GSL-SE here with a new 13B.

Well, fired it up for the first time, it ran, I pulled out onto the street and let it idle. It was idling kind of rough, and as it started to warm up, it ran rougher, idle got lower and lower and eventually it just died.

I restarted it, and it died again. If I gently hold the throttle, it doesn't die, but as soon as I let go of the throttle, it just kind of bogs down and dies. Doesn't seem like a fuel issue.

I think the intake screw is open all the way, and I've adjusted the throttle plate a while ago. TPS is also within adjustment, just checked.

When it does run, it runs kind of rough and uneven and the motor shakes. What should I check for? Vacuum leaks? Timing? I can't really check my timing, since it won't idle, but could it be running like that because I put my disty in wrong? Could it be bad spark?

I found a bunch of threads where people's engines are dying at idle, but they all seem to be results of different issues...so I'm not sure where to start in my case.

 

Oh, and possibly on a related note, the manual says to replace the variable resistor when replacing an engine, and re-adjust the mixture. Is that something I need to do, or should I be fine with what I got?

 

Look at it this way; your intake system was all tuned for the engine conditions you had before. Just installing a new block isn't going to run as well as it did before, because the intake system isn't tuned to your new engine.

The intake system on an -SE is complicated enough without introducing a new engine block with better compression, better oil control seals, etc.

And, based on what you're describing, it sounds like either an inadvertent air leak (vacuum loss), or the vacuum control system is out of whack. Get yourself out to the -SE Intake Pages and start over from scratch. I'll bet that once you reset everything, it will run much better;

http://www.nellump.net/peri/epi/firs...gslseIdle.html

 

Thanks, that makes sense. I've gone through the whole idle setup shebang with the old engine, and got it running fairly alright, so I think I remember most of the steps and it won't be confusing. I suspect there's more to it than intake setup, so I'm also gonna go down the looooong troubleshooting list in the FSM, check fuel pressure, test ignitors, vacuum leaks, timing and all that. But first, I at least have to make it idle, so I can test stuff. This kind of sucks, because I need to gently break this engine in, and instead it's not running right at all and that's probably not good for the engine.

 

there is a diagnostic connector on the CPU which is under the passenger footrest. There is info in the manual about the connections and blink sinals.

 

Do you mean ECU? CPU is on the driver side and doesn't control the engine. If so, it's part of the troubleshooting list I was going to work with, and it says I need System Checker 83. I bet Mazda would charge an arm and a leg for it, so I'll see if I can find info on how to make my own or something...

 

Ok, here's the update.

I've checked everything I could think of. Throttle body valve clearances and fast idle set to factory spec or at least as close as I could manage. Tested for vacuum leaks, couldn't find any. Checked the variable resistor and it seems ok. Vacuum switch ok. Checked the airflow meter and that also seems fine. I have fuel pressure, maybe not the exact reading as the FSM, but I think close enough. Checked both ignitors and they work and also have decent spark at all four plugs, so wires and plugs are good. Ran the diagnostic ECU error code check and nothing came up. Set the TPS on the cold engine, with fast idle cam disengaged. Pulled the disty and verified that it's aligned right.

After that I started the car up. This time it didn't die, so that's good. I let it idle for a while, it was still kind of lumpy and shaky. Hooked up a portable tach and the RPMs were all over the place, so I let it warm up some more and then it settled down a bit, but the idle began to cycle, so I redid the TPS and that sorted it. Did the timing adjustment, didn't seem to make much difference. Then I tried to set the idle to 800 and it was kind of hard, because it wouldn't stay at 800, instead it would just randomly be anywhere between 770 to 830, but I tried to average it out, so that I could set the mixture as well. It ended up kind of on the lean side, so I'm not sure if that's right or not. Was still a bit lumpy and shaky, but not too bad. Checked for vacuum leaks again, and found nothing. Fuel pressure still ok. Ran the error code diagnostic on the ECU again, and that was still good.

One thing I noticed is that my throttle shaft is kind of loose and sensitive. I can actually change the RPM just by touching it. Which makes it almost impossible to set the TPS correctly. I could set it, and then give it gas and the throttle would close at a different spot and the sensor would be off again. Tender stuff. So I think that's one of the main problems I'm facing. It's not that it's sticking, it's that it's just worn and loose and random. I remember oiling it up a while ago and it didn't really do much.

Anyway, it revs ok, but when I let go of the gas, it kind of dips, until it comes back to normal. And while it's warming up there's this random KRK KRK KRK sound coming from exhaust, like it's missing, but once it's warmed up it subdues and becomes a lot quieter.

Here's a video of it warmed up. I put the screwdriver onto the plenum to see how much vibration there is. Notice as I rev it, it just dives after that. Hmm... Oh, and for some reason my RPM went up and I couldn't bring it down to 800 even with the idle adjust screw. You can hear the KRK KRK a bit when by the exhaust, it comes through ever so slightly. I don't know what that is. I have a video of it being pretty loud, if you want I can upload that.

http://www.youtube.com/watch?v=QZIFyPz2_6g

So, thoughts? Ideas? Or does this look ok to you?

