Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

TBI oil pressure switch ?'s

Discussion in 'The Garage' started by bluejeep, Mar 30, 2004.

  1. bluejeep

    bluejeep 1/2 ton status

    Joined:
    Jan 9, 2004
    Posts:
    106
    Likes Received:
    0
    Location:
    Des Moines, IA
    TBI oil pressure switch ?\'s

    Having troubles with my TBI (88 motor) and was told by a shop to change the oil pressure switch. I went to take the old one off and the extension/elbow piece that it screws into broke off at the block, back beside the distributor. Dealer wants $25 for this extension/elbow. Anybody know what size the threads are that screw into the block? I want to use some common brass fittings for $5 and hook it up once I get the old piece out, and want to be prepared with the correct fittings to get it hooked back up. Thanks in advance... /forums/images/graemlins/1zhelp.gif
     
  2. azblazor

    azblazor 1/2 ton status Premium Member

    Joined:
    May 5, 2001
    Posts:
    1,953
    Likes Received:
    0
    Location:
    Arizona, Phoenix area
    Re: TBI oil pressure switch ?\'s

    I believe it's most likely 1/8" NPT - but there are definately variances - even between same years. I just replaced my daughters 89 and they listed 2 different sizes for that year. Her's was the 1/8.
     
  3. bluejeep

    bluejeep 1/2 ton status

    Joined:
    Jan 9, 2004
    Posts:
    106
    Likes Received:
    0
    Location:
    Des Moines, IA
    Re: TBI oil pressure switch ?\'s

    How much do they vary, any idea? It's visually easy to tell the difference between 1/8 and 1/4 NPT. I was thinking it looked like 1/8" NPT, but I wanted to see if anybody knew for sure. Any idea what that other available size was? Thanks for the reply.
     
  4. azblazor

    azblazor 1/2 ton status Premium Member

    Joined:
    May 5, 2001
    Posts:
    1,953
    Likes Received:
    0
    Location:
    Arizona, Phoenix area
    Re: TBI oil pressure switch ?\'s

    Well if it looks like it's 1/8 it probably is. But if it were me I would take it apart first. Isn't it already broken?
     
  5. bigburban383

    bigburban383 1/2 ton status

    Joined:
    Dec 30, 2003
    Posts:
    1,242
    Likes Received:
    0
    Location:
    Michigan, Royal Oak
    Re: TBI oil pressure switch ?\'s

    Yeah, just remove it and take it to the hardware store. Your gonna have to remove the distributor to get to it.
     
  6. bluejeep

    bluejeep 1/2 ton status

    Joined:
    Jan 9, 2004
    Posts:
    106
    Likes Received:
    0
    Location:
    Des Moines, IA
    Re: TBI oil pressure switch ?\'s

    Yeah, it's already broken and yeah, it's under the distributor. I was just hoping to stop at the hardware store on the way home from work....
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Re: TBI oil pressure switch ?\'s

    All the blocks I have ever seen are 1/8" front and rear oil fittings, and most of the time, 1/4" above the oil filter.

    I'm sure there is SOME variation, but 1/8" front and rear seems to be the most common. Some early blocks didn't have the 1/4" above the oil filter drilled/tapped.

    There are a few different sending unit/switches out there, Napa's "Echlin" catalog is fun to look in...lists how the connector needs to be pinned, what the values of the switch or sender are (0-90 ohms for example) functions, and 1/8", 1/4", etc. in most cases.

    I started out with a seperate oil pressure sender and switch, but with that catalog, found one out of a slightly newer GM vehicle that was 1/4", and did both functions, with one 3 wire connector. Just an idea.
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Re: TBI oil pressure switch ?\'s

    1/8" NPT /forums/images/graemlins/thumb.gif
     
  9. bluejeep

    bluejeep 1/2 ton status

    Joined:
    Jan 9, 2004
    Posts:
    106
    Likes Received:
    0
    Location:
    Des Moines, IA
    Re: TBI oil pressure switch ?\'s

    Got the broken off piece out last night and it appears to be 8mm x 1.0 threads where it screws into the block. I've ordered the replacement from GM, but I'm pretty sure the switch itself is 1/4" NPT where it screws into the elbow fitting.
     

Share This Page