Starts but won't run after rebuild
 

So after a long ways of dragging my feet, I finished the rebuild on my vert's engine and got it back into the car- and finally working on actually starting it (too many projects -_-; ).

I've gotten it to the point where it will start- it will catch and rev up and run for a few seconds without any additional assistance/putting oil in through the plug holes/etc.- but it won't stay running. If I don't do anything with the gas pedal, it will just sputter and die within a few seconds much like it would do if I'd flipped the fuel pump cut switch. If I try, I can keep it running for a little while longer by varying the gas pedal- but it's sputtering and not wanting to be running and I can't keep it going for very long.

I've pressure tested the fuel pump and it checks out just fine. I've also tried starting the car with the fuel pump jumper (hopefully) ensure that it's not getting cut off for some reason with no change in what happened when I tried starting it. With the jumper set I can hear the fuel flowing through the system and back through the return. The AFM is plugged in, though admittedly I've not tested it- but from my understanding if it weren't functioning properly I wouldn't be able to try and coax it running for a little longer after the initial start and it would just die (though I could be wrong here).

Suggestions? It's warming up nicely and I'd really like to be able to use the convertible (plus I'm going to need to move it out from where it is so the car in front of it can be moved too :blush: ). Thanks!

Still trying to figure this out... if anyone has suggestions, I'm going to be having another go at it later this afternoon and would REALLY like to be able to get it running.

Have you checked for vacuum leaks? I experienced an identical issue with my 10th AE that was solved by replacing a cracked hose connecting to the BACV.

Set your idle higher, it may help, especially if you reused seals or housings in the rebuild. Your compression will be poor until it's broken in.

As stated, check for vacuum leaks. Make sure your fuel lines are hooked up in the right order, that your injectors are hooked up correctly, check your timing (and if the CAS is maxed one way or the other and it's still not right you'll have to restab it).

What's the best way to check for vacuum leaks without the engine running?

I meant to poke me head under the hood this morning to make note of the fuel lines to say for certain, but I'm pretty certain that the line from the fuel filter is going to the forward connection (the one that goes to the PD) and the return line is hooked up to the rear connection. I may have which is which backwards in my head, but I know the line from the fuel filter is going to the PD.

I know at least one set of injectors are hooked up correctly since I had them labeled- the other ones I'm assuming are since the wires won't reach to swap them around.

The rebuild has all new seals, but I did reuse the housings- I'll try setting the idle a bit higher and seeing if that works, but I'm not the most confident in that once since it so much feels like it's just cutting the fuel entirely somehow. But it's definitely something to try.

You can pressure test an N/A engine, just like you would pressurize a turbo engine for vacuum/boost leaks.

Still trying...
 

After putting almost all my efforts (successfully) toward work on another of my cars, I had the time over the holiday weekend to have another crack at the RX's engine. The last time I had tried getting it to run I noticed that the BACV was 'chattering'- it was vibrating enough that I could feel it with my hand on the intake manifold with the car turned off. I tracked down the one from my parts car and swapped it in as well as replacing the vacuum hoses that felt the loosest and capping off several things that weren't essential (brake booster, cruise control vacuum feed) to try and eliminate possible vacuum leak locations.

It's still doing exactly what it was before: it'll fire up almost instantly, and go up to 3000 RPM, bounce there for about 5 seconds or so, and then unceremoniously die. Trying to keep it running at lower RPMs works for a short bit but not on the long run.

BUT... I found something that struck me as strange (but somewhat beneficial...). It WILL run pretty steadily if I give it enough throttle to sit around 5000 RPM- and it will keep running even under at least a slight load (enough to move the car forward 5 feet or so on a slight upward incline). I'm unfortunately figuring once I get the last few things I need to do finished up on the other cars that I'll have to use that ability to get it back into the garage and pull it apart to try and track down/resolve the problem. :/

sounds like a vacuum leak to me.

Have you tried unplugging the BAC and see if anything changes?
Is the TPS set correctly?
Spark plugs and wires hooked up correctly?

Triple check all of your wiring and make sure everything is hooked up, and that nothing was overlooked during reinstall.

********BACV was 'chattering'******************

Not so abnormal. BAC's work on a duty cycle of approx 120hz give or take. They also go full open when the key is HELD to START. Won't *chatter when key is Held to Start*. It's purpose in doing that is to add air during Start.

