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-   -   Misfiring fc ?!?!?! (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/misfiring-fc-1033223/)

illustrated_FC 04-22-13 09:19 PM

Misfiring fc ?!?!?!
 
Hey Whats up Guys
I Just bought an Rx7 86 its been sitting for about to week and we were told all it need was a bleeder screw on the radiator and a battery. Well the case is that before we even had turned it on an immense smell of fuel surrounded the car, there wasnt any visible leaks that we could tell from the fuel rails or in the engine. and as you seee the video the engine definitely had some misfiring problem. Also the guy who previously owned it definitely was not aware what he was doing do you guys have any suggestions why my fc sounds like this and why it smells like pure fuel? also i reved up on the third time for like until you hear that rattling sound let know what you guys pleasee . ask me for information or videos or pictures
thanks,
http://www.youtube.com/watch?v=tWutW...ature=youtu.be

wthdidusay82 04-22-13 10:20 PM

Sounds like it has an exhaust leak and the fuel smell could be the pulsation dampener leaking on the end of the secondary injectors fuel rail, if not then it could just be because you're not use to the rich smell of a rotary exhaust , if it has no cat the smell will be pretty strong, people driving behind you would even smell it, check your fuel lines for leaks, and check for vacuum leaks.

Also check your timing, tps adjustment, and check your spark plugs and wires.

If the 5/6 ports are wired open or removed it will cause a loopy idle as well.

illustrated_FC 04-23-13 06:57 AM

Ohhh okay thanks you know where I could find those timing tips ?

clokker 04-23-13 07:15 AM

You don't need tips, all the procedures are documented in the factory service manual.

Justin1992 04-23-13 09:46 AM

That's not a misfire but an out of adjustment (or bad) tps, really easy to fix. Warm the engine up to operating temp, shut the car off and turn the key to 'on'. Grab a multimeter and put it on*volts dc w/ the 3 decimal reading, ie 0.000v. Put the pos into the back of the green wire on the connector with it still plugged in and the neg on the battery. Adjust the screw on the throttle right there on the tps and get it reading as close to 1.000 volts as possible. May have to move the throttle a couple times and let it shut to get a good reading. You can do it unplugged with the engine cold using an ohm trick but its stupid unreliable and way off in all my experiences. I'm trying to write all this out on a phone but have better instructions at home on the PC if you need them.

The other sounds seem like an exhaust leak, as far as smelling fuel I'm not too sure. As far as aux ports, contrary to seemingly religious popular belief, the only time you're gonna get a negative 'reaction' from them is if they're stuck closed, but they don't open anyway until the secondaries kick in at ~4.5k rpm so you don't need to worry about that much yet anyways.

illustrated_FC 04-23-13 12:06 PM

oh okay thanks for information
also i noticed a rattling noise when the engine was running could that be also apart of the problem ?

SpikeDerailed 04-23-13 09:32 PM


Originally Posted by wthdidusay82 (Post 11447047)
Sounds like it has an exhaust leak and the fuel smell could be the pulsation dampener leaking on the end of the secondary injectors fuel rail, if not then it could just be because you're not use to the rich smell of a rotary exhaust , if it has no cat the smell will be pretty strong, people driving behind you would even smell it, check your fuel lines for leaks, and check for vacuum leaks.

Also check your timing, tps adjustment, and check your spark plugs and wires.

If the 5/6 ports are wired open or removed it will cause a loopy idle as well.

The pulsation dampener is on the end of the primary fuel rail towards the front of the car its the fpr thats on the secondary rail.

A heavily heavily flooded engine can smell of gas, although verify no fuel leak and make check to see if the smell is coming from the charcoal canister.

illustrated_FC 04-28-13 04:00 PM

wooowww guys i actually found where the fuel smell was coming from it was from the gas tank its covered in pin holes and needs to replaced i already drained the fuel but of course its not all the fuel therefore its still leaking fml .... i ll post pictures in a minute

illustrated_FC 04-28-13 04:07 PM

4 Attachment(s)
Would anyone have a spare one ??

wthdidusay82 04-28-13 06:37 PM

The junkyard would be th best place to go, itd cost a fortune to ship a gas tank, or find someone that has one locally.

illustrated_FC 04-29-13 12:55 PM

how much are you thinking ?

NCross 04-29-13 05:11 PM

Junk yard wont have a fuel tank. They poke holes in them to drain fuel while stocking the cars on the lot usually in my experiences. So they're useless.

The misfire could be due to rusty clogged up fuel lines, injectors, and fuel filters. Just keep in mind that a slight misfiring sound is a characteristic of rotaries. Even an engine in perfect tune will have a very slight tick to it. Especially when the exhaust is opened up.

wthdidusay82 04-29-13 10:14 PM

Www.car-part.com has junkyard listings for gas tanks

jjwalker 04-29-13 10:43 PM

when you open your exhaust up, as mentioned before, it'll pop and bang a bit as extra fuel gets burned off inside the exhaust.

As far as the TPS, I have never had luck with the voltage or ohm methods. I made a tester just like the mazda factory TPS tester, adjusted with that and I have had no issue. It only cost me 12 bucks to make it.

illustrated_FC 04-30-13 01:12 PM

oh i found a fuel tank thankss !! and tps adjuster how did you make it ?

NCross 05-01-13 09:49 AM

I would advise against using test lights for the TPS. It pulls too much current through the ECU and can cause a burnt circuit. Volt meter is far more accurate. Especially if it's analog meter. Digital meters are OK if you know the TPS is good, but they don't detect dead spots as well as analogs.

illustrated_FC 05-01-13 01:58 PM

oh okay thankks

jjwalker 05-01-13 08:50 PM


Originally Posted by NCross (Post 11455637)
I would advise against using test lights for the TPS. It pulls too much current through the ECU and can cause a burnt circuit. Volt meter is far more accurate. Especially if it's analog meter. Digital meters are OK if you know the TPS is good, but they don't detect dead spots as well as analogs.

I used 12v LED's, not a test light.

I posted this in 2009.


I tried the multimeter method andf failed, over and over. I got fed up and made a test light, and it was set perferctly with it.

Go to radio shack and purchase two 12v led's. I got the "5mm Red LED Assembly".

Get a baggy of male spade connectors.

On my particular LEDs I bought, the was a yellow and red wire on them. The red was ground and yellow was 12v (whatever you buy may be different). Twist the two ground leads together and crimp a spade connector then put a spade connector on each positive wire.

That's it.

The whole thing cost me $8 with sales tax.
And It looks like this...

123.jpg Photo by thebigbluecan | Photobucket


If you need a picture, I can post one if you ask.

illustrated_FC 05-02-13 09:24 AM

Oh i see its simple !


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