Egr Making Loud Noise

[AeroNautical]

Sorry about that poor camera work. It's my EGR valve making this noise. It works, I've tested it several times, but noisy as hell, when no gas is applied after it's been revving a bit. It happens constantly while driving, but almost impossible to recreate when recording as you can see in the video. Any ideas? The plunger in the EGR moves in and out slightly when making the noise, too. It only does it when idling. 

 

[MuddFoot]

my 88 cherokee did that the bigger hose that goes into your air box is eather really soft or at a wierd bend pull hose off and see if it still does it

[AeroNautical]

Edit

[AeroNautical]

I'd like to bump this up again, it's starting to drive me crazy, haha. The only thing I can think of is a new egr is in order, but thats alot of money to drop on a worthless emissions part. ( or so I've heard)

[xjustinx]

Mine makes the same noise when I start it up most of the time. I think its the Vacuum transducer (round black thing with vac lines connected to egr) making the noise.

[AeroNautical]

I suppose the easiest thing to do is replace it, but do you know of a fix?

[cruiser54]

Determine if the noise is from the EGR itself or the transducer. The EGR pintle should NOT be moving at idle. A faulty EGR solenoid could be allowing some vacuum to be applied to EGR at idle.....

 

Unplug the vacuum line at the eGR and see if there's vacuum present at idle and report back. 

[AeroNautical]

I did confirm it was the EGR itself, the pintle would move in and out at idle, causing it to be rough. I replaced it and it no longer makes the noise, and idles nice, but higher for some reason. My idle is at about 1200. That led me to believe there were leaks, but i sprayed carb cleaner everywhere and no spikes. I pull the pintle on the EGR back and the engine quits, so there isn't any vacuum leak. How long does it take for these ECUs to learn? 

[cruiser54]

Those ECUs are dumber than a rock. No adaptivity there. 

[AeroNautical]

Uh oh, sounds like I've got another problem, then..

[cruiser54]

Possibly bad TPS. Anyone ever screw with the throttle body adjustment screw? 

 

Of my tips shown in my signature, which have you competed? 

[AeroNautical]

I'd hate for the TPS to be the problem, it's almost new (few thousand miles), and adjusted according to your tips. Throttle body adjustment screw has never been tampered with to my knowledge. The idle has only gone up since I installed the new EGR valve. I've refreshed my sensor grounds, adjusted, cleaned, eliminated, etc almost everything on your list. Hell, it's your list that's kept my truck on the road. It's in my browser favorites bar. And as I've said, there are no vacuum leaks, the EGR is tight with a new gasket with no leaks. 

[cruiser54]

I wonder if your "new" EGR is leaking internally.......

 

Try starting it with the TPS disconnected on the "engine" side.

 

Also, at this high idle, cover the idle bleed hole in the throttle body with your finger. It's right above the IAC.

[AeroNautical]

Sorry it took so long to report. When I start it cold, it idles fine, about 7 or 800 rpm. As soon as it's warm and i've been driving a bit is when it idles at around 11 or 1200. That leads me to believe, since the EGR is only active when the engine is warm (right?), it's probably the new EGR giving me problems. I used the correct gasket, and just yesterday rtv sealed it to make absolute certain it's not leaking air, but no change. I couldn't find the idle bleed hole, is that the second hole with no line attached above the map sensor line on the TB? 

[cruiser54]

Remove the intake boot and look from the driver's side fender. The bleed hole is directly above the IAC in the throttle body.

[AeroNautical]

Alright, plugged it with my finger and it barely made a difference, lowered the idle just barely. Also started with the TPS disconnected with no difference, though I was surprised that the engine would rev without the TPS connected. Doesn't that tell the engine how much fuel it needs?

[cruiser54]

Tells me that the engine is getting air from somewhere it's not supposed to........

[AeroNautical]

Yeah, no doubt. When I start it, it jumps to 2000 and (when cold) comes back down to 800, or when warm it jumps to 2200 and falls to 1200. It all started when I put the new EGR in, but maybe that's just a coincidence. Something is sucking air in, and I've sprayed carb cleaner everywhere to get a spike with nothing. It hunts a bit when it's cold, too. 

[cruiser54]

Ever read post 14 in my tips? 

[AeroNautical]

I have not tried that, I figured since my idle was good until recently the butterfly valve was in a good spot, but I'm desperate right now. I'll give it an adjustment tomorrow. Thanks for bearing with me, cruiser. 

[cruiser54]

Air has to be getting into the motor somewhere. EGR, intake gasket leak, throttle butterfly is not closed properly.......

[AeroNautical]

I adjusted the butterfly, now the engine almost stalls when I put my finger on the idle bypass. It lowered the idle, temporarily. I can start it cold and it'll be at 700, but when it's warm and I apply throttle and release it, it goes right back up to 1100. It seems to me the computer is compensating incorrectly. If it were a leak, the idle would always be high, wouldn't it?

[cruiser54]

Whenever the butterfly is adjusted, the TPS needs to be re-adjusted on the engine side connector. 

[AeroNautical]

That makes sense, didn't think about that. The butterfly is adjusted and the TPS readjusted to your specs. It runs cold at about 600 and warm at about 800 now, occasionally hitting 1000, but usually coming back down. It still hunts a little, but that's a separate issue I have to figure out. As always, thanks cruiser. I'll be running through your list again soon to eliminate my c101 and adjust my CPS timing. 

[cruiser54]

Progress.

 

Hunting idle can be caused by a bad O2 sensor.

 

That said, I've seen the O2 sensor readings before and after a C101 elimination, and a sensor we condemned before , was just fine after.....