• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

YACT: WTF did I do?

J

jagec

Lifer
Here's the story.

I buy a $500 van to haul stuff around. It burns some oil. No biggie, but I got time on my hands, so I decide to fix it. I think it's the valves, for reasons I won't get into, so I go down to the junkyard and pull a new head from a low-mileage van for $30. After a lot of work and cursing of Toyota engineers (seriously, they could have moved the access panel TWO INCHES and it would be the easiest vehicle in the world to work on...as it is, the very rear of the engine might as well be on the moon. And then they go and put hoses there), I get the new head in (with a new gasket, of course). I hook up the exhaust and intake manifolds. I reconnect the thousands of vacuum lines. I install a "new" (from the junkyard) EGR cannister, since mine had burn holes in it. And some "new" hoses. I make sure all my connections are tight, everything's hooked up...and I crank.

The van turns over easily, but just as it's about to catch, there's this "psshhh" of released pressure, and a cloud of blue smoke appears in the engine bay. I try to find the source of it, but I can't. I even try disconnecting some hoses to see if it's coming out of there, but no luck. It seems to be from somewhere in the exhaust/intake manifold region, but the whole thing is practically invisible when the engine's put together.

What could it be? How could a "new" head cause something like this? I'm kind of stumped as to what it could be...

BTW, it's an OHV engine, so there's no way I could have messed up the timing or anything miserable like that.
 
Almost sounds like something is leaking somewhere.

Oh, and I hate toyota engineers too. I feel for you.
 
Edit:

A slow pssh sound? I first thought you may have pinched a wire, and the pshhh was the crackling of the insulation peeling off of it.

Have any pictures of the blue cloud? What does the blue cloud smell like? Raw fuel that got pushed out the intake through bent valves? Burnt wire insulation? Oil? If you disconnect fuel pump and coil primary what does the cranking compression sound like? You can do a auditory compression check that way.
 
This is probably not even possible, but could it be a leak in the master cylinder? Blue smoke normally would mean oil and I don't even know what color brake fluid burns ... doubt you could leak enough brake fluid to stall an engine though. Plus, parsimony would suggest the blue smoke is an oil problem with the new head. Is it even possible to dump enough oil down the cylinders to keep it from starting?
 
Liquids are not compressable.

So yes it would be very easy to cause a engine to bend valves or just be frozen by putting in alot too much oil.

 
But it cranks. So I don't think the problem is hydrolocking with oil. It's not the master cylinder...that's in a wierd place in the van, and nowhere near the engine. The cloud smells like oil IMHO. I'll try the fuel pump/coil thing to see what happens.
 
It sounds like you are having a leak(s) around a gasket. You will probably have to pull the head again and change the gasket.
 
OK, the pictures didn't turn out (you can't see the smoke), but here's a couple videos that show what's going on.

It almost seems like one cylinder is firing early, or something...I keep the key turned the whole time, but the engine kind of stutters at a certain point. The second video shows this very clearly. The first video has a nice little smoke display.

smoke
problems
 
Sounds like its misfiring when it does that.

Could be smoking out through the intake or something?

I'd say check the timing..
 
Originally posted by: Kalvin00
Sounds like its misfiring when it does that.

Could be smoking out through the intake or something?

I'd say check the timing..
Click to expand...

But I didn't touch the timing...*sob*
 
Originally posted by: jagec
Originally posted by: Kalvin00
Sounds like its misfiring when it does that.

Could be smoking out through the intake or something?

I'd say check the timing..
Click to expand...

But I didn't touch the timing...*sob*
Click to expand...
Dumb question, but are you sure you got the plug wires back in the right order?
 
Originally posted by: Heisenberg
Originally posted by: jagec
Originally posted by: Kalvin00
Sounds like its misfiring when it does that.

Could be smoking out through the intake or something?

I'd say check the timing..
Click to expand...

