OnebaddRx8

I will try to keep this simple and I have read many threads and tried many things to no avail down to one last fix, just looking for an opinion, I thought i was smart enough to figure it out but apparently not.

Car history 2004 AT 73k on car, @10k on Banzai Racing rebuild(stock) nothing special, new air pump, Borla cat back exhaust, Magnaflow High flow cat, new alternator, battery. Wires, coils, and plugs also at rebuild.
Premix 8oz. 2 cycle every tank (per engine builder he believes in it) tear downs don't lie.

I'm not having starting issues the compression is 8.5 or above on all faces both rotors.

My car will just die at idle, and sometimes it acts like its starving for gas and will start misfiring( Torque app said only on rotor 2).

This all started when i unhooked my battery, and yes i've read the threads. I was installing a new K&N drop in filter. So I started from scratch I unhooked it again and reset both, started it cold let it warm up fully went out drove it multiple times no problems. Get up next morning starts right up again letting warm up fully get down to the corner and it dies. I waited about 30 seconds to a minute it fires right back up take off drives fine for about a mile act like it cant get enough gas again starts misfiring then take offs and revs up to redline 7500 smooth under load no problems, couple miles later it dies again at a stop sign. It idles smooth doesn't miss (Torque between 815-830)
So here's what ive tried, and i let it go through the warm up cycle several times to reset fuel trims and it still did it.
-Replaced air filter with stock( didn't know if k&n was causing the problem since that's when it started.
-Checked fuel pressure it was good
-Checked wires and coils both good @10k on both
-New plugs
-New rear o2 sensor
-New battery terminal ends(both)
-cleaned grounds and regrounded with good star washer
-cleaned ESS and reset Nvram also
-cleaned MAF
-cleaned throttle body
-Lucas fuel injector cleaner
- Full tank of 93 octane ran most of the old gas out thought i may have gotten some bad gas that's what it acts like.
So what am i missing besides the fuel pump? I know it's overdue.
Since there is no fuel filter could the sock on the pump be clogged from premixing?
Any suggestions would be greatly appreciated and Thanks!

Gravey

iTrader: (3)

Have you tried another MAF? see if you can get a known good one, and try it in there.
Could yours have been damaged when you put the K&N in? Maybe the connector on it isn't tightened.

OnebaddRx8

Today I swapped plug wires and coils from rotor 1 to 2 same issue.
I'm to the point of changing the MAF that's a good idea.
I may just change the fuel pump from what I've read I'm working on borrowed time.

What is sad my 90' vert rebuilt by Banzai also, the original motor lasted 150k before it died a bad coolant seal, turned into apex seal catastrophic failure.
Still has original fuel pump, alternator, power steering, coils, starter, 25 years*later still working.
If they could of only made the 8 as reliable.
Thanks ^

Steve Dallas

I think the misfires are the key to your diagnosis.

Out of curiosity...

Continuing down the fuel sock hamster trail, what are you using for premix?

OnebaddRx8

Super Tech 2 cycle from Wal-Mart same thing owner of Banzai Racing told me to use. I'm trying to run some of the gas out to pull fuel pump. I drove it around my neighborhood and stopped at intersections atleast 50 times, died twice. Turned key off waited for 15-20 seconds fired right back up drove fine all the way to red line. When it starts misfiring sounds like it's only running on one rotor. Torque only shows misfire on rotor 2. That's why I swapped wires and coils just to see.
Never had a single problem with this car till I unhooked my battery and installed the k&n drop in.
Is there a basket on pump? Parts store could not come up with any type of fuel filter at pump or otherwise.
It only misfires when it acts like it's starving for fuel.
Are rotor one injectors first to be fed with gas off the fuel rail?
Ran torque app when I got home the check engine light has never come on thru any of this except during misfire. Only code was a pending code for misfire on rotor 2.
I do appreciate you guys for taking the time to help.

OnebaddRx8

Took it for a drive earlier first time out no problem stopping multiple times. About an hour later stalled twice started back up after setting about a minute the second time I was coasting into the gas station. I tried to start it up immediately and I'm pretty sure I heard gurgling coming from the gas tank!
I tried unplugging MAF sensor when I got home just to see what it would do and idle dropped for a second then idled smooth @ 950 didn't drive it as everylight on the dash came on I think when I unplugged it.
I know it's working but how do you know if it's bad?
Torque pulled 2 MAF codes and one air intake temp code when I disconnected it all went away when I hooked it back up.
Seems to be running rich even after warmed up. I have let it warm up completely and drove it atleast 5 or 6 times since unhooking battery.
Next step pull fuel pump???
What is the normal air/fuel ratio?
I'm trying to provide as much info as possible without being annoying.

OnebaddRx8

Since no one has really been able to help me I'm going to replace the fuel pump and MAF sensor. If that doesn't fix it I'm putting it on the trailer and taking it to Banzai and Chris can figure it out.

