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Discussion Starter · #1 ·
Hey guys, I have been getting misfire on cylinders 4,5,6 after I took off my EGR system. My car is OBD2 so I wanted to know if any of you OBD2 guys have done the EGR removal and have had this problem.
 

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William,

What makes you think it's the EGR removal? Plus, how do you know that 4, 5, and 6 are misfiring? Sounds like you're grabbing at straws. EGR has almost nothing to do with the delivery of fuel and spark.

Are you still running the distributor (i.e. have you change the ignition system)? Have you tried removing a plug from those cylinders to check spark? Have you done a compression test on the suspect cylinders?

I can't imagine that you *only* removed the EGR, and all of a sudden the car is misfiring. Am I right here?

C'mon man... do some investigating here. Treat it like someone with an ailment, and they came to your clinic for a spine alignment to fix it. Would you only ask them what they last did and use that to fix the problem?;)

-scott
 

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I also received a CEL(OBD2) this past weekend, ran the codes(301) and it indicated a misfire in cylinder 1. I checked the code book and it indicated that the cause can be related to: ignition/egr/fuel and some other things.

I changed the spark plug on cylinder 1, reset the ecu, and have driven the car 10 miles since, no CELs yet.
 

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Discussion Starter · #4 ·
Scott,

The reason why I know that cylinders 4,5,6 are misfiring is because I got OBD2 codes that state that misfire was detected in those cylinders..I didn't just grab it out of my ass. The reason why I know that I believe that it is my EGR removal is because I didn't have this problem until after my EGR removal. It states in my repair manual that if misfire is detected in cylinders 4,5,6 that you should check your fuel injectors, fuel pressure, EGR, and finally MAF. I haven't touched my injectors, fuel pressure or MAF so I concluded that it has to be my EGR.

I am still running w/ my distributor setup
 
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Did you remove your upper intake manifold or anything like that when you messed with the EGR stuff? I just did an NA-T on a 97 and made some plates to block off the EGR. Took me a while to figure out exactly what lines were needed and what lines werent. Are you sure you have all of the vacuum lines hooked up right? What about any plugs or connectors. Just blocking off the EGR shouldnt do anything to make the car miss. But then again, that is another question all together......

Does the car miss or are you just wondering why the light is on?
 

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tuanthuy_99 said:
Scott,

The reason why I know that cylinders 4,5,6 are misfiring is because I got OBD2 codes that state that misfire was detected in those cylinders..I didn't just grab it out of my ass. The reason why I know that I believe that it is my EGR removal is because I didn't have this problem until after my EGR removal. It states in my repair manual that if misfire is detected in cylinders 4,5,6 that you should check your fuel injectors, fuel pressure, EGR, and finally MAF. I haven't touched my injectors, fuel pressure or MAF so I concluded that it has to be my EGR.

I am still running w/ my distributor setup
First, chill... look at your orignal post. Do you see any mention of ODB2 codes pointing to cylinder misfire? You provided absolutely no background research on your part in the post. Plus, when is the misfire occuring; or are you just relying on the codes to tell you something is wrong? Details William... your original post lacks details.

Second, look at what the manual is pointing you to... *fuel* injectors, *fuel* pressure, egr, and MAF. Hmm... what makes a cylinder misfire... Maybe *fuel*, *air* (i.e. MAF), and *spark*? It's easy to determine if the egr is the problem. Just put the thing back together. However, I guarantee the egr removal isn't the source of the misfire. The only possible explaination related to the egr is if the ecu was *programmed* to cut the ignition or fuel if there was a problem with the egr. Did you overlook an egr diagnostic signal that gets fed back to the ecu?

Finally, I'm glad you didn't pull your conclusion out of your ass as so eloquently stated. Just realize that we can't read your mind. All I've every done in the past is help you. Unlike others on this forum, I've worked with you before, and you'd rather have someone do the work for you instead of doing it yourself. You know that's a fact.

Chill...

-scott

P.S. BTW, cross-posting to 3 different forums/sections is just plain rude.
 

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Discussion Starter · #8 · (Edited)
First, chill... look at your orignal post. Do you see any mention of ODB2 codes pointing to cylinder misfire? You provided absolutely no background research on your part in the post. Plus, when is the misfire occuring; or are you just relying on the codes to tell you something is wrong? Details William... your original post lacks details.
Details: OBDII codes are P0304, P0305, P0306 which stands for misfiring in cylinder 4, 5, and 6 respectively. Misfiring occurs while cruising on the highway. Back ground research I found which made me conclude that it was the EGR(also the fact that this misfiring never happened until after I removed my EGR system):

In the cylinder of an automobile engine, a flame ignited by a spark propagates through an air-fuel mixture and toward the
cylinder walls and piston. Conventional wisdom was, for years, that a major source of unburned hydrocarbon emissions was the extinguishing of the flame as it approaches the relatively cold walls of the cylinder. Many thought the process left behind a thin layer of unreacted fuel. Fuel research modeling has supported this traditional view until near the end of the ignition process, where data indicates that fuel trapped in the cold boundary layer at the wall begins to diffuse back out toward the high-
temperature region where it is rapidly consumed. Later research confirmed that unreacted fuel in the piston ring crevices is actually the primary source of unburned hydrocarbon emissions. Knocking occurs when the flame from the spark plug does not consume the gases in the piston chamber fast enough. The remaining "end gases" spontaneously combust, sending a
damaging shock wave (knock) across the chamber. To retard this process (knock), recirculated exhaust gases are injected into the fuel-air mixture to raise the air temperature quickly and, hence, the temperature of the intake fuel/air mixture to aid in consuming all gases, including "end gases" through preheating the mixture to eliminate potential "cold spots" within the cylinder. The EGR is injected near #6 cylinder, but it is not there to just help #6, but is injected into the intake near the cylinders to "up the air
temperature" just before intake and mixture with gasoline by the injectors.

