Author Topic: EGR issues. Need some help (Read 57323 times)

GrimReaper · « **on:** Sep 15, 2005, 05:51:31 PM »

86 22RE

I'm failing emmisions due to high HC (299 actuall 189 allowable). Well in my quest to find an intermitant miss causing the high HC I find that I can get rid of the miss by disconnecting the EGR. NOX was ok but I don't think it will pass without hte EGR functioning. The EGR appears to be opening on time so I think the control set up is fine.

So this has me scratching my head as to why I am getting a EGR induced misfire. Now this truck has issues due to some shotty work done before I owned the truck including some really crappy machine work done on the head when it had a BHG.

I have it down to a couple of possiblilities.

1. Control disc has issues but it seems to be ok and opening with it should.

2. When the bozo that repaired the HG put things together there was some sort of orifice restriction to meter the exhaust gas and it got left out when it was assembled. So I am getting too much EGR that I am sufocating the engine.

So my questions are

A. Is there a precidence on the RE for egr problems that could lead to misfire?

B. Is there some sort of orifice size restriction device on the EGR in some way that could have been left off?

Thanks

79coyotefrg · « **Reply #1 on:** Sep 15, 2005, 07:22:41 PM »

RE

oh mike,

calling Bigmike

YOguyDa · « **Reply #2 on:** Feb 01, 2006, 11:33:59 PM »

Im having the same issue at the moment and this is the only post that i can identify clearly with...But there arent any replies?

Anybody have this happen to them?

The problem occured when i reconnected the vacuum line from the manifold to the pvc, so my theory is that the pvc and the egr operating at the same time create too lean a mixture in the upper rpms, causing the MISS.

I need to pass smog pretty soon here and all i can figure is to plug the pvc at the manifold and leave the pvc line under the aircleaner so that it looks hooked up. I havent plugged it off yet to see if it helps with the miss, but im sure it will work......(Thats the only thing that changed, right when the problem came about).

Any other input?

toymech · « **Reply #3 on:** Feb 03, 2006, 06:36:44 PM »

How high was NOX when you failed? A stuck open EGR can cause high HC. How are you checking that its opening and closing? The engine miss goes away when the EGR is disconnected,id say your EGR is stuck open=vacuum applied all the time. Thought I was having the same issue,but my high HC is from a high duration cam. If you try to pass smog with the EGR disconnected youll fail for NOX=High combustion heat. Mike

YOguyDa · « **Reply #4 on:** Feb 04, 2006, 02:32:14 AM »

I dont know that GrimReaper is still having this issue, but i revived this 4 month old post because i was having the same issues described by GrimReaper.

One day i took off and my truck was sluggish and missing, so after checking every vacuum hose i could, i finally got to the egr line and when i pulled it, the truck smoothed out and ran fine. I checked the EGR(good) and even replaced it with another functioning EGR. I put a vacuum gauge on the line going to the EGR and im reading about 5inches at about 2000rpm. Its got me stumped as to how pulling the EGR vacuum line was a quick fix to a problem that isnt apparent at all. This problem started out of nowhere and seems more like a carb problem, but my carb functions just fine with the "functioning" EGR plugged off. Maybe im missing something obvious?? But nobody else seems to have any idea.....

toymech · « **Reply #5 on:** Feb 04, 2006, 09:32:49 AM »

If your pulling the vacuum line off of your EGR and its smoothing out,its leading me to beleive your EGR is getting vacuum at idle. You could have a vacuum line hooked up wrong,usually the EGR valve is ported vacuum=coming on at a specific throttle opening of the carb. My advice is pick up a haynes manual for your truck and go through the vacuum circuit for your EGR. These engines run rough to begin with,i can imagine what your truck runs like now. Keep me posted. Mike

YOguyDa · « **Reply #6 on:** Feb 04, 2006, 10:29:23 AM »

Everything has been vacuum tested.....EGR=0 inches of vacuum at idle, 6 inches at 2000rpm. The truck idles fine, but once i take off it misses and bogs down like i have a bad vacuum leak or my choke is closed, but because thats not the case, i dont know what to think. It seems worse when its cold, if that helps any? Personally, it seems like a carburetion problem, but why would it run good one minute, drive like

the next and then drive good again with the egr unhooked. Considering the egr system seems to be functioning fine, im confused

