Hi, I took off the EGR and the hose and there was absoultely no air flow thru the carbon build-up!
I cleaned it all up; bt whe I started it up there was a POP and smoke from around the manifold. The engine does sound like it's running rough but at the same time it sounds much, much more powerful.
Could the "smoke" and the POP have been the loose carbon I missed cleaning going thru combustion. It only did it once.
Beth

 

EGR doesn't give you power, it is use at higher speeds to help with emission. There is an articale on the web page. I bet the pop was just fumes or left over cleaner.

 

Thanks. for the reply Ryan. I understood that the egr was there to recycle any wasted fuel energy that otherwise would go out the tailpipe. So I thought because the parts were limiting flow it could make the engine run rough. I thought also because the car had been tuned-up with all the orifaces just about blocked with carbon wouldn't it change the way it ran if it was free flowing.
Im I just totally confused about this process? Beth

 

It will run better and smoother at speeds I think above 55. Thats when the computer opens up 1 or all 3 of the solnoids on the valve to allow gasses back into the pelentum.

The bad thing is if there is EGR opening during idle or low speed driving. BUT it will throw a code if it is.

This "dead gas" doesn't have any oxygen in it so in turn you don't have to put as much fuel in the engine because the dead gas acts like a place holder thus making your engine's displacement less. Now when you RUMP on the gas to lets say WOT the computer will close the EGR giving you back your full displacement.

The goal is to lower emissions and cooler combustion chamber temps, people who run with out it really aren't getting any benifit.

 

It should also be noted that the EGR will improve your gas milage as well. Did you put the EGR back on? If not that would probably explain why your car sounded louder (exhaust gases escaping out the EGR tubing/flange on the exhaust manifold instead of going through the muffler). Also if you left the EGR tubing that goes into the intake out, it could possible create a vacuum leak (I don't know if it would or not, I don't remember right off hand if the tube connects before or after the throttle body). But if I remember correctly (my engine performance class was awhile ago) one of the main benifits of an EGR is that it lets any extra fuel that wasn't used the first time be used by letting some of the exhaust gases back into the engine to be burned a second time.

 

If your EGR passageway is clogged, you could develop a light ping during low throttle high speed (crusing on the highway) operation. Your NOx emissions would also go up... and that's about it. EGR only activates during cruising conditions, and it's driven by, among other things, road speed. So some of these guys that bypass the EGR thinking they'll get more power at the racetrack are wrong- at WOT, the EGR is never engaged.

Ryan, there's three solenoids on the digital EGR? Wow! For 85-89 2.8's, with the vacuum operated EGR, there's only one solenoid.

Now, if her EGR valve itself was so clogged up with carbon that it couldn't close all the way, that would hurt performance- the EGR would be on all the time, letting exhaust gas into the motor during ALL conditions. So it could be possible that by cleaning it, now the valve is closing all the way, the engine isn't choking on exhaust fumes when it can't (non-cruising conditions), and the motor feels stronger. You can have a stuck-open EGR and not throw a code, happened to me. What year is the car again, Camaro1952?

 

YES TomP there's three solenoids on the digital EGR, computer can open them in one by one depending on how much it wants. ON THE digital systems it will set a code when the EGR is riding open. Yes things on a CAMARO tings have to be flat out BAD before they throw a code, case in point a IAC will never throw a dam code no matter how many times the engine dies.

 

On the vacum ones it's controled by vacum so the more vacum the more EGR valve is open, where as the digital ones use 3 small holes and control the amount by how many holes it wants to open.

 

anyway to convert an old vacume one to a digital system??

 

Sure a computer and wire harness change.

 

But Dale you have a 91, you have the digital one already!!!

 

Not on my s10 I don't. I hit this site for both of my 60 deg.'s People in this forum are WAY more knowledgable on the engine then my s10 site.

 

Hello, My car is a 90, 3.1 digital egr. It was totally packed with greasy carbon; I cleaned it out and the hose into the manifold. Well, no code 32 for 2 days then this morning it's back(course haven't pulled it again I am just assuming) It came on like it had in the past after a speed of 55 or so I have to de-accelerate and on it comes. It goes off when after parking until the same situation happens again.
I am afraid the noise I am hearing is a rod, my engine has app. 200000 miles on it. Any help is most appreciated. Beth

 

Well I would just try one out of a junk yard. Sounds like it's NOT getting enough EGR. Is that what 32 means???

 

But isn't your s10 a 93, I'm pretty sure they had it on the 93's but if you did a swap or something then yeah you need it and a wire harness and different computer

 

Its still vacume controled, but yet controled buy some electronic device?? Vacume survo or some crap. I have no polution control on it, I'm wondering if I really need it.

 

Dale, is it a 3 piece system, connected together by vacuum lines? The UFO-shaped EGR valve (one vacuum inlet), the cylindrical shaped EGR solenoid (one vacuum inlet, a T'd off vacuum outlet), and a square shaped EGR diagnostic switch (one vacuum inlet)? That's what the 85-89 2.8 f-bodies use.

