Ok, I searched everywhere but I can't seem to find the exact problem that I have so here goes.

Truck is a 04 5.4 with about 75k everything stock except an Airaid intake.

I wsa driving for about 30 mins, stopped at a gas station, went inside for about 5 mins, came back out and tried to start the engine...after starting to crank normally, the engine did what seemed like a backfire and a weird clanking noise. After maybe 1 min I tried cranking it again, it took a bit longer to start but it did. I start driving away and all of the sudden smoke is blowing thru my AC vents!!! WTF?? I stopped at a red light and I noticed a high idle, then an erratic idle going from 500-1000. I got to work, then about 3 hrs later I start the truck and the CEL is on and I have an erratic idle. Also when I come to a stop it seems like the idle is high around 1000 and it starts to drop after maybe 2-3 seconds after stopping.

I've been driving like this for about 3 weeks now, I can't seem to find a vacuum leak anywhere. I cleaned the MAS and nothing.

What the hell would cause smoke from the vents, thats my biggest question?


THanx for any info.

 

Totally weird.
What did the smoke from the vents smell like? Any smoke in your cab is gonna be a strong scent.

A/F smells sweet and cloying.
Electrical smoke is strong and acid.
Oil smoke is nasty and lingers.
Fuel smoke stinks of gasoline.

I would just sorta suspect you liquid locked a cylinder from an injector staying open, then belched unburned and semi-burned fuel up through the air intake at the rear of the hood. That's where your vent air comes from.

Do you have any more information?


Chris

 

Thanx for the reply.

There wasn't a huge amount of smoke but it did smell of gasoline.
Would something like that cause a vacuum line to blow off? Maybe thats the reason for the erratic idle.

 

Sorry, was out Christmas shopping... Late, but what can I say, I'm a guy...


Anyway Gasoline can arrive at the top of the engine in two ways. If the engine fires at the wrong time the fuel mix is 'burped' back up and out of the intake.
Since we don’t have spark plug wires or a distributor cap, this is not common on these trucks.

Or two: hydro-lock where liquid fuel (as opposed to the mixed vapor) gets into your cylinder.
This is caused by an injector sticking open letting fluid (gas) pouring into the cylinder.

Then when you crank the engine around the liquid fuel, which is not compressible, has to go somewhere. It can break a piston, break a rod, or even break the head. Or if there less than enough to shatter the aluminum, it can be forced up and out the intake where it may be ignited and belch out the top of the engine.


I think your problem is stuck injector(s). Search the forum and you will see a number of 5.4 injectors sticking open.

This can be VERY serious. That is, it is common for this to break the engine.

Look for black soot inside the tailpipe, stink of raw gas when running and gasoline smell in the oil.

If it is a stuck injector it will idle really poorly, probably smoking at idle.

Don't drive it like that.

Don't be cranking it if you even suspect this.
Cranking the engine over with fuel pouring on the piston is a straight invitation to buying a new motor.
This one you better take to a shop, soonest.
Best of luck
Chris

 

2004 engines don't have injector problems.

 

Quintin, what do you think is wrong with his truck, clank, fuel vapor out the top, rough idle?

Dunno about the TSB's or chronic problems, but I've seen lots of cars/trucks with stuck injectors, lots of brands, years, models.
That's in 20+ years in autoparts.
May have something to do with fuel. Water in the tank will also damage an injector.

Chris

 

I'm not sure about the smoke out of the vents, but a stuck open vapor management valve could cause the rough running/idling concern. Seen lots of those on '04s.

 

i am having an idling and light throttle take off. where is this management valve at.

 

Thanx for helping out Chris.

Talk about Christmas shopping, I just did mine this morning LOL.

Ok, now as far as an injector stuck open, I don't think thats the problem. The truck idles prefectly smooth, the idle just jumps every 10 or 20 seconds to about 900 or so rpms, but its not rough, I have no smoke from the exhaust, the pipe is black but not wet and it doesn't smell like excess gas at all. I have no gas smell in the oil at all.

I remember when my friend was on his way down to FL from NY in his brand new navigator...he never made it in the navigator, an injector got stuck open half way down. Completely different symptoms than what I have. No power, rough idle, car stalling.

My truck runs just fine now except for the CEL light and the idle surging.

I'm just wondering if it might be a vacuum line that got blown off by that incident at the gas station. Would that be possible? Sort of like a backfire?

I looked over some of the vacuum lines this morning (I'll give it a better look later today) and they seem fine but there is one going far down between the firewall and engine, I can't seem to get to it. Anyone know where that connects to?

I hope its not a big problem....short on cash to rebuild an engine right now and I really don't want to return that Sony Bravia we just got ourselves for Xmas LOL

Thanks for all your help,

Dave

 

Check what Quintin suggested, of course.

I have seen vacuum lines blown off by back fire, but it's sorta rare. There is a big vacuum line to the passenger side of the throttle body you might check.
A big vacuum leak can make your power brakes seem weak.
Never saw a vacuum leak that would let your idle drop to normal then surge up.
Normally a leak causes the idle RPM to go up and stay there.
Drive by wire may be a little difference, but while putting a vacuum gauge on my truck I ran it with a medium vacuum leak. Idle went up about 200 RPM and stayed there.

You don't have a ScanGauge or tuner to check the CEL?

Drop by an AutoZone or whatever and get them to check the OBDII messages. Usually free.
That would probably tell you what's going on.
Best of luck and have a Merry Christmas
Chris

 

I have an 04 5.4 with 77000 miles. I had the same problem a few weeks back. I went to Wal-Mart. When I came out and started the truck it seemed to kick a few times as it tried to turn over. Then it backfired and stalled. The cab has an overpowering exhaust smell. It started right up and ran fine on the way home. The truck has been checked by me, a mechanic friend and a local Ford garage. No one can find a thing. All vacuum lines have been checked. Ford had it on their computer for 3 hours. Nothing. It is going to a different Ford garage after the New Year. The truck runs great until I come to a stop. The Rpm's are high at an idle (About 1400). After about 10 seconds they drop to 500. Then they will begin fluxuating between 300 -500 until the truck stalls. It only does this at a stop and only when warm. On the highway, runs like a top. CEL tells me I am lean on both banks. This just reeks of a vacuum leak. But where??? I will let you know what the Ford dealer discovers next week. If you find anything in the meantime, I would appreciate a heads up.

 

Great suggestion - I would start here.

 

Thats what I think it is too, a vacuum leak. Autozone checked my codes, same as yours! Lean on both banks.

I believe there is a vacuum like going somewhere deep between the firewall and the engine. I can't seem to reach it as there is no space there. I think thats the line that blew off




Hey SSpiro?????? Are you Steve from club3G????????????

 

It could be a stuck injector, I just had that happen to me. It was stuck open.
Made for really really rough idle, would be fine driving and it also through the CEL light and a few times my truck wouldnt start.

40 bucks in parts ( new spark plug and injector ) covered under warranty. Now everything works great again!

 

My last post about it, just a few days ago!
https://www.f150online.com/forums/sh...d.php?t=267406