 

pulsing and the drop after rev souds to me like vacume to me the computer doesnt sound logical to me the engines were not tuned to the car they were mass produced they all got the same tune and there is no difference in that aspect.

did you put al new seals on the intake system? i have ad pulsing when i whent cheap and didnt buy new seals

 

Intake system seals? I'm not sure what that is. Do you mean gaskets? Yeah, all gaskets are brand new and all mating surfaces have been cleaned and prepped. I misted some starter fluid around the vacuum areas and didn't notice it getting sucked in or anything like that. Only vacuum related malfunction I can think of might be the BAC, but I tested it and it seems to work.

Here's a video of the KRK KRK KRK sound.

http://www.youtube.com/watch?v=RiRY4pwsQCM

It's there when it's idling at certain RPMs, like higher up, around 900-1000, but around 800 it's barely noticeable, as you've seen in the previous video. And it idles at random speeds all the time. I'd let off the gas and it'll be at 800 or next time I let off the gas and it'll be at 1000. Wow baby yeah surprise me. D'oh. I thought maybe somehow one of the seals got damaged when I started it up for the first time and it's slapping around, but I just checked compression and it appears to be good and even. In fact I listened to the engine itself with the stethoscope all over the place and heard nothing but smooth, even cycles.

 

Ok, just did a second compression test and filmed it so I can examine it better, and it seems both rotors have kind of uneven compression...and the front rotor is lower compression overall... So on two rotor faces it has about 70 and the other face has about 80, if my tester is any good, that is. Hmm... So that's probably what the KRK KRK and crap idle are all about. Damaged side seal? But how? I barely even drove it...just out onto the street, so it didn't smoke up the garage.

 

One side seal won't impact compression on two faces... only corners or apexes do that. Could be as simple as a weak corner-seal spring.

 

Ooops, I meant apex seal, not side seal.

Could it be that it's just stuck somehow? The engine's been sitting for what now...half a year I guess, while I was working on other parts of the car. It was sealed and plugged and everything, but still is it possible that even on a new engine something can get stuck from sitting too long? I guess I could inspect the seals through exhaust ports, but I can't really think of anything I could've done to make it fail on first start.

Maybe I chipped the seal or scratched something... A scratch in the housing would leak compression on all rotor faces, though, yeah? So it can't be that...

This is really confusing and frustrating.

 

Well, I examined it from the fart side, pulled the headers off and checked the seals through exhaust ports. Everything seems to be in order, they all have good amount of resistance. On my old motor couple of the seals were bad and had no spring back, I kind of remember what that felt like, and none of these feel like that. Plus I get six confident whooshes out the exhaust ports when turning the engine by hand.

So now I'm kind of doubting apex seal damage.

I've been searching around for hours, and found some info that suggests the exhaust noise might be a result of afterburn or something similar. I don't have an ACV, so obviously no anti-afterburn valve. Ceramic coated headers make for even hotter exhaust gases, maybe that's not helping either. Kind of makes sense, actually, that at higher RPM idle more unburned fuel is dumped out and that's why I'm getting the KRK sound at 1000 RPM and not at 800 RPM. Just a theory of course...

 

OH FFS what is going on! Today I messed with it some more, replaced the cracked/broken purge valve with a PCV for now. Yet no matter what I try, it doesn't seem to make much difference, and sometimes it makes things worse. I unhooked the 2nd gen coil and switched to the old stock coil, and didn't notice any change. Still same crap. Swapped wires around. Disconnected wires. Moved plugs around. Redid the TPS. In fact, it seems if I set the TPS correctly it idles horribly and cycles up and down, but if I turn the TPS screw a few times clearly taking it far out of adjustment, I can get it to smooth out. Disconnecting and even plugging the BAC doesn't do jack.

I also tried to readjust the timing. All it does is change the RPM and when almost fully retarded it seems to run a bit better. The whole system feels out of wack. Hell, maybe my distributor is bad. Possible? When I check the timing, even though it's spot-on, it doesn't seem to be steady, like it fluctuates by a few mm, especially the leading.

Idle quality is completely random, I'm guessing that exhaust KRK KRK is a misfire or something of that sort, because I can't figure out what else it would be.

Did another compression test, front rotor is still lower by like 15 psi and kind of uneven (see video). When I release the valve, it climbs up to maybe 110 before stopping, while the rear rotor climbs to like 120 psi.

Where's what I filmed.

http://www.youtube.com/watch?v=xb77cMWu-o4

I'm afraid to touch this car anymore, with all this experimentation I feel like I'm doing damage to the engine... I thought I had a pretty good understanding of how the system works, but the results of my adjustments totally do not match the expected outcome. Setting everything to factory spec, like the FSM says, makes the car miss and idle like crap.

HALP!

 

I read a wile back on a aussie site about a guy who clamed to olyptical stress on his E shaft he found this out after he had the same issue you are having and ended up tareing down his fresh rebuild.

all in all it was the old e shaft that looked in good order that screwed him.

i guess he did some math on the shaft and he stated that shaft had warped now my father owns a machine shop and i know metal that thick doesnt just warp but it could happen with enough heat and stress.
the wankel may be stress free but we all know they get lots of heat...
it may be a possiblity but again this was a artical by a guy i dont know.