Okay, maybe this is totally normal...but it doesn't seem that way.

I have put a total of around 40 miles on my freshly rebuilt motor. (a friend who's rebuilt close to 10 rotories and I did all the work) What it's doing is it won't start by itself...it gets close, but it just won't kick all the way over.

Now, we hook up a 4 wheeler, leave the car in gear and pull start it..it'll fire up about the time the rpms hit 1200 rpms. If the rpms drop below 1200-1300 the car will die, and not start up again under it's own power.

Now, i set the timing w/a timing light at close to a 1300 rpm idle speed...i know it's too high, but i can't keep it running any lower than this.

I have the wastegate actuator arm pulled off, so I won't accidently hit high boost during breakin...but this thing is a dog. It'll barely do 60 mph down the road. It's not smoking anymore, and the temps are normal, and the oil pressure is at 60psi @ 1200 rpms, and cruising down the road.

I used RA seals, and the solid corner seals...AND pressed in new rotor bearings....

Plz help me figure out wtf is going on, or if it's normal and just needs a few more miles put on it...

Thanx in advance.

 

I second that, I've got a fresh rebuild, and I'm having almost the same exact problem. Any help would be greatly appreciated.

 

compression test?

 

Open the throttle a little bit... when I rebuilt my engine giving it a little bit of throttle got it started after hours of trying with no luck.

Otherwise I'd say it's a matter of weak battery or starter?

 

It's completely normal for a USED ROTORHOUSING rebuild. You have a non-flat housing surface and a new flat apex seal, so you do get some compression loss for a while until the seals wear to match the housings and seal up better. Compression will come up as you put miles on...this is what breakin is.

With the added $1200 expense of new rotorhousings you can avoid this problem with a flat housing and a flat seal, and a very good seal/compression right from the get go.

The $1200 is not worth it most times, IMO. Just tolerate the low compression for a thousand or 2 miles untl it comes up and go on with life.

 

Thanx Kevin, I'll just keep putting some miles on it. It's good to hear that from someone who rebuilds so many motors.

Thanx again.

 

Is it also normal for a rebuild on used housings to take and act of congress to get started, and never be able to start under it's own power?

Mine prolly has about 20 miles on it, but for some reason my compression/ ability to start and stay running seems to be getting worse instead of better. It started right up, twice within an hour when I picked it up from the shop. But since I've gotten it home, it's done nothing but give me hell!!!

(my appologies if you consider this thread jacking)

 

Sometimes the plugs get semi-fouled due to burning off assembly lube and it doesnt show up until they cool off and you try to restart the next day.

Assuming you have an 86-88 model, you need a fuel cut switch. Treat it as a flooded engine. In fact, during breakin of a borderline-compression rebuild in an 86-88 car, go ahead and plan to use the switch religiously. When the engine is running, flip the switch off, and let the engine stall due to lack of fuel. When you come back and want to restart, leave the switch off, crank the key. This gives the engine a few rotations to build "cranking compression" before the fuel goes shooting right in. It's also helpful to open the throttle about halfway, which allows more air into the engine to raise compression further.

After 2-3 seconds there will usually be enough residual fuel in the fuel rail that the engine will actually start for a second or 2. Immediately upon it starting, you should turn the switch on. It should continue to run normally.

Doing it this way you should never have any starting problems, provided everything else is "right" on the engine.

 

Thanks for the advice, looks like I'll be installing a cut off switch then just as soon as I can get my hands on
A] a switch and...
B] that fuel cut switch write up I saw floating around here not too long ago.

 

I have a fuel cut switch installed...but it still won't start by itself. It seems to get REALLY close, and according to my SAFC I'm cranking at 460 rpms, but it just won't go.

I'll probably pull the plugs again tonight and clean them all up, now that the car isn't smoking anymore...maybe the plugs are fouled.

 

I installed my cutt-off switch, and I've got the same problem!!! well, almost. Mine doesn't even try to start, it just turns over...and over...and over.

I have brand new plugs and I've cleaned them at least 10 times trying various things to get this thing started. They have some blackness on them but they still get spark. I would consider getting new plugs but what's the point when the same thing will happen to them.

 

Hey don't be mentioning v8 swap in my thread!

