It seems to me that my issue with the pressure sensor CEL correlates entirely with the weather. From what I've read, having a cone filter combined with cold weather (not THAT cold...) can cause the light to come on at high throttle.

Now that I've got a restrictor in the vacuum hose, that's the only thing I can think of that's causing it (outside of a possible vacuum leak that continues to allude me... damn thing doesn't want to run much at all unless the timing is advanced, and while it doesn't idle all that low MOST of the time, it doesn't respond as much to adjustments as it used to when I knew there were no vacuum leaks). It doesn't seem to actually effect performance other than making me not want to give it much throttle during early morning or late at night...

I don't have any hesitations when it's warm outside and the light doesn't come on, and no noticeable ones when it DOES. Also, I don't see anything wierd coming from my vacuum gauge (it drops off to about zero when you give it a lot of throttle and then builds back up, and it has around 15-16 at idle).

Does anyone know whether having the pressure sensor code stored in the ECU (although not "active" per say) would cause it to revert to the fixed vacuum amount (which also kills the changes in timing)? Or would it only do that for something that's unplugged, out of adjustment, or otherwise bad? Usually as soon as you plug something back in or adjust it, those codes go away immediately, though.

The pressure sensor code only goes away when I reset the ECU, though, which brings up the next question...

I heard someone claim the FC has a learning ECU, which typically means you'll have idle issues for a while after resetting the ECU... this doesn't seem likely as the FC is basically first-gen EFI and not that advanced. Just want to make sure either way though.

The next issue is my fairly decent but a little worrisome idle. Usually it will idle properly at around 750 but sometimes it will dip down to 300, which annoys the crap out of me (since I don't like stalling in traffic...). The other problem is that it should be idling much higher considering the current setting its at (idle screw sticking way out). This makes me think maybe the BAC is what's keeping it at the proper 750 most of the time, but it doesn't change, or actually gets slightly better, when the BAC is unplugged or disabled. Which IMO points back at vacuum leaks.

Seeing as how it typically idles a bit better while cold rather than warm (whereas it used to idle much better when warm rather than cold) makes me wonder if maybe I'm losing compression from not having enough oil from the OMP... since two of my OMP lines are custom replacements, I can't really confirm whether they're delivering the proper level of oil. Two of the lines (one original and one new) are full of oil, whereas the other two basically look like they're either partially filled or nearly empty, although with a little inside (the OEM one is partially filled, the new one being basically empty, at least when the engine is off).

Perhaps two of the OMP lines are only supposed to get half the oil of the other two (I would figure the ones for the rotor housings get more), but I figured I need to confirm this because it's had me worried since I put the engine in the car.

Also, the fact that the car doesn't run well at all at stock timing annoys me too. Perhaps I have a vacuum leak on the UIM or LIM from the last time I took it off to repair it... the last time being to replace some busted fuel lines, and then to free the 6PI system before that. God I hope it's not the UIM... I didn't use a new gasket last time, although it looked fine (yes I realize it's a matter of being compressed once, not a matter of looks, but I didn't have the time or money to order the gasket).

And even though the idle isn't rough persay, at least in terms of RPMs (it was until about a week ago until I fixed a few vacuum leaks), the sound that comes out of the tail pipes could be described as a 16 year-old cat with a slightly hairball rather than purring like a kitten... but that's probably from running rich... The sound it makes also seems to change with the idle setting as well, as well as the timing (timing increases the noise the exhaust makes at idle but doesn't nessicarily make it sound smoother).

Which brings me to my next point... what steps can one take to prevent the car from running pig rich? My uncle who was following me in his car a few weeks ago said he could smell the raw fuel. But I suppose that's part running rich, part having a barely-working emissions system (thank the lord I don't live in California). By all means, having vacuum leaks should cause the car to run lean, not rich.

I suppose the least I could do is get a narrow-band AFR gauge to give me a rough indication of WTF the engine is doing.






Well, that's all I can think to bitch about, and my wrists are tired too.

Yes, I realize I was rambling the entire way through, I was sort of doing that on purpose since I'm tired of making a whole bunch of seperate threads. I also know from experience that only a small minority of the questions will actually be answered (the rest of the replies will be people saying they have the same problem). The same things applies to most species of simple lifeforms...so I just asked as many as I could.

...haha.

 

I'm going to simplify a few things since I feel like actually getting answers at the moment:

1. Can the S5 LIM gasket be reused? It's metal but I don't know whether it's meant to be compressed once or can it be reused many times?

