1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

1991 DB51T Vacuum / Carb troubles.

Discussion in 'Suzuki Carry' started by Chad Osos, Nov 8, 2019.

  1. Chad Osos

    Chad Osos New Member

    I've already gone through all of the suggested 3-5 threads with most of the info.

    The previous owner butchered my vac setup and took the vac choke off the carb and converted it over to manual choke. I have since replaced the entire carb with a factory replacement - and now I am left trying to repair the carnage left behind.

    My truck is a 91 DB51T, Manual Trans, 4x4 (no diff lock), with a 3+2 carb.


    There are 2 vac ports on the engine that are both currently plugged/unhooked. Where do those connect to?

    There is a vac line running from the front of the truck to underneath the driver's seat. I am guessing that is for the front diff? Where is does that connect to and is it even needed? I have a mechanical 4x4 lever, and a push button on the dash. When I pull the lever, it lights up. When I push the lever back down the light stays lit until I push the button & then the light goes off.

    There is currently nothing hooked up to the VSV on the carb #1.
    There is a screw at #3, that allows that whole piece to move up or down - what does that adjust and how is it tuned?
     

    Attached Files:

    Last edited: Mar 15, 2021
  2. Chad Osos

    Chad Osos New Member

    anyone?
     
  3. WendyM

    WendyM Member

    There is a post here (search Vac lines- I think Don from Japan posted a good one) that shows the vac lines for 96 dd51t...probably close to what you need. also check "desperately needing help" for carb info. Go to suzuki.epcdata.ru/carry if that doesn't work google epc.ru and go that way. Pick your model and you will find parts pics for every sys on your truck (with google translate). also site called megazip has pics and parts (for carb...don't know about vac lines). from your unknown pic 1=accessory idle, 2=choke pull off, 3=choke(throttle plate adjust) But there is a screw to adjust it in behind # 1 actuator on my truck. Your carb is a little different than mine. Go to members or find a post from scanner and go to his profile page, click all posts...read, read, read!! he has tones of good info on carb and lots of other stuff. Hope this helps :)
     
  4. Chad Osos

    Chad Osos New Member

    Already went through those threads. Unfortunately, it did not help my situation. The diagrams posted were all for 3+2 carbs, which is great as it tells me how to tune the carb - I have that nailed and even adjusted the hidden choke/idle screw, but that does not fix a faulty idle if the vac system is not set up correctly - which seems to be my issue. Unfortunately, the only vac diagrams I have found were for DB51T, or DA51T.

    The diagram I posted is actually a merge of the various diagrams I found online. My truck does not have an "idle switch", and I can't seem to locate a "vac switch", either. I also do not know where that red vac line plugs into on the carb that runs from the "idle switch". I am guessing it goes to the Accessory VSV on the carb?
     
  5. WendyM

    WendyM Member

    the use epcdata.ru or megazip...to see if your model originally had the switches in question... beyond that I don't know. Maybe find someone here that has your model/year, they might know.
     
  6. Chad Osos

    Chad Osos New Member

    So, my 4WD was not working despite the lights being on - we have a foot of snow yesterday, so this was a great test!

    The DB51T 4WD is vacuum activated - and if you have a leak or the hose is disconnected, the lights will still come on, but it will not actually engage the front diff. From what I read, the switch is on the diff so I connected the line from the front of the truck directly to the vac port on the manifold. My 4WD now works correctly.

    I have most everything else hooked up and working. The ACC VSV is not hooked up, but the truck RPM does not drop significantly running any of my lights and whatnot, since I've converted everything to LED.

    I would still like to see some pictures of the factory lines and how these are all routed.
     
  7. WendyM

    WendyM Member

    find the discussion "Help with 1990 Carry DB51T 4WD MT carb question" in the suzuki carry forum, scroll down to post #5 - the last two pictures show difference between vac lines on 3+2 and 2+3 carbs and an overall vac line map different from the one you have. I found one on EPC but it was hard to read.
     
  8. Chad Osos

    Chad Osos New Member

    That was the same exact diagram i modified and added the text and lines coming off the carb, instead of having it set apart like post 5. I have already scoured those threads.

    I also need to know where his line #3 runs to out of that manifold port, because it does not match the #'s on his diagram. Right now, I hooked that port directly to my 4WD vac lines running to the front diff. I also had to pull the check valve off the idle vsv. It was holding vac after the vehicle was off one direction and if I flipped it, it did nothing.
     

    Attached Files:

  9. WendyM

    WendyM Member

    Ok, so I crawled around my truck-should be close to what yours is. Line #3...Choke pull-off actuator has 2 ports in the line from it. Port closest to actuator, I will call A and furthest away B. From Port A line goes to a delay valve and then to a "T". The line off the T (90 degrees) goes to port 2 (1 being furthest away from engine) on the thermo switch. Back at the "T", the main line A goes to "C" port on carb (#2 on a 2+3 carb or #3 on a 3+2 carb). Line B goes directly to port 1 on the thermo switch.

    4x4 switches....Switch closest to front of truck I'll call A and switch closest to rear-B. On the A switch line goes to a "T". The line off T at 90 degrees goes to bottom of switch B. Back to the "T", the main line comes up towards passenger seat and has a valve (white end facing down line) and then joins into a metal line attached by rubber hose to manifold by the thermostat.

    The line from the manifold port in your pic goes to the port on the bottom of your air filter canister that is closest to the rear of your truck--the other port goes to a valve farther back on the air intake assembly.
     
  10. catalyst

    catalyst New Member

    I appreciate you trying to help, but i am not able to follow your post. :(
     
  11. WendyM

    WendyM Member

    In your original post, the first attached picture shows 4 hoses: #1 hose at thermostat #2 hoses beside thermostat with silver hose clamp on it. That is the one that that the switch for 4x4 attaches to (on my truck) follow that hose towards front of truck and you might find a port for vac hose from 4x4 switch to fit on.

    In the picture of vac diagram it looks like line #3 goes from C port on your carb to the idle up actuator(marked #1 on your carb pic.)

    try this page suzuki.epcdata.ru/carry/281_da51/engine/181/ It shows all the vac lines, I found the second and the last diagrams useful. Looks like your missing switch is part number 95551-**** you still have to dig more to find which of the multiple choices is the correct one for you.
     

Share This Page