Thanks for the info on the 3 solenoids, Ryan! Makes sense for emissions. 'Fact, I wonder if using a digital EGR would lower emissions on an 85-89 car that has trouble passing the dyno test. Hm.

 

Tomp, close, Vacume line comes off TBI, to a black louverd box, that has 3 wires to it, then out comes another vacume line to the UFO brass egr valve. Thats all thats left on my truck anyway I also get exahust fumes in the cab bad due to the back of the cab cut out for speakers. Thats why I'm wondering if the elec egr will work better, to cut down on them fumes. Hum??

 

Black box sounds like the egr diagnostic switch... but on the f-bodies, it's not louvered. How do the vacuum lines run... is there a solenoid somewhere? The EGR diagnostic switch reports to the computer if it sees vacuum. On the f-bodies, there's also an EGR solenoid. Here's how the vac operated EGR works on the f-bodies...

When the computer wants EGR, it activates the EGR solenoid. The EGR solenoid allows vacuum to 2 things via a T-fitting: The EGR valve, and the EGR diagnostic switch. The EGR valve sees vacuum, and opens. The EGR diagnostic switch sees vacuum, and sends a signal back to the computer. If the computer does NOT see that signal, it "knows" that the EGR valve hasn't gotten it's vacuum. This is why a cracked vacuum line throws code 32 for EGR. The solenoid can activate, but if a vac line is cracked, the EGR won't open. I wonder if, on your truck, the EGR diagnostic switch and EGR solenoid have been combined- it would make sense.

I was wondering the opposite a few weeks ago- if a vacuum operated EGR system could be adapted to a 90-92 f-body, to replace the digital system. This way, someone wouldn't have to spend $100 on a digital EGR... they could get the stuff from a junkyard.

There's actually one part that bothers me on the vacuum operated EGR system- and according to GM, it doesn't exist. On the back of the solenoid, there's an EGR filter. It's at the opposite side of the vacuum lines, and looks like the EGR solenoid case, but it's not- it's got little notches in it to accept air. If you pull the back of the EGR solenoid off, you're really pulling off the filter cartridge- it looks like a little conical K&N inside. The GM service manual says that should be replaced every 37,000 miles- too bad you can't buy one anywhere. Mine's 201,000 miles overdue for replacement!

Oh, hey, I bet the louvers on your "black box" are the same as the cutouts on EGR solenoid!! So maybe the two are combined on your truck!

As to the exhaust fumes, I don't think it's EGR.. unless your EGR valve is bad. Any way you can wall those speaker cutouts off? They were cut right into the firewall? Ouch. Be careful of CO while you're driving... you don't want to get sleepy on the highway!

 

Yea, its called a selonoid, I looked it up online. It does that that filter thingie in it. I have pulled it out, looked at it, a bit, stuck it back in, and put it on the truck. I am trying to fig out how on my current set up, the exahust gases get back to the intake, that stuffs kinda missing Thats why I'm wondering if I can take it all off

Exahust fumes, its the BACK of the cab that is cut out, and booted thru for my speakers that are in the bed of the truck. Kinda like a campershell w/o a window, but its the lower half, and I have a bed cover. I was looking at the egr pic off a 93-95 cpi 4.3l, and it looks like the bolt up is the same, and its a digital egr.

As for swapping the egr on a 3.1mpfi, and an old school 2.8 tbi, they are no way located, installed the same. Mpfi is mounted on the manifolds, the tbi is mounted on the back of the intake.

 

Hi, One more question please.
There is a "T" hose (vacuum line) connection right near the distributor behind the plenum. One is a black hard plastic hose, and the other is about 5/8" soft rubber hose. Well I broke the hard plastic one and I taped it up with duct tape for now. But I have searched my Chilton's and cannot find what these hoses go to.I really need help. Had to put a new battery in tonight, so I sure can't afford a new EGR will take your advice and go to the junk yard. How do I know where a engine noise is coming from? I think it's from the rear of the engine, but I am not sure. What about the different noises? Is that something I would need to learn from experience? If it's a rod knocking can I fix it myself? I used to help my dad and my 4 brothers work on cars, but I son't know about that.
Help!!!!!
Beth

 

HOLD on I think we found your problem. Your code could be seting because it's not reading the right plentum pressure. YOU HAVE TO GET a new hard plastic hose and hook it up to that spot on the plentum and to the MAP sensor on the fire wall, it's hanging there, has a green connector on it. You can get the hose at the dealer or at a junk yard, make sure the one you get at the junk yard isn't cracked or something.

The make sure your EGR is connected also and clear all codes by disconnecting the battery for 1 minute. If the code still reappears then go to a junk yard and get an EGR valve WITH A warrenty or if it's way cheap just take it. Get a new gasket at autozone or some place.

 

Engine noises, check your oil make sure it's fresh and up to the right level. Make sure you have oil pressure on the dash gauge. Have you changed your oil filter latly maybe your losing pressure and your getting a dry knock. You will have to describe the noise further.

 

Usually, them hoses go to the 1. plenium/tb, 2. the ducting in the cab for your ac/heater/defrost, and 3. on my s10 it had one go the the vacume bubble.