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.
Yes, I know there are multiple threads about diagnosing misfires, but none of them match my problems. I have a 2004 RX8 AT that I bought in 2015. When I purchased it, it hated starting. Cold, hot, didnt matter. Took it to the dealer and they said it was "pushing compression through the radiator" and needed an engine. I didnt buy it because i know the signs ie bubbles in the coolant jug; there are none. Took it home and proceeded to throw parts at it. Diy LS coil conversion, plugs, ess sensor, starter etc. Had a crack in the fuel pump housing so I bought a used one with 60,000 miles on it, still didnt help so I replaced the pump itself with a high output 265lhp pump in the used housing. Even had the injectors sent to be cleaned and tested and they were fine. Someone suggested to swap the original ess sensor back in and that made a difference in how it cranked over, but it still wouldnt start. Even a set of used stock coils wouldnt help, but turns out the ls conversion wasnt helping.At that point i threw caution to the wind and decided that there was nothing to lose so I tried one more thing. I took a can of PB Blaster, removed the plugs, and turned the motor over by hand backwards. Once I saw an apex seal i sprayed it down and worked it in and out by hand. Repeated for all 6 seals. Left the spark plugs out and cranked it over to expel all the crud. Threw plugs in and now it starts every time, with only a little delay when its hot. I replaced the plug wires yesterday and now its running even better but has brought to like a major misfire, i will attach a video of the miss.
TL;DR: Replaced a bunch of parts, including fuel pump and coils, and have a very bad misfire that I cant solve.
He engine was replaced 37,000 miles ago. Dont know what the issue is, but it ran for about 5 minutes with no miss at all yesterday. For that 5 minutes it ran smoother than it ever has. Throttle response was damn near instantaneous, no vibrations felt in the car, etc. Heres what the front plugs looked like when I pulled them. I should also mention that up until last week it was sitting for a good while. So the gas may have gone bad, and I had 2 ounces of lucas 2 stroke oil premixed in the old gas a while back. I put a bottle of heet and octane booster in it last night. Could it just be bad gas or something clogged?
Heres another video of the issue. This video was taken before the other one I linked, and was taken after sitting overnight so it was a cold start. I can't tell if its a fuel cut or an ignition cut. Could I maybe just need to get it on the road and drive it?
Ive looked at that thread probably 30 times over the last 2 years I've been trying to fix this car. You say youve seen my other threads. If so, then between them and this thread you would know yhat I have checked almost everything that thread lists
It's not a misfire, your check engine light is not flashing. I know it sounds bad, but it's not quite the same thing as a misfire.
Could be many things, but what is the check engine code? Bet that would provide more info.
Also I suggest keeping all your info on this problem to a single thread, so it's clear what has and hasn't been done.
Are you on old coils or the LS conversion now?
The first video I linked towards the end the check engine light was flashing. These are the only codes its showing at the moment. All the ones dealing with the secondary air injection are due to the air pump being unplugged. Am currently running syock used coils as my diy ls conversion wouldnt even start the car
Well, just decided to try and drive it around the block. It started fine, died the first time i put it in drive. Let it sit for a few minutes so i could make a phone call. Restarted it, threw it in drive. It didnt stall but it also had zero throttle response
So if understand correctly, the only codes you have are P0300/0301/0302? 301 or 302 would imply a problem specific to a single rotor, 300 would imply something upstream from the rotors that affects both of them, like SSV/APV
If you can read the codes, can you also read fuel trims? What are they?
Have you done the 20-time-brake-press trick to clear the ESS profile? Considering you swapped ESS's back and forth, that might be a good idea.
Also I listened to it again with headphones. Have you had the compression tested? Your exhaust pulses don't sound even, you might have 1 or more faces with significantly lower compression.
So if understand correctly, the only codes you have are P0300/0301/0302? 301 or 302 would imply a problem specific to a single rotor, 300 would imply something upstream from the rotors that affects both of them, like SSV/APV
If you can read the codes, can you also read fuel trims? What are they?
Have you done the 20-time-brake-press trick to clear the ESS profile? Considering you swapped ESS's back and forth, that might be a good idea.
Also I listened to it again with headphones. Have you had the compression tested? Your exhaust pulses don't sound even, you might have 1 or more faces with significantly lower compression.
Thats just the code currently pending, its also thrown one for P0506 "rpm lower than expected" and P0172 "too rich". But those were cleared and havent come back. I have done the brake stomp multiple times, the oil pressure gauge sweeps but it doesnt make a difference. Which video did you watch with headphones? The first one where I revved it, or the second one while idling? If its the second one then that is main issue I am having. It seems like either something isnt firing consistently, be it spark or fuel, and it sounds/feels like the engine is spitting/coughing. I did do a compression test a year or so ago, before I doused the apex seals with PB Blaster. Back then it never wanted to start regardless of temp, but the compression was fine. I don't recall the numbers but I know they were all fine. Since doing the PB Blaster trick with the apex seals it starts MUCH easier whether hot or cold, and every time at that. So if anything, the compression is better now than when I had the test done. Heres a picture of afr and fuel trims while idling, note that I have the air pump disconnected, an injen intake, and a gutted cat.
I also noticed that if I rev it up, when I let off itll bog down and almost stall so the pcm flips it full rich. I'm going to try and source a set of new oem coils, and run a fuel pressure test this weekend.
