82SC White Fuel Smoke on warm up

JMH82SC · 03-25-2009, 04:43 PM

I’m looking for ideas regarding white smoke on start up. The smoke is NOT OIL it’s like incomplete combustion. The smoke is white and has a sulfuree cap gun fuel smell. Smoke is only a issue once car is started and happens 65% of the time cold and 5% after warm start but only after starting, you drive 50 feet and all is well. No smoke under acceleration or letting off the gas at high RPMs. For back ground it is a 82 SC top end rebuilt new guides, seals, and springs all other top end parts in spec. New rings, piston/cylinders all in spec. Rebuilt CIS has all new rubber and hoses. One clue is sometimes the car will start instantly with the bump of the key and sometimes it needs 15 seconds on the starter. It seems when it starts instantly it hits all six but if it takes 10 seconds one or two hit, starts on 4 or five and in under 5 seconds it is on all six. Oil consumption is on the low side 1800 miles to 1 quart. My first diagnostic test is going to be a CIS pressure test and see what the numbers look like. All ides welcome.

82SC Stock
Stock CIS
Test pipe
Cold Bosch Plugs 5 heat range

vreference · 03-25-2009, 04:50 PM

Even among water cooled engines, white smoke is almost exclusively water vapor. On a watercooled car, excessive "white smoke" can indicate a blown head-gasket. Otherwise, vapor seen on a cold start that goes away shortly in warmer months or remains in the winter is normal. Water is a byproduct of combustion. There is an explanation involving brake fluid but it's so unlikely without other symptoms it's not worth going into.

JMH82SC · 03-25-2009, 04:58 PM

I agree on water vapor but this is smoke. It has a fuel smell but not a raw gas smell.

ossiblue · 05:03 PM

Just ideas here, along with some questions to get things started (no pun intended.)

Does it really take fifteen seconds on those hard to start times? Fifteen seconds is quite a long time to crank and not get a start. Could it just seem like fifteen seconds? If it truly is that long, here is a possiblity: the cold start valve may not be working correctly so you are trying a cold start without the shot of fuel to immediately fire the engine. It could also explain the times when the car fires with one bump of the key--in those cases it is working, but may be leaking or getting "stuck" thus allowing extra fuel into the intake resulting in the white smoke you see. If you try a cold start for fifteen seconds, remember you are pumping raw fuel into all cylinders with no ignition--result too much fuel and white smoke, not to mention possible hydro lock.

I have no real clue is this is the case, but it is a place to begin and it could explain your symptoms. Regardless, let us know any new piece of information. Someone will nail this one.

edit: Just read vreference post, and that makes sense too. The fact you smell gas does not preclude that the smoke is not condensation. It could easily be water vapor mixed with the ignited fuel.

bcoats · bcoats's Garage

wonder if could be ignition system related and causing an over rich condition? I had similar issues on my 930 a while back

JMH82SC · 03-25-2009, 05:37 PM

Revisiting starting sometimes it is instant you do not hear the starter and other times it takes more like 6 seconds. I’m 1000% sure what I see is fuel smoke and not condensation, in the mornings sure the condensation covers up the smoke but just like 3PM today it was smoke only. Another thing comes to mind as the PO has the fuel pump to run W/ the key not the CIS micro switch, just a thought.
bcoats what type of ignition issue did you have?

ossiblue · 06:04 PM

Reread your first post and have another question. When the car starts on the first bump of the key, is there smoke? If so, then ignition doesn't seem to be connected to the problem, unless bcoats can shed some light on the problem he had that may explain it.

Glad to hear that it really isn't fifteen seconds during a hard start. Since you say a hard start sounds like a firing of one or two cylinders, then four or five, and finally six, you may have a leaky fuel injector(s) or the plate in the plenum is not fully seated. This, coupled with the constantly running fuel pump could be flooding the car. The constantly running pump is a safety hazard should the car stall in a crash (I suggest taking care of that asap), but simply running with the key is not the cause of excess smoke unless there is leakage into the cylinders.

edit: You may have two unrelated "problems." One is the start problem which could be related to WUR, or other CIS components. The other is the smoke which may not be related to the starting issue and may not even be a true "problem". If it were me, I'd attack the start problem first and continue monitoring the smoke quantity and times you notice it.

JMH82SC · 03-25-2009, 06:10 PM

As for smoke on instant start with bump of the key yes 50/50 on smoke. Could the WUR create a pressure issue that could foul the cold plugs and cause smoke till car is put under any load? As for testing injectors I could pull them and see if they leak with the key in the on.

ossiblue · 03-25-2009, 06:28 PM

Quote:

Originally Posted by JMH82SC

As for smoke on instant start with bump of the key yes 50/50 on smoke. Could the WUR create a pressure issue that could foul the cold plugs and cause smoke till car is put under any load? As for testing injectors I could pull them and see if they leak with the key in the on.