 

sounds like a primary injector clip is damaged or injector is plugged up or sticking.


i never have problems starting, restarting or lack of power on rebuilds even with used housings.

other possibilities are spark plug wires in the wrong locations, even i do this simple thing wrong sometimes.

 

lol, my most sincere apologies, I'd never actually do that, but I think the statement gets my point across...

I'd like to mention the beautiful purr of my engine, but wait, IT WON'T START It seemed like this car was much more fun when it was just a dream and a poster up on my wall
*makes sad face*

 

If I continue having issues, I might swap out my primaries with my old 550cc secondaries that I took out when I put my 720's in. Mine idles just fine, so I'd seem to think that the primaries are fine...

 

j/k

takes some time making sure everything is in good working order, its a good idea ohm testing the sensors and visually inspecting the electrical connectors before fully reassembling the engine, it will save you a lot of headaches in the long run.

 

Just checked the plug wires, and they're where they're suppose to be.

Perhaps I should have had you do my rebuild then, feel like movin to Florida?

What exactly are the symptoms of of a damaged primary injector clip/ plugged or stuck injector?
Cuz the few times I've been able to get it running, it'll stay running as long as you keep your foot on the gas. If you let off the gas the RPM's just keep dropping till it dies. But the past 10-15 tries it just turns over, it doesn't even try to start.

 

symptoms are a serious lack of power, extremely hard to start, sounds like a lawnmower and the idle is rough if you can even get it to idle as though running on one rotor, because, it is..

you may want to double check all the vacuum lines as well, a leak can cause the car to stall out at lower RPMs.

 

That's the thing, when I had it running/driving it seemed like it had plenty of power, but if you came to a stop and didn't hold down the gas it would die.

It is ridiculously hard to start though. It actually idled rather smooth, back when it wold actually idle. Now would vacume leaks make it difficult to start, or just difficult to idle?

I actually have a thread that covers this in a lot more detail if you would be so kind as to lend your $00.02

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/t2-rebuild-turns-over-but-wont-start-576866/

 

yes, a vacuum leak could make it hard to start and idle, mainly check the intake ducts to be sure they are secure and not cracked. you can also try and isolate leaks with carburetor cleaner or an unlit proane torch but be careful around extreme heat sources or sparks/open flames.

 

Maybe I'm wrong, but it seems like those methods require the engine to be running to locate the leaks. If that is in fact the case that doesn't do me very much good.

 

now you are forced to either find the problem by taking apart the top end of the motor or resorting to ATF and starting fluid to get the engine running by the sound of it.

 

Sounds to me like you need to treat it like a heavily flooded engine, which it likely is after all this cranking. INject some oil into the plugholes, install new leading plugs, fire it up and hold the rpms up for a while as it burns off the oil. Perhaps raise your idle manually on the throttlebody prior so it will idle on it's own (high idle is okay) while you poke around looking for vacuum leaks, loose plugs, etc.

 

I did that, thoroughly cleared out the engine then put in some oil, and it cranked up. Now that I have the fuel cut switch in, I just starve the engine to kill it and when I go to crank it back up, it will actually start (maybe not on the first try)

Now I need to fix this idle. It bounces from 800-1200 and sometimes it'll hold at 1000 or 1100 for a minute or two, then it's back to bouncing up and down.

I tried jumping that little connector, and adjusting the idle, but that screw has no affect at all, it just keeps bouncing. Could this bouncing have something to do with why it won't hold any kind of idle while in gear? If I had an ohmeter I'd try to check the BAC but I don't, so are there any simple test to either confirm or rule it out as the trouble maker? I'm goin to the store to get some carb/brake cleaner to check for leaks brb.

 

So this is an automatic? IT's a little harder to get the auto rotaries to hold a good idle, especially when they're weak (a tired original engine, or a not yet broken in used housing rebuild).

Just manually raise idle on the throttlebody for breakin, and to get the stable idle in gear. Use the small flathead setscrew inside the 8mm locknut on the front corner of the throttlebody.

The bouncing idle could be a result of a bad or misadjusted TPS. Also, at certain high idle points, the engine will always act a fool by revving up and down on its own. FOr what reason, I am unsure, but it perfectly mimics the problems a bad TPS causes. This rpm area is about 1200-1500. Simply change the rpm and get it out of the "happy spot" and it should stop bouncing.