2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Do injectors spray when car doesn't start?

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Old 12-13-04 | 08:56 PM
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Do injectors spray when car doesn't start?

This comes directly from my friend, "You need to ask the people at RX7 club, 'If the crankshaft is not turning over, does the ecu still tell the injecters to spray into the combustion chamber'" (well, at least thats the best of what I could remember he said, I"m sure he said it in much cooler sounding terms that I don't understand, hehe). Basically, my car isn't starting, I presume because a starter (it sounds like it has no resistance, just spinning freely). My dad claims he smelt gas and therefore believes its my fuel pump (not saying hes wrong cause I donno crap about this, but he doesn't usually think very logically so theres reason to doubt him). To me, it seems logical because if the car isn't starting, then the gas in the engine isn't being burnt off and therefore just keeps building up. But my friend says that when the car doesn't start, the ECU tells the injectors to stop spraying till it does..... or something like that. Can somebody set me stright here please? Thanks
Old 12-13-04 | 09:03 PM
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Well, it should like shes just flooded, the more you crank it the worse it gets. When it gets bad, the engine stops building compression and just spins freely like you said. Just unflood the engine and she should be fine, try push starting it if you really can't get it.

When that happens to me, the best thing to do is pull the plugs and clean them off, or better yet, get new ones. Then crank the engine for awhile with the EGI fuse out and the plugs out...then when you get most of the gas out, try starting it again. If shes really flooded you can pour a little bit of thicker oil (20w50 does the trick) in each of the leading plug holes and crank it by hand for a little while, then give it another try.

Good luck!
Old 12-13-04 | 09:07 PM
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there is a switch in the MAF that shuts off the injectors when the maf is shut.

chances are pretty good, though, that your car is flooded.

if the engien is turning over and it is turning quickly, the starter is OK.

there's a fuse box just in front of the driver's side strut tower. pull the cover off of it and pull the fuse closest to the motor. Crank the engine over with the throttle held wide open, crank for 5-10 seconds.

after you've done that, put the fuse back in and then try and start it, hold your foot to the floor while you're doing that.

if you're lucky, it'll fire right up.
if not, pull the spark plugs out, repeat the first step above to unflood it.

While the spark plugs are out and it's cranking, listen to the sound the engine is making... if it sounds even WOOSH WOOSH WOOSH WOOSH WOOSH WOOSH WOOSH that's good.. if it sounds like a galloping horse (WOOSH ppft WOOSH ppfft WOOSH WOOSH WOOSH ppft etc)
then you're done, come back on the forum and ask about engine rebuilds.

clean the spark plugs (assuming the engine sounded right) (get all the crap off of them, if they haven't been replaced in a long time REPLACE THEM)!, put them back (make sure you put the ones with the -T in the TOP and the ones with the -L in the LOWER), and connect up the wires again, making sure that you get a proper connection, and all the wires are in the right order. L1 goes to the LOWER plug in the FRONT, and T2 goes to the TOP plug in the REAR.

Make sure you put the fuse back in, and try and start it up, again with the throttle held to the floor.

it should fire right up.
Old 12-13-04 | 09:08 PM
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Can you explain to me how it is that RX-7's flood? When I tell him that, he thinks I'm crazy. He says, "No fuel injected car ever floods."

Edit: I have a switch to shut off my fuel pump. I did shut it off for a little bit and crank but it makes me nervous to do it for long so maybe I didn't do it long enough. And god I hope its not the engine, I just did a compression test like two moths ago that said I had almost 100 psi in both rotors all with even jumps.

Last edited by Jester; 12-13-04 at 09:14 PM.
Old 12-13-04 | 09:27 PM
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From: Windsor, On
okay
try shutting the fuel pump off, flooring it, and cranking for 5-10 seconds, then while its still cranking, with your foot STILL ON THE FLOOR, turn it on, it might fire up.

if that doesn't work, then pull the plugs and go from there.. they're probably fouled.

I don't know how or why they flood, but they do, and boy do they do it easy.

LOTS of EFI cars flood... but older one's especially.
Old 12-13-04 | 09:40 PM
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I've never had an FC flood so bad that it wouldn't start with the throttle floored and cranking 10-15 seconds. Oddly enough, that's exactly what the owner's manual (series 4!) says to do. Eventually, it will catch on one rotor, and you have to rev it to ~3k and hold it a ~2k for a few seconds. It will blow plenty of smoke as the gas burns off, once that slows down, both rotors will be going fine and it's back to normal.
Old 12-13-04 | 09:42 PM
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Ok, tried the shutting off and cranking thing, didn't work. I don't have time right now to pull the plugs (unfotunately for me, this happened the sunday before finals week). I will do that sometime, like when finals week is over, hehe. I replaced my plugs probably about....... 3 or 4 months ago, if that tells you anything (and I guess my compression test was about htat long ago too). Two observations I notced that I donno if it tells you anything: when I turned the fuel pump on, the emergency lighs dimmed a little (I assume thats just cause it lost power cause then it went to the fuel pump) and secondly, I coulda got high off the smell of gas coming from my exhaust pipes
Old 12-13-04 | 09:48 PM
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The answer to the first part of your question.......NO.

The injectors do NOT operate unless the engine is turning over. It's the output of the Crank Angle Sensor that tells the ECU when it's time for an injector to *fire* each injector.

If you wanted, you could pull the crank angle sensor out, turn the key to ON and flip the gear at the bottom of the CAS. The injectors would *fire* as the cas was rotated by hand and the engine not turning over. That's the only scenario that I can think of where they would fire without the engnine turning over.
Old 12-13-04 | 10:24 PM
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You said you have a fuel pump cutoff... what happens if you leave it off & crank for a while? It won't hurt the engine. With a cutoff switch, the procedure for minor flooding is "Turn off switch, crank engine until it catches, turn switch on." I don't know if it would be the same for major flooding or not, but it's worth a shot.

-=Russ=-
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