97 5.4 Expy White Smoke Rough Idle at Startup

[tedallen]

I started experience a rough idle at start up, particularly if the vehicle had set for awhile, along with white smoke from the tail pipe about a month ago. Actually I started noticing an intermittent rough idle at startup for some time prior to the white smoke. About the time the white smoke started to get really bad, I received a P0133 code (oxygen sensor circuit slow response, bank 1, sensor 1). As I understand it, this would be the upstream sensor in the passenger side bank.

I should also mention that the rough running/misfire typically goes away within the first .25-.5 mile of driving, but occasionally I get a misfire/shaking after a longer period of driving, long after the point in time where the white smoke has quit being expelled.

Given the white smoke, my first fear was a head gasket leak. However, I got a loaner coolant combustion gas tester from AZ and it showed no indications of combustion gases in the coolant. I was suspicious that maybe the oxygen sensor had actually failed and was causing the PCM to default to on overly rich mixture in bank 1 to avoid a risk of burning valves with too lean of a mixture and that might be accounting for the rough idle and white smoke. However, in all the vehicles I have owned that had O2 sensors in them, I am yet to find one that actually had failed other than one where the wiring harness got damaged.

I also noticed that the white smoke had more of a fuel odor to me than that of coolant. I then found a YouTube link to a video showing a Ford 5.4 fuel injector that would leak into the cylinder with KOEO and was producing white smoke and rough idle. I am now wondering if this might be my issue. My vehicle now has over 315K miles on it and I have never replaced any of the fuel injectors.

Short of pulling the fuel rail loose and performing and looking for seeping fuel injectors and/or looking for any that might be spraying in KOEO as in the YouTube video, does anyone know of an easier or more reliable way to test for this condition? Given the vertically mounted and deeply recessed spark plugs, I'm not sure how viable it would be to try to remove plugs and check for raw fuel in the cylinders.

I'm still not 100% certain it isn't a head gasket issue, but I'm sure hoping it isn't. There is a small amount of coolant loss, but I know there is an external leak in the radiator plastic tank on the passenger side that doesn't always leak.

Here is the YouTube video link:

https://www.youtube.com/watch?v=-ARVK-ivf1g

Thanks,

Ted

 

[Copper93]

You can use a fuel pressure gauge and check pressures and leak down times. My 97 is also blowing white smoke on start up. I'm not losing any coolant or oil. there is no mixing between the two also. I believe the white smoke is from water in the exhaust pipe. There are low spots in the system and when the truck is running it blows the water out. That's the only thing I can think it would be.

 

[thenaaks]

Try this just for the heck of it: after driving the truck, pop the hood and loosen the coolsnt cap to relieve pressure on the cooling system. I was having rough idle, smoke/steam at start up after sitting. I believe it's just a tiny intake manifold gasket leak, allowing just a small amount of coolant to leak into a cylinder and foul the plug.
I've been loosening my cap, and haven't had a rough startup in 3 months.

 

[tedallen]

Thanks. I was wondering if it was possible for an intake manifold gasket leak to make its way into the cylinder(s) without also having to make it through a leak somewhere in the head. I'll give this a try for a few days and report back. I'll loosen it every time I make a stop. it has been pretty consistently having the issue for last several weeks.

Ted

Try this just for the heck of it: after driving the truck, pop the hood and loosen the coolsnt cap to relieve pressure on the cooling system. I was having rough idle, smoke/steam at start up after sitting. I believe it's just a tiny intake manifold gasket leak, allowing just a small amount of coolant to leak into a cylinder and foul the plug.
I've been loosening my cap, and haven't had a rough startup in 3 months.

 

[thenaaks]

I've got mine a bit loose currently. Loose enough that pressure does not build. Haven't had any boiling or overflow, so I'm leaving it loose for now. I got tired of popping the hood every night, and I'm too lazy to fix the gasket, for the time being.

 

[98EXPnSRQ]

Coolant is leaking into one or more cylinders. This is very serious. My brothers F150 had this happen and one morning he started the truck and the engine block cracked when the piston attempted to compress the coolant in the cylinder. I believe it was the intake manifold gasket that failed. I would pull the manifold and replace the gaskets ASAP.

 

[tedallen]

This Seems To Be My issue

Well, I have tried your suggestion for a number of days now and it seems to alleviate many of my symptoms. The large amounts of white smoke at startup (similar to a Seafoam treatment) and the rough idle have pretty much been eliminated. There may still be a very small amount of coolant loss over this period of time, but if so, very little.

I guess I am going to look at taking the intake manifold off and replacing the gaskets at my earliest opportunity. I really dread trying to get the rear passenger side coil pack and plug out. When changing the plugs in the past, I've actually ended up giving up on that one and taking it to a shop and paying to have them change just that one coil pack and plug.

I guess that the intake manifold leak must be making its way into one or more cylinders without the combustion gases being able to make it into the cooling system since the tester showed know signs of combustion gases in the degas tank and I haven't noticed signs of coolant contamination in the oil.

I'd be curious to see an engineering drawing showing how coolant passes through the intake, cylinder heads, and block on the 5.4 2v engines.

I'm also going to see if I can find a pressure cap tester that will fit the cap on the degas/expansion tank. Just in case it is failing and allowing the pressure to be over-pressurized.

Thanks again for the info.

Ted

I've got mine a bit loose currently. Loose enough that pressure does not build. Haven't had any boiling or overflow, so I'm leaving it loose for now. I got tired of popping the hood every night, and I'm too lazy to fix the gasket, for the time being.

 

[thenaaks]

I'm pretty sure that it leaks past the orings at the 4 corners of the intake seeing area. You can see how close the water "holes" are to the intake holes. I suppose deterioration over time. I am going to tackle mine when it warms up a bit. Looks like kind of a pain to do.

 

[98EXPnSRQ]

Here's a picture of the block after the rod broke and pushed out of the side. If you are planning to still drive it, I definitely wouldn't let the cooling system pressurize.

 

[tedallen]

That is an ugly thing. One other thing that I started noticing long ago and am now wondering if it is related, is that after the vehicle has been running and warmed up, when I shut off the engine, I hear a sound almost like a teapot gurgling/squealing sound that starts at a lower pitch and gets higher in pitch until it stops which usually takes 15-30 seconds.

Do you know if this is the type of sound that could come from a pressure leak in the cooling system in the intake manifold? It does sound like it is in the upper center of the engine area maybe under/behind the throttle body.

The other thing is that when my fuel pump failed back in the spring and my vehicle sat for over a week before I completed replacement of it, when I tried to start it, the engine kicked back like it couldn't turn over. I checked the battery and even hooked a battery charger in engine crank mode to it and still couldn't get the engine to completely turn over. Finally, after many attempts, it finally turned over and started. I'm not wondering if this was because of coolant filling up one (or more cylinders) and the engine trying to compress the coolant.

Thanks,

Ted

Here's a picture of the block after the rod broke and pushed out of the side. If you are planning to still drive it, I definitely wouldn't let the cooling system pressurize.


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