20B 3 Rotor

iTrader: (7)

Well, after a long summer of it sitting, and having numerous people look at it, I made the decision to get the right monitoring equipment and a better intake, so right now I'm running a greddy intake, greddy boost oil pressure and water temp and a AEM uego air/fuel gauge as well as a downpipe probably put on when the motor was swapped out for a new one in 98 under a recall which all put on just under 240rwhp on a mustang dyno. The car feels alot stronger when driving, the temp seems to go a bit high to about 105-110c but I need to do a coolant flush, and the oil pressure seems to be staying at a constant 20psi, and the air fuel gauge will flutter between 14-17. Anyways when I have it in park, yes an automatic, it idles right around 700rpm where it should and oil pressure will be at a steady 15psi I believe but applying the brake will cause it to go to around 200rpm and the oil pressure will drop a little bit and flutter back and forth. When at a stoplight in drive it will be at 100rpm and really start to shake, as well as a slight whining noise so slipping it into neutral will cause it to idle fine. I believe she is still leaking oil, might be power steering but I dont think it is leaking from the secondary turbo as it is boosting a perfect 10-8-10 pattern. I had a similair problem before where mahjik had suggested adjusting the tps but I never got too becuase the oil leak took priority anyways since it is idling in park where it should I'm not too sure thats the problem, also it was doing this since I have bought it, I had the plugs changed and that helped a bit but it seems to have come back so I might try that again. So to sum it all up what could possibly cause this except for the tps, unless my thinking in ruling it out is wrong, I really appreciate all the help you guys have given me with this car.

oo7arkman

iTrader: (2)

I am going to be honest... That was a bit of a challenge to read. Too much random/chaotic thought process going on there.

Anyways, I would start with what Mahjik suggested and start with the tps. You may also try not only changing the plugs, but the wires as well. Maybe another idea is check and make sure ALL of your ground wires (motor, tranny, etc.) are connected and accounted for.

On the oil leak you need to get the car far enough off the ground to crawl under it to track down the leak. If it is the turbos you will see it leaking around the oil inlet/outlets (check out the FSM for location).

Your oil pressure seems a bit low, but that could simply be a bad oil pressure sender (a very common faulty part). The OPS connection may also just need to be cleaned. You should see ~38psi at idle after warm and the pressure should climb with increase in RPM. Typically ~60psi at 3000RPM and no boost.

The AEM UEGO wideband is a good wbO2, but it has been inconsistent with reading in the low 10.XX AFR's. I don't believe the linearity of the gauge system is low enough for what most rotary's run while in boost. Hopefully some of this helps.
-Noah-

20B 3 Rotor

iTrader: (7)

yeah sorry about that, I tend to kind of quickly write down everything without thinking about continuity and readability.

Anyways, I will start off by checking the plugs and wires, change the coolant (the dipstick isn't showing liquid just like greenish blackish blobs), and then go from there with the tps.

Also, one thing I noticed last night was, after sitting for about 6 hours at work, I had let it warm up like I usually do, except this time It puffed alot more white smoke then usual and it was running quite rich at just over 17 on the uego. I did my same thing to see if it dropped the rpm by applying the brakes, but it didnt nor did the oil pressure dip. Then during driving at stoplights with it in drive and my foot on the brake, it would idle at the speed it should and not shake. The temperature outside was around 10c, during the day it is between 15 and 20c.

So maybe my FD just likes to be driven at night?!?

I almost forgot, I have both the factory and greddy oil pressure gauge and they both show the same readings, so would that still mean it could be the sender or ops connection?

scotty305

iTrader: (2)

If this is a 93-95 RX-7 with the stock ECU and airpump installed and functioning, I wouldn't be surprised to hear of a wideband measuring 14-17 AFR at idle and during cruising. Disconnect the air pump and you'll find the stock ECU idles at something closer to 12 AFR without the air pump diluting things. You will probably see 10-11 AFR when you're accelerating hard at full throttle, with or without the air pump functioning.

20B 3 Rotor

iTrader: (7)

It's an aem uego air/fuel controller which constantly jumps between 14 and 17 and sometimes it wont even show anything because it jumps pass the max.

When the rebuild was done in 98 it was done by a mazda dealership with a new motor from japan put in, not a rebuild of the old.