Steve Dallas

It looks to me like you have done a lot (if not all) of what is recommended to diagnose a misfire. There are a few other things you could try in this thread:

https://www.rx8club.com/series-i-tec...t-here-222280/

The K&N probably had nothing to do with it, although it could cause the MAF to become coated in oil. Their filters are usually too oily from the factory and need to be refreshed before installation. They are also inferior at filtering, so things in the intake can get dirty quickly (oil + dirt).

I don't think your choice of premix is known to cause problems with the sock like Lucas UCL is, but you might stop using it and switch to Techron or Berryman B-12 fuel system cleaners for a couple of tanks and see if that makes any difference.

I use Lucas Semi-Synthetic 2 Cycle JASO FD oil as premix and have not had any problems with it. It is more expensive than what you are using, but probably lubricates better if your oil is TCW3.

That's all I got. And it isn't much.

OnebaddRx8

The 2 cycle I use is just universal 2 cycle owner of Banzai said it burns clean not a TCW3 oil.
I will give an update after changing the fuel pump and MAF. I truly think it's the fuel pump 73k and it's 4th engine we don't know what the fuel pump(original) has been through. I couldn't find where it had been replaced at anytime from Mazda. It bogged out like it was starving for gas when I drove it around the neighborhood yesterday never misfired just wouldn't go. I even pulled down the exhaust and checked*the cat but looked fine.
Thanks for the help!

OnebaddRx8

Do I need to reset anything after changing the fuel pump?

Grace_Excel

iTrader: (5)

I was following your most recent post about the purge solenoid valve and am about to mention the fuel pump. Anyway, no need to reset anything after you replace it, just make sure your fuel lines, electric plug, and the fuse are all in place.

OnebaddRx8

It acts like it's vapor locks for a few seconds then will misfire. Then it goes again like nothing happened. No clue to what is happening.

fish1

To me it's sounding like fuel pump.
No CEL's?.......I'm on my third fuel pump and have never had a CEL when the pump was faulty.
car would completely die, I'd wait 2-5 minutes and it would start and I'd drive off like nothing had happened.

9krpmrx8

iTrader: (46)

Just keep guessing, you will figure it out.

OnebaddRx8

Thanks for the suggestion but the fuel pump is brand new. Doing same thing as old pump, k& n filter started all this. Threw a small evap leak code, I searched and found that the purge valve solenoid is related to that code...and it constantly clicks after reaching normal temperature.

dannobre

iTrader: (3)

I would check the wiring on the fuel injectors

And check the throttle body. Many idle issues that aren't resolved by ignition and fuel fixes turn out to be the idle circuit that is built into the throttle body

OnebaddRx8

Seems odd I had no issues no codes what so ever till k&n filter was installed. I'm trying a new MAF tomorrow if that doesn't work I'm going to donate some more $ to Chris@ Banzai racing he built it he can figure it out.
My 25 year old rx7 convertible starts and drives every day go figure the 8 is a maintenance nightmare and headache in comparison!

fish1

Purge valve solenoid can be a common problem.
Replace the VFAD solenoid when you're in there at the same time.

OnebaddRx8

Thanks 3 solenoids under there correct? Should I change them all? I'm only taking it apart once if at all.
I really just wanted someone to lift the hood when their car is warmed up and tell me if the purge valve solenoid constantly clicks.

OnebaddRx8

Just in case anybody wants to know what was wrong well I kept guessing you *****! Funny no where in the FSM did it say you may have bad gas! I drained the tank and filled it up with fresh 93 and haven't had a f**cking problem since so YES IT DOES happen!
Thanks to everyone else that tried helping!

ShellDude

iTrader: (12)

I do recommend one guess at a time though. You'll never know root cause otherwise.

Also, have you reset the ESS following the 20 brake stomp method?

Ah.. Just read your last update.

OnebaddRx8

I did reset everything and it kept doing it. I knew it was fuel related I've had 13 rx7's and have seen it all. My vert is way less complicated no computers to reset. As long as you have good compression, it comes down to air, spark and fuel.
It never did explain why it would only show a misfire on rotor 2. Makes me also wonder if the coils are getting weak. Only @ 10k on them since rebuild but you never know.

Steven4177

Haven't checked fuel pressure. Car is at the dealer as of 8 am this morning. Getting all the recalls taken car of( ball joints, airbags and fuel pump replacement). I have already tried to swap the coils and plugs around and it didn't move rotors still staying on rotor 1. And the injectors are the one that came one the "new" motor.

Cucos

a compression test looks like are you in playing with a intake manifold and probably lost a bolt or something into the engine

Ricky SE3P

iTrader: (10)

I would be inclined to believe he has probably figured out and resolved the issue, or moved on, in the 4 years since he posted all of this


Doesn't anyone read date stamps anymore?