.

toymech · « **Reply #7 on:** Feb 04, 2006, 04:45:46 PM »

Hey,it just dawned on me. Did you check you fuel pressure and your compression? Just need to know what they are before we pin everything on the EGR,no vacuum at idle is a good thing. I dont know how your getting it to run better with that EGR hose off. Check out the fuel pressure and compression and let me know what ya find. It sounds right now like it may be a carb problem or something simple. Later Mike

YOguyDa · « **Reply #8 on:** Feb 04, 2006, 08:22:25 PM »

I havent checked the compression on account that the engine has about 4k miles on it.....But i shouldnt rule it out i guess. I actually thought about the fuel pump, but i didnt dwell on it for too long. The fuel level (in the bowl) seems to stay within specs, but im not for sure if that rules out fuel pressure? Unplugging the EGR has me stumped too, i cant make sense of that considering the condition of the EGR system. I rebuilt the carb and replaced the intake manifold gasket a couple months ago, And its been running perfect until now. Maybe its one of the electro valves on the carb? I dont know, i'll poke and prode a little more and see what happens. Thanks Mike.

YOguyDa · « **Reply #9 on:** Feb 07, 2006, 07:11:39 PM »

You can un-stick this thread, Because the case is CLOSED! Hell yeah!

I was messing with the truck today, and figured out the problem. It was the EGR Modulator Valve located on a bracket connected to the EGR. I hooked the EGR up and pulled the throttle until it started missing (around 2000rpm's), then i disconnected the line from the modulator and wallah! It cleared out and ran smooth. When i pull the vacuum line from the EGR it also clears out and runs smooth, so i did some research on the Modulator and it appears to function like a wastegate on a turbo, but instead it regulates how much vacuum the EGR gets. The diaphragm in it is probably weak and is not letting the EGR open up all of the way. That sounds backwards when compared to my initial thoughts of the EGR being pulled on too far, but the modulator's functions reject that theory.

TEST DRIVE RESULTS:

After unplugging the vacuum line supplying the EGR and plugging it, I took it for a test drive and found that the miss was gone. It ran fine, but it felt like my timing was off, it had very poor throttle response, poor gas mileage and acceleration was very very bad. On the other hand, it was DRIVEABLE.

After plugging the vacuum line supplying the modulator valve and plugging it, I took it for a drive, and i was FLOORED with the results. My truck performed the way it had before this whole epidemic. Very responsive to throttle, more than great acceleration, and it ran smoother than silk through the entire rpm range. I couldn't be happier at the moment.

toymech · « **Reply #10 on:** Feb 07, 2006, 07:37:01 PM »

Notice how all that emissions crap is always the problem,lol. Glad everything went well. Mike

YOguyDa · « **Reply #11 on:** Feb 08, 2006, 02:28:58 AM »

I notice it every time my truck starts acting up.....Not once has anything accept for emissions

slown me down, i hate it. Thanks for all the help Mike.

Uncle Jesse · « **Reply #12 on:** Feb 08, 2006, 11:17:34 PM »

If you suspect the modulator, first check to make sure the filter on the top of it is clean.

Also, it seems to me that 6" of vacuum at 2,000 rpm is high. When I tested mine 3-3.5" of vacuum would fully open the valve.

Oh, and remember that the modulator runs off of exhaust backpressure too. It's the hose that comes out the bottom of the modulator and attatches to the egr on the exhaust side of the valve. They like to carbon up, and the little tube there may be plugged.

EGR valves and modulators aren't the cheapest in the world, so maybe some cleaning could save you some dough.

YOguyDa · « **Reply #13 on:** Feb 08, 2006, 11:27:35 PM »

The hose supplying the modulator is clean, and the filter was clean also, it was just a little dried up. If im correct and the modulator does act like a wastegate, wouldnt unplugging it give the egr too much vacuum and cause it to run just as bad as having a clogged one? That is why i figured the diaphragm is a little weak and not giving the egr enough vacuum...It runs EXTREMELY good with the modulator plugged off. Correct me if im wrong. Thanks for the interest in this thread.

