FRAMING JOHN DELOREAN - ON VOD www.framingjohndeloreanfilm.com
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 14

Thread: Has anyone ever listened to their injectors?

  1. #1
    Formerly: Josh S. Parzval's Avatar
    Join Date:  Oct 2014

    Location:  Leesburg, NJ

    Posts:    144

    My VIN:    7178

    Club(s):   (DMA)

    Has anyone ever listened to their injectors?

    While troubleshooting my engine yesterday I decided to listen to my injectors with a stethoscope and a couple sound like they are screeching... like an old 300 baud modem. I'm pretty certain that's not right. The majority of them sound like a nice oiled sewing-machine hum and click.

    Actually.. they all were fairly noisy at first, but most of them smoothed out while I was monkeying around. I did put a can of gas treatment in the tank earlier that evening. But perhaps that could be coincidence. However, the miss I was experiencing seemed to go away as well... and no noticeable stumbling on revving. I didn't have the time to take it for a road test last night, but I will today.

    Can anyone confirm what the injectors should be doing / sounding like? I don't imagine the sound of them should change much during operation. And I also assume they should all at the very least sound the same.


    Thanks!
    Josh
    "If you're going to spend your inheritance on a car, why not do it with some style!"

  2. #2
    Senior Member
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    8,570

    My VIN:    10757 1st place Concourse 1998

    A low screech. You may also be hearing air leaks past old, hard injector seals. The screech will get louder as the revs increase and they squirt more fuel. The frequency valve makes a buzzing sound that varies in frequency. The motor will hunt and you can hear the revs go up and down. A cacophony that you can hear as you walk up to a running PRV.
    David Teitelbaum

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

    Location:  Leonardtown, MD

    Posts:    9,000

    My VIN:    03572

    When you do a flow test (put injectors in jars and press the air plate) you do get a screeching sound.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  4. #4
    Senior Member
    Join Date:  Aug 2015

    Location:  Novi, MI

    Posts:    413

    My VIN:    4665

    Quote Originally Posted by David T View Post
    A low screech. You may also be hearing air leaks past old, hard injector seals. The screech will get louder as the revs increase and they squirt more fuel. The frequency valve makes a buzzing sound that varies in frequency. The motor will hunt and you can hear the revs go up and down. A cacophony that you can hear as you walk up to a running PRV.
    +10 points for excellent word choice.

  5. #5
    Senior Member
    Join Date:  May 2011

    Location:  Oklahoma

    Posts:    107

    My VIN:    1058

    It's easy to jump the rpm relay and put the injectors in clear cups and watch their spray pattern. Look up the process.

    Sent from my SM-G920R4 using Tapatalk

  6. #6
    Senior Member
    Join Date:  May 2011

    Location:  Oklahoma

    Posts:    107

    My VIN:    1058

    Also I would say everything is ok. They do make a solid screeching sound. They flow constantly

    Sent from my SM-G920R4 using Tapatalk

  7. #7
    Senior Member DMCVegas's Avatar
    Join Date:  Oct 2011

    Location:  Las Vegas

    Posts:    2,497

    My VIN:    6585

    As others have said, that is perfectly normal for the injectors. As an example, here are 8 of them undergoing flow testing on a bench. You can hear what they sound like without the noise of the engine muffling them.

    https://youtu.be/6yrwqspHhak?t=1m2s
    Robert

    People they come together, people they fall apart...

  8. #8
    Senior Member
    Join Date:  Jul 2015

    Location:  Tacoma, Wa

    Posts:    2,208

    My VIN:    4877

    Club(s):   (PNDC)

    the squeal is caused by the hamsters inside the injectors being squeezed
    Rob Depew
    Tacoma, Wa
    '81 DeLorean 4877 Grey, Auto, 4 wheels
    The Ressurection of 4877......
    Website
    YouTube
    My Patreon

  9. #9
    Formerly: Josh S. Parzval's Avatar
    Join Date:  Oct 2014

    Location:  Leesburg, NJ

    Posts:    144

    My VIN:    7178

    Club(s):   (DMA)

    Quote Originally Posted by David T View Post
    A low screech. You may also be hearing air leaks past old, hard injector seals. The screech will get louder as the revs increase and they squirt more fuel. The frequency valve makes a buzzing sound that varies in frequency. The motor will hunt and you can hear the revs go up and down. A cacophony that you can hear as you walk up to a running PRV.
    The PRV definitely is musical. I grew up on air cooled VWs, so I'm used to noisy engines.

    Quote Originally Posted by Bitsyncmaster View Post
    When you do a flow test (put injectors in jars and press the air plate) you do get a screeching sound.
    This will be next. It'll also let me see if the seals are good when I pull them.

    Quote Originally Posted by DMCVegas View Post
    As others have said, that is perfectly normal for the injectors. As an example, here are 8 of them undergoing flow testing on a bench. You can hear what they sound like without the noise of the engine muffling them.
    That vid's pretty much how some were sounding, though at idle, and not all of them either. I didn't rev it up to hear what they would do then, I guess I should have. Well, I'll do that tomorrow just to see. Testing the spray pattern will be likely be the next project.

    Thanks everybody!
    I knew someone had to know what they sound like.
    "If you're going to spend your inheritance on a car, why not do it with some style!"

  10. #10
    Senior Member
    Join Date:  Nov 2014

    Location:  Northwest Florida

    Posts:    324

    My VIN:    Midproduction

    Yes! I thought the same: just beautiful!!

    Quote Originally Posted by iflights View Post
    +10 points for excellent word choice.

Page 1 of 2 1 2 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
  •