| 6/10/2014 9:55:56 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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I have a 94 suburban that has just started starting hard and at idel When you press on the gas it will spit and sputter and blow black smoke. I bought this vehicle 3000 miles ago the previous owner put a blueprint in it it now has 12000 miles on it it has a Chevy 355 with a mild cam. Lifters Edelbrock TBI intake stock throtle body and headers
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| 6/10/2014 4:34:31 PM |
Chevy 355 black smoke |
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luckylouie42
Cedar Grove, WV
74, joined Mar. 2008
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sounds like fuel is too rich,
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| 6/11/2014 12:50:34 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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That's what I thought. I changed plugs and wires checked the air filter. Fuel return line fuel pressure. Played with the air screw and distributor position. It gets worse when I run it with no air filter. When I changed the plugs they seemed to be partially melted on the electrodes too
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| 6/11/2014 5:27:47 PM |
Chevy 355 black smoke |
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naughtyguy13
Ozone Park, NY
35, joined Jan. 2012
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That's what I thought. I changed plugs and wires checked the air filter. Fuel return line fuel pressure. Played with the air screw and distributor position. It gets worse when I run it with no air filter. When I changed the plugs they seemed to be partially melted on the electrodes too
Melted on the electrodes?? what did you put copper plugs? try double tip platinum it can withstand greater heat and avoid carbon build up..at least then you can rule out crappy plugs...possibility valve seal might be leaking oil in engine and you have a clog catalytic converter or its running rich and you still have a clog catalytic converter.
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| 6/11/2014 6:34:21 PM |
Chevy 355 black smoke |
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pappasmurf54
Stanford, KY
57, joined May. 2014
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Hey guy's , the black smoke is too much fuel , your flooding .how much black smoke an doe's it smooth out ?
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| 6/12/2014 4:48:39 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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I was running ngk v power spark plugs. They weren't melted bad but they were melted. I have no cats just headers in front of flomaster exhaust. Could it be the map sensor? I've played with the air screw and took the TB apart and cleaned the parts everything seemed fine there
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| 6/12/2014 4:52:46 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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Hey guy's , the black smoke is too much fuel , your flooding .how much black smoke an doe's it smooth out ?
It's just in low rpms during acceleration. Then smoothes out and seems to run fine
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| 6/12/2014 10:23:15 PM |
Chevy 355 black smoke |
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naughtyguy13
Ozone Park, NY
35, joined Jan. 2012
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Too many possibility....I hate guess work without a scanner...but if u got rough idle it could also be that map sensor u talked about or injectors..good luck
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| 6/12/2014 10:30:53 PM |
Chevy 355 black smoke |
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ksgreasemonkey
Junction City, KS
35, joined Aug. 2013
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The old tbi chevys had a module on the side of the distributor that was know to go bad. Which would cause no starts. Misfire issues and even rich running. Came across that years ago on a 93 gmc truck. Changed the 30 dollar part and it ran better.
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| 6/13/2014 4:55:02 AM |
Chevy 355 black smoke |
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marriedncheatin
Twin Falls, ID
50, joined Jul. 2012
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Op you might get some throttle body cleaner to spray and clean the inside of it..also with the rough idle which I will preface.. I'm not a Chevy guy but I know a lot of the Chevy manifolds do have problems and they do leak and can cause rough idle until they warm up...even some of the newer Chevy 350 with no water jackets in the intake manifold will have the same issue..after they warming up the motor will smooth out and run better..I think it is a common problem with Chevys
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| 6/14/2014 9:59:41 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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The old tbi chevys had a module on the side of the distributor that was know to go bad. Which would cause no starts. Misfire issues and even rich running. Came across that years ago on a 93 gmc truck. Changed the 30 dollar part and it ran better.
This has seemed to fix my problem. Also had allot of corrosion in the cap and on the rotor so I replaced all three. Runs better than when I bought it now thanks for the help guys
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| 6/14/2014 11:38:42 AM |
Chevy 355 black smoke |
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karrpilot
Oswego, IL
53, joined Jul. 2009
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I have also run into this distributor driven gear getting chewed up over time. Not worth it to replace an engine, then toss in a 20 year old part back in.
Just don't get cheap and use Chinese parts from Auto Drone.
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| 6/16/2014 2:27:59 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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I have also run into this distributor driven gear getting chewed up over time. Not worth it to replace an engine, then toss in a 20 year old part back in.