But I didn't touch the timing...*sob*
Click to expand...
Dumb question, but are you sure you got the plug wires back in the right order?
Click to expand...

Think so, but I'd feel like a real moron if that's all it was, so I'll check.
 
I did a bit more work on it, and got the thing to start. It runs...ROUGH. I have to give it some gas to keep it running. Interestingly, it doesn't seem to run much worse if I pull the #3 spark plug wire. This was the cylinder that had the chipped valve before, and would foul out. I'm starting to wonder what caused the chipped valve in the first place, and if it will happen again on this head.

There's also a hissing noise while the thing's running. I guess one of my hoses must be cracked or something. Figures in a 200k car that has high engine bay temps...
 
possibly your number three cylinder is not holding its compression.
and yeah, it sounds as if your timing is off.
 
How is the cam timing? Are you sure that you set the cam timing in the right spot when you put the new head on?

ZV

EDIT: Didn't read that it was pushrod and not OHC. Did you have to remove the injectors? Are they all back in the right places?
 
Originally posted by: Zenmervolt
How is the cam timing? Are you sure that you set the cam timing in the right spot when you put the new head on?

ZV

EDIT: Didn't read that it was pushrod and not OHC. Did you have to remove the injectors? Are they all back in the right places?
Click to expand...

No, the injectors came off with the intake manifold. I didn't touch them.
 
Originally posted by: jagec
Originally posted by: Zenmervolt
How is the cam timing? Are you sure that you set the cam timing in the right spot when you put the new head on?

ZV

EDIT: Didn't read that it was pushrod and not OHC. Did you have to remove the injectors? Are they all back in the right places?
Click to expand...

No, the injectors came off with the intake manifold. I didn't touch them.
Click to expand...
Did you adjust the valve lash (if it's a solid lifter engine)? If it has hydraulic lifters are you sure that none of the lifters in the new head are collapsed? Jammed pushrod? If the spark timing is verified good I'm at a loss. I'm assuming that you used a new head gasket and made sure that it's seated right, if you didn't it's possible that you're getting coolant in the engine and that could be causing the misfire.

ZV
 
Originally posted by: Zenmervolt
Originally posted by: jagec
Originally posted by: Zenmervolt
How is the cam timing? Are you sure that you set the cam timing in the right spot when you put the new head on?

ZV

EDIT: Didn't read that it was pushrod and not OHC. Did you have to remove the injectors? Are they all back in the right places?
Click to expand...

No, the injectors came off with the intake manifold. I didn't touch them.
Click to expand...
Did you adjust the valve lash (if it's a solid lifter engine)? If it has hydraulic lifters are you sure that none of the lifters in the new head are collapsed? Jammed pushrod? If the spark timing is verified good I'm at a loss. I'm assuming that you used a new head gasket and made sure that it's seated right, if you didn't it's possible that you're getting coolant in the engine and that could be causing the misfire.

ZV
Click to expand...

new HG, the Chilton's says hydraulic adjustment. I torqued the bolts to spec, but maybe this is another Supra fiasco and I should over-torque them? Don't think so, though. Maybe I should pull the head again and make sure everything's right...it SEEMED so when it put it on, but who knows...
 
Originally posted by: jagec
new HG, the Chilton's says hydraulic adjustment. I torqued the bolts to spec, but maybe this is another Supra fiasco and I should over-torque them? Don't think so, though. Maybe I should pull the head again and make sure everything's right...it SEEMED so when it put it on, but who knows...
Click to expand...
Even if the lifters are hydraulic, a couple in the used head may be defective (collapsed). Are you sure that they're all good?

And yeah, I'd check the HG again, it's possible that there's a tiny crimp in it somewhere.

ZV
 
Well, since I've already put this much work into it, and I'm not sure that putting a bunch more work will fix it, I went ahead and pulled the power to the #3 fuel injector, and spark plug boot. Now it runs on 3 cylinders, but as long as it keeps running I won't complain. I can't believe this turned into such a big thing.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top