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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1993f250 on September 04, 2017, 10:50:11 PM
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Just put the first real miles in on a new engine, 350 mild port 230/230 .050 cam.
It did fine the short trips testing and what not but today it started smoking real bad if you let off the gas after giving it more than half throttle, let it idle too long, or dont touch the throttle down hill. At all other times it does not smoke.
Car following me says white smoke, looked a tad blue in the mirror. It seems to have started missing at the same time, could this be a lot of excess fuel not getting burnt?
Its 90 and i drove 50 miles with no temp issues
Any help is appreciated
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You could be burning coolant.
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You could be burning coolant.
Thats what i thought at first, drove it at least 50 miles though and no coolant loss or temp issues. It wreaks of gas though and i have the edekbrock running its stock set up for now
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Checked it over. Does not appear to be losing coolant but my oil level did rise, it is NOT murky like it has water in it. I noticed my valve cover breather was also puffing a little smoke at idle, same white/blue color but it is not oily at all. It smells like gas.
Any ideas?
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Does the engine have a mechanical fuel pump? Pull the dipstick and let a drop of oil fall onto a completely clean and dry fingertip. Does the oil quickly track out along your finger ridges or does it hold together in a tight circle? Automatic or standard transmission?
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Does the engine have a mechanical fuel pump? Pull the dipstick and let a drop of oil fall onto a completely clean and dry fingertip. Does the oil quickly track out along your finger ridges or does it hold together in a tight circle? Automatic or standard transmission?
Yes mechanical pump. I pulled the fuel line when it started doing this to see if it was pressure but it did it all the way until the bowl ran out.
Ill try the trick with the oil here in a bit and get back.
Th350 also new
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Does the engine have a mechanical fuel pump? Pull the dipstick and let a drop of oil fall onto a completely clean and dry fingertip. Does the oil quickly track out along your finger ridges or does it hold together in a tight circle? Automatic or standard transmission?
Oil doesnt quickly track out but it does after couple seconds. I also pulled a couple plugs, 1 is covered in fuel for sure. Still wet and wreaks. 3 looks like it might be lean but ok.
(https://uploads.tapatalk-cdn.com/20170905/023ed7c4b0fbef08522e3ab8c7f60683.jpg)
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I checked it with a timing light real quick and the light stopped after 2k or so on cylinder 1 so im thinking loss of spark, it was fine when i set the total timing.
I still need to check the rest of the plugs.
Im thinking Loss of spark so that cylinder is filling up with fuel getting in the oil and exhaust?
Any other ideas?
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Modulator valve is leaking
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Does the engine have a mechanical fuel pump? Pull the dipstick and let a drop of oil fall onto a completely clean and dry fingertip. Does the oil quickly track out along your finger ridges or does it hold together in a tight circle? Automatic or standard transmission?
Oil doesnt quickly track out but it does after couple seconds. I also pulled a couple plugs, 1 is covered in fuel for sure. Still wet and wreaks. 3 looks like it might be lean but ok.
The oil drop should retain a circular shape on your fingertip. Check the oil for fuel dilution, especially if it seems to be making oil. Severe fuel dilution of the engine oil will result in crankcase fluids pushing past the piston rings as the fuel washes the oil film off of the cylinder walls. It will also allow combustion gases to blow past the rings and pressurize the crankcase. Pistons and rings starving for lubrication, not-to-mention the bearings, is a bad thing.
ATF, if drawn into the engine and burned, will cause copious white exhaust smoke. Since the white smoke consistently occurred at minimum manifold pressure, AFT in the combustion chambers was a good bet. However, the blueish tint of the exhaust smoke and crankcase vapor again suggest fuel dilution of the oil that is preventing an effective ring seal. To avoid the potential for costly engine damage I recommend that you follow up on this possibility before running the engine again.
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Modulator valve is leaking
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^^^^This^^^^^
Pull the hose off the modulator and drive it. If the smoke continues, then you know it's not the modulator. If the smoke stops then you know it probably is.
Now the trans may not shift into 2nd or possibly third OR take along time to do so with the modulator unplugged. So be forewarned.
