GMC P3500 with GMC B 3.9L/4BT 5 speed manual
4BTSwaps.com is the premier Cummins Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 10 of 10

Thread: GMC P3500 with GMC B 3.9L/4BT 5 speed manual

  1. #1
    New Registered User
    Join Date
    Mar 2013
    Location
    Cincinnati, Ohio
    Posts
    5
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default GMC P3500 with GMC B 3.9L/4BT 5 speed manual

    I Just bought a 1993 GMC P 3500 step van. What should I know about general maintenance and upkeep. I have never owned a Vehicle with a diesel engine

    before. I had Intermittent problems with power bringing it home over a 500 mile stretch. Some times it would barely do 45 MPH up a slight incline and

    other times it would go 60 up a steeper hill. What is causing that? The guy that I bought it from, said that it had 105 horse power and that it got

    17MPG. The Engine is a B3.9L/4BT engine with a 4 speed plus low and rear manual and an inter-cooled turbo on it.Engine Data Tag says it was made in 93'

    and I think the numbers on the tag are 921918 Is it possible to give it more HP or Torque and/or fuel mileage? Also, how often should the air/fuel and

    oil filters and oil be changed. Is there anything else that should be tuned up. Any help or suggestions would be welcome. Thanks
    Luis
    Last edited by lmgmcp3500; 03-30-2013 at 01:38 PM. Reason: more tags

  2. Remove Advertisements
    4BTSwaps.com
    Advertisements
     

  3. #2
    Registered User
    Join Date
    Dec 2012
    Location
    Prior Lake, MN
    Posts
    921
    Thanks
    25
    Thanked 10 Times in 10 Posts

    Default

    The 4BTA (A means aftercooler) those are rated at 120hp. So if you get an intercoole/aftercooler you may get power out of it. Oil should be changed roughly every 5,000 miles. If its black you change it. Air filters are around 12,000 miles unless you live and drive on a dirt/gravel roads then its more often. From what I have been told a K&N Air filters let more particles in through the engine so going with paper filters may be better.

    Oil changes are around 7500 miles. If you run an Amsoil bypass with 2 filters it may go to 15,000 miles.
    Last edited by Lowegt; 03-30-2013 at 06:38 PM.
    The only thing that really stops you from achieving what you want is the size of your wallet.
    -1999 F150 XLT 5.4L V8 Triton 4x4 extended cab 8' box 248,000 miles...slowly dying

    Aaron

  4. #3
    Isuzu Diesel Innkeeper
    Join Date
    Jan 2007
    Location
    New Zealand
    Posts
    6,887
    Thanks
    298
    Thanked 216 Times in 136 Posts

    Default

    Changing diesel oil when it's black is a waste of time.
    Isuzu 4BD1T Junkie.

  5. #4
    Registered User
    Join Date
    Mar 2008
    Location
    Green Bay, WI
    Posts
    1,949
    Thanks
    1
    Thanked 18 Times in 11 Posts

    Default

    Quote Originally Posted by Dougal View Post
    Changing diesel oil when it's black is a waste of time.
    Most diesel syn's (rotella etc) will blacken after the first 150-300 miles as the new detergents begin to work. While these deteregents are not exhausted from doing their job for another few thousand miles... the color change occurs almost immediately... (a couple engine hours)

    Change your oil accordingly to your use and the size of your oil pan. 6BT's with 15 qt pans..... 8-10k on light duty use..... 4BT w/ a small modified oil pan .... every 3-5k
    1966 Chevy C-10 Shortbed Fleetside
    5.3L LM7/4L60e LSx swap
    Project 1966 C10 LSx Build Thread - 67-72 truck forum

    **OLD**1947 Ford 1.5 Ton DRW
    Cummins 6BT P7100 - HE341 Turbo
    Eaton Fuller RT-6610 10 speed - 4 Link Rear / IFS/4whl Disc/all on air

  6. #5
    Isuzu Diesel Innkeeper
    Join Date
    Jan 2007
    Location
    New Zealand
    Posts
    6,887
    Thanks
    298
    Thanked 216 Times in 136 Posts

    Default

    Quote Originally Posted by 47Ford - 1.5Ton View Post
    Most diesel syn's (rotella etc) will blacken after the first 150-300 miles as the new detergents begin to work. While these deteregents are not exhausted from doing their job for another few thousand miles... the color change occurs almost immediately... (a couple engine hours)

    Change your oil accordingly to your use and the size of your oil pan. 6BT's with 15 qt pans..... 8-10k on light duty use..... 4BT w/ a small modified oil pan .... every 3-5k
    Exactly.
    Longest I've gone with clear oil on my 4BD1T is 700km. But only after I'd removed the oil sump and cleaned it for resealing. Normally there's a layer of awful in there leading to black oil almost immediately.