All I've every done in the past is help you. Unlike others on this forum, I've worked with you before, and you'd rather have someone do the work for you instead of doing it yourself. You know that's a fact.
I appreciated all of the help that you gave me Scott and I have always thanked you and have offered to help you also, but that is not true stating that I would rather have someone else do my work. Yeah maybe I asked you to help me drill my block and you got my oil return line but I did everthing else to install my turbo kit. On my last car, I did everthing on my own(including putting a new motor, transmission, wiring it up, etc.) and never sent my car to a shop to get fixed. You've only known me for a couple of weeks and you come to superficial conclusions. Please....

P.S. BTW, cross-posting to 3 different forums/sections is just plain rude.
I posted in 2 different message boards...this one and clublexus. Big damn deal..I am sure there are some guys that browse supraforums and not clublexus and vice versa. That also goes with the NA section and TT tech. If I offended you by cross-posting, I am sorry. Please.....:rolleyes:
 

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Discussion Starter · #10 · (Edited)
It is definitely missing...The car feels like its missing especially while cruising on the highway.

Brad, I read your reply above and I also installed block off plates..I put a resistor for the EGR temp sensor but did you put any type of resistor for the EGR VSV?
 

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Discussion Starter · #12 ·
Aliga,

Thanks for the info...Too bad that I threw away that sensor. Aliga, did you totally take off the EGR system(EGR vacuum modulator, EGR valve, and EGR VSV)?

William
 

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Not sure what all the components you mention are: but this is what I kept installed, i think it is called the egr actuator, the flying saucer looking thing near the back of the firewall. I also capped two lines after removing the egr system, one nipple on top of the actuator, and one nipple on the bottom of the actuator.

Hope this helps.
 
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I got rid of pretty much EVERY one of those vacuum lines. The only one on the upper plenum that I used was to the FPR VSV I think. Dont remember for sure. I didnt fool with the resistor cause the car didnt throw a code till the customer had already picked it up. I know this, it runs like a top. A/F is a flat line at about 11.8:1. I also took off the silly butterfly thing in the upper intake. The butterfly is still there but I wired it open and took off the valve that opens and closes it.

I'm pretty sure you just messed something up. Make sure you hooked everything up right. Blocking the EGR itself is not what has caused your problem unless you did it wrong.
 

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Discussion Starter · #15 ·
Aliga and Brad, thanks for replying....

Aliga, on your EGR actuator(flying saucer looking thing), you capped the bottom part of it and which one on the top? There are three different vacuum ports up on top which are labelled P, R, or Q on the EGR actuator. Did you cap the Q port which tees to the EGR valve and EGR VSV? I know that the R port and the P port from the EGR actuator goes straight to the throttle body which are also labelled R and P on the throttle body.

After I reset my ECU, I would get the cylinder 4,5,6 misfire code whenever I drove long distances(200 miles) When the car was cold, I would never really feel any type of misfire or hesitation. I could only really feel the hesitation while cruising on the highway for some time(30 min+).
 

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William,

I capped the Q port where the tee is. You can see the the vacuum line coming out of Q on the left, which goes to a tee(y shape tee), and then one of the ends is open, this was capped.

As Brad indicated, you can do away with the saucer, since it appears to be some sort of vacuum hub without the egr in place.
 

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Discussion Starter · #17 ·
Aliga,

I have tried it both ways.. I have tried it like Brad's way by removing the entire EGR system including the saucer looking thing and taking off all of the vacuum lines

1) vacuum line that goes from side of throttle body to EGR VSV(capped this port)
2) vacuum line that then goes from EGR VSV to port Q of the EGR actuator(vacuum modulator) which is also teed to the top port of the EGR valve
3) vacuum line that goes from port P of the EGR actuator(vacuum modulator) to the throttle body at port P(capped this port)
4) vacuum line that goes from port R of the EGR actuator(vacuum modulator) to the throttle body at port R(capped this port)

Thus what I have taken off the car is the EGR actuator(vacuum modulator), the EGR VSV, and the EGR valve w/ temp sensor.

I installed my blockoff plates and then wired in a 10K-Ohm, 1/2 watt resistor #271-1126 for the EGR temp sensor. I still had the EGR VSV connection dangling.

This was my first setup and it caused the affects I have been talking about...Then I tried it like your setup Aliga with the flying saucer looking thing with the EGR VSV which is a little better . Too bad I threw away the metal tube that connects the EGR valve to the block because if I had it, I would have put everything back together....

thanks guys..
William
 
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