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Old 04-23-2008, 08:15 AM   #1
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EGR Bypass

Hey guys, I'm new to this post but had a question. I just bought my favorite car in the world, 92 firebird, and it has 5.0TBI. The service engine light is giving a 32 meaning the EGR value issues. Anyway, upon inspection of this system I noticed that the previous owner has disconnected the hose at the bottom of the EGR and connected it to what looks like the radiator overflow tube. Does anyone know the purpose of this? I am thinking of hooking the EGR back like it should be, but was wondering why someone would bypass it, maybe more horsepower? Should I not fix it? Will it effect performance or hurt my engine?
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Old 04-23-2008, 02:18 PM   #2
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Re: EGR Bypass

i'm confused... so the radiator is overflowing into the egr valve? pictures help.
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Old 04-23-2008, 02:56 PM   #3
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Re: EGR Bypass

I know its a weird hook up...I will take a picture and post it this evening, I think it is a way to stop up a vaccum line...I am not a mechanic, but it is a hose coming out of the top of the radiator and going into the hose that used to be connected to the bottom of the EGR. Any ideas or suggestions will help...I'll get you the picture...thanks
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Old 04-23-2008, 04:13 PM   #4
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Re: EGR Bypass

which hose are you talking about? The one that connects to a weird little black box on top of the engine or the one that connects to the metal tubing on the driver side? Either way it probably means that ur car is pumping exhaust into the radiator, which idk if it will do harm to the car but I wouldnt think it would be good either. This probably was done to add horsepower because the EGR system takes a lot of power away from the engine. If you wanna keep the setup like that I would reroute the EGR hose somewhere where it can exhaust the gasses without melting things and it would be a good idea to unplug the tiny hose that connects to the side of the snorkel on the intake as well. I bypassed my EGR system and it really opened up a lot of power for my 89 z28.
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Old 04-23-2008, 06:51 PM   #5
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Re: EGR Bypass

Here are some pics...see if you can make anything of them. Any help is greatly appreciated. I hope you can get these pics to open.
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File Type: jpg 92 bird.jpg (58.4 KB, 243 views)
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Old 04-23-2008, 08:39 PM   #6
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Re: EGR Bypass

Does your heater work? the hoses you have pictured are heater hoses. i've attached a pic. the round silver thing in the pic is the top of the EGR valve, which is bolted to the intake manifold. There are 2 fittings on the firewall for your heater core. the metal pipe in your first pic should have a hose on the back of it which attaches to one of them. Hose 1 should attach to a "T" fitting on the end of that metal pipe in your first pic, there should be another hose coming off the same "T" which plugs into your radiator where the hose you are pointing to is attached. hose 2 should go to your other firewall fitting. and hose 3 should go to the rear passenger side of the intake manifold where there is a fitting. it looks like the hose from the back of your intake manifold has been bypassed and sends the hot coolant straight back to your radiator.
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Old 04-23-2008, 09:23 PM   #7
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Re: EGR Bypass

heater doesn't work...so hopefully the heater core is still ok, as long as i fix the hoses...I was worried about that one...I think I'm going to re-hook back up the items you said. Is there any horsepower benefit for bypassing EGR or heater hoses? What is the thing that I am holding in the pics? the cyclinder with the round thing on it?
would you re- do what has already been done? It runs fast, but the stupid SES light comes on around 70 mph after a while....it drives me crazy...32?!?!?
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Old 04-23-2008, 10:44 PM   #8
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Re: EGR Bypass

The first thing you should do is clear that code. check the wires and vacume lines on the EGR solenoid and the vacume line on the EGR valve. To check the valve itself stick your finger up through the hole in the valve (if it will fit)and push up on the diaphragm, it should move easily. you could just remove the vacume line that goes to the TBI from the solenoid and plug any loose ends effectively disabling the egr valve. if you do unplug it you could possibly run into some detonation issues, but you will not feel the car pulling harder.

