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.

6.2 diesel questions..

Discussion in 'The Garage' started by Maxp3, Dec 17, 2004.

  1. Maxp3

    Maxp3 Newbie

    Joined:
    Dec 17, 2004
    Posts:
    4
    Likes Received:
    0
    Location:
    Georgia
    I have an 86 K5 with the original motor(259K miles) that still runs good but is hard to crank . I don't know if the glow olugs are bad or if the electrical system is bad. It has power windows but are real slow going up or down and all the lights dim if you use the heater fan.. It has a new alternator and two new batteries. So my dilema is figuring out if the low voltage prob is affecting the cranking prob...Im sure you have disscused this before but It may take me a few days to read everything..
     
  2. joez

    joez 1/2 ton status

    Joined:
    Oct 21, 2003
    Posts:
    2,512
    Likes Received:
    0
    Location:
    New Lenox, Illinois
    Probobally a bad ground somewhere, that could cause a problem with the power windows and headlights. As for the slow cranking, probobally just an old starter.
     
  3. Maxp3

    Maxp3 Newbie

    Joined:
    Dec 17, 2004
    Posts:
    4
    Likes Received:
    0
    Location:
    Georgia
    Thanks for the reply.. I put a new starter in last month and paid real close attention to the wiring...I will check or replace the cables just for giggles
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    I had a bad cable not that long ago. Looked completely fine from one end to the other but had a bad spot somewhere inside. Damn near left me stranded at work one night. I replaced them all with 2/0 welding cable and soldered lugs.

    Rene
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,583
    Likes Received:
    945
    Location:
    Massachussetts
    Needs a lot of amps

    The 6.2 can be reluctant to crank fast enough if there isnt enough current getting to the starter--if your truck is more than 10 years old,new battery cables are a good investment--make sure the batteries are both good,one bad one will kill the other one,causing poor cranking too.The OEM cables are aluminum/copper hybrids,not pure copper,upgrading them by making new ones from heavy welding cable you can buy at the welding store (and you can get the lugs for the cable ends there also) -- will ensure all the power from the batteries will get to the starter--its important you get the motor spinning fast--its real hard to start a 6.2 even with good glow plugs if its cranking too slow(glow plugs wont affect cranking speed though,but it wont want to start good if more than one isnt working)..And another thing--might want to make sure that little angle bracket on the starter to the block is still there,and installed tightly--it doesnt look important,and many people leave them off on gas engines,but not having one on a diesel can allow the starter to twist a peice right out of the blocks mounting bolt pattern(othewise known as the engine block!):yikes: :yikes: :yikes:
     
  6. Maxp3

    Maxp3 Newbie

    Joined:
    Dec 17, 2004
    Posts:
    4
    Likes Received:
    0
    Location:
    Georgia
    Thanks, I will try the welding cable first..God knows I don't want to fool with the glow plugs...I made sure I mounted the angle bracket back in place. I thought that may be something that may happen with a high torque starter.


    Anyone know a good online company to get wheels from? Not into that 20 inch stuff. Just plain ole 15 or 16 inch aluminum will do..
     
  7. 79Beast

    79Beast 1/2 ton status

    Joined:
    Dec 9, 2001
    Posts:
    1,155
    Likes Received:
    0
    Location:
    Georgia
    I'm not sure what you mean by "hard to crank". Does it turn over too slow, or is it just a little hard to start. Remember that diesel engines are compression ignition engines. Meaning the heat created by the piston compressing the air in the cylinder causes the fuel injected into (in this case) precombustion chamer to ignite. If your engine has high miles, it will not have the compression it once did and that will make it harder to start. Also, faulty glow plugs will not help the situation. If it's not a slow cranking problem, I would replace the glowplugs right off. That's assuming the glow plug control box is working properly.
     
  8. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
  9. Maxp3

    Maxp3 Newbie

    Joined:
    Dec 17, 2004
    Posts:
    4
    Likes Received:
    0
    Location:
    Georgia
    By hard to crank I mean not firing up. But the batts wear down real quick in the process. Sometimes it seems as though its starving for fuel. I will try the cables then work my way from there.


    I'm looking for some plain solid alum or with 8 holes...nutttin fancy just tired of looking at the old stock wheels. BTW, Tires are Cooper 35x12.50 15 incher's
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    First it sounds like you have fairly weak batteries, the duals should provide quite a bit of cranking power. Does it fire up any faster when you give it a little throttle? I am not really sharp with the 6.2's but with the cummins when it doesn't want to fire up very easily like it's starved for fuel....it's usually an injection pump on it's way out.

    Weld make a really nice 8 hole design, very pricy though. Eagle makes a decent cast 8 hole design that is fairly popular. Mickey tompson also makes the classic 2 which is also cast, not forged like the alcoa version that is no longer manufactured. :mad:
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    I'd say you prolly have a couple of glow plugs that are dead. Try plugging it in for an hour or more before starting it the next time. Chances are that'll help.

