Weak start due to black smoke

[Rhaegon]

Good morning, I have a 1982' 6.2 that cold starts fine 90% of the time, regardless of outdoor temp. But some days black smoke starts puffing out of the tailpipes BEFORE it starts(usually white or blue). When this happens; I might as well give up because it will never start after that, just gets weaker and weaker. I found a bad ground and put NO.1 grounding cables on it and they do not even get warm to the touch when this happens so i guess i got one thing out of the way.... Found a weak battery also, now it is fully charged now they both read 12.82v. (a jump from another running vehicle does not help) Also on the days it WILL start, it WILL start with ONE battery! So it seems to have nothing to do with amperage ... Any reply will be appreciated, Thanks.

[DmaxMaverick]

The black smoke is curious. This means one of 2 things. Either your air intake is blocked, but it has plenty of heat and fuel. However, it should start, even with excessive black smoke. Or, your injection pump is trying to leave you. The next time this happens, at the first indication of it, do not try to make it start. Remove the air cleaner cover before trying again. If it starts as normal, check your entire air intake plumbing, including the air filter element. Otherwise, it's probably time for a fresh IP.

[trbankii]

But some days black smoke starts puffing out of the tailpipes BEFORE it starts(usually white or blue).

Wait… Is it black smoke? Or white? Or blue?

[Rhaegon]

Wait… Is it black smoke? Or white? Or blue?

Sorry Mate what i meant to say was, if it smokes when cold...which it does ... it is a white or blue smoke never black...this post is about Black only and not starting when it is black...because it always smokes like a train but always...well 90% of the time starts :)

[Rhaegon]

If this helps when I posted it was 38F and would not start i added a Stanley Battery Maintainer 1.5V for TWO hours and it started right up ...it is now 45F...Thanks for reply! I will try this dmaxmaverick :( i am not sure how to link your name Have a great day guys ttyl

[Rhaegon]

The black smoke is curious. This means one of 2 things. Either your air intake is blocked, but it has plenty of heat and fuel. However, it should start, even with excessive black smoke. Or, your injection pump is trying to leave you. The next time this happens, at the first indication of it, do not try to make it start. Remove the air cleaner cover before trying again. If it starts as normal, check your entire air intake plumbing, including the air filter element. Otherwise, it's probably time for a fresh IP.

Is this the same as a fuel pump? I have 2 tanks of course and the water in fuel light next to glow plug light on dash is always on...would it help to disconnect the other tank ?

[DmaxMaverick]

Is this the same as a fuel pump? I have 2 tanks of course and the water in fuel light next to glow plug light on dash is always on...would it help to disconnect the other tank ?

No. The "IP" is the injection pump. It's the pump in the engine valley with the fuel injector lines connected. The fuel LIFT pump is located on the passenger/right side of the engine. It's mechanical, and looks/works exactly like older GM gasser V8 fuel pumps.

WIF = Water In Fuel (lamp). If it is on, you have water in your fuel, your filter is plugged, or the circuit is not correct (I don't recall if it's NO or NC, but can check later).

Disconnecting the other tank won't likely do anything to help your diagnosis, unless there's something wrong with it (like empty or has leaky lines). Issues with the switching valve wouldn't be uncommon, though.

BLACK smoke at cold start does not indicate a lack of fuel, or air in the fuel. Quite the opposite, actually. If anything, it may (as you've seen) smoke blue/white, due to too little heat, perhaps from poor glow plug performance/failure. The only cause I've seen for black smoke at cold start, is a failed injection pump.

[Rhaegon]

The black smoke is curious. This means one of 2 things. Either your air intake is blocked, but it has plenty of heat and fuel. However, it should start, even with excessive black smoke. Or, your injection pump is trying to leave you. The next time this happens, at the first indication of it, do not try to make it start. Remove the air cleaner cover before trying again. If it starts as normal, check your entire air intake plumbing, including the air filter element. Otherwise, it's probably time for a fresh IP.


I tried removing the air cleaner cover and it started this morning... BUT i had to hold the throttle to the floor and it smoked blue worse than it ever has and it would not start up again, so I am thinking now the reason it started the first time is because i had the trickle charger on it for 12 hrs. Makes no sense to me though because the charger only gets them to 13.10 when 12.80 is what they are normally...it's almost like the starter needs that extra juice, it can't be that when it will turn over (not fast enough to fire up ) with one battery though but add the other battery and still doesn't turn over any faster. Maybe one of the batteries is bad, I'll have them both checked.
I am probably using the wrong term when i say start<<< what i mean to say is >> the starter is not turning the engine fast enough << I have been to interstate battery and other places trying to find someone that can check how much amperage my starter is pulling because it seems it requires more than the batteries have. How would I go about testing the load or pull of the starter to see if it is bad or binding up or something ? Thanks

[trbankii]

What shape are the battery cables in? Search the forums a bit. Corroded battery cables will lead to all sorts of starting issues.

[Rhaegon]

What shape are the battery cables in? Search the forums a bit. Corroded battery cables will lead to all sorts of starting issues.

