XLRX8

Hi guys,
Having some issues and could use some more advice.
04autoGT with 112. Really about 77k on a Mazda Reman placed in June 06.
Bought as a project with low compression:
Rear 56, 48, 65 @215
Front 62, 64, 63 @216

Pulled and gutted the cat although it seemed to be in OK shape. Started it a few times while uncorked and it sounds cool and seemed to be pretty responsive. At no time have I heard the cooling fans kick on. After doing a hillbilly flow check on the exhaust using a shop vac set to blow, I reinstalled the gutted cat.

Tried to locate my APV valve but instead found myself removing the cover from my oil metering pump. Put that back together while trying to approximate the adjustment it was previously set at. I STILL cannot locate the APV and I am even reluctant to mention this given the response others have received when asking for help locating it – whatever. Moving on, put the battery box back in and the air box (with new filter) but not after doing a through steam clean of the engine / engine compartment. (I’ve always done this on other cars without fear of ruining any electronics or getting a little water past the throttle body but oddly I’ve been warned twice in the last week about “being careful” so I mention this in case it helps with diagnosis)

Had a half tank of whatever so I added 4 gallons of chevron premium along with 6OZ of the “good” premix I ordered along with about 8oz of sea foam and an old old bottle of methanol based gas dryer.

Added 4OZ of sea foam to the crankcase in prep for an oil change, and started her back up. Car is extremely quiet it seems but noisy under the hood (like noisy lifters). Brought it to temp and ran for about 15 min with little or no revving and the fans have still not come on.

Started again last night and discover the chattering is my SSV valve (had a code early on and it was stuck but came free with a little jostling of the linkage – don’t recall it being noisy before but I was open header too) At any rate if I apply some light pressure to the SSV it mutes the noise.
With the confidence the noise was not the engine along with 15min of gasoline purge at near idle from the previous day I went ahead and tried to rev it a bit.

>>>>>SUPER non responsive. Like 3-5 seconds to reach redline from idle. Nothing like the responsiveness of when it was open collector.

There’s some info…any opinions on what to check next? What might be the cause of the sluggish response?

I’m trying to parley my time / money until I can find a 6port/6speed donor car to swap drive trains. Not expecting a full resurrection but somewhat hopeful of low performance use of the car for a while if I can pull off a few sea foam fogging treatments and a dealer PCM update for “low compression”.

dannobre

iTrader: (3)

4 port AT you will have a difficult time finding the APV 😉

XLRX8

Thank You.
So....this translates into "there is no APV on a 4port Auto" correct? The answer in this string should help those other poor fools (like me) from spending hours researching both here at RX8Club as well as under the hood.

Again I almost didn't even mention this struggle so that my already feeling stupid wasn't exacerbated by "asking such a foolish question" on this site and then getting a response like I should have known better.

dannobre

iTrader: (3)

There are only 4 intake ports on your motor..the APV valves are on ports 5 and 6 on the 6 port motors

Don't feel bad....there are no dumb questions.....

Just need a tough skin for when we want to have a chuckle at your expense

XLRX8

Thanks dannobre,
See now.. I though I read (here) that 4 vs 6 port had ONLY to do with 4 or 6 injectors (2 more injectors to supply fuel at the higher RPM's the 6 port develops) How far off from reality is that? haha

My skin would be thicker if i didn't feel so stupid already...there is a F*&% Load of stuff to learn about these engines!
XLRX8

XLRX8

Well, doesn't sound like a stuck APV is responsible for the super slow throttle response HAHA. Any other ideas anyone? I would hate to pull the cat again just to see if it returns to a more snappy throttle response - although if it did, wow what's that about?
I mean I could pull the plugs, or pull the ESS sensor or just go forward with the fogging??

At my rate of learning any of the above will take hours - that I've committed to invest - but would sure like to feel better about what to do next. Would like to actually drive it someday.

Thanks in advance.

dannobre

iTrader: (3)

Is it really slow? It could be in limp mode. Does the throttle react normally? IE will it free rev to 6-7K...or does the throttle react slowly and limit the RPM?.

