name:
    rem9
    Steve,
    I have conducted the following tests and still am at a bit of a loss......
    As a reminder, this is an 86 TR that has run flawlessly until a week ago. I have checked all fuses and all are ok. Relay "C" is suspect I suppose after the test results below. Please see the comments after each test. The fuse on top of it is ok and has a clean path to terminal #30 on the relay base(ie 0 ohms).

    There was power on the starting injector's fuse when cranking.

    1. Find the water temp switch pointing out the LH side of the thermostat housing (it is not either of the gizmos on top of the thermostat housing with the molded connectors). It will have 2 separate spade-type connectors -- one red wire and one orange/black wire. The red wire is the main +12V supply from the relay "C" in the black triangular box to run the injection system. This wire should be +12V during starter cranking and during engine running.
    ***There is no voltage at this point at any time. I traced this back to the harness that goes into the triangular "box" and confirmed I do have continuity. Then went in and confirmed I have continuity to the relay socket on terminal #87. (this per the schematic)

    The attached diagram shows the 4 white horizontal connectors at the bottom of the fusepanel (and you should be able to probe the wire connectors with everything plugged in):

    2. The violet wire in 5th from right position of the "x" connector is the +12V output from the tachometric relay and should go +12V during starter cranking or engine-running.
    *****Confirmed. Tested okay.

    3. The two white/blue wires in the 2nd position from the left on the "y" connector are the output from the starter solenoid and should go +12V during starter cranking only.
    *****Confirmed. Tested okay.

    4. The 4th (beige wire) and 5th (beige/black wire) from the right on the "y" connector are the fuel pumps -- should go +12V during starter cranking and engine-running.
    *****Confirmed. Tested okay.

    I have also checked the continuity of the ground connection going to the "C" relay and it checks out okay. I have an enlarged schematic of this system on the wall of the shop which has been helpful. What is the function of the "C" relay?

    What is the location of the tachometric relay? I assume it to be okay as the fuel pump tests were okay in terms of power..... is that an okay assumption?


    Thanks for any assistance or guidance you can offer.

    Russ
     
  9. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,167
    Texas
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    Steve Magnusson
    Good work so far -- no power at that red wire is a killer. Don't condemn relay C quite yet, but it's the next place to go looking. The violet wire in the "x" connector going +12V during cranking is a good sign for the tachyometric stuff (relay & sensors). That same violet line (after going to the fuel pump relays on the fusepanel) actually leaves the fusepanel via the violet/white wire in the "j" connector, 6th position from the right, then thru the small round C13 connector on the triangular black box to reach terminal 15 on relay C.

    So it now gets down to checking all the signals at relay C:

    terminal 30 should always be +12V (even with key "off").
    terminal 31 should be a good ground.
    terminal 15 is the command line to close relay C -- i.e., relay C closes when this line goes +12V -- if terminals 30 and 31 are as above.
    terminal 87 should go +12V when relay C closes -- i.e., terminal 87 is connected to terminal 30 when relay C is closed.

    Assuming terminal 30 relay C is +12V and terminal 31 is a good ground:

    1.) If the "x" connector violet wire goes +12V during cranking, but terminal 15 at relay C does not go +12V -- you've got a problem in that wiring chain from the voilet wire "x" connector to terminal 15.

    2). If terminal 15 goes +12V during cranking, but terminal 87 does not -- then the relay C is probably toast.

    With regard to the "function" of relay C (like the fuel pump stuff), it's a crash safety feature -- i.e., a way to cut the +12V power in the whole injection network if the engine stops running and the key is still "on".

    The tachyometric relay is mounted behind the fusepanel -- but since you've already verified that it's output is OK (i.e., the violet wire in the x connector goes +12V during cranking) I don't think you'll need to go there.
     
  10. REM9

    REM9 Karting

    Jun 17, 2001
    173
    Finger Lakes NY, USA
    Full Name:
    rem9
    With a great deal of thanks for his time and effort, Steve provided the guidance that helped me isolate the problem. It was in fact the protection relay (Stribel 928.615.124.00). Why it failed is beyond me, but it's now fixed. To those of you who ever run down this path, a few side notes. While checking relays and wiring I also noticed the fuel accumulators were "weeping" just a little. Not a good situation given their proximity to the exhaust headers. In any case, the first reaction was to get a dealer price for these parts (yes, I knew it would scare me). The relay was $255 and the accumulators were $355@ (x2). Again, with the guidance of Steve, I ended up getting the relay through T Rutlands for $92 and the accumulators are on their way from importec.com for the much easier to swallow price of $71.55@. The interesting thing is I got the part from Rutlands overnight, very impressive. The accumulators are a std Bosch part from all suppliers and even find their way into a number of volkswagen models.
    So as I send this, the TR is now fully operational and I have driven it back into the storage area of the building. Many thanks to those who provided input with a special thumbs up to Steve. I hope I can return the favor in the future.

    Relay part#: 61766200 (also used in my 328!)
    Accumulator part #: Ferrari 123135 (Bosch 0438170042)
    Importec part # E4000-13575

    Best regards to all of you. Thanks Steve for your time and effort and Rob for making this list such a resource to those of use doing our own work. Have a great new year.

    Russ
     
  11. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,167
    Texas
    Full Name:
    Steve Magnusson
    Glad you got the TR sorted Russ -- I think your earlier observation about a TR's electrical system complexity being a bit daunting (and not a positive thing) is a legitimate criticism ;).

    You mentioned your 328 -- do you have a F "collection"? (Why not add to your Profile a bit?)
     
  12. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,563
    USA
    Full Name:
    Hugh G. Rection
    That is great to hear, Steve is an awesome technician in his own right.

    BTW, it should be noted that importec sells factory Bosch parts, not generic parts. Just wanted to stress with folks that you are in fact getting the EXACT part for many times less. I ordered new upgraded brass Bosch fuel injectors from Importec for 1/3 what FNA wanted. As long as you have the Bosch part number, you can use Importecs part look up. They don't carry all of the Bosch line, but if it is used on a more common car (VW/BMW/Mercedes) they will have it.
     
  13. REM9

    REM9 Karting

    Jun 17, 2001
    173
    Finger Lakes NY, USA
    Full Name:
    rem9
    Steve, I tried to list the collection but there wasn't enough room offered on the profile. I list it below. There are lots of open country roads up here so a sportscar can stretch it's legs on occassion. It's a fairly diverse collection, all of them having a different appeal to me. The 59 TR-3 I have had since I was 16. The Mustang GT fastback was built on my 16th birthday and I am in the midst of doing a ground up on it.
    1987 Ferrari 328S
    1986 Ferrari TR
    1984 Corvette C-4
    1980 Triumph TR-7 Conv;
    1977 Porsche 911S
    1973 Triumph TR-6
    1972 Triumph GT-6
    1970 Jaguar XKE Coupe
    1968 Mustang Fastback GT
    1968 Austin Mini Cooper
    1962 Triumph TR-4
    1959 Morris Mini RHS
    1958 Triumph TR-3
    1958 MGA 1500 Conv
    1963 Spitfire vintage racecar

    The bays where I work on the cars are heated and air conditioned. Helps when the weather is other than ideal, which is most of the time up here.

    Russ
     

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