    At this time of year I'd be using about half throttle at start-up, and if it's much below freezing I'd use full throttle.

    Rene
     
  12. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,583
    Likes Received:
    945
    Location:
    Massachussetts
    mine starts great (so far)

    tRustyK5 is right--my 6.2 wont start very well unless I depress the gas pedal about halfway,or closer to floored the colder it gets--when I first got my diesel,he helped me out a lot,my truck was not running at all,and he walked me through the basics and with his help I isolated the problems,a combination of air leaking into the fuel lines through old dry rotted rubber hose,after I got it to run and decided the motor sounded decent,I bought 8 new glow plugs after I tested the old ones and found only 2 were working at all!--I could only get 7 to go in,1 cylinder the glow plug wouldnt come out after I unscrewed it,because the tip is probably swelled up(I guess the oem glow plugs did that a lot)and rather than break it off and have to take the injector or head off,I left the disabled one in it,and called it done--it has started every time even at 0 degrees last winter.I put in AC G60 glow plugs,and learned how to manually bypass the glow plug controller to ensure easier starts--I like the truck a lot--I'm willing to bet a lot of the 6.2 diesels get traded in or junked,when there really isnt that much wrong with them--people freak out when they hear "injection pump" thinking its a huge repair bill,when many times its something simple like the rotten hoses mine had--that and the poor reputation of the ill-fated olds based 350 diesel the 6.2 replaced--.:crazy:
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    Thanks Robert. Glad I could help...

    I think you and I had all the same issues near the same time. If I didn't get a ton of help from the true diesel guru's here I wouldn't have got my own truck going let alone help you out in some way.:bow:

    Rene
     
  14. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,583
    Likes Received:
    945
    Location:
    Massachussetts
    No,Thank YOU tRustyK5!!

    I also owe a lot to you for being the first to answer my questions I had on the diesel--the truck had undergone much major work before I got it--a used engine was installed,the tranny rebuilt,but the meknics at the GMC dealer couldnt even get it started after the motor swap!--they fried the starter(hence the rebuilt delco in it now!)and they practically gave my friend who buys cars and trucks there wholesale(trade ins and back row specials!)the truck as part of a "package deal"in other words,if you want the good cars and trucks,you MUST take the diesel one too--like it was a burden!!--maybe to them it was,but I got a good truck very cheap thanks to him passing the deal he got on to me!--now I have a chance to buy another desireable truck from him,,a 89 K3500,454.TH400,14bolt(SF I think),fisher plow,"new" style body,with IFS:mad: and body not bad at all,he is willing to take my 79 C10 I also got from him 2 years ago in trade + a very reasonable amount of cash--I'm very tempted to go for it--I've not much use for a 2wd 1/2 ton here in winter,and it would sit in the garage taking up space till spring anyway,to avoid salting it up and rusting it--I will miss the emission exemptness of the 79,but not the fact it costs nearly the same to insure and drive,as this newer 4x4 that can earn its keep with the plow--plus this truck just had a recent tranny overhaul and timing chain,water pump,valve job,and extensive brake work,I only need to replace a leaking brake line and some exhaust repairs to make it roadworthy-----only thing is,I will have 400 bucks in my life savings left after this purchase if I go for it---I have been told I should be selling the 79 and NOT buying ANY more trucks(yes mother!) but I think this investment could be worth it--even if I hate this truck,I can sell it for more than a C10 is worth--its a big gamble though--I can recoup some cash by junking the 74 K20 and selling the 400 SB too---how come good deals like this only come around when its nearly impossible to afford them??:confused: :mad:

    Thanks to all the CK5ers who have helped answer some of my questions--hopefully I will get a job right after the holidays and get some cash back into my savings account,and be able to get back on my feet again and get a real membership to CK5--I know some of you are thinking,yea,right,he's broke and he's buying another truck!!--but the truth is,my mother is in poor health,I might lose everything I built on her property any day,might not be able to live here after she passes,so I'd like to have at least one newer EFI equipped vehicle I could tow all my posessions out of here with if nessasary--theC10 isnt well suited for that--I need to upgrade,but am torn as to whether I should take the financial gamble--what would you guys do if you were me??:confused:
     
  15. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    Glad to help

    Pretty tough call when you're in a financially vulnerable position...

    i'd say if you know you can put the truck to work and recoup some of your investment it might be a good deal for you. Many guys here make killer cash plowing snow here, even though we don't often get snow. When we do most retailers and business's are desperate to have their lots cleared ASAP...so anything with a plow or even bucket is working 24/7 until it's all gone.

    I'd prolly sacrifice the 74 and the C20 and get the 89...then make sure it stayed busy making you money. If things don't go as planned I'm sure the 89 would net you a better return if you had to sell it.