Try and reset the ecu..and see if it revs normally...and then stops working properly after about 8 sec

XLRX8

I was just wondering what this limp mode was all about. Yea the battery was out for several days so maybe (hopefully?) I'll reset with my odd reader???and try again.

Thanks Dannebrog

Gravey

iTrader: (3)

Yeah "Dannebrog"'s a good guy, always there with good advice when needed! ...Just don't get on his bad side! PLEASE DON'T BAN MEH!!!!

XLRX8

Geese! Sorry Dannobre.. iPad knows a better way of spelling I guess. HaHa

So, it does look like I've got some sort of limp mode. I reset the codes and for 8-10 seconds it seems responsive. Then it revs slow but can still go to redline, slowly.

I did hear the fans going this time so that system seems to be working. Started it again after dinner and again at first it seems responsive, then a noticeable change like an ac compressor load and then it's back to slowmotion rev madness.

Seems I read tha messing with the OMP will trigger a limp. I did mess with it when I accidentally took it apart looking for the elusive 4port APV system?

Exhaust is smoking now, can't say I recall that before, so that makes me feel more comfortable.

So unless it's the stupidest idea in the world, I'll fog the motor tomorrow (made a super cool adapter - will post it separately, perhaps on the $100 mod string along with a battery box trick I think I invented) ok, fog then dump and change the oil (going middle of the road 10-40) then put on the air dam thingy, drop the car off blocks an the go drive as hard as limp mode will let me to complete the fog treatment per instructions.

How / when does limp go away? Few drive cycles to recalibrate? Not too worried (unless it will make my fogging a moot point cause I can't blow out what's loosened up before it re-hardens ) because the next step then is to go to dealer and get my freebies: airbag, something else and a "low compression" PCM update to retard and squirt at startup. If the motor is not so far gone and will start hot at the dealer then
I'll Fork out for a tranny service.

Then I would "like" to "plan" on driveing it for a while doing a fog treatment once a payday for a while the checking compression again.

Sorry I know that was a bunch of bla bla so basically

1 is the limp mode going to negate the seafoam procedure
2 how do I reset limp mode (I'll be searching again in the mean time)
3 does any of my proposed actions sound so stupid that I will be destroying my motor beyond repair?

Thanks for anyone whom has read this far. More thanks for any good advice.

XLRX8

Loki

iTrader: (1)

If money is an issue, just fog with water. It's just as effective. Or start with water to get the easy stuff off and then do a pass of Seafoam.

But, the OMP limp mode isn't going to go away. You have to actually fix the OMP, if that's the issue. OMP limp mode isn't supposed to let you get to redline at all.

You said there were codes? Do you think maybe they might be important?

XLRX8

Thanks for your feedback.

The only codes I recall were the p2070 (shutter valve was stuck) and the p0037 low bank something somthing. There were several flashing icons on my free, 1st time ODB CAN reader apparently indicating there are other pending codes...guess I'm not ready to know them yet 😉

Seems since the last code reset the 2070 came back. It is a chattery little valve and can't help but wonder about its efficiency. Rattles so much it "feels" like there valve is .020" smaller than the bore. Don't fully understand the function there (provides more flow at higher zooms via a second set of runners/injections?) would gladly rip into it but that's quite the procedure I see, so it seems to work, just noisy.

Don't know if it is a true "limp" mode I can take it to redline - it just doesn't get there fast. Haven't had it on the road yet so don't know what this behavior will translate to on a loaded drive train. The OMP does have a different than before adjustment that perhaps needs reconciled by the system but I'm not sure. I don't think I screwed any thing up...but for the record and future generations here is the OMP full details for scrutiny and evaluation.

