Valve adjustment, tightened EGR pipe... now major vacuum leak

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UGA2018 said:
Thank you! I have to think it is related to something i've done recently with the truck but maybe not.
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Understandably. Booster plays a pretty big role in vacuum tho. So an easy thing to rule out. Granted I've never had one go so if it does maybe loosing the brake pedal is more likely than having it be too hard to push.
 
I thought I would bump this back up to the top in case there are some more ideas out there. I appreciate anyone willing to jump in on this!

Here's a few potential theories that jump out to me:
- I hooked up the vacuum lines wrong after doing the valve adjustment. I think the probability of this is low since I have checked multiple times. The vacuum leak is so great that it would have to be a big line that is not correct and there are not that many of those so this is low probability to me.

- valve adjustment was done wrong - I was pretty meticulous here and cranked it after I did the valve adjustment, before I put everything back together, and it seemed great. Not sure even if it was done wrong how that would impact vacuum though.

- When I tightened the EGR pipe (in pic above) it did something. This makes the most sense to me. I wonder if the exhaust that leaked at this the gap before I tightened created less pressure on the EGR system because there was less air since some was escaping. Possibly since there is more air now the EGR system got screwed up. Maybe stuck open. And so there could be the vacuum leak.

I'm sure there could be other theories but these jump to the top of my mind. Any other ideas to explore?

thanks again!
 
Valve adjustment? Of course, IF it was done wrong it could affect compression. Low compression can cause low vacuum.
If you adjusted the valves too tight and they never fully close that would cause low compression.
After you cranked it did you check the lash again?
 
I didn't check the lash again after I cranked it. I grabbed this video which to me shows that it was runnning smoothly. So I felt good and put it all back together.

Do you think this is enough or should I pull the valve cover off again and recheck everything?

 
NeverGiveUpYota said:
Is that video at idle?
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Yep.... that's the video at idle after the valve adjustment and before I put everything back together. The only thing that happened between this video and the vacuum leak was putting it all back together and tightening the EGR pipe coming on the manifold.

I guess I'll check those valves again but this video makes me think that isn't the problem. But at this point... heck if I know! :)
 
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The only part of the EGR system that could cause a vacuum leak is the EGR valve not fully seating. Everything before the valve is positive exhaust pressure. If the EGR J pipe that bolts to the manifold was removed, (as an example) the noise from the exhaust would be loud as heck but there wouldn't be a vacuum leak.
 
OSS said:
The only part of the EGR system that could cause a vacuum leak is the EGR valve not fully seating. Everything before the valve is positive exhaust pressure. If the EGR J pipe that bolts to the manifold was removed, (as an example) the noise from the exhaust would be loud as heck but there wouldn't be a vacuum leak.
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That's good to know. Thank you. I didn't remove that J pipe. Just tightened the bolts down on it which I thought could have triggered something with the EGR.

I'm now going back to your suggestions that maybe the valve lash is too tight. I'm going to recheck that tomorrow and go from there.

Just a thought on the valve lash.,.... would it be possible that the engine could run a smooth as you saw in the video at first and then get worse/vacuum leak show up? Maybe it just takes time to show up?

Sorry about all of the questions but I'm still learning a ton here and trying to get to the bottom of it. The help is much appreciated!
 
So I see a collapsed vac line off the distributor vcv, the evap cannister not hooked up to the solenoid.

But That vac leak is too big for that. That leak should be audible. Do you hear any loud hissing at idle? Vac line from manifold to brake booster good?
 
Thanks for the input @mattressking . No hisssing sound. That collapsed line has been line that. Need to replace it but it's nothing new.

I am starting to think that the valve adjustment was too tight. Maybe that's what's causing this. The vac line to brake booster is there and in place.
 
Sorry, I'm just catching up with this thread. That's a pretty significant loss of vacuum. I bet your leak is at the manifold. You probably leaned on the intake manifold when you adjusted the valves, or tweaked it when you were messing with the EGR pipe. I'd take some carb spray around the gasket and see if you can't find it.
 
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