Integrals

Leading is on the right... dont mind the moistish appearence, they touched some antiseize on the way out and got a little 'wet'.

Either way, they aren't horrible, but the leading seems to be building up alot of carbon on them.

I am basically having issues entering boost. I previously changed the spark plugs, unplugged the battery, and added new grounds and it ran greaaaaat for a week. Now all of a sudden its back to backfiring / misfiring on acceleration when going into 3-4+psi of boost at any rpm.

I did a vacuum job to it a while back and it ran much better after that, replaced all the check valves, checked the solenoids, ohm'd out the coils, and replaced plugs and wires.

Ran great, then the issue came back. What would your thoughts on the plugs be?

I did change the leading plugs and took it for a spin, no difference.

I currently have the trailing plugs out of the motor to let any fuel thats in the combustion chambers to evaporate to see if its just a bit flooded.

Let me know your thoughts and ideas.

Oh the only real mod done to it is it has 3" downpipe/exhaust with a decat.

Stock computer. Not burning coolant and oil, no smoke.

rx73rotorj

White is lean and Black is rich so they look a little rich to me!
Im having this trouble to in my car.

Do you have an aftermarket fuel pump?
Re Check the vacuum lines
Clean Plugs
Rewire the fuel pump with 10 gauge amp wire.

Wargasm

I agree, those are rich looking to me. Are both rotors like that or just one rotor? Are you sure that you have the correct plugs in the correct positions and that they are the right model of plug?

For your mods, you should be running stock plugs.

Kento

Rich or lean where in the rpm band, and at what throttle setting?

You cannot make any judgements on a/f ratio by looking at the plugs. The only thing looking at them in this state will tell you is the general status of your fueling (and actually, if you're lean, you'd probably find out in a much less pleasant method the moment you go wide-open throttle...); i.e., if your plugs are black with soot, then it's pretty obvious you're pretty far on the rich side (although again, you'd probably notice that your car belches black smoke when you get on the throttle, doesn't really accelerate like it should, etc.).

The only way to use plug color as a method of determining a/f ratio (and even then, it only gives you a general idea of a/f ratio at wide-open throttle in the top-end portion of the powerband) is to do a "plug-chop" (running wide-open for extended periods, then "chopping" the throttle shut, and immediately shutting off the engine...which would be hazardous in a car for obvious reasons). Then, the area you need to examine is the base of the porcelain insulator, not the top of the electrode. If you run the engine at other throttle settings and rpm, it changes the color on the insulator, and then the color is basically useless as a gauge of any type.

Integrals

i've double checked, the plugs are the proper NGK BUR7EQ and 9EQ and are installed with the Trailings on top, Leadings on the bottom.

No smoke whatsoever. Its wierd as when I change them, the car runs great for about a week.

I changed the leading (the black ones) last night and it made no difference, so im going to change the trailings tonight and see if it perks back up.

They are the same in both rotors, the leading plug is noticibly darker..
THe porcelain is a hair more brown on the leading vs the trailing.

grrrr!

Integrals

oh i am not WOT'ing the car, im doing like 40% throttle just enough to spool and getting 3-4psi of boost at that throttle position at around 3k-4500rpm.

It will do it at any RPM as soon as it see's the boost.

I just did a Vacuum line job and check all the solenoids and replaced injector seals and FPD. It ran about 6 days PERFECT after I did all that work so I thought that i fixed the problem while doing the vacuum lines. Apparently not.

Narfle

iTrader: (16)

If you were running lean you would be posting a much more melancholy thread. The double edge of the rotary is that its fairly boolean. For the most part it either works or it breaks. And, should it be in less than perfect shape you should be able to tell(rough idle, low vaccuum, stalling, coolant buzzer, poor low end power, late turbo spool). Furthermore, given the lifespan of spark plugs, they will not show A/F ratio with any accuracy. Your engine experiences different A/F ratios, depending on load and rpm between every stoplight. Imagine the diverse conditions covered in their service life. At the very best they could potentially, but superficially and vaguely, display the A/F condition experienced immediately before shut down. Your plugs are brown and black indicating a rich mixture. Let me guess, the brown one is trailing and the black one is leading. But, the rotary engine runs rediculously rich for most of its life, not to mention the effects of oil injection on spark plug color. If youre dying to know, go get your car dyno'd. Believe it or not, even with a stock car, it's worth the money just to see whats up.