As for my OMP, it was nice and clean in there. If you've had one open you'll know, Or correct me iffen I'm wrong. Working from under the hood (vs on the bench or with the engine otherwise removed) I had to remove the sensor to put the cover back on. The potentiometer is spring loaded in the CCW direction matching the direction of rotation of the metering mechanism itself - full CW=closed - tang near horizontal then rotating CCW to full wide open tang near vertical. Came apart easy enough but i couldn't get the tang to interface with the slot in the potentiometer. From my experience the switch needed to be free to rotate CCW beyond the adjustment slots, then once engaged (very notable as it is the only way it will seat) the switch/spring Pot thing can be rotated CW enough to reinstall the screws in the adjustment slots and ultimately to the "proper"adjustment point.

Now there's the million dollar question (aka will I need a new motor next question): What is that magical "proper" adjustment. Somebody please please clarify if I am way off here, please. Because there's not much I can find here and the MAZDA manual is limited to R&R (kinda disappointing for a workshop manual...but it's free and at least as good as a shiltons)

So as I deducted from limited info combined with a little systems operational speculation it seems the PCM tells a stepper to open x pulses (at y process parameters too? Such as rpm or vac/load levels IDK) as e mec opend the tang turns a spring loaded pot ( don't know it the resistance increases or decreases sat it turns and it only matters for a feedback change/delta...but I couldn't hod the meter pins to pins and turn it
Anyways my original setting (on the potentiometer to OMP houses get) looked to be fully cranked CW. At this position it is loading the spring tension as much as possible and in my brain that is likely making the system at maximum sensitivity or leanest possible. IDK but with promising I felt safe enough backing it off the peg about 1mm (of approxamately 12mm adjustment range) figure iffen I'm wrong and the system is inverted to my thinking then I am a touch below maximum metering. If I'm right then I've bumped up the metering a touch off the low end.

Anyways theirs some more blabble

Don't know if it is a real limp mode
Still don't know how limp modes are corrected/reset/validated
Don't know what this limp behavior will translate too when the wheels hit the asphalt
Certainly don't know exactly what I'm doing but have nuttin better to do.

Headin out to fog,oil, drown test run. Hopefully all goes well

I thank everyone for their feedback and I'll check back soon

Loki

iTrader: (1)

You might want to look for a replacement OMP. They're not supposed to be disassembled... so if a replacement unit is available, that might be faster/easier than trying to figure out how they're supposed to look inside.

The codes are important, how are we supposed to figure this out if we don't know what the computer is seeing? For example, if there's not a code set for the OMP, then we're chasing the wrong thing... but some generic OBD readers don't recognize OMP codes. So you may want to clarify this.

XLRX8

Nobody likes limp mode, I'm sure of it!

Sure glad I didn't fog yet. Ok then. Brought the car to temp and Limped the car around the block. I think I attained a whopping 40mph!

Have a hard p0410 (secondary air injection system malfunction)
Have a pending p0171 (system too lean bank 1)
The 3/3 code is a pending p0410 so I don't know what that signifies (being duplicate with 1/3)
There are still 3icons blinking but can't remember (will update)
The DTC or DTS light is on and no response when pressing the DTS button on the dash.
The tire pressure light is on.

Waiting for the light above my head to come on��

I'll need a little more diagnosis on the OMP before I swapnician that out of there. (Hear it's a $1,000 item although I haven't confirmed) they can't be so sensitive as to the trauma it endured with me taking it apart and my guess adjustment...or at least I hope not.

I'll continue to try any suggestions that come along but I think I'll call the dealer, have them prepare for whatever recalls that are due and have the PCM flashed. Maybe I can get some information on the OMP operating parameters - seem an elusive subject for the few hours I've investigated the topic.

My zoom zoom is zip

Loki

iTrader: (1)

Hmmm. So since you can read the codes, can you also look at the fuel trims? LTFT and STFT at warm idle and driving around, as well as airflow and afr? That 'system too lean bank 1' sounds weird. Post the results here.

XLRX8

Thanks Loki,
No, I cCan't see the fuel trim. Have just a entry level reader. The stuff your talking now is a little further down the learning curve from where I am now. In time I do want to get into that but have a lot to read till then. Haven't even a clue of even where to begin deciding what programmers to buy or what computer software I need or access to custom maps n tables and and oh my..there's a lot to wrap your head around.