Just don't get cheap and use Chinese parts from Auto Drone.
I'm contemplating putting heads intake cam and carb in then putting a Mallory distributor in. For being a new motor it' really lacks in power having to downshift twice going up a hill just to keep speed.
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| 6/16/2014 10:17:21 AM |
Chevy 355 black smoke |
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ksgreasemonkey
Junction City, KS
35, joined Aug. 2013
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If its losing speed under load. It probably isnt the motor. Drivetrain slip. Gear issues. Parasitic loss has to be taken into account. A basic 355 will only make in the range of 240 to 275 hp. The one i did for my 41 chevy we ended up over 300 hp but bumped compression to 12:1 by the time it was all said and done. To run right we had timing at 29 degrees
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| 6/16/2014 8:57:26 PM |
Chevy 355 black smoke |
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pappasmurf54
Stanford, KY
57, joined May. 2014
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Check your timing an fuel pressure regulator , doe's it have a vaccum line to it ?
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| 6/17/2014 11:03:20 PM |
Chevy 355 black smoke |
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ronleeseberg
Mauston, WI
50, joined Jan. 2012
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If you are running well with the repairs you have done so far, you may want to try running a better grade fuel in the tank too. Many people experience power issues if they have lower grade fuel in a mid to high performance engine.
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| 6/19/2014 9:44:10 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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Only run 91 octane in it the tranny is remaned right befor I bought it don't know the ratios. And the rear diff is a new Detroit e locker with 5k miles on it right now and don't know the ratios there either.
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| 6/19/2014 10:27:20 AM |
Chevy 355 black smoke |
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luckylouie42
Cedar Grove, WV
74, joined Mar. 2008
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usually if the gas octane is too low, the engine will knock, and the valves will rattle like hell when you accelerate.
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| 6/24/2014 10:43:21 AM |
Chevy 355 black smoke |
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hogie40
Williston, ND
26, joined Nov. 2012
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No knocks or rattling valves. Has tbi heads and intake.as far as I'm concerned both are junk and can be sold as scrap. Although as of right now for a suburban it is getting good gas mileage 17-19 mpg on the highway but is gutless and can barly pull a 17 foot Fiberglas boat
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| 6/24/2014 5:34:18 PM |
Chevy 355 black smoke |
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ksgreasemonkey
Junction City, KS
35, joined Aug. 2013
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But with tbi you have options. Spacers, planed intakes. Could pprobably swap the pair of injectors to something larger.
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| 7/7/2014 3:08:31 PM |
Chevy 355 black smoke |
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mrteddybear68
West Islip, NY
49, joined Sep. 2011
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Stupid question. Did you check the output of the coil?
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| 7/19/2014 11:26:38 PM |
Chevy 355 black smoke |
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vanir
Victoria
Australia
47, joined Mar. 2008
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yup weak spark gives the same symptoms as rich running, but instead of flat spotting at open throttle midrange it's gutless at low range and part throttle and likes to splutter.
Sounds like you sorted part of it with distributor module etc. but you might want to refresh the whole spark from coil onwards and check the advance curve.
Was the spark curve adjusted to suit the aftermarket cam?
Burnt plugs with rich rather than lean running tends to be about the advance side of things through the range, wetter mixture is cooler and hurts power for that reason, it's a net gain when you bump compression and compensate for increased exhaust timing overlap. But then you need spark remapped.
What are the cam specs? Are the heads stock?
In any case, straight up the immediate problem sounded like weak spark. But you've a bit of fine tuning to do to really get it running right, since the cam is aftermarket. Increased valve timing overlap for one drops dynamic compression so you must bump static if you want a gain as opposed to no improvement with a better exhaust note and higher maintenance bill.
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| 7/21/2014 1:44:31 PM |
Chevy 355 black smoke |
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hellofromastor
Astoria, OR
41, joined Apr. 2014
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Does the truck run a ballast resistor? ( the white porcelain bar on the fire wall) if your melting or even corroding spark contacts you may need a new or replace the ballast resister. I have done motor swaps in the past and needed to take out and add a ballast, depending on the make model, year.. Ect... It will run fine for a short time.. Then over load the spark contacts... I have had it happen as fast as 1 mile or even 50 miles.... Just my two cents
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