4.7 No start, Exhaust smoke engine Question

I know that the initial "exhaust smoke" leads most people to think this is head gasket, but I don't think so, please read why.

Engine has about 250,000 kms or 155,000 MILES. We have had it for a year or so, always dealer maintained and never driven hard, and it has never overheated. My wife last drove it, everything was great, no symptoms of anything. Parked it and 2 days later when we went to start it, it would not start, turning over and HUGE white smoke. (so like everyone I assumed head gasket). Another weird part is if it is trying to start and you let go of the key, the key will return and is NOT stuck, but half the time the starter will just keep trying to start for an extra 10-20 seconds. Like it is still getting the signal from the key to engage starter

Checked oil and no coolant noticed on dipstick, and the dipstick level was not high.
Checked coolant and nothing noted, no milky etc. It was a bit low, like 1/3 -1/2 cup, topped this up. It has not dropped since top up 3 days ago.
Checked oil cap, nothing on it

Pulled plugs, they were a bit black so replaced them with new. While plugs were out we turned engine over with starter a few times thinking maybe coolant would come out. NOTHING, top of pistons were dark, not shiny like sometimes happens if you run an engine with coolant in the oil.

Compression test done, all cylinders were within 20-30 PSI of each other.

Here is where it gets weird. If I spray throttle body cleaner direct into the intake, engine will start and continue to run as long as I spray the fluid. If I press down on gas pedal while spraying, or stop spraying fluid, it will die. While it is running with throttle body cleaner engine sounds and runs awesome, however there is still a pile of white smoke.

Since it would run with spray I thought fuel delivery. I bypassed the relay and can hear the fuel pump running. I undid banjo bolt on fuel rail and it had lots of fuel (have not done pressure test)

So, it could be 2 issues, 1st is a starting issue since it starts with spray, and the second issue being the head gasket (smoke) but I am doubtful that 2 unrelated issues would happen at same time with no symptoms.

I am thinking maybe a sensor or a computer sending it a very rich or lean signal or something?

Another thought is contaminated fuel? However it has only 1/4 tank of gas left, so we burned 3/4 of a tank of this tank of gas and had no issues until everything all at once.

Wondering if anybody here has had this happen, or seen it before? My next resort is dealer, but I am very worried they will replace head gasket charge me and it will still be something else.

Hoping someone here can help with an idea.

 

Scary....


Does the exhaust smell like burning coolant?

Might be getting to much fuel?

Any codes??

 

No the exhaust is not sweet smelling like I would have expected.

And ran it for codes and NOTHING came up

Only other part that does lean towards head gasket is that when it was running with the spray into the intake we removed the radiator cap and it was under lots of pressure. It was only running for about a minute so not hot, just high pressure. I thought coolant PRESSURE would be lower. ?

 

Any chance it has rained heavily during those 2 days that it was parked?? or was exposed to water entering the intake manifold or induction system?? I "hydrolocked" my car during a heavy storm with a cold air intake, would not start, but if I sprayed starter fluid in there it would come on, but would puff out white smoke, or vapor depends on your take... I was able to keep it on and running, but I don't drive it as much in the rain anymore. Additionally I cleaned out the IACV for good measure and if you do this purchase a gasket otherwise it will inhale coolant..... It still works, and its been fine...

 

I would check the injectors. Might be dumping fuel ? Just a guess. Does the smoke smell like gas?

 

Thanks guys
Blackdenom. NO rain during the time, no puddles , not driven thru water or anything like that. I will clean the IACV , thanks
TX- Exhaust doesn't really smell like gas either, but Im not sure what it smells like. I will do a pressure test, but that is kinda how I am leaning is fuel related. But what are the chances of ALL 8 injectors suddenly going at once bad enough that it won't start and get to this? How can I check all the injectors? Also what computer or valve or relay controls the amount of fuel that is supplied to the injectors? That seems more likey to have failed than all the injectors

 

VVTi Engine?

 

Sounds like your starter relay is crapping out and sticking.

When you checked fuel at the rail, did you make absolutely sure all the washers are in order? If not, you'll get fuel out of the line, but not into the rail.

 

I am not sure. I just read that the 2005 model would be the VVTi and mine is a 2004 model. I don't see ay badging saying VVTi.
I took the fuel rails off, checked each injector by plugging one in at time and turning starter over to feel the injector clicking. Then we checked each injector on the rail too and all of them powered the injector.

Started the engine again using spray, left all injectors unplugged. Ran it for about 2 minutes to burn off whatever may have been in the system and smoke almost completely away.

plugged the injectors back in and smoke returns. MIght be a bit better than original , but still won't start and still smoking bad.

Frustrating

 

How old are your o2 Sensors? Catalytic Converter?

 

So injectors are working but possibly dumping to much fuel! Flooding engine causing smoke?

Prob just one injector wide open could cause this.

Other thoughts, your fuel might be trash.

 

Fuel pressure regulator?? Just guessing at this point. Is there any codes??

Maybe these pics could help in some way.

 

04 will continue to crank after the key is released. That's not part of your issue.

If it runs on starter fluid I'm guessing the injectors aren't firing if you've got fuel pressure at the rail.

