Totally mind fucked right about now. Last night I started the car just to let it idle because I haven't run it in 2 weeks. It was fine! Started fine, warmed up fine, idled fine. Shut the car down, drank some beers, watched some football, went to bed.

Wake up and say "What a nice day! I'll go for a ride!"
Get in car, crank and it starts kicking like it's too lean when starting. Odd... didn't happen last night. It keeps struggling and I get a nice after-fire pop. Hmm... Try again, same old kicking but this time I coax it to life with some right foot. The car is now running but struggling to hold. Eventually the BAC starts to help and the car idles up at 1200RPM ON THE DOT. But the engine is shaking like crazy, it's running very lean (14-16:1 ratios) and the vacuum is poor around 10. When the car was normal just like any other day it pulling 17-18 vacuum.

More "load" would enrich the fuel, so why is the car very lean at low(er) vacuum?

I pulled of my intake just to check all my vacuum lines and verified everything was in place. I put everything back together and started it up. Same old story. This time I went crazy with starter fluid. Any more and I think I would have set the car on fire. Nothing. No vacuum leak. I thought maybe the pump could be dying but the fuel pressure is close to 40PSI. Oil pressure is fine if that matters. If I give it gas it hesitates, but does rev up.

Right now the engine is fully warmed up and too hot to work on, so I can't check compression. When it cools down I will try the poor mans test at least until I get my hands on a proper gauge.


I have no clue what is happening. The car was fine 12 hours ago.

 

I have been told a bad coolant temp sensor will read "cold" when bad, causing less fuel to be thrown into the engine. If compression is good, maybe something to look at. Also fuel system.

 

^I should add that the sensors are reading well. I run a haltech and I am verifying everything with my laptop. I am thinking something is wrong with a primary injector even though they were fully serviced <800 miles ago...

 

Cold readings won't lean the mix anyway, cooler temps call for more fuel, not less. Hence why colder thermostats or no thermostat is mostly good for high fuel consumption due to slow warm-ups.

For the OP - I'd doubt your engine "blew" on startup, since under essentially no load even a lean mix shouldn't be able to cause serious detonation, just hard starting - I think you're on the right track looking at injectors; recent changes are always a good place to start with troubleshooting.

 

You are right, ment to say if it is reading "hot". I believe this is what the ECU defaults to when the sensor isn't connected properly. 176*F.

 

Well I ran a poor mans compression test for now. I hear 3 strong "whistles" from each rotor, and can feel 3 good puffs too. I also made sure both injectors are firing by hand spinning the CAS. They are both firing. I'd hate to think a low mileage injector has gone bad so soon.
I just checked my intake and hoses again, everything in place.

Still baffled.

 

I had this same problem with a friend of mines setup, long story short it was a factory 13bre with high miles.he broke an apex seal in the front, so............ i rebuilt him an engine w/ new rew housings 2mm aftermarket seals etc..... a really nice engine , first start up very nice got the engine to purrr pulled bout 17-18 vac
let it cool to check everything , re started the engine sounded great !!!! few revs and WTF ???????? motor jus popped in garage under 4 k in vac ?????? after teardown i was shocked and amazed ............................ a fu#$in piece of the broken apex seal from the previous engine got stuck in the external wastegate
and somehow got sucked into the engine durring free rev, i'm not sure if i'm the only one that has this happen to. jus thought id share , it was a learning exp
for me and now i check everything twice GL

HOPEFULLY this is not your problem...........

 

double check your map sensor

 

I'd lean towards injectors even if they are low mileage. This reeks of an injector failure. I think I've had to deal with a bad injector on damn near every single RX-7 I have worked on except my own. Even if it is clicking, the solenoid could be lazy or the nozzle could clog. Maybe a bunch of trash got loose in the fuel system and clogged the inlet screen?

 

i had that nice after fire pop myself, it blew off 7 of 10 vac caps! recheck all your lines

 

GAH... Just tried to start again. Same story. I will have to let it cool down again and I will pull the injectors out. This SUCKS.

 

When you started the car because it had been sitting for a couple of weeks after it was started how long did you run the car before shutting it down? 10 minutes, 5 minutes, 1 minute, 15 seconds?

 

2 Weeks ago it was fine. Then last night it was fine. I'd say it idled 15 minutes last night. Car has never overheated.

I pulled the injectors. The little filters look clean. I guess one (or both) are dead or dying here. I have to dig up my old ones and see if any of those even work any more.

