Hi rotary peeps, before I jump into the problem that I am having, Ill list all my upgrades.
RX7 FD 93
- 13b-rew have 27k miles on rebuild.
-BNR stage 3 twin sequential turbos, driving at 14psi, with apexi avcr boost controller
- Power fc ecu and commander
- Air to fuel ratio guage, idels around 11 and throttle around 12-13
- 20w50 castrol natural oil
-EGR delete
-catless downpipe 3" catless mid pipe3" hks catback 3"
-replaced turbo silicon hoses.
- rx7 fc oil cooler. Stock oil cooler removed.
-stock intercooler stock radiator.
-255 fuel pump( forgot the brand) well known though.
I could have more but cant remember off the top of my head... Anywayss.

So I have been driving this car pretty normal nothing crazy not stepping on it, and if I drive it for around a hour its fine. Bring it home, let it cool down slowly n all.

**But when I drive for around 2 hours, and its around 90 degrees F. ill drive and out of no where, my engine starts so struggle on idle, and I look at my air to fuel, and its around 15 on idle, so right away I give a little bit of gas at around 2-3k rpm and when i hold it there the car goes to normal air to fuel 11-13, but if I let it idle without giving gas it goes back to running lean which i did not let happen so I turned my car off and waited until it cools, then I start it up after it cools, and the car is back to normal. I kept a eye on my water temperature and its in the middle like normal, my oil pressure guage does not work, (known malfunction in fd's). SO what I think is the problem is. 1st Maybe I need a new intercooler, because the stock cant handle these new BNR turbos, and over time the engine and turbos get hot and the intercooler can not cool quick enough so alot of hot air gets into the engine and starts to create air and fuel mixture problems. OR 2nd, I need to invest in a oil pressure/temperature guage, and maybe my oil temp or pressure is either to high or to low after driving for a long time, which creates the engine to somehow over heat, But doesnt make sence to me because how can the oil be overheating, wouldent that make my water temperatures go up as well? Maybe the idea of going with a RX7 fc oil cooler was a bad idea, maybe something to do with the stock thermostat?

PLEASE inform me of what any of you think can be causing this, and or if any of you ever got this problem before and how did you fix it. Thanks

 

it's probably a tuning issue, such as lean mapped intake or water temps after the engine has severely heat soaked.

 

If the water temps are to hot wouldent I see my water temp Guage go high?

 

So you think I need a new radiator for my water? Sometimes if I step on it hard this will happen before 2 hours.

 

do you have a commander? if so watch your actual water temp to see if there is a relationship between the lean issue and a certain temperature.

the stock gauge won't rise off the middle until about 230F, so you obviously aren't having any serious cooling system issues.

 

So I did some testing. *update* drove my fd in traffic and stepping on it here and there at outside temperatures 86f. My power fc stats highest air temperature was 65c with me stepping on it alot. Water temperatures went no higher than 95c my car didnt lean out anywhere, it was driving really good. I have just one last question that can solve this whole problem, when the car is cold slept overnight, and when I check the radiator coolant resovuar, should the water be on L or H l for low and h for high? when the car is cold and has not driven for 12 hours. Because mine was below low when I checked this morning.

 

in almost all cases the reservoir level should not change, the system in these cars rarely siphons or purges from the overflow unless there is a problem.

fill it to the top line and monitor it.

 

Thanks rotary that fixed it ... I feel so lame now. That was the simplest fix ever

 

Do not trust the oem water temp gauge !