rkostolni

Ever since I installed my turbo every once in a while the temperature gauge would fall during hard acceleration, but it was only once in a while. Lately though this problem has gotten worse. Every time I am on boost the temp gauge starts falling and gradually falls until I get off the throttle. This is also accompanied by a loss of power. I remember someone else here having this problem and I would love to know what they did to remedy it. If anyone else has any ideas I would love to hear them as well!

epitrochoid

isnt there a dongle that forces the ECU into open loop by making it think it's running cold? some people have removed it with better results..take a look into it

Jon

That is how the emanage is able to compensate boost with more fuel without the stock computer noticing the richer mixture and adjusting itself back to stock. And the power loss is probably a change in timing or maybe even the throttle plate not opening entirely during acceleration under cold temps. Could even be the flaps in the intake manifold not opening while the engine is cold.

rkostolni

So there is no way to fix this huh? Of course aside from a stand alone. So is everyone else having this problem? Note, it is usually only obvious in 5th and 6th gear because you aren't under boost long enough in lower gears to notice it.

RXhusker

Try removing the dongle -- there is a whole thread devoted to explaining the process with pics and instructions. If it doens't help you can always plug it back in -- it is certainly worth a try.

adrian-1

I posted the dongle thread but have since found out from Greddy (Benny) that it's an important part of the air/fuel maps and it should not be removed.

I'll check next time I drive it to see if my temp gauge goes down in 5th/6th during boost.

Jon

Yes if you remove it the stock ECU will try to hit its target air/fuel ratio of like 14.5 even though it no longer controls all the injectors it can still affect the tuning.

Speedrx8er

Hmm, I reinstall the Dongle and the car is very sluggish.

Greddyturbo1

Which map are you using

Speedrx8er

stock map. have not load any maps yet. no e-tool

MazdaManiac

iTrader: (3)

So they say.

Of course, many of us do not have the dongle and the tuning is correct.

rkostolni

Jeff, how do you tune when the ECU is in closed loop?

MazdaManiac

iTrader: (3)

I just add fuel with the additional injection MAP as needed.
Though the ECU will trim some fuel, it can't pull it all, especially in the mid range where the primary 2 injectors normally don't fire at all in the OEM MAP.
Generally, I haven't really seen any closed-loop activity while in boost at or near WOT.

rkostolni

Hey Adrian, did you check to see if your Temp gauge goes down when on boost?

Rasputin

Make sense as the PCM goes in open loop at absolute loads well under 1...

tuj

Wait, this is contrary to claims some where making that the ECU will not go into open-loop AT ALL below 5k, even at WOT. I personally don't buy that. So what's the story? Does it go open-loop at WOT, regardless of RPM?

MazdaManiac

iTrader: (3)

Some have reported some spots between 3800 an 5200 where the ECU will, seemingly, attempt to stay in closed-loop at high load (not necessarily WOT).
These spots are not fixed. They are probably based on load which is a combination of TP, MAF and RPM.
What I think this actually could be is the cumulative effect of LTFT on the fuel delivery. Even though the PCM is not in feedback, it still trims fuel and a -18% LTFT is going to make a significant impact.

adrian-1

Yes, tried it today. My temp gauge slowly goes down while under boost but only noticeable in 5th and 6th gear (like you said). Must be a side-effect of the dongle.

rkostolni

Okay so, it appears this is normal and it makes sense that it happens. My question now is, since the engine thinks its cold is it limiting throttle position, reducing timing, oil volume, etc?

When testing this I have held the engine on boost for a while to see just how low the temp gauge would go, and it appears it will go all the way down, in around 8 seconds. At some point I'm sure the ECU must start acting funny and doing bad things, my question is what.

rkostolni

Another question popped into my mind. Every car must suffer from this same open/closed loop problem. So how do other people get control of their air/fuels.

MazdaManiac

iTrader: (3)

Actually, until now, most didn't.
The transfer into open-loop happened at a preset throttle position, regardless of any other factors. The level of control exerted by the RX-8 PCM is a new high.

Additionally, some manufacturers (like Nissan, for instance) have made their PCM code more easily "hacked" intentionally because of their attitude toward the aftermarket.