On a side note I came inside and washed up. Then for extra cleanliness I have a big bottle of hand sanitizer on a high shelf. I went to squeeze some into my hands and it was a bit clogged, resulting in alcoholic gelatinous goo shooting into my face. and all over the wall I might add. This **** burns! Can you ******* believe my luck?

 

lol. You have luck like mine.

Have you checked your fuel pump, it's screen filter, and the fuel filter?

 

full mod list?

is everything good with the plugs and the ignition system?

 

Everything on this car is relatively newish, all less than 1000 miles as far as the "replaceable" items go. All filters are new, plugs, et cetera. I had the pump out a while back to replace the fuel level sender. Everything was clean then. Like mentioned before, I thought for a second about it being the pump, but I have nearly 40PSI idling and the pump is running. Something happened this morning the instant I cranked the car. I do not suspect a coil or ignition problem. If that were the case it would be running too rich (weak or no spark means tons of fuel in the exhaust), but my car is extremely lean and unhappy. I made no changes from last night to this morning. It has to be the injectors because the car kicks a lot when cranking (too lean) and when it's running the ratios are too lean.

I can't for the life of me find and extra pair of injectors I had, although I don't know their condition regardless.

Anyone selling a pair of pink 550's center keyed?

 

SINCE I was reading and browsing I'll share a personal story with you. A few weeks ago this SAME problem happend with my corvette, I swore up and down the injectors we're the problem because everything pointed to them.

Whel one day, with the car running (yes I am aware you cannot do this in the rx7) I pulled each injector plug one by one, about 4 times for a total of 32 times. I pinpointed the injector closest to the drivers firewall as the culprit. So I thought, why not go one step farther? I shut the car off and pull that spark-plug out, and replaced it with a dummy, and then grounded the plug out with the wire on it.

I started the car with the plug I took out grounded to the A/C compressor, and it sparked 3 times (3 turns of the crankshaft) and the engine started, but wait, it STOPPED firing after the car started? So I restarted the car about four more times, each time it stopped firing after the engine started running.

I check various things, the coil can't be it, or it would be erratically sparking/not running. Couldn't be the ignition module or the same thing would result, as well as with a cracked cap/rotor. So I turn to the opti-junk on the front of the engine, it uses optical sensors and fires each plug independently, could be dirty, broken, destroyed, or water-damaged contacts. The point being it was NOT the injector.

This engine would buck, lose power, refuse to start and run, wouldn't idle worth crap, would kick the starter, got progressively worse as it got warm. Just keep it in mind and make sure you check your ignition system thoroughly.

 

^you spelled well wrong


And OP....I'd say best bet is just swap a v8 in it!!

 

^Haha, at this point, i'd rather not spend more money on it, but I guess I have to. I just want to get rid of it eventually.

I guess every cloud has a silver lining though. 3-4 weeks ago I took a drive for an hour. When I was 1.5 blocks from my driveway coming back, the clutch slave took a dump and left my stranded to push my car home. At least it didn't happen on the way out!

And with this bad injector/massive lean issue, good thing the car didn't even get down the driveway! Imagine I hit boost and my injector died. I would have made a very very different thread.

 

Cry us a river, your a turd

Keep us updated beefhole. If you give up i will trade you

 

^I do like the idea of a STOCK, or close to, low mileage '91

Got any spare injectors?

 

I highly doubt it. I did have a full set of S5 TII injectors in my fathers attic but i believe i sold them along time ago. I will let you know next time i stop over his house, which should be soon. IF you give up well im ready to trade, just bought a basically new stock clutch and K&N drop in filter too! lmfao

 

You'll be first in line if/when the day comes!

 

I shall be waiting

 

OK update for those that care to look, or remember this thread. Also because I am happy.
I was wrong and ignorant to ignore the suggestions of an ignition problem! Apologies to those who suggested it. Turned out I had a bad leading coil. I spent a lot of time trouble shooting my wiring after I had sourced some "new" primary injectors and they failed to remedy the issue. I never would have thought a bad coil could make the engine run so lean. It wasn't even firing!

Anyway I finally got a "new" leading in this morning and she started right up. The engine seemed smoother and more responsive too compared to when it was even running!

So... what's going to break next