94SRUNNER · « **Reply #14 on:** Feb 15, 2006, 02:42:07 PM »

I have a question to throw out to everyone. I am preparing to remove and clean the entire EGR system on my truck. Also replacing all the vacuum lines and installing new gaskets. Any advice on the best way to go about cleaning all of the EGR plumbing.

toymech · « **Reply #15 on:** Feb 19, 2006, 04:58:25 PM »

I think the best stuff ive used for cleaning carbon is MOPAR carbon cleaner. its a foaming agent,great for desludging your intake too. just stop by your chrysler dealer and ask for it,great stuff

Phazertwo · « **Reply #16 on:** Mar 09, 2006, 08:50:26 PM »

I just rebuilt my 22R motor and added EFI. The truck runs awsome untill 2000 RPM, than it miss's like crazy, but is still driveable. It seams to run fine as long as I am on the gas, but when I level off, it misseslike nuts! I am running a stage II lLC cam. When I had the whole thing apart, I used carb cleaner to clean my EGR. Will eveything that was tried on the carbed engine work on a RE?
thanks for any and all help!

PZ

YOguyDa · « **Reply #17 on:** Mar 09, 2006, 09:59:54 PM »

Im not sure about the EFI/carbed stuff switching over, but i was having the same exact problem with my truck(carbed) and it ended up being the modulator valve that is sitting in a bracket attached to the egr. I plugged up the vacuum line going to it, (coming from the vacuum switch on the valve cover) and it runs awesome! I've since replaced the valve and it runs the way its supposed to with a good one hooked up. Try it out and let me know what happens.

Phazertwo · « **Reply #18 on:** Mar 12, 2006, 01:59:52 PM »

I pulled the line to the EGR and it runs much better now, no misses anyway. It seemed to run good. Now I just need to tell if its the modulator or the valve??

YOguyDa · « **Reply #19 on:** Mar 12, 2006, 02:22:45 PM »

Im almost positive its the modulator....It controls how much vacuum the egr gets. There is a vacuum line that runs to the back of the modulator valve...if you pull that one and plug it, it leaves the egr functioning, yet un-regulated. I ran with it plugged off for about a month before i finally replaced the modulator. Ran great that whole month.

I'd suggest re-reading this whole post, to give you an idea of possibilities and things to check, but the modulator was my problem in the end....That was after i checked the egr diaphragm(good), replaced the egr(good), Scratched my head

, then gave up

, then looked at my fuel mileage

, then popped the hood

, scratched my head

, pulled the line to the modulator...and Walla!

.

Phazertwo · « **Reply #20 on:** Mar 13, 2006, 03:18:21 PM »

I have been pooring over this thread for qutie a while now. I took a modulator off of my 4 runner (DD, runs great) and put it on my truck. No change. I did clean the filter on both.

Today I am going to replace the EGR valve its self. I don't think its going to make a difference because I tested the one thats on there per the FSM and it was fine.

When I unpluged my EGR i pulled the vaccume line off of the top of the valve, not off of the modulator. I will have to pull the modulator line and plug it and see if it runs better.

My last thought is my vacuum suply. I am running a stage II LC cam.
Intake Exhaust
Valve Lash .008 .012
Valve Lift 460" 460"
Advertised Duration 290° 290°
Duration @ .050" 240° 240°
Lobe Center 102° 118°

Intake Opens 18° BTDC
Intake Closes 42° ABDC
Exhaust Opens 56° BBDC
Exhaust Closes 4° ATDC

I know that radical cams efect your vacuume, but would it efffect it that much?

TIA
PZ

YOguyDa · « **Reply #21 on:** Mar 13, 2006, 04:14:36 PM »

Hmm, i wish someone else could jump in. We'll see how the new egr does, if that does'nt help i'd consider the cam and all other possibilities. Im sure some other guys are running that cam, and could probably tell you if they had any problems.

Phazertwo · « **Reply #22 on:** Mar 13, 2006, 04:28:01 PM »

I picked the cam becasue others had talked about running it. I just got my EGR off, and realized that the other one is off of a carb truck. The valve is the same, but the housing isn't....

I have a feeling that my TPS is still messed up ( I have tried to calibrate it like 10 times, and never really get better results. My idle still sugers, and even with the EGR unhooked, it still misses when i am crusing over 2k...