I have replaced them with military grade terminals with NO.1 wire. One grounded to block the other to firewall. I was told I need one to firewall but I would think both to block would be better ground? On that note I disconnected the solenoid and the truck starts the same. I mean when it does (it still is not).
I thought it controlled the glow plugs but they still come on with it disconnected... What does the solenoid do? why was there a positive wire even going to it...someone must have rewired something ...
http://i1380.photobucket.com/albums/ah179/LestatCraven/c205_zpsyonsqm4u.jpg

[DmaxMaverick]

One ground should go to the engine block, the other to the FRAME. NOT the firewall. It should have ground straps from the engine and frame to the firewall/body. Running a ground to the firewall will cause all kinds of havoc with the electrical and electronics! Not to mention you will not have full voltage to the starter. If rewiring, I recommend that BOTH grounds go to the engine block, with ground straps to the firewall and frame. This will allow for maximum current to the starting circuit (which includes GP's).

Excessive white/blue smoke indicates the glow plug system needs attention. If it's cranking too slow (less than 100 RPM's), the first suspect is the battery cable health or their routing. #1 Mil-Spec is better than OEM, as long as the terminals are well connected. Poorly or incorrectly grounded and you'll have issues.

The batteries should be considered a "pair". If one is bad, the other will suffer, and they should be replaced as a pair. If you "leap frog" replace the batteries, you will not get full life out of either. A bad battery will kill the other, long before you know one is going away. You are much better off with one good battery, rather than one good and one bad. They are not isolated, and are always connected parallel. Get your batteries and cables straightened out before suspecting the starter.

[Dvldog8793]

Howdy
Both batteries should be grounded to the block with good(new) straps going to the frame and firewall. Make sure that the places on the frame/firewall are clean bare metal. I use a copper based never seize to coat all connecting points. Make sure the starter connection is TIGHT.

Batteries should be replaced as a set. Even if one is load tested good, replace them as a set, try to buy your batteries from the same source and match the dates. Make sure your charging wire is in good condition. One bad cell will take down both batteries.

I assume the solenoid you are referring to is on the driverside fender wall? That should be for glow plugs. I would check the glow plugs. They should read a short to ground from the center connector with an OHM meter. These should also be replaced as a set.

You can easily test what the starter is PULLING by using a high amperage clamp on meter. It just clamps on over your positive cable and most of them can be set to hold the peak amperage draw.

With everything in good order, if it still does not seem to turn over fast enough then pull the starter and have it bench tested or rebuilt at a good shop. There are some GREAT posts on this board about R&R starters.

Sometime the lift pump on these trucks will allow the fuel system to bleed back, meaning it will have to crank a little bit to get fuel up to the pump before it lights. Make sure you have a good fuel filter and no water in the fuel light. Also if the engine has some miles on it compression could be an issue with starting.

Not sure what to tell you about the black smoke issue. Never seen that before. as Dmax said sounds like an IP issue.

Hope this helps, Good luck!

[Rhaegon]

No grounding straps anywhere. I shall buy new ones, will any grounding strap do? This leads me to a big question. Is there a site dedicated to 82 C20s ?

http://i1380.photobucket.com/albums/ah179/LestatCraven/1_zps9ejblbm5.png

Glow plugs are Definitely a problem, someone wired them to firewall because they have to be jumped with a wire if the engine is warm. When it has been running for about 40 min. they don't automatically come on and the truck will NOT start unless they are jumped to the solenoid (see pic). Of course when it is cold they come on about 4 times when you turn the key to start.
How do I check the RPM's?
I hope parallel means the drivers side battery + goes across top of radiator to passengers side battery + and starter cable is spliced with passengers side battery +. Passengers side is grounded to firewall and Drivers side is grounded to Block That is how it was setup when I bought it...

I had a friend mention compression and bleed back...can you link me a trouble shooting guide for them? :confused: He won't answer his phone but I think he said if i see puffs coming out of tailpipe the compression is bad but if i don't see puffs then not getting fuel?

Thanks

[Dvldog8793]

Howdy
the grounding strap can be a standard one found at most auto parts stores. Just make sure it is long enough. It should be braided bare wire with bonded ends.
Yes, batteries should be: pos to pos to Starter. neg to block on both. block grounded with straps to the frame and firewall.
From the sounds of it your glow system might have multiple problems. I would start by checking the glow plugs. Sounds like the relay is working. The sensor that runs it is mounted in the valley of block and they were prone to having trouble. There is good article here that describes an upgrade to a newer style of glow sensor.
Also looks like much of your wiring has been hacked into. If it were mine I would start by trying to "unwire" things and get it back to at least close to original wiring.
For a C20 sight, I am not sure. I have found that The Diesel Page is about the best site out there for ANYTHING with GM diesels and chassis info.

[trbankii]

I hope parallel means the drivers side battery + goes across top of radiator to passengers side battery + and starter cable is spliced with passengers side battery +. Passengers side is grounded to firewall and Drivers side is grounded to Block That is how it was setup when I bought it...

Yep. That is correct wiring. Did you also upgrade that cable that runs over the radiator? That is usually the problematic one.

[Rhaegon]

Yep. That is correct wiring. Did you also upgrade that cable that runs over the radiator? That is usually the problematic one.

Yes, TYVM! but i bought pre-made wire before i knew Interstate battery could make it for me with #1 @ better price so I am upgrading TY for HUD!