 

Check wiring harness for rodent damage.

 

Things I would be suspicious of are all fuel delivery related.
1. Fuel pump
2. Injectors (seems unlikely all would fail, and at least 2 or 3 would need to fail for it to not want to start)
3. Fuel filter (under the drivers side on the frame if equipped, otherwise in the tank with the pump)
4. Relays and wiring related to fuel pump and injectors.
5. Fuel pressure regulator (never heard of this part failing)
6. Inspect the gas tank to see that there is actually 1/4 tank of fuel left as you stated. Fuel gauge could be lying to you.

I would not be concerned with head gasket initially or the "smoke" you see. Likely unburned fuel or starter fluid since your spraying non stop unlike the injectors. Odd that it smokes without being able to start. Something would need to burn that fuel to get it smoking.

 

Did you fix this issue? I have 04 with same issue. Can you please share solution?

 

I clicked on his username, dude was last seen 2 years ago, I think you're SOL on that one. That's the shit part: Lots of people come here asking for help, then they don't bother to share what solution worked. Dick move, kinda, if the issue was solved. It's bad enough to join onto a forum with no intent to chat, post asking for help, then disappear after getting it.

What are your symptoms, like, what color is the smoke (blue or white?), what does it smell like (sweet, burnt?), when does it smoke (startup only, all the time, only after sitting for days), and have you done a compression test yet? There are a few different things that will cause smoke, but they have different symptoms. You really should get a compression test done if you're worried, though. Any overheats lately?

 

I have all the symptoms mentioned the difference is Head gaskets have been changed heads were checked and new timing belt installed when reassembled no change to the condition when starting back up upon further investigation driver side cat glowing red after running have loosened the exhaust manifold to see if it was just a clogged cat but no change did notice fuel spitting out of the exhaust with all the smoke used meter to check injectors and it appears they are keeping continuous signal and flooding the cylinder. I unhooked injectors cleaned plugs confirmed coils and started engine back up upon first hooking up injectors ran fine took down road and back but once engine rpm went to slow back down it started smoking and missing again upon looking under the hood same condition back spitting fuel and smoke from exhaust and injectors not shutting off.

 

Have you pulled codes yet?

 

There are four types of smoke, we really need to know which it is, because each type has its own set of causes/solutions:

1. Smokes at startup only => Usually injectors, power steering air control valve, or similar
2. Smokes entire time the engine is running => can be heads, head gasket, rings, bad O2 or MAF leading to poor combustion, bad coils or plugs
3. Smokes only when accelerating => Most often ends up being rings, but can be air/fuel-related
4. Smokes from a specific location other than the tail pipe => Varies depending on location.

I'm also curious to know the answer to this. Are you throwing a check engine light, and are there codes, pending or stored?

I'll give my usual schpeel here: Basic engines only need air, fuel, and spark to run. EFI engines like in our trucks require metering via sensors to detect how much air is incoming (via the MAF sensor), so it knows how much fuel to inject into the cylinder, fires off the coil for the spark with correct timing, and then relies on the O2 sensors to check the resulting combustion before/after the catalytic converter so it knows if it needs to trim that fuel mixture any. Because it's so sensor-dependent, using non-OEM sensors, or having one bad, non-performing sensor even slightly out of spec can lead to really weird shit happening.

Other questions I'd ask :

• Have you noticed your power steering reservoir runs low from time to time? (it's a serious/critical question - see link in 1st bullet section down below)
• Have you or a previous owner ever purchased any truck parts off the online sites for Walmart, eBay or Amazon? They're notorious for selling very legit-looking counterfeit parts.
• Are you running any non-OEM (i.e. non-Toyota, non-DENSO) parts for any of these?: MAF, O2 sensors, spark plugs, other? These engines prefer OEM parts.
• Are your fuel injectors stock, have they ever been replaced at any point?
• If you shine a flashlight through the smoke, which color is it, blue, grey, or white?
• Have you tested or replaced the O2 sensors or MAF at any point?

That's a hell of a lot of work and money spent when a 5-10 minute compression test should've ruled out the heads and head gaskets.

You should know that there are plenty of things that can cause smoke and burning rich:

• If your power steering air control valve fails, like this, it'll smoke at startup, but eventually taper off, easy way to test for this here.
• You have aftermarket and/or leaky fuel injectors slow-leaking fuel into the cylinder(s) after turning the truck off, which then burns and smokes at ignition
• When re-installing the fuel rail at some point, a seal/o-ring stayed inside, and wasn't pulled back out before reinstall of the rail, causing bad/leaky/double seal
• I'll stop there because my fingers are tired....

 

New to the forum so here's a first time post.

I'm experiencing the same issue of "smokes at start up only". It'll smoke for 5 seconds and then drive perfectly fine after that. No misfiring. No error codes.

I saw Shifty's post about the 'typical' cause of smoke at start up either being fuel injectors or power steering leak. I checked the air control valve on the power steering by pinching the tube, and the RPMs increased and decreased like the guide said they should. Don't think that's the problem now. I've also checked the PCV valve to make sure it wasn't staying open or closed and allowing oil to seep through. That was good as well. Along with that, I've trimmed all loose and cracked hose ends that I can find and reattached for a good seal.