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Does the engine have a mechanical fuel pump? Pull the dipstick and let a drop of oil fall onto a completely clean and dry fingertip. Does the oil quickly track out along your finger ridges or does it hold together in a tight circle? Automatic or standard transmission?
Oil doesnt quickly track out but it does after couple seconds. I also pulled a couple plugs, 1 is covered in fuel for sure. Still wet and wreaks. 3 looks like it might be lean but ok.
The oil drop should retain a circular shape on your fingertip. Check the oil for fuel dilution, especially if it seems to be making oil. Severe fuel dilution of the engine oil will result in crankcase fluids pushing past the piston rings as the fuel washes the oil film off of the cylinder walls. It will also allow combustion gases to blow past the rings and pressurize the crankcase. Pistons and rings starving for lubrication, not-to-mention the bearings, is a bad thing.
ATF, if drawn into the engine and burned, will cause copious white exhaust smoke. Since the white smoke consistently occurred at minimum manifold pressure, AFT in the combustion chambers was a good bet. However, the blueish tint of the exhaust smoke and crankcase vapor again suggest fuel dilution of the oil that is preventing an effective ring seal. To avoid the potential for costly engine damage I recommend that you follow up on this possibility before running the engine again.
Gonna do some more troubleshooting on the ignition tomorrow. Once i get that figured out ill check fuel pressure and make sure to change the oil before i drive it again
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Not to belabor the point, but to clarify, it seems you maybe experiencing more than one issue - the white smoke from one cause (possibly ATF), the bluish smoke from another. If you do have fuel in the oil, the fuel pump diaphragm is probably perforated and a pressure test may not provide a reliable diagnosis. Keep us apprised.
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If you are running a mechanical fuel pump there should be a weep hole at the top of it. See if it has fuel coming out of the weep hole, if it is the diaphragm is bad and needs replacement.
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Not to belabor the point, but to clarify, it seems you maybe experiencing more than one issue - the white smoke from one cause (possibly ATF), the bluish smoke from another. If you do have fuel in the oil, the fuel pump diaphragm is probably perforated and a pressure test may not provide a reliable diagnosis. Keep us apprised.
Would the diaphram going bad cause the pressure to rise slowly at idle then jump a few psi quickly? It seemed odd when i put the pressure guage on it
I do understand theres another issue going on though, gonna change oil and track down the source of the spark loss and then go to pump. Unless the above makes it obvious pump failure and ill replace it before i start it again
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If you are running a mechanical fuel pump there should be a weep hole at the top of it. See if it has fuel coming out of the weep hole, if it is the diaphragm is bad and needs replacement.
I saw no signs of that during the drive and i did look at it and the lines for leaks but i will check again next time i start it!
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If you are running a mechanical fuel pump there should be a weep hole at the top of it. See if it has fuel coming out of the weep hole, if it is the diaphragm is bad and needs replacement.
I saw no signs of that during the drive and i did look at it and the lines for leaks but i will check again next time i start it!
you wont see the leak when its hot cause it evaporates. it needs to be on initial start up
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If you are running a mechanical fuel pump there should be a weep hole at the top of it. See if it has fuel coming out of the weep hole, if it is the diaphragm is bad and needs replacement.
I saw no signs of that during the drive and i did look at it and the lines for leaks but i will check again next time i start it!
you wont see the leak when its hot cause it evaporates. it needs to be on initial start up
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Good to know!! I got oil, a pump in case, a new vaccuum canister, and plugs. Ill be messing with it tomorrow ill let you guys know what happens. Thanks again!!
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So i pulled all the plugs tonight and it looks like i got a bad box. 4 of them were fine and 4 of them looked like they hadnt been firing and soaked.
Replacing those and putting a regulator on the fuel line tomorrow and we will see what happens
Oh and the oil def had gas in it. About 1/4 of a quart
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Well one fuel pump, a vaccuum modulator, pcv, oil change, and set of plugs later its running correctly. Still working on the tune, bogs when you mash on it (doesnt even really wanna run out my converter stall). Then its good when it picks up, plugs look great now
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