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StonecoreTx 02-26-2010 10:24 PM

Inspection/emission problem
Earlier this week I decided to take my Mk3 to get her a new (Texas) inspection sticker. I was pretty sure it would pass, however, it didn't.

I just replaced my passenger quarter fender and fixed my taillights and turn signals, so I figured time its time for inspection!

My mk3 is a 86.5 7mgte with a r154 and it failed emissions.

second opinion from fellow mk3 owners would help
I'm thinking i need to check/replace DP,EGR,VTV,VSV, maybe a cat converter?

I'm running high in HC's and CO's but passed dilution. any advice?

High speed
pollutant - Standard - My reading.
HC - 220 - 247
CO - 1.20 - 3.92

low speed
pollutant - standard - My reading
HC - 220 - 428!
CO -1.20 - 1.52

mirage83 02-27-2010 12:03 AM

For the high HC check plugs, EGR, vacuum lines, stuff like that. Even your timing being off some can raise HC.

For CO, check your O2 sensors/wires, air filter. The TPS, coolant temp sensor and/or the AFM could also be responsible.

cre 02-27-2010 12:49 AM

EGR will cause high NOx, I don't think it's suspect here.

HC and CO are both due to running excessively rich. I would start with checking for diagnostic error codes, then check plugs, air filter and timing... then we'll move on to bigger things.

Check codes:

Look in the MKIII FAQ for info on setting timing; You probably don't need to worry about the mechanical timing, just the spark advance.

mirage83 02-27-2010 01:21 AM

I knew a bad EGR can create high NOx, but for some reason I was thinking that a leaking or bad EGR might be causing a rise in HC under some conditions.

cre 02-27-2010 03:22 AM

Nah, a leaking EGR shouldn't cause any changes in your engine's emissions as the gasses are inert. A clogged or otherwise nonfunctional EGR will contribute to greater amounts of ping or knock which would result in the ECU pulling timing and adding fuel but it would also result in a big increase in NOx.

Cameroonski 02-27-2010 08:33 PM

Glad to see a fellow supra owner near by, I'm from Pflugerville just north of you and have been workin on a supra i bought for a few months and still havent had the chance to get it inspected. I'm pretty sure i have to fix at least an exhaust leak, but I also cleared out the cat. So I might run into the same type of problems that your having. All I can say is good luck! :x:

StonecoreTx 03-05-2010 05:44 AM

I looked at my EGR system today. I ran into an interesting problem. No EGR valve. a modulator connected to nothing. no block off plates.
The guy I bought the supra from said it has a jdm head so maybe this supports it all and why i'm not passing emissions. jdm or not?
Should I install a EGR valve or get block off plates?
does a JDM 7m have EGR cooler?
The car seems to have been running without block off plates for some time and should this be a concern?
modulator with no ERG valve... conneced to nothing.
no block off plates. looks like this. are block off plates necessary if EGR is missing/removed? does JDM have EGR port like above? located just under the modulator a bit. (obviously that is not a ERG flange but it looks similar.)

cre 03-05-2010 06:41 AM

The heads are the same, the cooler is capped though, IIRC. The EGR modulator port should be covered too though.

So, what were the NOx results? Have you by chance looked to see if the ECU is USDM or JDM? I'm curious and would like to know more.

I'm not sure if it's the same situation with JDM GTE intakes, but the GE's intake doesn't have any of the porting for the EGR. To add EGR to a JDM 7M-GE you have to swap over the upper USDM intake plenum/surge tank and the USDM "Y" pipe. I suspect that you would need a USDM upper intake plenum/tank along with the cooler plate and the modulator. The wiring may vary a little too, but I am unsure.

Have you checked for error codes? Checked anything Mirage suggested?

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