Injen intake eh. Do you want to try that with the stock intake? Some of the cheaper intakes screw up the airflow for the MAF, making the idle unstable.
It's weird that your LTFT is MINUS 10%. That means it think it's giving too much fuel, meaning it's getting less air than the MAF is measuring.
What's the airflow voltage and g/sec reading at idle?
I would try with the stock intake if I still had the complete intake. Im missing the little box that goes on the accordian, and the "velocity stack" inside the box.
will try and get a freeze frame of all the data my scanner shows.
Last edited by ShadowGryphon; 03-30-2017 at 12:58 PM.
Injen intake eh. Do you want to try that with the stock intake? Some of the cheaper intakes screw up the airflow for the MAF, making the idle unstable.
It's weird that your LTFT is MINUS 10%. That means it think it's giving too much fuel, meaning it's getting less air than the MAF is measuring.
What's the airflow voltage and g/sec reading at idle?
This is Idling with the stock intake reinstalled, with MAF number 1. Gonna swap in my spare MAF sensor and compare
Injen intake eh. Do you want to try that with the stock intake? Some of the cheaper intakes screw up the airflow for the MAF, making the idle unstable.
It's weird that your LTFT is MINUS 10%. That means it think it's giving too much fuel, meaning it's getting less air than the MAF is measuring.
What's the airflow voltage and g/sec reading at idle?
Ok, you win. Managed to find all the pieces of the stock intake and reinstalled. That helped. Went from throwing codes for running rich to codes for running lean. Was putting tools back into my tool bag to put back in my toolbox tomorrow morning when I go to work and found the stock fuel pump in the bottom. Started to wonder if maybe all the aftermarket things I did might be whats wrong. Pulled the fuel pump to find that the fuel strainer sock and the clamp that holds it on were sitting in the bottom of the pump housing. Swapped the upgraded pump for the stock pump, put everything back together, did the brake stomp, primed the fuel lines and cranked it up. Started right up to a rough idle. Gave it a few minutes to relearn the idle and fuel trims and now its running perfect, no miss, no throttle lag, nothing. Will experiment with the Injen intake to see if it was just the pump, but for now it looks like you were on the right teack asking if I should try stock parts. Thank you.
Now that its working properly it has thrown a bunch of codes:
P0336: ESS Sensor (have a spare)
P0076: VDI Solenoid circuit low
P0661: SSV Solenoid circuit low
and multiple codes that are die to an unplugged air pump.
Should I be concerned about the SSV or VDI codes? Or could those be due to how long the car sat? Both valves move freely in the intake by hand. I know where the solenoids are, and thats why I'm hoping its something simple.
Hmm. The VDI and SSv solenoids could have gone bad. Do the codes come back if you clear them? I too hope it's something simple. But it might just be the solenoids. A circuit low code has pretty few potential causes.
I believe they do come back. I have had the upper manifold off a few tines so there is a slight chance I didnt fully seat the connectors. Will see about pulling the upper manifold tomorrow to check the connectors, especially since it is throwing a "circuit low" code for all 3 solenoids lol. Heres all the codes it threw the last time:
it also threw a couple U codes earlier but those havent returned yet
Good news on the intake.
It seems they're more trouble than they're worth for the most part.
Most people here agree the stock intake is very good as is, and it appears from what I've read is the sound difference is the most obvious improvement.
Idk if there is a sticky about aftermarket intake pros and cons, but we really should have one.
Good luck with your solenoid issues.
I'm will check that before I check the solenoids. I know I have had the upper manifold out a few times as well as both valves in the intake (pulled one to do injectors, and checked the SSV for carbon buildup) so there is a huge chance its something I did, like what happened with the fuel pump.
At this point I believe this car is mocking me. After reinstalling the stock fuel pump into the housing yesterday it idled and revved perfect, shifted into gear without stalling, started while hot with no waiting, etc. Got home feom work and wanted to test if the problem was aftermarket intake AND high output pump or just pump and it wont start. Honestly I am wondering if the stock pump is providing enough gas once its at operating temp but not enough volume when its cold. The stock pump is a used one I bought on ebay 2 years ago with 60k miles on it.
It's just pulling an April Fools prank.
Starting the car doesn't require a lot of fuel at all. You could try to check fuel pressure, it is possible that used pump has failed on you. If that's the case, you have terrible luck.
I'd check the plugs. Best indicator of what's happening in the combustion chamber. Perhaps it has flooded for an unexplained reason.
Since the only thing that has changed between yesterdays cold start and todays attempt was the fuel pump swap, I am inclined to believe its the pump lol. But yeah, I think I have some extremely bad luck when it comes to my 8 lol
I'm on my 3rd pump in less than 5 years.
The last one was about a year old if that, and less than 20k I'm sure, maybe much less.
The older pumps must have had a design flaw because there have been many posts about modding or replacing them with better ones.
I have an '04, and the new pump has been redesigned, so I'm hopeful it will last.
I'm on my 3rd pump in less than 5 years.
The last one was about a year old if that, and less than 20k I'm sure, maybe much less.
The older pumps must have had a design flaw because there have been many posts about modding or replacing them with better ones.
I have an '04, and the new pump has been redesigned, so I'm hopeful it will last.
Wheres the best place to purchase a replacement, and what brabd for that matter? I can get a Delphi for $130 on RockAuto, and was about to order it but dont want to do it again for atleast another year lol
03-29-2017, 12:32 PM