Integrals

Those plugs also keep in mind are Pre-vacuum job.

I pulled a set of post-vacuum job, and the leading is now much less discolored, still dark but not like that.

Im going to pull th emanifold off again though as someone mentioned that the injector clips could have jiggled off and might be causing my issues with boost.

I dont know i just want to double check everything at this point...

Narfle

iTrader: (16)

things to try for your issues

02 sensor, map sensor

Integrals

I checked the pressure sensor and it appears to be working fine.

Havent checked the o2.

I did check the Fuel pump and it was weak, so i did replace it along with the filter (god damn that filter) but still not avail.

Integrals

Now that i think about it, the o2 sensor has been replaced by the previous owner but they just threw a butt connector on it. Im gonna replace that as they are cheap and redo the connector so its properly attached.

I dont think thats the problem but it needs to be remedied anyways so I'll get it outta the way.

I already found the exhaust ground wasn't attached and put that back on too. Bleh.

Today im not driving the car and will pull the UIM off again and see if something came loose cuz it ran GREAT after i did the vacuum job.

GoodfellaFD3S

iTrader: (213)

It wouldnt be a bad idea to swap out the map sensor with a known working one.

sevensheaven

iTrader: (1)

I don't know about the back firing part, but the time I had any miss firing after a new plug change was caused by a weak battery. It's just a thought, may not be your problem at all.

Terry7

rajeevx7

iTrader: (11)

I agree w/ the map sensor. Check all the wiring to it that you can find. Make sure it's not freyed. Then put a good one in just to be sure. Not sure what the ohm spec is.....

rajeevx7

iTrader: (11)

New O2 Sensor yet??

Integrals

Doing an new 02 sensor in minutes

The battery is brand new, the alternator is outputting 14v.

Will work on checking the MAP... gotta find a known good one too.

gracer7-rx7

iTrader: (16)

have you checked your TPS settings yet?

danny hahn

Thanks for the tip, I never thought to compare the insulator.

I typically run 9's all around. Your your trailing 7's look fine.

Basic question but, Is your idle right? do your coils test out?

scotty305

iTrader: (2)

How old are your ignition wires? It's possible your plugs aren't seeing a nice strong spark, and misfiring is preventing them from cleaning themselves. That would make the car run pretty poorly also.

-s-

Integrals

Update, the wires are new, all fuel emissions items have been replaced... The car is running solidly, but still starts a lil slow when hot. The coolant system checked out pressure wise, and no coolant is disappearing so I dont think its seeping coolant into the chamber.

Since its cooled down in AZ, the plugs have become more and more brown, but im concerned as the leadings have a lil brown fuzz on them. Grrr...

Integrals

The car runs a solid 12.5-12.7 AFR through the RPM range at WOT, 10psi, stock twins.

Didn't think I needed to change the L plug to the 9... your thoughts?

RX7 RAGE

iTrader: (22)

That is lean my friend. You should be in the low 11s at WOT.

Integrals

Seriously? Wow my car stock with stock ECU ran mid 12's from low rpm to mid rpm and high 11's at 6800 to redline.

When I added the powerFC and DP/Exhaust, I simply mimicked the fuel curve of the OEM computer (added fuel in quite a few areas), and got rid of the negative splits.

The local rotary tuner said mid 12's were very comfortable for a stock ported engine with stock boost patterns.... 10+ they said start going for the 11's.

Infact thats what one of the tuning guides on here by I think Dale said...

Gosh I need to buy chucks tuning notes.

Integrals

O btw the boost problems are gone now. Ended up being a faulty Precontrol...