Given your description, it doesn't sound like the WUR causing a fouling issue because once it starts and all cylinders catch, you have a smoothe idle, correct? A faulty WUR that over-richens a mixture would produce a hunting idle situation which you don't have. That doesn't mean the WUR is within specs because you still have a start problem independent of the smoke.

When you test the injectors by pulling them, you will know immediately if one or more leaks. Since your pump starts with the key, be very careful, prepare the test material, and it probably would be good to have an assistant do the key turning so you can monitor the injectors. The injectors should not show any fuel leakage or spray until you lift the plate in the plenum--then, be prepared because all six will spray at once. Have a fire extinguisher handy too

JMH82SC · 05:09 AM

I just pulled the injectors on 1,2,3 because of access. As soon as I moved the key to the on position all 3 injectors started to lightly spray not leak. Turned everything off and went back to test it again and 10 minutes later no spray or leaks. I moved the sensor plate and injectors spray like normal and when plate is back to its resting position no spray or leaks. I think this is key to the problem.

ossiblue · 03-26-2009, 06:19 AM

Could very well be. There should be nothing from the injectors until you lift the plate. Check to see if the plate arm is getting hung up.

mca · 03-26-2009, 06:30 AM

Quote:

Originally Posted by JMH82SC

I just pulled the injectors on 1,2,3 because of access. As soon as I moved the key to the on position all 3 injectors started to lightly spray not leak. Turned everything off and went back to test it again and 10 minutes later no spray or leaks. I moved the sensor plate and injectors spray like normal and when plate is back to its resting position no spray or leaks. I think this is key to the problem.

I posted this same question about a week ago. I only have 4500 on a full rebuild (also brand new injectors) and I haven't seen any smoke - not driving, not at start up.

Then, one morning I got a nice puff of white smoke. It smelled like sulfur as you described. The smoke quickly cleared - certainly not oil.

Car runs great - idle is perfect, not using oil, temps nice and cool, timing spot on, mixture spot on.

When I cranked it up this weekend 5 or 6 different times there was zero smoke. I don't think you have anything to worry about. Could be due to increased humidity and change in temps (vapor as described above). Maybe it is a combo of vapor and fuel.

T77911S · 03-26-2009, 09:32 AM

Quote:

Originally Posted by JMH82SC

I just pulled the injectors on 1,2,3 because of access. As soon as I moved the key to the on position all 3 injectors started to lightly spray not leak. Turned everything off and went back to test it again and 10 minutes later no spray or leaks. I moved the sensor plate and injectors spray like normal and when plate is back to its resting position no spray or leaks. I think this is key to the problem.

i understand you to say that they sprayed the first time? if that is the case, you either have leaky injectors or the plunger is not completely dropping down to its resting position. IE it is sticking and allowing fuel to spray.
what you might do is turn the key on, lift up on the plate very easy, you should feal resistance right away, if there is "play" before you feel the resistance, the plunger is sticking.
or you could go ahead and spend the money and get the injectors cleaned and tested.
i am not sure if you can get a mirror and light in there to see if the plunger is dropping all the way down, might be worth a try.

JMH82SC · 03-26-2009, 09:50 AM

I suspected the plunger but after testing could not duplicate the issue. I’m now sure the smoke was fuel related due to a few factors. I have the common key issue where it needs to be giggled a few times to get to the start position all the while the fuel pump was on and I can only image the amount of fuel in one way or another switching key on and off. I pulled out my wiring diagrams and found that the fuel pump ran full time because the sensor plate wire was cut at the relay. Once everything was wired correctly it would start and then stall, so after some testing I remembered I have a non-working factory alarm and pulled out all the blower stuff. Once I had access to the alarm I made a jumper to bypass the alarm and like magic the sensor plate switch started working like new. Now the fuel system is working as the factory intended. The good news is NO SMOKE, this thing fires every time with a bump of the key and hits all six out of the box.

stlrj · 09:32 AM

Quote:

Originally Posted by JMH82SC

I’m looking for ideas regarding white smoke on start up. The smoke is NOT OIL it’s like incomplete combustion. The smoke is white and has a sulfuree cap gun fuel smell.

82SC Stock
Stock CIS
Test pipe
Cold Bosch Plugs 5 heat range

Sulfur or rotten egg smell is usually a sign of rich running conditions. Normally the sulfur in gasoline is converted to sulfur trioxide unless your mixture is too rich, then it converts to hydrogen sulfide, the sulfuree smell you describe.

http://www.sjmautotechnik.com/trouble_shooting/exhaust.html

Rotten egg smell: Sulfur is being emitted from the exhaust due to a faulty catalytic converter. This is usually caused from running rich for too long. If this condition is allowed to continue, eventually the fume build-up will cause the engine to shut down. Catalytic converters usually last for 50,000 miles; if this condition occurs prior to this mileage interval, check the fuel system.

http://www.cabby-info.com/exhaust_system.htm

Cheers,

Joe