    Good luck!

    Rene
     
  16. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,583
    Likes Received:
    945
    Location:
    Massachussetts
    Thats what I was thinking--

    I have been thinking about this all weekend--I want this truck pretty bad,but if anything at all goes wrong with it,I'm screwed!!--I have been trying to get up the courage to say goodbye to the C10 and do the swap--I could probably get more than my friend wants to give me for it if I sell it myself,but he needs cash soon,I dont have time to look for a buyer,and this time of year is tough to sell anything,especially a 2wd truck,people spent all their money on xmas..he said he will have the truck advertised in the want ads for a grand more than I can buy it for,and he will likely get it too-the truck is far from mint,it has some cosmetic flaws,and high mileage,but as you said,it will bring more than my C10 if I had to bail out--since I have the 82 K20 diesel to plow with,its not a must have--but I have been used to having 2 plow trucks--its nice to jump in the other one if one breaks down,and you can continue plowing,or use the other truck to pull the other out if you bury it in a snowbank--I am losing sleep over this deal--one part of me says "buy it you fool,before its gone--"--the other part is saying"why do you need another truck when you have one already that still needs work--get your teeth fixed and new glasses,go back to work and buy something REALLY nice"---decisions,decisions--it wouldnt be so hard to decide if I had plenty of cash,a steady job,or my mothers health was better,and I had a gaurenteed place to live when she passes--but I guess nothing ventured is nothing gained--I fear if I do get this truck and lose the C10,something expensive will go wrong,and I'll have no reliable economical transportation(the 9mpg the 454 will get isnt very encouraging either!)--I have only a few days to decide,and this oppertunity will be gone..
    Thanks for your input Rusty!!
    Anyone else have an opinion on what I should do??---You guys may have more insight than I on this situation--all I can think of is that 454 and having a newer truck-:eek1: :eek1: :shocked: :bow: :screwy: but in a way,I might be doing a foolish thing by risking all my money--But I'm 46,single,and basically have nothing to show for all the hard work I've done--and the truck IS fifteen years old:blush: ..Am I being stupid for wanting this truck now,at this difficult time:confused: --or am I dumber for not owning it already:confused: ...I'd like to hear all your opinions,you guys might make me realize somthing I havent really thought of yet!:crazy:

    Oh yeah--sorry I hijacked this post--I think I should have started a new post!:blush:
     
  17. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    Might be a good idea to start a new post. I doubt anyone is miffed at the hi-jack, but you might get more views and more opinions with your own post. It don't cost nothin...:)

    Rene
     
  18. Maxp3

    Maxp3 Newbie

    Joined:
    Dec 17, 2004
    Posts:
    4
    Likes Received:
    0
    Location:
    Georgia
    aaargh...This thing is getting harder to start

    Ok, folks the diesel has won. I replaced hoses, cables and the glow plugs are new. Still it starts worse than before. With fully charged batts and a can of Starting fluid is the only way my 6.2 will crank now. Thats on a 60 degree day here in the south.

    Anyone know where I can get a wiring diagram online?
     
  19. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,394
    Location:
    E-town baby!
    Could be a bad lift pump.

    Could be a slight leak in one of the fuel lines allowing a bit of air in.

    Could be poor compression too.

    The earlier lift pumps were able to let fuel drain back when they began to fail. You might want to try a new lift pump. They're not that expensive, just a bit tough to get to.

    Rene
     
  20. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,583
    Likes Received:
    945
    Location:
    Massachussetts
    I'd try the fuel pump too!

    I added an aftermarket electric fuel pump to my 82 diesel. It had a new lift pump on it when I bought it,the electric pump was on it too,but not connected--I leave the electric pump on when the engine is running and during starting--you can hear the difference in the way it runs with the electric pump on,and I think it helps it start better too..another plus is you can use it to help "prime" the fuel system when you change the fuel filter,simply turn the pump on and open the bleeder screw,and let it run until fuel comes out steadily,with no air,and its bled!..

    I have been amazed at my 6.2!--I plowed my large "Y" shaped driveway several times during our recent blizzard(33 inches!)and a few more times a few days later when we got 8 more inches,and I even drove it 15 miles to a friends house to plow his yard--I noticed my fuel gauge went from 3/4 of a tank to just under a half!--I bet I had it running over 2-1/2 hours,and the trip to my friends was in 4wd all the way(my transfer case wont shift out of 4wd for some reason!)--my 400 small block in my 74 K20 would have sucked a full tank down like nothing doing the same thing!:blush:

    Reading my posts about "the truck that got away" got me a little bummed--another guy bought that truck from my friend for 2500 bucks,and he's already made enough plowing to nearly pay it off already!:blush: --But I'm glad in a way,I didnt need to be completely broke,and I still have the diesel to plow with!..Maybe another "deal" will come along and I can grab that one!...:crazy:
     

Share This Page