stuck EGR valve / low vacuum (1 Viewer)

[salvage60]

I have had my 85 FJ60 for 24 years and have gone through just about everything in that time, suspension, engine rebuild, 5 speed, body work... It was time for California smog again and for the last few years the truck has not gotten a lot of use so I went through the usual checklist of timing, vacuum, idle speed before taking a quick freeway lap on the way to the test center. About 20 minutes into the drive I pulled off the freeway to top off the tank and it immediately stalled. It started right away but I had to use the hand throttle to keep it running (1500 rpm min), I limped home and popped the hood and it all looks normal. Then I got a bit more serious:

fluids -fine
vacuum - extremely low, under 10in at over 1000 rpm
plugs - #1 was fouled, # 6 was marginal
compression , 1-6 - 128, 128, 125, 127, 131, 65

I replaced the plugs but that did not make a difference and i am having a hard time seeing the low compression on cylinder 6 causing the low vacuum. My next step was to try and narrow down the vacuum leak. Before the drive is was over 18 and steady so I started disconnecting and plugging every system that could be leaking, PCV, brake booster, EGR... no change.

I feel like the next step is to pull the carb and look for a crack in the intake manifold but want to make sure I don't miss testing something before I can no longer start it.

Thoughts?

My guesses are:
1. intake manifold
2. intake manifold gasket
3. head gasket
4. Head?

What is odd to me is it ran like top and then instantly did not so seems like a break / crack

A little over 100k since the stock 2F rebuild.

Thanks for any advice.

 

[OSS]

Your EGR valve has stuck open.

Get the engine started and running (sputtering), then connect a length of vacuum hose to the top nipple of the EGR valve.

If you suck on it and nothing changes- the valve is stuck open.

If it’s stuck open, blow as hard as you can on that hose until it feels like your cheeks are going to explode - and the valve should pop free .... and engine will then race.

That’s my guess anyway. It has happened to me more times than I can remember.

Also tapping on the top of the EGR valve with the plastic handle of a screwdriver can help too. Don’t be shy.

 

[salvage60]

Thanks OSS. I forgot to mention that I had at least cycled the EGR with a hand vacuum pump and can hear it click when released. Just about every smog component has been replaced / refurbished in the last 50k.

 

[salvage60]

I will add some more to this. I pulled the carb, intake and exhaust manifold. No real surprises but could have been tighter on most of the bolts. I am sure this is some of the vacuum leak. The low compression is what worries me the most so I decided to check the valves even though they are cold. Just checking for some wiggle on the rocker they all move except for 4,5,and 6 exhaust valves. Not sure if I should just try and loosen them up and put it back together or if this means I cooked them and pull the head.

 

[NeverGiveUpYota]

I will add some more to this. I pulled the carb, intake and exhaust manifold. No real surprises but could have been tighter on most of the bolts. I am sure this is some of the vacuum leak. The low compression is what worries me the most so I decided to check the valves even though they are cold. Just checking for some wiggle on the rocker they all move except for 4,5,and 6 exhaust valves. Not sure if I should just try and loosen them up and put it back together or if this means I cooked them and pull the head.

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I’m no expert but if they don’t move then I’d say the valves are stuck. Would a leak down help diagnose that? Or any chance you have a boroscope? I suppose tho if they really don’t move… you know what you need to do.

 

[salvage60]

Sorry, should have said that better. The adjustment was just tight enough there was no play in the rocker arm. I found a "cold spec" for the valves and ended up loosening them all a bit but the back three exhaust valves were the worst. I may try another compression check to see if it made a difference in #6.

 

[The Machinist]

Sorry, should have said that better. The adjustment was just tight enough there was no play in the rocker arm. I found a "cold spec" for the valves and ended up loosening them all a bit but the back three exhaust valves were the worst. I may try another compression check to see if it made a difference in #6.

If the lash was too tight on #6, that would explain the low compression. Essentially the valve would have been just barely cracked open when it was supposed to be closed, allowing the compression to leak out.

I would reset all of the valves to spec and recheck the compression.

