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.
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.
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