Richter12x2

iTrader: (1)

First of all, it's an S4-NA 6 port.

Finally finished the rebuild and got it all back in the car, but it won't start. It just cranks and cranks and speeds up, sometimes it almost catches, but then doesn't.

Finally, towed it behind a friend's pickup and dropped the clutch and the engine started and ran fine, but as soon as I let off the gas, it would die. Finally held the gas to about 3000 and disconnected the tow cable and drove it back into the driveway, where I put it in neutral and ran it at 3000 rpm for about 30-45 minutes with a rock on the gas pedal

About 25-30 minutes into it I went through a spell where the idle dropped and the engine started chugging. Tried to rev it with the rock and I got no noticeable response.

Looking around, I discovered the hose from the cat to the back of the engine was disconnected but was too hot to do anything about it while the engine was running. Would that cause my symptoms?

I checked timing with a timing light and I may have a sporadic plug wire, or I may have a cheap inductive timing light, and it's hard to tell at 3000 rpms anyway (since the engine won't hold an idle) but it seems to correspond to some dipping in the engine. :P

Additional information that may be relevant -
all emissions are removed from the engine itself.

All vacuum lines are plugged except the large hose from the front of the throttle body that goes to the 4 way vacuum diaphragm for the OMP, and one of the small ports which connects to the fuel pressure regulator on the upper fuel rail.

That includes the Vacuum sensor or whatever it is on the passenger side firewall. I don't think that would cause that though, or could I be wrong?

It's a 6th port, but the ports are currently unactuated and left closed. For right now, I'd like the car to idle :P. I'll probably eventually go with the aquarium pump mod.

Throttle body screw is pretty loose, again, trying for any idle, then I can tune for a better idle.

I'm getting no reading from the TPS. I have a SAFC II currently set for no modification. I had a reading when I first plugged the harness in but now nothing, even when I wiggle the connectors. I broke the wire that has my RPM input, but when I touch it back, it works fine. It's not installed incorrectly, because it was installed before the rebuild and I didn't disconnect any of the wires.

On the other hand, the engine runs, WOOHOO! It runs for longer than 5 minutes without blowing its watery coolant load all over the pavement. And other than the raucous noise that I presume is bouncing back out the air pipe from out the cat (the one that goes to the back of the engine that is disconnected) it doesn't make any weird noises.

I did a compression test when I was trying to get it moving off the (crappy) starter. It came up at about 50-55 on the front rotor and 55-60 on the back. Which I thought was low until I found the table with compression adjusted for RPM, and I realized my starter wasn't even causing the tach to move. So my thought is that I'm getting 55-60 front-back at about 100-150 rpm, which isn't terrible.

Any ideas?

The typeface used in this book is Arial font. Arial was developed by the Belgian monks in 1293 so that experienced internet users won't have to install new fontpacks to look at pages that aren't Times New Roman.

classicauto

iTrader: (3)

That would cause a GIANT vac leak, and thus, probably zero idle.

As far as I know, the ECU needs it...but Ive run the car with it unplugged during some diagnosis and it didn't effect it (of course, it was running like **** already from the problem I was diagnosing )

Richter12x2

iTrader: (1)

Nice. I thought the airpipe to the cat was just scavenging more emissions stuff. Learn something new every day. Imma have to go check that out now.

Richter12x2

iTrader: (1)

I guess it makes sense that you wouldn't want unfiltered air going into your exhaust. :P Lord knows what could happen.

Well, that was most of the problem. Now it starts up like clockwork (other than my crappy starter which takes about 3-4 button presses to get it to turn) What would I do without you? *sniff* I love you man. You're gonna wonder why one day you see a kid at school named ClassicAuto. And you may ask that kid "Is your name really ClassicAuto?" and the kid will say, from behind his black eye where he gets beat up for having a silly name, "Yes, my father named me after a great man who had a profound influence in his life, and he says my many black eyes and split lips are but a small price to pay for the advancement of all mankind."

So for you sir, a hearty

Now I feel better as I chase down the reason it won't idle (I did connect the vacuum sensor and it's better, but still not quite there) :P and wonder why I suddenly don't have enough wire to connect the TPS and the little circular connector to the potentiometer on the passenger side inner fender.

But having to drag the car around the block to start it was massively inconvenient, so that was the big thing.

Patman07

Did you ever rebuild any engines before this one? Where did you find the instruction to do so? I might be doing the same in the short future.

classicauto

iTrader: (3)

no prob man! anyway I can help...and if you want you can just name kid Joe!! hehe

Patman - atkins sells a comprehensive rebuild DVD

Richter12x2

iTrader: (1)

Nope, first time ever. I actually bounced back and forth from the downloaded FSM from the FAQ, the Chilton's manual. (Actually, only used the Chilton manual because I could leave the page open to the page that shows tightening order for the 18 bolts that go through the whole engine) and various posts here on Rx7club.com and nopistons.com (Mostly due to me doing silly things like "Oh, I've got my engine apart, why not disassemble and paint my throttle body!) For reference, if you do that, pay attention not only to the ORDER they come off in (I thought I was doing so well) but also the DIRECTION they come off in. Running through the throttle body disassembly guide in reverse and having a spare nearby got me straightened out though.
I actually watched the Rotary Aviation Bruce Turrentine video, too, but in all honesty, I could have done without it. It was nice to see it done though. The most valuable thing I learned from that video is don't install your apex seal springs until after the rotor is in the rotor housing. I spent the better part of an hour trying to slide them under that damned rubber band. :P

Another indispensable tip is that if you're reusing the 3 piece apex seals, go ahead and superglue the whole damn thing together, because they'll break apart when you fire the engine over anyway. Also, that little angle they put in those things is freaking sharp as hell. I was cleaning one with a towel and all of a sudden noticed that I'd cut a line through the towel and deep into my damn thumb!

