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EGR+misfire

25K views 22 replies 8 participants last post by  speckthedeck 
#1 ·
I'm not even quite sure where to start with this anymore. I've been on a couple other forums and they seem to leave me on my own groping for answers. I have to give all the information so it makes sense, and hopefully someone can give me true answers :(


Also, before all this I had already replaced cap and rotor, plugs and wires. EGR code happened maybe 6 months after that.

99 Prelude SH

EGR code: blocked or broken
*Removed, cleaned, replaced with new gasket
Misfire codes: Cylinders 1-4, multiple random misfire
*Replaced plugs (white) and wires
Misfire codes: Cylinders 1 & 2, multiple random misfire
*Injector cleaner
Misfire codes: Cylinders 1-4, multiple random misfire
*Replace fuel pressure regulator
Misfire codes: Cylinders 1, 2, 3, multiple random misfire? (Read from mechanic sheet)
*Diagnostic test (waste), replace fuel filter, change plugs to NGK (white), and replaced PCV
Misfire codes: Cylinder 1
*Move injector from Cylinder 1 to Cylinder 2
Misfire codes: Cylinder 1
*Unplugged EGR
Misfire codes: Cylinder1, 3, multiple random misfire
*Reconnected EGR, disconnected EGR solenoid plug
Codes: p1491... No misfires...

I was hoping to block the EGR and do some kind or resistor, but the more I read about that the more hopeless that becomes. Personally I don't want to pay for an EGR solenoid or an EGR. I don't live where emissions are an issue. I would just like to not have a CEL.. or misfires for that matter.

Please help me....
 
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#3 ·
ok dud e i had the same car and the same problem. first take of your iack valve and clean it then take out your egr valve and clean it with carb cleaner then tighten your fast idle control valve. if that doesent work your will need to clean out your egr ports witch is a BlTCH to do. then you should be all set
 
#7 ·
Lets see...

When all is plugged in I can very rarely feel any misfire. I describe it as something easily confused with a somewhat bumpy or wavy road. With the EGR itself unplugged it did feel like a true misfire. Everything plugged you would think it ran fine, except for the CEL.

I already took the EGR off and cleaned it, it was the first thing I did. The ports.. I tried to clean, I brushed in there as much as possible and tried to vacuum it out. Other than that it didn't seem like I could get anything in there to clean it out. I'll have to look into the idle control valve, I thought about the IAC, but never made a move on it.

P1491 was thrown because the EGR solenoid was unplugged. The original code that the man told me said "clogged or broken EGR" I never got the actual code for. It could have been P0401, I'll never know.

I had already bought the EGR block off plate, it's in the middle of shipment.

It's not that the EGR doesn't work.... it's that.. it doesn't work correctly? It says it works but that somewhere the engine finds a misfire, but doesn't directly associate that with the EGR?
 
#18 ·
P1491 was thrown because the EGR solenoid was unplugged. The original code that the man told me said "clogged or broken EGR" I never got the actual code for. It could have been P0401, I'll never know.
This is the guessing part I was referring to.

Now, if I were in your shoes, here's what I would do.

1) Find another Prelude owner and swap EGR valves. Clear CELs (clock/radio fuse) and see if they come back. If they do, you've just ruled out the EGR valve.

2) Pull the EGR ports and clean the system thoroughly with: combustion chamber cleaner (MOPAR brand), a long thin wire brush attached to a cordless drill, a shop vac with funnel on the end, a tap, 6 stubby 10mm bolts, and some loctite. Use the tap to thread the EGR port plug holes. Use the 10mm bolts in place of the plugs. Secure them with the loctite. (This will make for much easier cleaning the next time it's required.) And then obviously test the system again to see if the CELs come back. If they do....

3) Steal the other Prelude owner's ECU and give that a try.
 
#10 ·
It's possible. You have to really clean the **** out of those ports. You could have other problems, but I've learned to start off doing the cheapest, possible fixes first. Don't just throw a bunch of expensive parts at it untill you get it right. Start off by doing anything that you can DIY for cheap, like cleaning the EGR ports.
 
