FRAMING JOHN DELOREAN - ON VOD www.framingjohndeloreanfilm.com
Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 21

Thread: No buzz from Frequency valve

  1. #1
    Junior Member JKDelorean's Avatar
    Join Date:  Aug 2021

    Posts:    8

    No buzz from Frequency valve

    I have no buzz from my FV - I’ve had the car for a few months and don’t think it Has ever worked. I’ve checked that I have 12v to one of the FV wires, that I have continuity from the bulkhead to both, I’ve checked that that the ECU has ground continuity from both the relevant wires and that there is continuity from the ECU to the FV and from the relay to the ECU. The ECU also has 12v to it.

    I’ve jumpered the RPM relay between the brown and yellow/red wires which I think should give a noticeable buzz at the FV but have nothing. I’ve also disconnected the O2 sensors for these tests as that should give me 50% at the FV I think.

    Anything I’m missing before I start to blame a knackered FV or ECU?

    Any help or expertise would be greatly received.

    Jon.

  2. #2
    Junior Member
    Join Date:  Jul 2011

    Posts:    24

    I recently had a similar issue. Rob Grady was the one to point me in the right direction. In my case it was the relay. Ordered a new one, FV buzzes away

    Sent from my SM-G996U using Tapatalk

  3. #3
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    9,000

    My VIN:    03572

    The lambda relay has to be the correct one which is different from the others. But if your getting 12 volts on the FV and at the same time getting 12 volts to the lambda ECU then it would be the correct relay. In that case probably your lambda ECU is bad if you have both grounds. It could also be the FV is frozen but a dwell check would show if the FV is getting dwell but not buzzing.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  4. #4
    Senior Member
    Join Date:  Nov 2019

    Location:  Pittsburgh, PA

    Posts:    503

    My VIN:    Yes.

    Club(s):   (DCO) (DMA) (DCUK)

    I have some spare lambda ECUs if you think that's the problem.

  5. #5
    Junior Member JKDelorean's Avatar
    Join Date:  Aug 2021

    Posts:    8

    I’m in the UK so not that close to Pittsburg.

    Is it possible to open it up and see if anything is awry?

  6. #6
    Senior Member
    Join Date:  Nov 2019

    Location:  Pittsburgh, PA

    Posts:    503

    My VIN:    Yes.

    Club(s):   (DCO) (DMA) (DCUK)

    Quote Originally Posted by JKDelorean View Post
    I’m in the UK so not that close to Pittsburg.

    Is it possible to open it up and see if anything is awry?
    Well, closer to Pittsburgh (PA) than you are to Pittsburg (CA). DeLorean EU have them for 178 Euro:

    https://www.delorean.eu/catalog/prod...ducts_id=51001

    I don't think DGo have any. Mine are rather cheaper than that, but whatever works for you.

  7. #7
    Senior Member
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    8,570

    My VIN:    10757 1st place Concourse 1998

    I got a few going by just plugging and unplugging the plug to the FV a couple of times. A little bit of corrosion is all it takes to keep it from buzzing. If your mixture is too far off it also won't buzz and if the O2 sensor is bad it won't buzz. There is a ground wire just for the FV that attaches to the intake manifold and if that is not attached it won't buzz. A bad Lambda relay (or the wrong one) and it won't buzz. Bottom line a few possible causes.
    David Teitelbaum

  8. #8
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    9,000

    My VIN:    03572

    With a cold engine the FV should buzz the loudest (duty cycle is 50%). Does not matter if your mixture is off or O2 sensor is working.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  9. #9
    Senior Member
    Join Date:  Jul 2020

    Location:  Danvers, ma

    Posts:    104

    My VIN:    4328

    Yea like Dave said 02 sensor has no effect on whether it buzzes or not. Leave it disconnected and u shoukd get 50% and buzzing all the time. I had the same problem and it ended up being my lambda ecu. Swapped it out and she started buzzing like crazy. I leave o2 sensor disconnected and run open loop

  10. #10
    Junior Member JKDelorean's Avatar
    Join Date:  Aug 2021

    Posts:    8

    This is a great help, thanks. I’m going to get a replacement ECU and cross my fingers that that’s the issue.

    Am I right in thinking that without the FV I would be running rich? I have a ‘separate’ but likely linked issue that my exhaust headers are getting too hot which I am thinking is unspent fuel igniting in the headers.

Page 1 of 3 1 2 3 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •