Need expert advice. New cat STILL glowing with reman
 

I am posting here because I cannot yet post in the troubleshooting forum :-( I'm looking for some thoughtful advice.


Backstory:


Trying to make this short, but it is relevant. I purchased an 2006 RX-8 Shinka 4 months ago. At that time the car ran very well, no issues at all. I was well informed, and did my research regarding compression issues, read the new member forum, etc...I had a compression test run before purchase. They car scored 6.8-7.2 at an independent shop with little deviation across rotor faces. I had it retested at Mazda before purchase, and it scored in the low to mid 7's across the board, so I knew what I was getting. The car ran well for several weeks. Due to concern with potential ignition issues and compression, I took a look at the cat one night as a precaution and found it glowing. Right about this time the exhaust started sounding raspy or "pingish." I quickly replaced plugs which made no difference, so I installed BHR coils and wires with the same result. As a last resort I replaced the OEM cat even though the substrate of the existing cat looked fine. During this time there were no CELs, not even at WOT. At the advice of RIWWP I had another compression test run, and the results were lower so I talked Mazda into paying for half the cost of getting a reman. I was just out of warranty at the time.


Post Reman (500 miles on it)


The reman was utterly sluggish for the first 50 miles, then gradually picked up some guts as the seals broke in, and started running pretty well. I went easy on it, gradually easing into revs over 500 miles. I still haven't gone past 7.5k, and I'm not doing WOT runs (and I don't want to turn this into a break-in discussion). I checked the car for the glowing ring of death after every drive during this 500 miles. It glowed a little initially which I contributed to the low compression of the reman breaking in, then went away completely when I replaced the MAF. The MAF replacement was simply a precaution. Things seemed to be going really well...Now the red ring of death is back as is what I presume to be pinging (argghh). The exhaust sounds just like the previous engine did when it started exhibiting symptoms - raspy/pingy. It sounds a lot like pre-ignition on a piston engine.


So...


I dropped the front of the cat today for inspection. There is a dark spot, but otherwise no appearance of clogging or damage to the substrate. The dipstick has not dropped in 500 miles, but I also have a feeling the tech overfilled it. OMP and injectors were checked at the time the reman was installed, so the dealership says. I premix with Idemitsu.


I have no CEL. The EGT's at B1S1 seem too high to me (~1650 at 60MPH in 6th). AFR measured and commanded run very close together in the 14.7-14.9 range at cruise, around 15 at idle. (new) MAF gps is low, at 4.8 at idle, picks up 1gps to ~5.5gps with AC. LTFT is 0 at idle and 3.7-4.7 at freeway speeds. The exhaust manifold has white deposits on the inside, which (with my limited knowledge) points to a lean condition not indicated by the AFR.


Before I get chastised for not immediately testing compression on the reman, I find it very coincidental that both engines would exhibit the same symptoms, both the old and new cat glowed or glow, and the ignition and engine were swapped during the duration of symptoms, and I never had a misfire CEL. It seems plausible that I may have a failing fuel pump or other contributing factor causing a lean condition that is not being fully recognized and/compensated for by the upstream O2. Or..the OMP is not working right and thus not properly cooling and lubricating.


Very interested in some thoughtful posts. I will get and post some data logs tonight - too freakin' hot right now. I will also get a compression test on the reman, but my goal is to determine if I've got another condition creating excessive heat cooking the seals. No sense going through a repeat...


Current State: Glowing Cat, BHR ignition, Reman w/500 miles, no CEL, doesn't appear to be burning oil (hard to tell @500 miles), occasional hard COLD start and/or hard hot start, but not consistent, doesn't sound "right" raspy/pingish sounding exhaust.


Looking forward to some input! Thanks.

EDIT: Added pic of cat. The picture looks much worse then it did with the naked eye. It has about 1500 miles on it.
https://onedrive.live.com/redir?resi...nt=photo%2cjpg

Barber,

If you ran the new cat on failing ignition it's possible it's already cooked. Also, more often than not the front of the CAT is not the first section to fall apart. The rear closest to the resonator is what usually blows through first. IIRC the members that were at Jesse's meet were shown a cat prior to gutting it that the rear had blown out. Thank you to Bill (jesse's brother) for scoping it for us :)

There is a thread about testing fuel pressure as well. If yours is original (fuel pump)more than likely it's close to the end of its life.


That's all I have for you right now hopefully that helps some.

Travis

Hi Travis,


Thanks for the reply. That is interesting info regarding the cat. It could be clogged further in, and it makes sense that more catastrophic failure would follow as the inlet becomes super-heated due to the clog. Makes me wonder how people ever get to that point without any premonition off the impending disaster...


The coils on the reman were stock coils for 500 miles. Those coils had about 15k on them. I put them back on in order for Mazda to honor the warranty work. The plugs have maybe 1500 miles on them and were inspected by the dealer. I put the BHR coils back on today when I finally had a chance. I've been relocating to the Seattle area for work so it's been hectic trying to get auto any work in.


I saw a thread where a similar issue was resolved by fuel pump replacement, but I expected to see fuel starvation reflected in the measured AFR. I'll keep digging and get some logs. A BHR mid pipe and fuel pump may be in order. I just hate to keep the cycle going. I should probably have this reman compression tested as well (sigh). I may as well by a compression tester at this rate!:(




Thanks,.
Dave

a new ignition system is no guarantee of not having a failed coil

https://www.rx8club.com/series-i-do-...-wires-222641/

never assume, test ...

Agreed. I picked up the exact tester on the way home today. We shall see what is says...Who knows, may both OEM and BHR coils have issues. I will test and post results.

Alrighty then... So I finally got some time to test the coils. Either my ground is bad, all 4 coils are bad, or I have another issue.

Here are the results:
Inconsistent spark on all four coils. Pop. Pop.... ... ... pop....pop......pop pop. I got a couple of brilliant sparks each go round, but completely inconsistent. Gently wiggling the ground made no difference.

I tried ground clip to jumper cable and jumper cable to passenger side ground. The spark jumped into the water line. I moved my jumper cable to the strut bar and gave it a good bite and relocated the tester (duh). Same results, so I adjusted the other end. I clipped the jumper cable directly to the screw on the tester and ran the ground clip back to it (pic attached). Same result. I moved the jumper back to the chassis ground bolt, same result.

Tomorrow I will double check the tester ground and fashion a better one directly to the chassis. I do not like the one it came with. The screw wiggles, which bugs me as well. I want to rule out the ground as the issue.

Is the gap too large? I'm using what it called for on the tester. A few sparks jumped right across.

https://cimg1.ibsrv.net/gimg/www.rx8...310265858b.jpg


https://cimg4.ibsrv.net/gimg/www.rx8...ef6ad8b19d.jpg

Umm, no, you didn't ...



.

Wow, thank you so much for the detailed and informative response. It is so nice to have such a fantastic welcome from the community after providing so much detailed information.


Cheers.

did you read this link I went out of my way to share with you (see below)? Does your tester match the one I recommended using?

No it doesn't ...

Yes I agree that the tester is not the same. I'm not sure how, but I got it mixed up with one from a different thread. Probably because I'm busy as hell every minute of the day, but no matter. The importance is in the gap and the ground. I will purchase the recommended tester as well and compare the two. I'm glad you went "out of your way" instead of just helping. It makes your assistance much more meaningful. :Peace:

Could the "inconsistent" firing plugs be the leading plugs?

At idle?

I have heard the lead spark plugs cut out/off at idle under some conditions and that the ECU runs the trailing plugs extremely advanced, at a "negative split".

Are the trailing plugs consistent?

Also, doesn't the "white" in the tail pipe also mean too lean, or too far advanced?
Any possibility the spark plug order is wrong?

Just follow the link I gave you and ignore people who operate on incorrect hearsay and assumptions

I have an HEI spark tester like the one you recommend coming in today (GearWrench - HEI Ignition Tester p/n 2756. I want to retest the coils and rule them out. If spark is consistent I will move on to fuel pressure and compression. I found a single mention in the forums of the ignition condenser (capacitor) causing issues. I will pull it out and test it. https://www.rx8club.com/series-i-tro...-coils-256831/




I don't want to ignore anything that might come back to haunt me, even if it is just bad compression on the reman.


Thanks,
DB

The white coloration is in the exhaust manifold. I noticed it when I checked the front of the cat for damage. I am retesting ignition today. I am going to methodically test everything I can think of/identify: coils, fuel pressure, compression, O2, etc. until I have an answer. I logged some data yesterday, and I should be able to get it into excel today.

Apparently it's pain to get the open plug tester. The one that arrived was the new style. Consistent spark on all 4 BHR coils using this tester. Tester ground resistance was tested using multi meter to adjacent chassis ground. Videos here for reference:


https://plus.google.com/108207504801...os/p/pub?hl=en