blowing thick white smoke and misfiring
09-24-2010, 09:40 AM
#1
2nd Gear Member
Thread Starter
Join Date: Dec 2007
Location:
Posts: 286
blowing thick white smoke and misfiring
hey i have a 03 gt 4.6 that has recently started acting up. i do have full exhaust with no cats and bbk t/b plenum ect. it also has a sniper tune. im not taking any of this into thought as part of the problem because i have had these parts for a year and no problems.
it started to develop a miss. barely drive the car so didnt think much of it because it only did it at start up and would seeem to go away. after a while of this it started to smoke a little out of the exhaust. looks to be white with no blue in it. pulled plugs and looked to have coolant on them. replaced plugs and did intake gasket....still no fix. still misfiring and smoking heavy white smoke. so i order a new intake manifold(no i did not get a dorman). i did see a crack on the inside of one of the runners so figured that may be the problem. replaced it and still same problem.
what else could this be? sticking injector? i dont think head gasket as there is no oil in coolant or coolant in oil. also it really only smokes at idle, once i get in the throttle it clears up but if i sit at a light it will start to smoke. it doesnt ALWAYS do it either but seems to be happening more often now. any thoughts would be appreciated. i need to fix this
it started to develop a miss. barely drive the car so didnt think much of it because it only did it at start up and would seeem to go away. after a while of this it started to smoke a little out of the exhaust. looks to be white with no blue in it. pulled plugs and looked to have coolant on them. replaced plugs and did intake gasket....still no fix. still misfiring and smoking heavy white smoke. so i order a new intake manifold(no i did not get a dorman). i did see a crack on the inside of one of the runners so figured that may be the problem. replaced it and still same problem.
what else could this be? sticking injector? i dont think head gasket as there is no oil in coolant or coolant in oil. also it really only smokes at idle, once i get in the throttle it clears up but if i sit at a light it will start to smoke. it doesnt ALWAYS do it either but seems to be happening more often now. any thoughts would be appreciated. i need to fix this
09-24-2010, 10:22 AM
#3
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
You need to do compression and leak-down tests, the results of those will tell you a lot about what's going on the the combustion chamber.
I would be inclined to believe you have a failing head gasket--it is possible for coolant to get into the combustion chamber without contaminating the oil...
I would be inclined to believe you have a failing head gasket--it is possible for coolant to get into the combustion chamber without contaminating the oil...
09-24-2010, 12:12 PM
#4
2nd Gear Member
Thread Starter
Join Date: Dec 2007
Location:
Posts: 286
well i had coolant on 1 plug on drivers side and 2 plugs on passenger side. i dont think that both head gaskets would go bad at same time. car never over heated and only has 45k on it. i really dont think head gaskets
09-24-2010, 12:32 PM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Also, it is entirely possible for both head gaskets to fail at more less the same time, as they are both exactly the same age and have seen exactly the same duty-- speaking of which, long periods of sitting idle are never good for any piece of machinery, internal combustion engines in particular...
09-24-2010, 01:42 PM
#7
2nd Gear Member
Thread Starter
Join Date: Dec 2007
Location:
Posts: 286
i just cant see it being head gaskets. the car doesnt ever sit, it just gets driven very few miles since i work 7 miles from home. like i said its never been over heated and i regularly change coolant. the motor has less than 50k miles too. i have not checked the plugs again after the new intake install so im not sure they still have coolant on them but its still blowing smoke. my question really is just is there ANYTHING else that can cause this smoke to pour out like it is? it only does it at idle but goes away after you get on it. i dont have a way of doing a leak down or compression test right now and i really dont want to tear this car apart without looking at all my other possible causes. let me know guys i appreciate everything
09-24-2010, 01:55 PM
#8
5th Gear Member
Join Date: Aug 2007
Location:
Posts: 3,189
they told you the intake manifold. that too can explain coolant in the plugs and white smoke.
you can pull it off and check it for cracks and/or torn seals. pretty easy to do that. and unfortunately if thats ok....your looking at head gaskets nomatter how unlikely you think it is...sometimes **** just breaks.
you can pull it off and check it for cracks and/or torn seals. pretty easy to do that. and unfortunately if thats ok....your looking at head gaskets nomatter how unlikely you think it is...sometimes **** just breaks.
09-24-2010, 04:00 PM
#9
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
i just cant see it being head gaskets. the car doesnt ever sit, it just gets driven very few miles since i work 7 miles from home. like i said its never been over heated and i regularly change coolant. the motor has less than 50k miles too. i have not checked the plugs again after the new intake install so im not sure they still have coolant on them but its still blowing smoke. my question really is just is there ANYTHING else that can cause this smoke to pour out like it is? it only does it at idle but goes away after you get on it. i dont have a way of doing a leak down or compression test right now and i really dont want to tear this car apart without looking at all my other possible causes. let me know guys i appreciate everything
White smoke at idle means that it is sucking coolant into the combustion chamber; there are only two likely paths by which this can happen:
1. The intake--either a cracked manifold, bad gasket, or both;
2. A failed head gasket;
There are two other possible paths that are far less likely because you indicate there is no cross-contamination of the oil/coolant:
1. A cracked or defectively porous head;
2. A cracked block;
If you are steadfast in believing the head gaskets are OK, then you need to pull the intake manifold and check it and the gaskets...
That's it...
---------------------------------------------------------
BTW, I would be very surprised to find that OEM replacement intake manifolds for our cars were not all made by the same manufacturer. It's a relatively complex molded assembly, with a relatively small potential market--I doubt that market could support even two manufacturers.
09-24-2010, 04:31 PM
#10
4th Gear Member
Join Date: May 2009
Location: DFW, TX
Posts: 1,925
I will respond once more and then be silent:
White smoke at idle means that it is sucking coolant into the combustion chamber; there are only two likely paths by which this can happen:
1. The intake--either a cracked manifold, bad gasket, or both;
2. A failed head gasket;
There are two other possible paths that are far less likely because you indicate there is no cross-contamination of the oil/coolant:
1. A cracked or defectively porous head;
2. A cracked block;
If you are steadfast in believing the head gaskets are OK, then you need to pull the intake manifold and check it and the gaskets...
That's it...
---------------------------------------------------------
BTW, I would be very surprised to find that OEM replacement intake manifolds for our cars were not all made by the same manufacturer. It's a relatively complex molded assembly, with a relatively small potential market--I doubt that market could support even two manufacturers.
White smoke at idle means that it is sucking coolant into the combustion chamber; there are only two likely paths by which this can happen:
1. The intake--either a cracked manifold, bad gasket, or both;
2. A failed head gasket;
There are two other possible paths that are far less likely because you indicate there is no cross-contamination of the oil/coolant:
1. A cracked or defectively porous head;
2. A cracked block;
If you are steadfast in believing the head gaskets are OK, then you need to pull the intake manifold and check it and the gaskets...
That's it...
---------------------------------------------------------
BTW, I would be very surprised to find that OEM replacement intake manifolds for our cars were not all made by the same manufacturer. It's a relatively complex molded assembly, with a relatively small potential market--I doubt that market could support even two manufacturers.
+1. I have seen some weird stuff before man, factory defects in heads and stuff like that. If it's not getting in from the intake, then it has to be coming in at the head.