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ProDarwin
ProDarwin PowerDork
3/17/18 7:41 a.m.

I got the tests to run!  Yay!

 

berkeley.

 

 

 

ProDarwin
ProDarwin PowerDork
3/17/18 7:47 a.m.

Anyone know how to get more detail on these?

 

ProDarwin
ProDarwin PowerDork
3/17/18 8:11 a.m.

This seems to match up fairly well (yellow matches, blue does not).  But it doesn't really help at all.

 

alfadriver
alfadriver MegaDork
3/17/18 8:26 a.m.

The purge flow one, I'm not so familiar with- have any leaks?

The cat monitor- there's a few ways it's looking at it- the older method is to compare the switch ratios of the front sensor to the back sensor.  So when you are driving in a specific range, the ratios are well known enough that you can see where the catalyst efficiency is damaged enough to be 150% of the standard.  

The newer method is to see how long it takes for the rear sensor to react after turning the fuel back ON after an extended time with it turned off.  The shorter the time, the more the catalyst is not working from stock.

So for that failure- how much do you want to spend to fix it?

FWIW- the second catalyst (which I think you are monitoring now) is loaded much lighter than the first one, so it's more likely to show both codes even with a pretty fresh catalyst.  The first one does ~90-95% of the work, which is why it's the one being tested.

ProDarwin
ProDarwin PowerDork
3/17/18 10:19 a.m.

Fair enough.  If the first one isn't there though, the second one does 100% of the work, right?  smiley

I'm not sure what the best route is to correct.  I'd like to confirm 2 things first though:  the sensor is far enough into the exhaust stream - the bung looks pretty thick and I'm wondering if its just too far removed.  Also I would like to confirm the wiring didn't impact its reading as I've heard a lot of reports of that happening on this car.  Sadly, I don't know how to confirm either.

It seems like my other options are:  

Mini catalyst:  https://www.amazon.com/LEDAUT-Degree-Catalytic-Converter-Stainless/dp/B01MTA6OXG/ref=sr_1_13_sspa?s=automotive&ie=UTF8&qid=1521299535&sr=1-13-spons&keywords=02+bung&psc=1

or add the stock header cat back in.  Either temporary just to pass emissions, or permanently if there is someway to make sure it doesn't blow up and take the motor with it.  As this is a rallyx car, it is subject to high loads, lots of compression braking, and lots of vibrations, so its on the high end of the risk spectrum.

We never recieved one (99% of these cars you see have gutted this cat to save the engine).  A replacement looks like it is anywhere from $140 to $450.   Also, our exhaust won't bolt up to one, so some sort of adapter is needed. 

 

 

 

 

On the EVAP, I guess I just need to check the whole system.  It doesn't seem like a leak ( I just fixed one of these), as it isn't tripping either of the leak codes (05 and 07).  This doesn't appear to have a flow sensor, so the likely culprit is the purge valve itself.

alfadriver
alfadriver MegaDork
3/17/18 10:30 a.m.

Given that it even runs the test, and it's tripping an actual fault, I would say that it's far enough into the stream.

Since you have a thing to read the OBD readiness and whatnot- can you record the data and post it?  That will tell you about which version of the monitor you have.  And if some kind of buffer on the sensor would even work.

On that note- from my perspective- the items you list on Amazon is very much not a legal item as it's advertised.  If it clearly stated that it was for non road use only, then one could claim that it was for motorsports or other usages that have some exemptions.  But the wording is that it's 100% for bypassing an OBD thing- it makes it very not legal to sell.  So I'm going to leave it like that.

The most straight forward solution is to use the original catalyst.

As for the failures- is physical failure *that* common in RallyX?  That's the only one that might damage your engine- but even that isn't that assured if you physically break up your catalyst.  Not sure how that's a reasonable reason to remove the catalysts.  

(BTW, NOT using a cat during RallyX is legal- just to be clear.  It's well off road.  It's the state laws that surround getting there is the sticking issue)

ProDarwin
ProDarwin PowerDork
3/17/18 10:49 a.m.

Yeah, the mini catalyst is definitely not legal.  Nor is removing the first cat.  Or gutting the stock one.  The only legal option here is a stock cat or stock replacement - but those run the risk of failure.

I don't know if its common in RallyX, I just imagine its more likely than tame street driving.  Its very common on the street.  There are lots of blown QR25DE engines from this.  Nissan had a TSB for this for a while as well, but even the TSB replacement cat/header combos have grenaded and taken engines with them, just at a lower rate.  I don't know if the aftermarket replacements are better or worse in this regard.  I also don't know how far into its life they usually fail - if its only a problem after 50k or something, I'd be fine with replacing every 50k if its only $150.

 

I'll see what I can dig up from the data.  I'm not sure it tells me which version of the monitor I have.

alfadriver
alfadriver MegaDork
3/17/18 2:33 p.m.

In reply to ProDarwin :

I was wondering about that catalyst. On one hand, it is pretty rare that there is physical damage to them. 

But your engine is from the beginnings of PZEV, and everyone was experimenting with light and thin wall substrates. So in that light, it does make sense. 

 

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