YOguyDa · « **Reply #23 on:** Mar 13, 2006, 04:34:31 PM »

Sounds like you got a few things to work out, with the new EFi. You should start a new topic about your efi swap and see if anyone else that has done it has advise. Im not an expert and my truck is carbed, so im limited as far as troubleshooting. Sorry.

eightyfive · « **Reply #24 on:** May 18, 2006, 01:14:33 AM »

sorry to kind of highjack your problem but i think mine is also egr related...please confirm or prove me wrong..

at idle, my truck has a slight miss and studders. sometimes it idles good and sometimes the RPMs drop slowly eventually causing the truck to die. i give it some gas and drive it for a mile and it can hold idle longer but will eventually die. what's the deal? EGR issue?

YOguyDa · « **Reply #25 on:** May 18, 2006, 07:07:14 AM »

Sounds kind of like a vacuum leak....Vacuum leaks could be caused by the egr, but you would have to track it down to really know(process of elimination). You might want to check the vacuum line going to the ppv valve on the right hand side of the carburetor. Sometimes the diaphragm goes out and leaks gas out of the float bowl rigt into the vaccum lines and eventually into the intake manifold. Its been a while, so im not sure if i had those symptoms when i had that problem, but might as well check it out while you're checking for vacuum leaks.

Phazertwo · « **Reply #26 on:** May 18, 2006, 09:26:30 AM »

he has an EFI system. But it could still be a vacuume leak. You can try shooting some carb cleaner on the vaccume lines and see if the RPMs go up. If they do, than you have a leak, and you just need to track it down.

However it could be EFI related. your TPS my not be telling the comouter that you are at idle. (idle validations messed up) I am not sure, but it could be your idle air motor. But I think that can only increase idle, not lower it. When it does idle good, what is it idling at? It should be ~750 rpms.

PZ

badwheelr · « **Reply #27 on:** May 20, 2006, 08:40:17 AM »

Man I hate those EGR's

, So what I did

on my 80 20R was when I put the new motor in, I removed all the EGR crud and fabbed a block off plate and walla no more EGR. We here in OREGON have DEQ tests and the dummies :hammerhead:that work in these stations can't tell an EGR from a gas cap.

The truck runs great and it passes with flying colors. Oh I forgot to mention the little tag under the hood, it is a non cat, non emission truck lucky me. And best of all I love my MARLIN CRAWLER.

eightyfive · « **Reply #28 on:** May 20, 2006, 12:38:43 PM »

yes i do have efi...when it idles good it idles at about 800, smooth. then when it feels like acting up, it drops and studders like crap. anyway thanks, i'll check the vacuum and report back.

GrimReaper · « **Reply #29 on:** Jun 25, 2006, 07:37:14 AM »

I never did get this totally resolved. I left the EGR unplugged and since they don't lift the hood here and my NOX was withing range they passed me.

Here is what I have found out as possible causes.

Modulator bad causing an inappropriate amount of EGR.

Restriction in exhaust. This would cause a misreading by the modulator via the bottom port into the exhaust and it would also cause a higher pressure so more exhaust gas forced in.

I pulled the cat on mine for a quick test to see if I had excessive back pressure and still had the problem. I have wrote my issue off as the Modulator. I have another here but didn't get around to trying it yet since I passed and now I am breaking in a new motor.

I had a 89 Supra that had a bad Modulator as well. All was fine till you get the operating temp and the BSPV it think they call it opens to allow EGR function. Well once it pulled vacuum it couldn't' bleed it off. So as you would come back to idle it would stall. Restart the engine ant till you ht about 2k it would be fine. Swapped the modulator and cured that.

Somebody had some Cam concerns. I am running the engbuilder 268 and with the EGR off its running great. Very slight lope at idle but still pulls excellent vacuum. Unless its areal radical grind on the cam I don't think thats your issue.

Another thing I found on the RE motors is the solenoid valve in line on the fuel pressure regulator is fubar. I am running it direct vacuum and was at time of last emissions and it seems to be running just fine that way. My economy improved. Rodger Brown at 4Crawler had the same issues and the same solution.

http://www.cygnusx1.net/supra/library/TSRM/ec/EC_12.html thats for testing the modulator on a 7M but its still valid for the 22R motors. I think there is a link on 4x4wire for a 85 FSM. In 87 they changed several things including reading the codes so the FSM for 85 is good for 86 as well but better find a 87 up for any ECM diagnostics if your truck is newer.

GrimReaper [OP]

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