2. Should all of the OMP lines be filled? Or should two be filled and two be partially filled?

3. Does the FC's ECU actually have a learning function?

4. What causes a car to idle well when cool (even right after the high idle shuts off) but crappy when it's warm?

 

1. I think so. I don't see how it would be different once you compressed a new one...

2. They should all be filled. That's why there's four.

3. I don't think so. There was a thread about it a while back you could search for.

4. Sensor settings. Although I've never seen a sure answer, the temperature sensors and such will report different once the car is warm. That could throw off readings. However, in my case, my idle fluctuates once warm indicating TPS. I'm not sure how a TPS would be affected by heat...

 

Similar Lifeform~~~~~~~~~~~~~>>>>>>>>>I have a smiliar problem. When i start the car either cold or warm it wont idle properly. It will just shut off on me. My car always used to go to 2500-3000 RPMS for a few seconds then it will come down gradually to 750 or so RPMs. After i got it back from a shop it wont idle properly.

HOT WEATHER:

I have to keep my foot on the gas at 3000 RPMS then gradually bring it down to 750/1000 RPMs. But if i will take my foot of the gas it will idle really really low just like VALK. And it will just shut off. So i have to keep my foot at 750/1000 RPMs for a bit longer till the car is warm enough.

COLD WEATHER:

Same issue as hot weather but once i let go off the throttle the car will idle on its own at 750RPM, and ocassionally it will climb to 900/1000 RPMs. NOt always true but appears more often during cold weather.

I heard that i may have a vacuum leak, could it be that maybe a vacuum hose is pinched. Which will still require me to do some inspections on my vacuum lines.

Do i have to remove my UIM, and LIM to find the troublesome hoses or are there any recommendations you guys have to where/which vacuum hose is the problem?

I am also concerned with the yellow/translucent OMP lines? I want to replace them, does mazdatrix sell them?

Pretty much i would like to get my car to idles on its OWN like it did back in the days.

Jason NYC

 

Yes they do, but look here first: https://www.rx7club.com/2nd-gen-archive-72/rebuilding-omp-oil-injection-lines-348068/

 

Thanks, i see mazdatrix got them, buti bet there just like the old ones.

But these are way nicer, SS OMP Lines lol

http://www.rotorsportsracing.com/per...g/OMPlines.htm

Jason NYC

 

 

Ok, you have a check engine light and it says pressure sensor. Why don't you replace the pressure sensor?

 

Well why cant i go to Homedepot and take some of the SS lines from the plumbing section and change the fittings or so to fit my car? Isnt that possible?

 

yea, just rebuild the lines. there's no reason for stainless unless you want the bling. there was a guy that used to be on the forum i think that made ss omp lines for the fc for $80, and would give a discount if you sent your old ones in. i forget who it was though.

 

http://www.scalliwag.com/

but good luck getting a hold of him.

 

I have no clue.

 

Sup Eric, well its not just about the bling, but i would rather not have to think about them or replace them again, save myself the time and headache. Plus its very hot under there dont want any sudden failures due to heat and it catches me when im on the road and kaboom , no oil and engine goes bye bye.

I will actually look into it, i gotta hang out more in homedepot they got mad stuff.

Man this guy Valk gonna be heated, hes not getting any answers lol

 

narrowband won't tell you ****, except whether the car is closed looping or not.

and if you think you have low compression, do a compression test. Correct me if I'm wrong, but on an s5 you should be in limp mode if your OMP isn't working.

 

My theory is that a vacuum leak is being made worse because of the increased vacuum that comes from increased compression (once the engine is warmed up).

I'm gonna see if capping off the AWS hose makes a difference... I think I might have a leak there. But it sucks so strong that a real vacuum cap is the only thing I'm willing to block it off with.

Also, what I wondered was why would the lines that go to the LIM need as much oil pumped through them as the ones that go to the rotor housings? If they need the same amount of oil, I can't see why they would make such a delicate piece of equipment like the OMP (assuming it actually meters different amount of oil to the injectors, otherwise why would they call it the oil metering pump?)


I just hope that having low oil pumped through my OMP hasn't FUBAR'ed my housings and stuff over the last 3000 miles (I need an oil change...). I would do a compression test except... it's a PITA. And besides that, my car starts too easily and pulls to hard (well, at least when it's warm out) to have low compression.



One more question: Is it normal for the engine/exhaust to make sort of a ratcheting sound during decel?

That's the only way I can describe it (it doesn't sound dangerous but I'd like to eliminate it if it's not normal). It's done that forever (or at least since I put the engine back together).


I've got some more annoying vibrations when I give it throttle as well but I don't have a clue as to how to find them (I think maybe they only happen when the car is being driven and under load?).

I think I fixed one of my annoying squeaks...which was probably the hood latches (WD40...but I'd probably need new ones, or some kind of dampening to fix it permanently).