#12 ·
yea man so the iac valve and the fast idle control value you need to screw that thing in its right under your throttle bodie trust me it might not sound like thats the problem but it might be i did all this to my car and my cel went away
 
#13 ·
I've been putting it off since I've been waiting for figure out which course of action I wanted to take. I thought I would take the EGR off and inspect things again, but I failed to take it off when I had the chance. When I cleaned it the first time I was at my dad's and had used his tools unknowing that he had used a joint to get the bolts off.

I've been trying to find this tool that will test pressure in the lines to see if there is a leak somewhere, but... I don't even know where to look. I figured I could test all that and make sure it isn't just a line, or perhaps the EGR diaphram itself. I don't want to block it off and decide that it was the wrong thing to do.

Also was debating doing the IAC, as I have been the whole time. It has it's own code to throw and of course there is nothing of that. But lately I'll start it up, drive a little ways have the rpm's up at 3000 and put the clutch it, sometimes it will drop down below 500 and other times it will not. I thought I read somewhere that cleaning the IAC would help that, but again... procrastination.

I'm trying to save money to go on a trip so I haven't exactly been tossing money into the situation, although I did in the beginning thinking it had nothing to do with the EGR. I suppose just knowing the "misfire" is gone keeps me from rushing around for answers, regardless of the CEL and ATTS light in my face.
 
#17 ·
I'm getting codes for cylinder misfire. The latest being cylinder 1.

Before I unplugged the solenoid I would get misfire codes in any number of cylinders randomly, as you can see by what I posted before, it jumped around. And constantly the multiple random misfire code.

301, 302, 303, 304, 1399 that people say doesn't exist. Should I write it out again? They don't all come up at the same time, they could be in any order, at any time. As I said before the sequence that I did things gave way to different codes being thrown. I'm not sure if it's when I checked them, or if it had nothing to do with how long I went between reading the codes.

There is no EGR code being thrown when the solenoid and EGR are plugged in, being the reason why I never felt the need to check them. I don't get any other codes that lead me in any other direction. So yes, I am going off of a lot of symptoms because the codes are too large of a range, I'm sorry you can't see that.

My guess? What guess do you see. There are no EGR codes unless I pull the solenoid plug, it throws the 1491 because it is NOT plugged in, hence no lift. But when it is pulled there is no... I repeat NO misfire codes at ANY time at ANY length of driving. So I would say, it has to do with the EGR system. Or is that illogical? The whole point being that regardless of the codes that show up it has led me to no solution except the symptoms. Would you like me to go over the symptoms again? Or are they not sypecific enough for you?

I have to say that I've put up quite a bit of information as I've seen other people that fail to describe their problem fully for other people to understand. And I greatly appreciate everyone's help and opinions from their own experiences, the entire reason why I'm here. So no, I didn't put up the specific codes because I figured everyone who was helping me was already versed in it. Thank you for your help, up until this point.
 
#19 ·
Yes that was the only thing I could guess at.

There aren't very many prelude owner's in my area, and none of which that I talk to. So I doubt they'd let me take their EGR :laugh:

No one ever said to pull the ports, just to scrub them a little when removing the EGR for cleaning... I guess I'd have to look at it. Didn't seem like something that just pulled out. Hmm...

Thank you, once again.
 
#22 ·
Speaking of misfire, what does it mean when you feel a miss, you know it. However, there is no CEL, and it only does it when warm, and VERY rarely. I mean, it used to only mis like that once or twice within a couple seconds,a nd then not do it again for amny many months. However, recently, It's been doing it more times in a row, and more often.

I have never, nor do I know if the rotor and cap, plugs or wires have been repleced. Feul filter too. So I'm thinking it's time for a full on tune up, what would you say?

I hate my car doing that, but it is so rare and random, still, that I don't really know how to react. When accelerating, even right after it misses a little, it accels perfectly. I have NEVER experienced my car missing while acceleration, nor has it done that with the A/C on. hmmmmm, this is so simple, but so weird.
 
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