a search might get more info on the matter.
There is no horsepower to be gained at the expense of the heater. the thing in your hand is a control valve, it routs hot water from the intake manifold to the heater when activated and bypasses the heater when it's off. the pic shows the hoses hooked up to the firewall where the heater core is.
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Last edited by topless89; 04-23-2008 at 10:48 PM.
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Old 04-23-2008, 10:54 PM   #9
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Re: EGR Bypass

ya I agree with topless...those are the heater hoses and no they won't add more power by rerouting. The EGR is a different story though GM did this to add to efficiency of the engine, but it does kill a good amount of power. The exhaust gasses are pulled from the headers and rerouted through the intake to completely burn all the gas. The problem is it is also burning other hydrocarbons and reduces the %O2 that enters the cylinder and heats up the intake temp. If you can effectively reroute the EGR line and disable the vacuum pump your intake will pull only cool, fresh air into the engine. This results in more power, but will reduce MPG. It made a noticeable effect in my car but if you have emissions in your area it will cause a fail in smog test
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Old 04-23-2008, 11:32 PM   #10
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Re: EGR Bypass

You got more power just from disabling your EGR?? My EGR valve is on its way out (really stiff to open with finger) and the motor KNOCKS LIKE HELL!! So be careful, I bet that just putting a block off plate might cause the car to knock too.

Oh BTW, I have resolved the knock issue by running premium 93 octain. But, the minute I put any 87 or 89 octain in there, it knocks real bad again!

Here:

http://youtube.com/watch?v=x1MyOODy9W0

http://youtube.com/watch?v=XiBzxxvy3FQ
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Old 04-24-2008, 01:40 AM   #11
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Re: EGR Bypass

ok well i did away with my egr bullcrap a while back and just hooked the egr hose up two a vacum port on my tbi, i get a check eng light and i just took the light bulb out and all worked out fine for me my 305 pulls harder? oh no wait..its probably just my hooker 2055s that made the difference
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Old 04-24-2008, 08:30 AM   #12
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Re: EGR Bypass

Thanks for the info and pics...I think I can actually get to this problem and fix the correct things, my heater may work after redoing the hose issues and now I think I know where the EGR is. HA Great advice topless89, I really appreciate the help!
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Old 04-25-2008, 05:04 PM   #13
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Re: EGR Bypass

ya it is a noticeable pull...more responsive at least when I hit the gas it kicks harder...I didnt block off any hoses all I did was unplug the little vacuum hose in the snorkel and unplug the hose connected to the back of the metal tubing that blows hot exhaust towards the snorkel. I redirected the hose to blow air out the back of my hood, in cold weather it works almost as well as my defroster to evap all the frost lol! Nothing is blocked so the egr thinks it is working properly and no check engine light comes on
----------
o and ps...90 firebird, your probably getting knocking from egr valve getting stuck open...too much exhaust in the intake means not enough o2. Itll throw ur ignition timing off, higher octane prob works bcuz ur not burning as much gas in the first pass n the egr is jus throwin it right back into the cylinder again

Last edited by comealive305; 04-25-2008 at 05:09 PM. Reason: Automerged Doublepost
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Old 04-25-2008, 11:37 PM   #14
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Re: EGR Bypass

Quote:
Originally Posted by comealive305 View Post
ya it is a noticeable pull...more responsive at least when I hit the gas it kicks harder...I didnt block off any hoses all I did was unplug the little vacuum hose in the snorkel and unplug the hose connected to the back of the metal tubing that blows hot exhaust towards the snorkel. I redirected the hose to blow air out the back of my hood, in cold weather it works almost as well as my defroster to evap all the frost lol! Nothing is blocked so the egr thinks it is working properly and no check engine light comes on
----------
o and ps...90 firebird, your probably getting knocking from egr valve getting stuck open...too much exhaust in the intake means not enough o2. Itll throw ur ignition timing off, higher octane prob works bcuz ur not burning as much gas in the first pass n the egr is jus throwin it right back into the cylinder again
No, you are not even knowing what the EGR is. You are talking about the THERMAC valve. That has no affect on performance, unless the motor is still in warm up mode in the winter. It doesent pull exhaust gasses, it pulls hot air from the "stove" of sheetmetal around the manifold, to help the car warm up on a cold day.

The EGR valve is the one that is bolted right to the intake manifold. Looks kinda like an flying saucer, and uses a vacuum solenoid. That actually takes some exhaust gas back from the exhaust ports, and directly feeds it into the intake manifold.

