Vacum leak near EGR, wont start

:banghead:

After starting, idles rough for a few moments and stalls. Looks like a small hole right under where the EGR mounts is sucking air in. If I plug this hole with a towel, it runs fine.
Is there supposed to be a solid plug here? I don't recall this hole before, but I'm not sure. The hole is about 1/2" diameter, bored into the lower intake manifold, at a 90 deg angle. It looks like it is supposed to be part of the return path from the EGR back into the manifold. There is no thread, but just an inside small lip, like a plug would just fit snug or something.
Its an 99 Isuzu trooper w/ 3.5L engine. Went by a dealer, nothing in the schematics for this, and they didn't have any 3.5 engines to look at. May need to find a dealer w/ some used trucks and pop the hood. In anycase, the machanic wasn't sure, but said they didn't sell the plugs if that is what it needed... very odd.

Thanks for any help, Mike

I have the 3.2L sohc so I could be wrong, but it sounds like you blew out your PCV valve. Is it a perfectly round hole with a black lip/fitting?

Can you post a pic?

If it is your PCV get it from the dealer - $6 part.

I'm pretty sure its not the PCV. I'll post a picture when I get home tonight. It's actually just the return bored hole/line from the EGR mount. This is really bugging me :crying: I found a used dealer a few miles from here w/ some 2001 troopers, I may also run by there and pop the hood for a quick see.

Here is the picture with a yellow box around the phantom hole. Can somebody with a 3.5L engine check to see if this is supposed to be pluged or if a hose is missing? Thanks!

http://home.comcast.net/~mlingk/egr.jpg

http://www.icess.ucsb.edu/~greg/rodeo/egr.htm

http://isuzufaq.ibctech.ca/#faq1

can you feel air being sucked in or pushed out from the hole? There should be a nut there if I'm not mistaken.

marc

You're right, definitely not the PCV valve location.

Haven't a clue, sorry.

Keep tabs on those OEM heater/coolant hoses at the firewall passanger side, might want to get rid of them in the next year.

From the picture on the cleaning page, it looks like some sort of screw plug. I'll need to check again tonight, I didn't feel or see any threads previously.

It's sucking air in, when I plug it with a shop-towel, it seems to run perfect.
While driving on the highway over the last month, sometimes it would give slight hesitation while just doing a straight 75 mph. Hopefully it was just this plug coming loose but had not fallen out yet.

I wonder if I could just put some exhaust muffler tape over the hole if I can't find the plug?

-Thanks for the picture, Mike

Keep tabs on those OEM heater/coolant hoses at the firewall passanger side, might want to get rid of them in the next year.

Are you referring to the hose w/ the clamp? I guess I wasn't aware that these get replaced. I'll look over them and see how they look.

Just got off the phone w/ St. Charles Isuzu, they said they don't sell this part seperately, and they don't believe it is supposed to ever come out of the 'hole'. They said I would have to buy a whole new lower intake manifold at $350.00

I'll see if I can find something at the hardware store first. :frown:

By looking at your pic... On my 3.5 2000 Trooper that location is plugged by what looks like a hex nut and attaches onto the other end of it. I'll go out and try and get the size for you. It's possible vibrations caused this nut to come loose and fall out over time.

I actually wondered about that nut myself. I wasn't sure of its function, I thought it held the EGR in place?? Guess not.

Good Luck
Angelo

This discussion got me interested enough to get off my ass and go look! I snapped a couple pix with my phone and you can actually see the nut! Unfortunately, I'm not sure how to upload the pix from my PC to this thread, if you want I can email you the pix.

Anyway, what I was able to find out is that is actually an allen key size 6 bolt that is pretty hard to get loose from my short time trying. I can't imagine it just falling out but I'm sure we've all seen crazier things. I don't know that there is a nut on the other side or not, I couldn't see in there far enough.

I looked online and the bolt looks something like this:
http://www.crc2onlinecatalog.com/images/AllenBolt01.JPG

Like I said, just email me and I can send you the actual pix I took.

Angelo

I'm not sure if this link will work, but I think I figured a way to show you the pics using my yahoo acct. Hope this works...

http://pg.photos.yahoo.com/ph/strikly4dahoes/detail?.dir=8ae9re2&.dnm=a8e5re2.jpg&.src=ph

maybe try a junkyard for the part. I am shocked St Charles can't get it. Try other autoshops too. I have read of them comming loose and causing poor performance and a diesel like sound. Never heard of them comming off, but it seems possible since they can come loose.

here's the pic from 00trooper
http://f3.yahoofs.com/users/41e1b10dz4162433c/8ae9re2/__sr_/a8e5re2.jpg?phgv1kEBnXqdp1cY

here's your EGR
http://home.comcast.net/~mlingk/egr.jpg

Thanks for the pics and info guys. What worries me is that there was no threads in the hole, and if there was anything screwed in on the backside, it may have been sucked in the intake manifold. Maybe I should take it apart and take a look.

For now, I found a 1/4" brass test-cap from Lowes and used muffler epoxy stuff to cement it into place. Seems to be running fine now, as long as the heat-cooling cycling doesn't break it lose from the hole.

Thanks for the pics and info guys. What worries me is that there was no threads in the hole, and if there was anything screwed in on the backside, it may have been sucked in the intake manifold. Maybe I should take it apart and take a look.

For now, I found a 1/4" brass test-cap from Lowes and used muffler epoxy stuff to cement it into place. Seems to be running fine now, as long as the heat-cooling cycling doesn't break it lose from the hole.


that is odd that whatever goes there is gone. I wonder what the point of it is? Especially if it is never supposed to come out.

That's great it is running fine since you plugged it up, so at least you know the problem. If it seems like the idea you came up with won't hold, it may not be a bad idea to visit the dealer and order the new pieces you need. All the suction over time may loosen it up. If it pops out it may cause some damage or cause you to stall out at an inoportune time.

It's a lot of money, but may be worth it. Check some junkyards too. Taking it apart may give you a better understanding of what's needed too, so that's a good idea.

marc

Two possibilities that I can think of would be either a diagnostic port for measuring/troubleshooting EGR vacuume problems or they drilled it out from the solid molding to create the EGR hole for the air path and then they just plugged it up after boring.

During testing I was able to use a shoptowel corner to plug it up, so in an emergency, I think I'm ok. There is also a slight lip just inside the hole, so the part I used won't go in any further than it already is, and the stuff I used gets 'weld' hard so I think it should be good. The vacuume wasn't that strong either..

that's cool, it seems you should be good then. Is it running 100% fine now? It sounds like it is, so that's cool.

marc

Still a little hard to believe that you can't get that particular bolt from the dealer... Something like that would drivie me nuts until I plugged it with the actual part that belongs there, but if you're fine with it, then more power to you!

Angelo

Still a little hard to believe that you can't get that particular bolt from the dealer... Something like that would drivie me nuts until I plugged it with the actual part that belongs there, but if you're fine with it, then more power to you!

Angelo

Yeah, I talked with two dealers. They said, the part wasn't sold seperately.. All the salvage places around here have already sold out all the engines from the troopers, including the intake manifolds.. I'm not thrilled myself about the repair, but I'm not going to dump $350 to plug a hole either. I'll just keep an eye on it for now.
With fuel prices right now, it's delated to backup duty anyway..