Usually it's a large air leak that would cause your symptoms as mentioned a couple times above. Where? Can't tell from here

The black inlet duct that connects the afm to the throttle body should have a half inch in size plastic nipple on it with a hose, and that hose connects to the PIPE on a series four on the top/back of the dynamic chamber and leads over to the left side of the engine where that pipe feeds the air bypass solenoid ... and BAC I think. Anyway make sure that hose on the inlet duct is attached and the Pipe is connected to hoses on the left side of the engine (rear of engine on left).

Or if injectors are installed a bit crooked or with rock hard grommets on the bottom that mates with the intermediate housing......large air leaks can result.

Got me. Can't tell from here.

Is your AFM connected?

Unplugging the BACV: I believe it just didn't bounce as much when it went up to around 3K, but still died just the same.

Plugs/Wires are hooked up correctly. I've more than double-checked this as when I swapped in the previous engine to this one, I got them switched around- so it's the first thing I check.

TPS: Have done nothing with it between swapping out engines- so no, I've not gone through and re-adjusted it.

All the wiring that I can easily get to has been checked over several times- I'll be checking the rest when I pull the upper intake (and possibly more )to try and hunt down the vacuum leak.

The pipehose from the air intake is hooked up- it does indeed run all the way back to the BACV.

The injectors are definitely something I'll be checking. Once I get the car back in the garage I'll likely be pulling them completely and sending them off to Witchhunter to be cleaned/tested/new O-rings installed just to eliminate them as a problem (they're looking kind of rough as well). I transfered over the hardware from the old engine to the 'new', so it's possible that there's a vacuum leak there- so far that's looking to be the best candidate for what my problem is.

The AFM is hooked up- I've not run through the test for it, but out of curiousity tried starting the engine with it disconnected and it wouldn't fire over at all, so I'm acting on the assumption that it's working as it should.

Finally have things on the other cars stable enough to really dig into this and try and get things worked out.

I was pleasantly surprised that I was actually able to pull the car up into the garage under its own power- though I imagine that its clutch wasn't thrilled with me for it since it required keeping the RPMs up in the 5K range and largely using the clutch to control things. But it's now in the garage- and I think I've probably tracked down the source of the likely vacuum leak causing it to not run: sometime in the rebuild, the rubber grommets between the primary injectors and the block got lost, so there was likely a lot of air leaking in there. Ordering a complete new set of them for both primaries and secondaries as well as new o-rings for the injector air bleeds to ensure I've got as good of a seal as possible. I'm also still sending the injectors off to WitchHunter for cleaning/testing- several of them have gotten rather distressed-looking on the outside and I'd prefer the piece of mind that they're all behaving properly.

Unfortunately, I've got one more gremlin to track down- there's an oil leak someplace. My suspicion based on what I'm seeing is that it's the seal between the block and the oil pan, even though that makes no sense since I cleaned off both surfaces, put in a new gasket, and used gasket sealant on it. It's also annoying since I'm not sure there's a way to really do much about it without pulling the engine again, something I really want to avoid.

I'm having the same problems as you currently and found this thread while searching. Did you
ever get the problem resolved? I would like to know what it was. My car fires right up, runs for
maybe 3 seconds, then dies. I can play with the throttle and keep it going, but it is very rough.
And this is all just a sudden problem. Car was fine just the day before.

Try jumpering the fuel check connector and see if this makes a difference at all.

Just tried that, and it makes no difference either way. Is that good or bad?

the first thing to check is that all your intake and intercooler piping after the airflow meter is seated and clamped properly.

Ive checked all intake piping, manifolds, ect. with no leaks. Its not a fuel spark issue.
MAF resistance test checked out. Next I will check TPS and buy a new water thermo
sensor (the connector is broken and barely keeps connection). What else?

I too am having this exact problem with my swap. All three of us need to keep in contact, haha. Going to work on it tomorrow so hopefully I'll get somewhere. I have no vacuum leaks, I seem to be losing fuel pressure after it fires up, and the fuel pump is tested so I'm at a loss. I'm bringin a couple friends with me tomorrow to throw in their input. Frickin rotaries!

This is where I messed up after my rebuild. Plugged it in and everything ran fine

these issues are vacuum leaks.