My EGR valve is not stuck either. It closes fine. The problem is, it takes quite a bit of effort to move the diaphragm with a finger. Also, recirculation of the exhaust into the intake does not cause knock. It reduces it. It also helps fuel milage quite a bit I guess. My buddie just replaced it in his 95 pickup, and it did wonders for his gas milage on the highway.
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Old 04-26-2008, 01:59 AM   #15
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Re: EGR Bypass

thanks slow90. i was about to post the same reply, then i remembered when i first started toolin around on my car and i thought the THERMAC was the EGR just like comealive did. since i'm posting again i'll just remind anyone disabling their EGR without the need (engine, cam. mods) that it can lead to detonation "knock". when your ESC picks up knokc it retards the timing, retarted timing is not the key to performance (exclude power adders).
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Old 04-27-2008, 07:59 PM   #16
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Re: EGR Bypass

Does anyone know if the EGR valve has a gasket under it? I have trouble shot my egr system and know my code 32 is either my egr valve or carbon build up underneath it. It I pull the EGR off, will I need a new gasket to bolt it back on? and is that the right place to try to clean out the carbon that can sometimes cause clogs?

My EGR solenoid functions correctly and the diaphram on the egr valve is movable...the vaccum lines are all good and the solenoid does pull vaccum. Any other ideas? I am thinking its a bad egr valve, but to just clean out some debris under it would be much cheaper. Am I correct in my assumptions? Any help is greatly appreciated. Thanks
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Old 04-27-2008, 08:09 PM   #17
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Re: EGR Bypass

you should replace the gasket. you can use a drill bit to clean out the inside of the valve. i wouldn't reccomend cleaning out the passages in the manifold with it attached to the engine.
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Old 04-27-2008, 09:46 PM   #18
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Re: EGR Bypass

so you are saying, pull off the egr...clean it...don't mess with the part underneath it that is connected to the engine? I don't want to mess anything up and if all it takes is bolting on a new EGR then that is what I'll do. That is an easy fix. On other posts, I have heard that it is ok to take a rifle cleaning kit and run it down into the intake area...is this a bad idea? From what you say, I should just clean the egr valve and not mess with the underside that it bolts too. Right?

Thanks topless89 for your expertise...I will soom be an EGR master and will be able to help others as well...it is all a learning experience.
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Old 04-27-2008, 10:01 PM   #19
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Re: EGR Bypass

a rifle cleaning kit for the manifold is not a bad idea, you just don't want to unleash a bunch of debris back into your intake manifold through the EGR passage. hopefully cleaning everything out will help. i bought a new EGR from Auto zone and was surprised when it rang up at $60.
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Old 04-27-2008, 10:42 PM   #20
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Re: EGR Bypass

Did the $60 EGR from autozone work good??

Also, you could always use carb cleaner, or some "deep creep" sea foam, to clean the passages. Maybe a toothbrush in the openings. Just try not to get anything "physical" like a bristle, or metal shavings, into the motor.

Finally, what do you guys use to get the EGR off?? Mine has these bolt heads that look like the end of a torx screwdriver! Does somebody make a torx reverse socket or something?? Would it even fit, it looks like the valve itself would be in the way of using a socket maybe. Torx box-end wrench lol??
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Old 04-28-2008, 01:05 AM   #21
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Re: EGR Bypass

i'm not sure about the bolt heads on yours. mine were regular. but it was a serious pain to get the socket in there, i ended up bustin' my knuckles an dusing a small wrench held at an awkward angle. the valve i bought works fine and came with a new gasket, but i suspect there has to be a cheaper on for sale.
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Old 04-28-2008, 04:17 PM   #22
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Re: EGR Bypass

Well $60 is nice compared to the $120 I expected.
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Old 04-29-2008, 12:23 PM   #23
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Re: EGR Bypass

yes i agree, the olny reason i had two bypass mine is because when i first bought my car i replaced my fuel pump, and my throttle body, and my injectors were in wrong. They were leaking lots of gas into my intake and it backfired! and cought fire and melted all of my egr wires, and smog wires,and vacum lines on that side what can i say it was my first time working on TBI and i should have done some research. The good news is i didnt have two go carb, but i still get a check engine light every time a start up but i know its from my egr not being hooked up correctly, so just take the bulb out and run it till she drops.
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Old 04-29-2008, 12:23 PM
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