    I run 10,000km intervals because they are easy to remember. Isuzu recommend up to 16,000km (10,000 miles) with the dual bypass filter and agreeable usage.
    Isuzu 4BD1T Junkie.

  7. #6
    Supporting Member
    Join Date
    Jun 2010
    Location
    Newton NC
    Posts
    3,035
    Thanks
    0
    Thanked 126 Times in 118 Posts

    Default

    First off, welcome to the forum. To know more about your engine I would suggest you go to Cummins Quick Serve on line and set up an account. The basic service is free. Enter your 8 digit engine serial number (ESN) off the ID tag and you can find out every part in your engine and it's specs. If it was ever rebuilt by Cummins it will tell you that as well.

    Your varying power problem could come from a number of sources and is kind of hard to trouble shoot. It could be a weak injection pump or combination of other factors. Two gauges you probably don't have on a step van are turbo boost and pyrometer. They can tell you a lot about how the engine is running. Another that is very helpful is fuel pressure from the lift pump. The lift pump on these engines that feeds the injection pump is not know to be the world's best. It's a simple item to replace and not very expensive.

    As far as adding performace you have tons of options. If you are getting 17mpg I wouldn't expect that to improve by worlds because you are driving a heavy vehicle with the aerodynamics of a cement block. The gas version of that van probably got half that. There are a number of tweeks to the injection pump that will cost you only the time of doing them. One problem with these engines is you don't always know just how many miles it has on it. After the lift pump, one of the first items on the list might be to have the injectors checked. Find a reputable diesel shop in your area, remove the injectors and have them pop tested. It won't cost a fortune and will eliminate that problem. If they are bad you can either have them rebuilt or replace them. Another item to check is the turbo. Look for any oil in the compressor housing or exessive side to side or end to end movement in the compressor wheel. This would mean a worn turbo in need of rebuild or replacement. Rebuild kits are cheap and this is something you can do yourself if you have the tools and the skill. Complete service manuals can be found on Holset's web site for free. If you're not sure when the engine was last serviced I'd change the oil and filter and the fuel filter. When you do that one be sure to fill the filter with clean fuel before you install it. Air in the fuel system can be a real headache.

    Since this is you first diesel you will find they are a different animal. Diesels are known to produce their power at lower rpm's than their gas cousins. The peak torque on your 4bt come in around 1700 rpm and peak HP at 2500 rpm. The engine has a governor that prevents it from reving too fast as you have probably already found out. Although you can change the governor limit it is good to learn how to drive within the engines specs. Take your time and look around the forum. There is ton's of valuable and free info here. An again welcome.

  8. #7
    New Registered User
    Join Date
    Mar 2013
    Location
    Cincinnati, Ohio
    Posts
    5
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    Thanks, I plan on checking out those links. My plan is o use that truck as a Mobil work shop for my construction business. I was also wondering if the low sulfer diesel fuel can cause any problems and do i need to add any additives to the fuel?

  9. #8
    Registered User
    Join Date
    Dec 2012
    Location
    Prior Lake, MN
    Posts
    921
    Thanks
    25
    Thanked 10 Times in 10 Posts

    Default

    ULSD won't hurt anything. Though just heard the EPA is going for even stronger emissions on Diesel engines and ULSD so there maybe problems in the future so stay sharp.
    The only thing that really stops you from achieving what you want is the size of your wallet.
    -1999 F150 XLT 5.4L V8 Triton 4x4 extended cab 8' box 248,000 miles...slowly dying

    Aaron

  10. #9
    New Registered User
    Join Date
    Mar 2013
    Location
    Cincinnati, Ohio
    Posts
    5
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    I realized when taking off the pipe that comes from the turbo, to the intercooler on my 4bt engine that there was black oil in the pipe. Is that unusual? I was wondering after watching some videos on YouTube, if maybe some of the seals in the turbo maybe leaking oil. I also noticed (while driving a few days ago) that I seamed to have no power and didnt hear the quiet whistle of the turbo and then a few min later I heard it and seamed to have more power. Haven't had a chance to do much checking into it yet. Thanks for any help or advice you can give.

  11. #10
    New Registered User
    Join Date
    Mar 2013
    Location
    Cincinnati, Ohio
    Posts
    5
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    Image 2.jpg
    do these numbers make any sense to any one. I also found a line of numbers on the fuel pump side of the engine block that was 9 didgets long. I'm having a horrable time finding the ESN on my engine. Could Several people please post some picts of what there ESN tag looks like so that i would give me some idea of what to look for. thanks. Luis

+ Reply to Thread

Tags for this Thread

Posting Permissions

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