When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The situation, 09 with no CAT and OEM muffler. New BHR coils/plus/wire less than a year ago. Car has 88k mile. Still starts and runs fine under normal conditions. If I do a hard pull, it is a little down on power and starts to sputter around 5-6k but hits a wall around 8k. It feels very similar to when the cat got plugged. I also noticed the volume from the exhaust is lower, similar but not as low as when the cat was still there. I am not sure how the factory muffler is constructed, so not sure if could have a failure inside that could cause it to plug it's self. Another thing that has lead me to think it is possibly the muffler is that it started after a hard pull and during a gear change the usual pop/bang out of the exhaust sounded a but funny. Usually it is very loud an sharp. This one came a little more muffled and it has been lower volume and not running right since. Under normal acceleration and driving it behaves like it always has. I also noticed it gets pretty rich when the sputter/missing starts. Around 11.4 according the the cars o2 computer. Tomorrow I am planning to jack the car up and inspect the ignition system to verify it is not anything there. I may disconnect the muffler as well and see if it is that. Guess that will be an excuse to get a new exhaust if it is the issue.
No cat. Stated that in the first sentence. Just the OEM muffler still. I found some pictures of the inside of the OEM muffler. Pretty complicated for a muffler. Does not look like it has any real ways to plug it's self up, really. So, I guess I am looking at ignition issues. Really annoying if it is since I just put the BHR set in last fall.
All the signs point to an exhaust obstruction. Take it apart and verify. Ignition is never a bad thing to keep fresh, but given that it is fresh, maybe just make sure it's all connected.
Just got in from inspecting things. Connections all good on ignition. Wires show no signs of damage. Plugs look great.
Took a couple pictures. They look about as good as they have ever been. Has about 3500-4000 miles on them. Car is not my daily so I don't get a ton of miles on it. But I still drive it a fair bit.
I guess the next thing is to disconnect the muffler and see how it revs. Maybe take it for a quick drive and tick off the neighbors. lol
Oh crap, your right. How did I not notice that. And how could that happen? I am guessing they have long since blown out the exhaust. I will get a new set and see what happens. Gonna have to take it in for a compression test and see if I damaged a seal. I don't think I have, since it has zero issues starting or anything. Might see if I can get a bore scope and look while at it.
I have not had any codes or noises to indicate detonation. Just the misfires that started and has me here now. Car has been running really strong up to this moment. I guess 12 years of trouble free operation had to come to an end at some point.
Plugs are the NGK ones that came with the BHR ignition. So, unless I got a faulty batch I would assume they are good. I wonder if I should contact NGK if the motor ends up damaged.
don’t bother, the straps being common is very common
if you look at the other pair with straps still present they look to be running hot, the ground strap discoloration is key; it looks discoloration heated all the way back to the body. It should only be discolored about 1/2 - 2/3 the length like so:
but potentially not possible on the factory heat range if pushed hard, so they likely overheated and burned off on the other two
there are many pictures on the forum showing them just like that, nobody noticing the ground straps are gone.
or it could be excessive dwell or timing, bad coils or wires, etc., the factory -7 lead plug is too hot for any kind of extended wide open throttle or track use, a track car engine will typically need -10.5 or -11 to avoid that issue. The NGK Iridium race plug for the RX7 “7420” has a thicker ground strap, but only comes in a 21mm length same as the RX8 leading.
comparison discussion in the racing area comparing the similar RX8 “7440” iridium race plug to the “7420”
the first thing to do in any ignition system issue is to break out the HEI spark tester plug and make sure you’re getting a good spark during cranking on all four and then go from there. This is especially true on the GM truck coils, even the overrated BHR version
With a healthy ignition system, starter, and battery all 3 of my Rx8's I've owned would start easily with significantly failing compression (I'm talking like my numbers were not even showing on the pass/fail chart they were so low)
Power in midrange and hitting a wall at top end, along with unusual exhaust notes and behavior were all symptoms the car demonstrated despite starting just fine even when hot.
I got the plugs in tonight at took the car for a drive. Initially it ran like crap under acceleration. After a few min it calmed down and started to run normal, except at high RPM. From about 7k and up it starts missing. Feels great everywhere else. Sound out the back still seems a bit muted at all engines speeds. Seems a bit more buzzy than normal. Not sure that is because the engine noise is lower or because the muffler has an issue. I guess the next step is to drop the muffler and take it for a drive. That will al least tell me what end the issue is at.
04-07-2023, 09:25 PM