I also have the dreaded under-dash rattle. I would take off my dash cap (already destroyed one demister panel trying to do it) to look for lose things under it, but I don't have one of those bent screwdrivers to get under the windshield.

Edit: One more note, it idles fairly well when you give it some throttle and it advances itself (making it idle at about 1100). But when it returns to normal idle it starts to get funky again. Which makes me thing vacuum leaks, combined with the pressure sensor code (which effects the advance) are causing the bad leak. With the way I set it, it should be idling at like 2000 RPMs (all the way out).

 

I believe your correct on the limp mode, but would the OMP know if a line was broken? I'm thinking no...

 

I know my OMP is working... It's just that I wonder why two of my lines aren't fully filled.

One of the remaining OEM lines it's maybe half-filled (it's sort of polky-dotted) while the one I made out of teflon (which has a different inner diameter but the injectors and stuff are the same) just looks a bit oily on the inside (basically empty).

The other two lines are fully completely.



Also, I know that narrow-bands are worthless. All I want it to tell me is whether I'm rich/stoich/lean.

I don't really need a wideband as it's the stock ECU.

 

I confirmed there's flow in the OMP lines when it's running, so theres probably no worries there...

What I really want to know is why the frak cold weather (and cold weather alone) would cause the pressure sensor code to flash when you give it any more than minimal throttle.

When it's warmer outside it runs like a champ but that stupid light comes on when it's cold (it's not THAT cold here... not anywhere near freezing) and it doesn't sound as strong.

I'm not sure whether or not I have a vacuum leak because sometimes it idles perfectly while other times it drops low or wavers. Just a while ago I was setting the idle/timing and it idled damn well at 750-ish, but it still doesn't respond all that well to changes in the screw. Also, the idle doesn't change when you unplug the BAC.

I guess I'll need to get some butane or get the parts to compress the intake and use that to look for hard to find leaks.

And I still don't like the way it sounds like it's running rough from the exhaust... not a steady sound, sort of chugs a bit. The only maintenance item I haven't changed is spark plugs (which still look fine). What can cause this besides vacuum leaks or bad timing anyway? AFM?



Oh yeah, the idle drops when I pull off the Relief Solenoid Plug. Normally this solenoid is receiving voltage at all times, so pulling the plug means it turns off and closes something, I think... but what? Perhaps that's part of my vacuum problem?

 

Since apparently the solenoid is off when in "cold" mode (don't know if it's referring to air or the engine), that may explain my funky running and low idle when it's cold out.

When the solenoid is off, it apparently makes the anti-afterburn valve in the ACV exposed to vacuum or something, and in case the valve is bad, it causes a vacuum leak.

This may also explain why my engine afterburns so much, primarily when it's warm out (it only afterburns when it's being driven in gear though...). And perhaps it explains the pressure sensor code (caused by a vacuum leak?).

I think maybe this came from when I took my ACV off to clean the check valve... or perhaps I just need to change out the ACV (which is the only way to repair the anti afterburn valve).

Now if only this would fix my...hmm...5 problems?

1. intermittent low idle

2. pressure sensor CEL when cold outside

3. constant afterburning

4. buzzing sound out of the ACV

5. non-functioning split air solenoid (probably related to #4)

Now if only I could isolate all those annoying vibrations during driving... especially the ones related to RPMs and throttle.

 

Update:

The guy at the Mazda place (who's been working with rotaries on and off for 30 years, although he's not an expert per say) doesn't like how my OMP lines have a lot of air in them (nor the fact that it's leaking like a ****)... Also, it seems like some of the lines may have a flow problem since it seems like the oil in two of them stops at a certain point and won't go any further. I can't imagine why... other than a bad OMP, or bad oil injectors (or injector vacuum hoses).

The leaks don't concern me too much as they really just make the engine bay messy (and leave the drip) rather than losing a lot of oil, but if my engine isn't getting enough metered oil, that IS a rather big concern (because of the air bubbles in the lines).

As soon as I'm able to come back here (since the intake/OMP/transmission parts I ordered from Mazdatrix aren't going to my apartment) I'll fix it then, and make sure each of the lines is going to the correct inlet.

 

Update:

I got a new (used) vacuum sensor and my problem went away.

Yay.

(now I can floor it all I want)

 

So your vibrations went away?? If not check your tranny mounts!!!My 88 n/a had a bad vibration whenever the rpm went up, idling or under load, the new tranny mounts fixed it!!!
Hope that helps!!

Apex

 

Nooo... the CHECK ENGINE light problem went away (thank god).

I still have plenty of thumping coming from the rear end... that's *probably* the rear diff front mount, but it might be the driveshaft u-joints (although they seemed OK to me...).

And as far as I can tell, the OMP seems to be working fine as well...

But I've developed plenty of new problems lately...