Here's the latest dig. Pulled the batt box n stuff to access the OMP pot. Readjusted it back to the setting I scribed before I removed it for ease of reinstalling the cover. I guess it wasn't fully pegged after all. At any rate, it's bac to where it was and put bac together. Reconnected the batt and reset the PCM. Started her up and she seems fine.

Ran her around the block and was able to hit 80 pretty easy. You can tell its weak ( reminds me of an old 280 auto z I used to run around..) but faster than my last 1.3 liter, an 86 Suzuki samurai haha.

Rund her round a bit then she died at a store. Had to wait bout 40 min to restart and then it was a panic to get home, not wanting to go slow enough for idling. She died as soon as I stopped in my parking spot.

No error lights cept the CEL. Only Code is P0420 (Cat efficiently...go figure &#128540

So now what I wonder. Will the "low compression" dealer PCM update fix the stalling or am I looking at coils next.

Seemed to be running roughly some. But will I expect some misfire codes before I fork out more money.

Found some bare cords on the front tires inside edges - woo hoo, new tires soon 🤗

Eventually I'll be able to start saving money for the rebuild/ conversion, whatever falls int place first.

Loki

iTrader: (1)

I'm not sure what the "low compression" PCM fix even is. There were software updates that increase oil injection and a few other things, but they're not really fixes, especially for compression in the 4's and 5's. By all means get those, maybe the extra oil will help with stability. The thing that's tough to fix without a new engine are the hot restarts.

I'd start planning for that rebuild sooner rather than later..

XLRX8

IDK Loki
When I called Mazda to get information on the rig they had mentioned "there is an optional, voluntary, PCM update for low compression. It injects more oil and retards the timing" that's all I know I assume the increased oil is only at startup to mimic a less worn engine. I don't know the implications over the long term or even if the long term means more than a 100 miles?

I've read here that some times these rotaries will go out rapidly and sometimes slowly, but it seems always in the context of they are going out regardless. Again not sure what going out fully means. Will it loose all compression but not scatter? Or do (all/most/some/few rarely?.) failed rotaries throw apex seals or side seals or something that inevitably will require expensive machine work or major component replacement? No one will put a finger on it and I guess that makes sense too but I've heard through a friend that his old buddy said the old rx7 Rodders in the day would just keep retarding the timing and "could run them with as low as 10psi...and basically run them forever"

So basically I have no idea what is most likely or how foolish my current actions are?

I don't think I could crack it open for under $600-$800 if I were lucky enough to get away with just Apex seals. Maybe luck would be $1,200 to $1,500 for everything.

IDK, I'm playing it as safe as I can. Gunna premix, fog weekly (4 to 6 weeks ish) and recheck compression often. This all assuming the dealer flash will allow hot starts. If she goes down hill any further then I'll yank it and see from there

IDK, IDK, IDK.

Appreciate all

Loki

iTrader: (1)

With those compression number, at least some big parts wjll need replacement. It's not just seals. Not that they're damaged, but worn out of spec. I suggest you start thinking in terms of buying a known good rebuilt engine rather than rolling your own.

I don't see how the dealer flash will help with hot starts, but by all means have it done. It can't hurt anything.

XLRX8

Progress Update

Warmed her up and emptied about 1/2 can of seafoam. Was just starting to smoke pretty good when I shut her down.

About 15 to 20 minutes later I fired her up. Bellow I got yellow tinted smoke.

Raced down the road teaching about 65 between shifts. Ran bout 3 miles then pulled back in. While still running I finished the rest of the can before shutting her down again

Another hard run all the way to redline a few times. Noticeably different. I can feel the power boost when the ports are operating near 5000

Really hopeful still,

Latest codes are p0171 and p0420 with only system 2A incomplete. I expect that is when the CEL will return. Also my oil light is on but not low. In fact I might be a little over full. 3 qt 10-40,0.5qt Lucas stabilizer and a swig of seafoam.

Think I'll pick up another seafoam and repeat the flogging after a few days driving. And a finish up with a compression test before the dealer update.

XLRX8