The thing is that it has got all the stock equipment that a 93 with original engine had, but since it was done in 98 they also put on some reliability upgrades that came stock on series 7 rx7's, just for example downpipe, efini y pipe, and a boost limiter that won't let the car boost if it is cold and some other things.

Now the car currently has just over 40 000 miles, I bought it from the original owner all stock. Now I have put on 3 greddy gauges and the aem air/fuel monitor as well as an intake.

I had thought of simplifying it and removing the air pump, but I didnt for three reasons :

1.just not enough money

2.I just didn't want to get into removing it and having to cap a bunch of stuff and getting different pulleys, just seemed like a headache

3. I wanted to keep it relatively stock so I could easily reverse anything I did if I wanted to sell it or just go stock

Just on a sidenote, where would I find just like a plastic cap/plug for a greddy intake since one of the pipes portruding from the intake I will be removing a hose from.

20B 3 Rotor

iTrader: (7)

I also forgot that what I realized was when it would idle down to 100rpm at stoplights in drive, if I switched on the headlights it would idle up to 300rpm and not shake so much.

20B 3 Rotor

iTrader: (7)

so its running about 17 on the air/fuel gauge in park at startup, with heavy white smoke but it didnt smell like anything at all, the oil pressure is about 10 psi maybe more and idle is 700 rpm

when driving oil pressure stays at or just under 10psi, but it will properly go up to the recommended 30 psi at 3000rpm when accelerating, the air fuel gauge will be anywhere from 14 to 17 cruising and accelerating

at stoplights it will stay at 16 give or take on the air fuel gauge, oil pressure about 10 maybe 15 psi, and idle at 100 psi and it will be very shaky, though popping up the headlights will cause it to idle up to 400rpm and it wont shake as bad

also, i forgot too mention that I had daytime running lights installed by canadian tire because I didnt trust the dealership in my area, would that maybe cause too much of a load on the engine and make it idle like it is, because what I am thinking is with the headlights, it is wired properly to tell the engine that there is a higher electrical demand so it needs to idle higher, but maybe they didnt wire it properly so it doesnt know it needs to idle higher, just a thought

also, I can go about 100 mile on 3 quarter of a tank of gas, Im not too sure if that is normal, I know fds don't do well on gas but that seems a bit excessive

20B 3 Rotor

iTrader: (7)

Well, I will try what you guys said, but I think I have figured out one of the contributing factors of the bad idle.

With the daytime running lights automatically coming on, the car doesnt realize that a higher electrical demand is needed so it will idle bad because it thinks there isnt anything extra requiring electricity. But when you switch them on manually it will know it needs more electricity so it will adjust the idle appropriately to compensate for that higher electrical demand.

What I realized was was when I switched on the lights to second position (1.off 2.running lights 3.headlights) it would idle properly at park and at stoplights with my foot on the brake and in drive. The only thing that might be a problem is that with it idleing higher it runs really rich at 17 or even past 18 maxing out the air fuel gauge, but when it idled low it would have the proper air/fuel reading in the low 15s.

So right now I cant figure out which is worse, bad idle with good air/fuel mixture, or good idle with bad air/fuel mixture.

scotty305

iTrader: (2)

Good catch, Gordon. I didn't notice the "17 AFR is too rich" comment.


20B 3 Rotor, it sounds like you're confused about how your wideband gauge works. It measures the AFR, short for "Air-to-Fuel Ratio."
In other words, Air/Fuel Ratio: Air divided by Fuel.

Lower numbers indicate more fuel (for instance, 11 parts air to 1 part fuel); that might be thought of as "rich."
Higher numbers indicate less fuel (17 parts air to 1 part fuel); that might be considered "lean."

20B 3 Rotor

iTrader: (7)

Ohh really, I guess I should have read the owners manual, so then in that case should I be running my car or will it cause damage to it.

Under normal driving condition it reads anywhere from 14 to high 15s. Its just at stoplights that it will idle lean at 17 and even past the max of the gauge at 18 (thats when I have already manually switched on the running lights to tell the engine to idle higher). But when I dont do that and the engine doesnt know the running lights are on it will read i think high 15s on the air fuel gauge and do the shaking problem.

Also, I noticed better performance at wot from stop when i had the running lights manually turned on then when I had them come on automatically and the engine wouldnt know to idle higher.