 

[Dekeman]

Indeed, as @The Machinist said ^, 65 is misleading if the valve was partially open due to adjustment. Does sounds a lot like a vacuum line failure or crack somewhere. Assume you also checked around the charcoal canister. You're a bit deep for this now, and I've never had much success with using the gas from a unlit torch to find leaks with the engine running, but others have. Also dangerous. Regardless, hope you get this sorted. Please update when you find the cause.

 

[salvage60]

So here is the update and the lesson I needed to learn again. I found the "cold spec" for the valve clearances and ended up adjusting all of them. Most of the intake valves were pretty close but the exhaust valves were all very tight. 4,5,6 were the worst in that order with #1 not far behind. After the adjustment I retested the compression in #6 and it came back higher than any of the other cylinders earlier readings. Lesson learned, check the valves when things are off even if it seems like something else. I guess what threw me is it ran ok before a 30 min. pedal to the floor lap trying to heat it up for the smog test and apparently the heat was just enough to push it over the clearance limit. In fairness to the motor it has not done many miles and even less freeway miles in the last few years.

 

[salvage60]

Ok, changing the title again and finally found the problem. Amazing this simple machine can get the best of me so many times. So I cleaned everything up, checked for flat and square then reassembled. Started it up and it basically ran like before. I had to hole 1900 rpm to keep it running and was only pulling 14 hg. I walked away for a week and then ran it again with my hand vacuum pump connected to the EGR. I had been able to hear it click before so assumed it was functioning. With the engine running at +/_ 1800 rpm opening and closing the valve made no difference. I would assume a there should be a noticeable difference as it will kill the motor at a normal idle. Next step was to pull the EGR valve. I could see the valve move and hear it click shut. I then ran compressed air through and could see it was wide open. It took a lot of hitting, carb cleaner, and compressed air but finally a big chunk came out. I confirmed it was sealing and put it back in. 19 hg @ 600rpm, at least back to the ok tune before this started.

Lessons learned:

1. adjust the valves more frequently
2. check egr valve with the engine running.

Thanks @OSS for the right advice in the beginning, I did bang on it hard and could also hear the audible click when vacuum was released.

 

[OSS]

That big chunk that finally got dislodged from the EGR valve came from your.... EGR cooler. There’s more chunks of rust rattling around inside it ready to jamb up the EGR valve again.
And the smaller chunks, which are hard as rocks, get sucked past the EGR valve and into a cylinder to bounce around, grinding on stuff until it breaks up and gets spit out the exhaust port.

The old rusty EGR cooler is a health hazard to your engine.

My 60 keeps dying

Picked up my FJ60 from Trail Tailor yesterday. Looks incredible, handling is amazing…engine sounds great. Here’s the weird stuff. When I come off the freeway and put it into neutral it just dies. (On the off-ramp) first time it wouldn’t start (or make any noise at all). Made it to valley...

forum.ih8mud.com

 

[salvage60]

@OSS , how right you are. I have only had the egr engaged for testing for the better part of the last few decades. I had suffered from the classic acceleration flat spot the egr valve vacuum hose disable fixed it. I am now down the rabbit hole of if the EGR function is ever needed for the primitive California smog test beyond visual. Here are some pictures of the carnage.

 

[OSS]

I suspect every EGR cooler’s innards look the same

 

[CruiserTrash]

I suspect every EGR cooler’s innards look the same

I can verify. I used 4 EGR systems to make one complete functioning one last year, and every cooler was like that. FYI the bolts to the cover often snap but are available new from Toyota. An hour spent scraping with a flathead screwdriver and wiring wheeling inside the cooler is good insurance against the chunks you mentioned. I have pitting on the cylinder walls of my 144k mile 2F and chunks from the EGR cooler is one of several possibilities I’ve entertained as the cause.

 

[salvage60]

I did consider installing some stainless screen material between the cooler and the valve but got worried it would clog up, will either run it or at least on a regular basis.. The days are numbered for passing the California treadmill test with a 2f.

 

[OSS]

If you’re disabling the EGR valve between smog tests, the cooler is going to get water inside it every time the engine is started in the morning- and not burn off.

Really- the safest way is to remove the EGR cooler entirely between tests and keep it dry so it doesn’t rust anymore.
That will require some blockoff plates and the hassle factor.