One more bit of advice that I am probably the only person qualified to give, is no matter how good an idea it seems at the time, don't wash your irons in the dishwasher. Rotor housings are okay, but preclean them first. Disassembling and cleaning the dishwasher took a great deal more time out of my day than I gained by putting the irons in there.

Richter12x2

iTrader: (1)

Alright, got a new problem and it's got me baffled.

After reconnecting the big vacuum hose and the TPS sensor, the car was idling on its own again. I calibrated the TPS, and adjusted the throttle plates to get a surging idle around 1000-1200 rpm. My next problem was a bad oil pressure sender, and an substantial exhaust leak at the manifold.

Ordered a new exhaust gasket, and replaced the oil pressure sender with another used one. Got everything tightened down, but now the car won't idle, and after a few seconds it tries to die even if you're holding it at 2000 by hand or foot. And I've got this weird whistling sound and a constant beep in the cabin. Not one beep pause, one beep like in the Faqs, but a single constant tone.
Just in case, I checked my coolant and oil levels, and my oil level is pegged directly at the top mark, perfect. The coolant is visible in the tank. I checked all the connectors for everything. I tightened my alternator belt too, because it was a little loose.
Still the same problems. This time I held the throttle to about 2500 for about 5 minutes, and every few cycles the car would want to die, but I didn't let it. Other than when it is actually in act of dying, it runs and sounds great. After 5 minutes it finally died out so I let it die completely. Right after the car died, I reached over by hand and hit the throttle wheel by hand again. When I did that, I heard a puff of air through the intake and saw the engine rotate just a kick.

WHAT THE HELL?!? Is my vacuum way too high, am I developing positive pressure in my intake between the rotors and the throttle plates? The exhaust was supposed to be the last thing to get my car working and it's somehow messed it up worse.

I'm open to suggestions and speculations. Is there a vent hose or something I'm supposed to leave open after emissions removal?

Richter12x2

iTrader: (1)

Sorry, isolated that last one to being in mid compression stroke. That makes some sense to me now, but I've got a new problem or developments on the old problem.

I had removed the emissions, installed block off plates for the ACV, sub-zero start, BAC and split air solenoid. Just as Aaron Cake and others had predicted, my car will not hold an idle until it's warm. Then the idle surges from about 1100 - 1300. Which I can accept for now, but I'll eventually want to correct the surging.

Since it won't idle until it warms up, I removed the block off plates and reinstalled the BAC and the air solenoid valve, and tested them while they were off the car to ensure they worked correctly according to the service manual. Installed them and adjusted for idle, let the engine cool and there's no change. It still won't idle until the engine heats up. What gives? If the reason it won't hold an idle is because the BAC and Split-Air solenoid were removed, then why won't it idle now that they're back? :P

adrock3217

You removed your cold start assist, didn't you? NOT the sub-zero start assist, but the throttle body cold start assist. (Thermowax, etc.). Without that, it won't idle on its own until warm.

Richter12x2

iTrader: (1)

Ah yeah, that makes sense. I'll have to think about it before I put that back on, but that's the answer. I presumed since both of those vacuum nipples were broken off it would have no effect. I guess I know better now.

Sweet, I actually feel better just knowing why the hell it's doing it. It's not a big deal because it only takes a couple of blocks to warm up enough to keep running.

If I do reinstall it, that's the hose that comes out of the rear iron, into the bottom of that thermowax thing, then out the side through the BAC tube, then back to the rear of the water pump housing, right?

adrock3217

Actually, thats just a coolant bypass line. It doesn't actually do anything..except heat soak your throttle body after long drives.


The thermowax doesn't need that line to operate correctly.


But yeah, for the sake of reliability, ease of use, and weight, I'm not running any cold-start helpers at all. I'll be keeping the BAC only, just because the Megasquirt uses it to set idle.


It's so easy! Just start the car, keep the revs up to like 1500-2000 for about 1 minute or so, and then it should be able to keep itself alive. Or at least, thats how my GTU worked. Although, it was garaged :-P

Aaron Cake

iTrader: (1)

If you are talking about the cold start thermowax and cam, then you absolutely need the coolant line. The coolant is what melts the wax that brings down your idle.

For the record, the function of the coolant line is to:
-melt thermowax, thus moving plunger, thus moving cold start cam, thus ending the 1500 RPM cold idle
-keep throttle body from icing up in winter
-keep BAC from icing up in winter, and overheating in summer
-melt throttle thermowax to allow full secondary throttle operation once the car is warmed

With the 'Squirt (or any standalone that supports an idle valve) you don't need the thermowax. You can use the idle valve to get a cold idle.

Richter12x2

iTrader: (1)

That's what I figured - since the vacuum lines being broken off didn't seem to hurt/help anything, I guessed it had to be the coolant lines bringing the heatage.

Down here in Texas, I'm pretty sure I won't have to worry too much about my throttle body icing over or the BAC freezing up. Since the RX7 is just a weekend warrior, I'll probably just find a ledge or learn to cope. Now that I know WHY it's acting weird, it doesn't bother me so much that it IS acting weird.

Now I can move on to other things like getting my new power windows to go up and down without carrying a battery booster and clip leads in the car and fabricating my sweet new leather seats so that they'll fit in and be comfortable without pushing my head through the ceiling. Oh yeah, and replacing my backup light switch so that I can pass inspection, since my sticker expired in June :P