I'm trying to figure out how to test the fuel injectors to see if they're leaking fuel into the cylinders when I shut it off and producing the smoke at start up. The smoke looks more white than blue and smells more like fuel than sweet.

***Key Context***
I bought the truck 9/1/23. There was a significant amount of repairs completed in 5/23...all the big ticket items. You can see the picture below to see what was done. The truck drove perfectly the fist 6 weeks. It wasn't driven much before I bought it, and I've put on about 1,000 miles since I've owned it. At that time, I started to feel a vibration in the steering wheel and whistling when turning. Looked at the power steering fluid and it was below the "cold-low" line when the engine was hot. As you see below, the rack and pinions were replaced. Since then, I've filled it 4-5 times. I know there is a leak somewhere, but I see zero evidence of oil on the ground, around the reservoir, or pooling underneath.

The person who sold it to me said the engine was replaced because "the valves leaked and gummed up the cylinders". I called the auto shop that did all the work and they told me to put an additive into the oil to recondition the seals in the engine. The theory is that if it had been sitting a while before install, there may be a slow leak from the seals. I did that as well and there's still smoke at start.

I don't think it's the head gasket or valve seals since it only smokes at start up. It's also hard for me to believe that the same issue happened a second time on a new engine. I tend to think it's more likely that whatever caused the issues to the first engine is causing the same issues now.

Any help or ideas would be appreciated!

 

What do you mean by 'smoke at start up' exactly?

Previous owner of my truck thought maybe it had a blown HG because of smoke at startup....when its cold......which is just water vapor from the exhaust.....

What is the temperature where you are? because about nine months out of the year, my truck 'smokes' when started' but its not a problem, or at least if it is, I've been driving it for years with it.

 

I live in SW Missouri so we've got pretty good winters here. I've thought about the temperature as well...this didn't really start until our first cold snap. Been mostly sub 70 for hi's since then. Below is a picture of the smoke I'm talking about.

 

FYI that PS valve you pinch tested can also fail another way which leaks PS fluid internally. That fluid gets sucked into the intake and can cause smoking...

 

Bypass the air valve - cap the valve, then cap the hoses.

Run without it through a few cycles. Does the smoke stop? Problem f'n solved, replace the valve. Stick with OEM. Yes, I know it costs more.

Either way, do us a favor please, and report back your result.

 

This is what my truck, and my other vehicles look like when cold started below about 50º. I also have a power steering leak, but its so slow, I've never refilled it. I don't lose any coolant or oil either.

If you are not overheating, or losing coolant, its not your HG. Running rich on gas, makes black smoke. White could be oil, but oil smoke doesn't vanish like water does, it drifts away.

It varies by humidity as well, higher humidity, leads to more and longer lingering vapor.

Check out this video of my truck....this was just a cool evening....look how much vapor there is.

https://www.youtube.com/watch?v=8KNYNeQg8zY

 

Smoke colors can be hard to tell online, in digital pictures. To me, that looks white, suggesting coolant. But if you've never overheated this thing, and even if you have a few times, I'd be shocked if it was a head gasket.

Power steering on the 1st gens, at least my later model '06, uses ATF in the reservoir, so a hydraulic fluid vs. motor oil which is a lubricant. I would expect it to burn roughly at the color I see in that picture, but again ... digital photo != real life.

 

Good news! Plugged the PS valve and the hoses. Immediately saw a significant decrease in smoke at start up. There's still some coming out, but nothing like it was. Guessing it'll take some time to get it all out of the hoses, etc. Also been tracking PS fluid levels, and the leak seems to have stopped with levels staying the same. Still early and need to do more driving. Planning on taking on a trip this week to see how she does.

When I removed the top hose to the PS valve, fluid immediately poured out...much more than a trickle. In hindsight, this is an easy way to check valve failure. If you're losing that much fluid from the reservoir without any noticeable leaks, there will likely be back flow into that hose if the valve is broken.

Question --> Now that we know the valve is leaking, do I need to replace it at all? I know other people have capped it off with a bolt permanently. Personally, I've not experienced any noticeable change to my daily driving with the valve gone.

For future reference --> Bolt size for PS valve opening: M14-1.50, 10mm

 

Thanks for replying back on this to update. I've suspected other people in the past who couldn't prove they had smoke were actually the valve but they didn't do that one simple test (nobody told them to, to be fair). Fluids settle when at rest, so you may have smoke for a while.

Anyway ... The whole purpose of that system is ultimately a power steering assist - maybe not necessarily just for you, the user, but potentially to aid with overall operation mechanically. Ideally, you'd want to have it functioning. I know that valve is expensive. Maybe this is one of those times when buying a generic first from the LAPS would be advisable, and see how you fare. And of course, please keep us updated so others can benefit from your experience.

Finally, speaking of benefits, you may want to check this thread so you can benefit from the collective wisdom of this forum, helping you solve some issues you may not've realized you had, and avoid some HUGE mistakes others have experienced with their 1st gen.