sethstephens21

So I recently decided to get back into fixing my 8. The issue I’m having is it starts up, it runs. Until it’s a bit warm, when the idle starts to drop down to normal idle the idle fluctuates from lower than 800 up to above 1k. I know it’s not coolant seals so please don’t say that it’s been comp tested comp is fine. This vehicle has the airpump delete and the air solenoid on the back of the UIM has a plugged tube like normal. I have two codes, p0661 and p2259. I really need help I don’t wanna give up again because I can’t figure it out. I’m also in northwest Florida so if someone really wants too help privately message me and we can get hands on to fix this car together damnit😭

Loki

iTrader: (1)

Was the air pump removed because the cat was removed?
p0661 and p2259 are both electrical codes for one of the intake solenoids (661) and the air pump solenoid. I don't think those would cause your issues unless the valves are also stuck open, but 661 will cause issues higher in the rev range, depending on which valve is affected.

Let's start with fuel trims, rpm and air flow data on a warm idle, or as close as you can get without touching the throttle. Trims should be near 0 and airflow at 800rpm above 5 g/sec. Report back what you find.

When you say "plugged as normal" is that vacuum goes to the solenoid but the solenoid isn't connected to anything? Or plugged as in "capped"?

sethstephens21

The cat was gutted so I’d imagine that’s why the airpump was removed. The line from the air solenoid to the airpump is clipped and capped but the solenoid is still plugged in. I have a video of my fuel trims and here’s what I get when the car tries to idle at 800 rpm. Stft is -12.5 but fluctuating. Ltft fluctuates from -4.7 to -5.5. My mad is also only getting about .91lbs per second.

Loki

iTrader: (1)

0.91lb/min is 6.8 g/sec, waaay too much for 800rpm closed throttle. Might explain why it's dialing back the fuel trims.
A few theories.. if the engine has been out, or injectors have been messed with in some way, it's very easy to mix up injector wiring and cause these types of fuel trims. If someone has tried to tune it, they might have screwed up MAF scaling so the car thinks it's getting 6.8g/sec but clearly not actually getting that much and pulling back the trims. I doubt the MAF is bad, they don't fail by reading high, but it's a distrant third option. You could give it a clean at least.

sethstephens21

has already been cleaned and replaced. I think they got in and fucked with the fuel map and maf readings cause everything on this car seems to be fine other than fuel trims and maf readings. Hopefully I could just reflash the ecu at my nearest Mazda but it has to be in the car doesn’t it?

Loki

iTrader: (1)

Yes Mazda will want the whole car to flash to as-built.

drew619

Hello, I have a 2009 rx8 w/~115,000 miles. The car is in very good condition. It has been in the family from dealership. I recently changed the air filters and then cleaned the MAF sensor. After I disconnect the battery to reset ECU and trims. After doing everything the car does not seem to have the correct idle rpm to keep the car running. The car stalls/shuts of if the clutch is engaged and it is not immediately put in gear and given glass. Any help/suggestions would be much appreciated. Thank you!

Loki

iTrader: (1)

You can start your own thread. The car needs to learn to idle after disconnecting the battery. Can you let it sit and earm up ehile idling until the fans statt to kick on? After that drive like normal but be ready to help it not stall the first few stops.
Otherwise if there's an open hose or crack anywhere in the intake that could contribute. Modifications like a cold air intake could as well.

drew619

😂I figured out how to start a thread after this post. But thank you so much this helps out tremendously! Yes the car can idle while warming up but it would stall when going somewhere. However I did what you suggested and after only two little drives the car was good to go and learned what it needed to!