Hey all, new to the forum and rx8's in general. Bought it knowing it needed coils plugs and wires. It had a slight misfire in the rear rotor when you got on it. So I replaced coils, wires and plugs. And the misfire got worse. It idles alright, if you rev it up it stutters around 3000 rpm then revs up and misfires more noticeable. Used the correct leading and trailing plugs/wires. Followed the wiring diagram to make sure the coils were wired right. I found the misfire troubleshooting thread. So far I have cleaned the maf , ess, reset the ECU, did the 20 brake stomp, was going to check fuel pressure, but I'm not sure where the valve is to connect the fuel pressure gauge. My car is a 6sp 6port if it helps. Any suggestions would be appreciated.

 

Do you have any check engine codes? 3000 rpm is around where the first intake valve (SSV) cycles. If it can't cycle due to bad solenoid or jamming, there should be a CEL for it.

Were there any unusual deposits on the old spark plugs?
Are the new coils known good?

 

The new coils are brand new, haven't put a timing light on them yet. The only code I have is the misfire code. It didn't cut out at 3k before I changed the ignition. And the old plugs were dark gray.

 

If you still have a cat, drop it and inspect it.

 

Oh yeah, forgot to mention the cat has been replaced with a mid pipe

 

Ill try to get a timing light on them today. Gonna have to bundle up. It's 1 degree F in Ohio now. Is there a Schrader valve on the rx8's for checking fuel pressure?

 

Sorry for the double post, but this just popped in my head. Anyone know how the coils ground? Do they ground through the plug or the metal sleeve that they mount with?

 

Not sure, but did you doublecheck the wires to be sure they were firmly 'snapped' on?

 

So today I put a timing light on my coils. They all fired as expected. And somehow misfire went away. I'm thinking it just took a while for the ECU to relearn the fuel trims? I still have the surge or hesitation around 3000 rpm when. I give it full throttle at idle. It also does the same thing when driving at different rpm ranges when you step on the throttle. I'm thinking weak fuel pressure, still need to check that.

 

When you say you were getting misfires, were you getting the flashing CEL, or are you going by the code?
If you're getting hesitation or stuttering without a CEL, it could be the pump.
I'm on my 3rd.

 

It was flashing and throwing a code. No code yet, other than the emission code for not having cats. Is there a valve for checking fuel pressure or Doni need to add one?

 

I think you need to add one.
I recall someone posting the part needed, but Idk what thread.
If it's an older pump, you might consider replacing it anyway.

*edit* Especially if it's an S1. They had a rep of being problematic.
Mine is, my 2nd pump was an S1 Airtek aftermarket from Advance, but the last one was revised like an S2, and to me, it runs even better now.

 

It is an s1 and I'm assuming is the original pump with 145k miles on it. I might order a pump just for peace of mind. While I'm at it I'll add in the fitting for fuel pressure.

 

Sounds like that could very well be it since the sock is built in with the pump.
If you have an Advance Auto near you, go online and get an online discount coupon, you can save quite a bit.
It's under the Carquest brand, but it's an Airtex with a lifetime warranty.

 

What's the advantage of buying the whole assembly vs buying just the pump and replacing it?

 

It's easier, it's a newer, better design, and you have a new filter.
Plus all of the mechanical parts are stronger.

Look up a thread I started recently, (I can't post links on my phone)
"Suspected fuel delivery issue" or similar to that.
I posted pics of the old and new.
Same company, same part number, totally different assembly.

 

Here ya go;

 

Alright. Thanks. I'll have to pick one of those up