RX8Club.com - Rough Idle - Stalling after long drive

RX8Club.com (https://www.rx8club.com/)

- Series I Trouble Shooting (https://www.rx8club.com/series-i-trouble-shooting-95/)

- - Rough Idle - Stalling after long drive (https://www.rx8club.com/series-i-trouble-shooting-95/rough-idle-stalling-after-long-drive-260137/)

Quote:

Originally Posted by BigCajun (Post 4790155)

Maybe a failing fuel pump?

I'm thinking that is my problem, but I replaced the factory one not even 2 years ago with an aftermarket one from Advance Auto.

My issue is very similar to the O.P.'s, but is very sporadic.
I haven't done proper troubleshooting yet due to time constraints.
It will run fine on the highway, but after it's warmed up and driven on city streets in stop & go traffic, and usually after idling at a light, in a carwash, or a drivethru line, upon trying to accelerate it will suddenly start hesitating, popping, and stalling for several minutes, sometimes dying.
I will feather the throttle to keep it running, and then it will start running fine like nothing ever happened.

I'm planning on swapping the pump assembly, unless I find something else, and I will post an update on any results.

Just have the fuel pressure checked with a fuel pressure gauge. If it's over 50, your pump is probably good. I'm still gonna go with a bad tune. It runs fine on start up because the car Injects extra fuel until the car reaches operating temp. After that there's just not enough fuel at idle for the extra air created by the supercharger. The only other thing I could think of is a failing coil. Doesn't sound like a fuel pump problem to me. That usually has problems under higher load.

Quote:

Originally Posted by Rustallion (Post 4790153)

Sounds like you are pretty familiar with these cars. But you said you reset the ecu? Does he have a proper tune on the car?

Ffs....... I pulled the intake off once again, guess what I found.. the owner flipped the plugs on the primary injetors :///

After correcting the wiring I drove a bit and the low load fuel trims learned from -22 to 1%.. idle is really nice now.

While I was in there anyway I measured the compression. Looking good around 7 bar. I expect number to go slightly up after some more miles.
https://cimg4.ibsrv.net/gimg/www.rx8...24dccf3cd6.jpg

Rpm goes up and down cold start.

Hello mine is a 05 MT 6spd. im having a frustrating problem wirh my car when cold start the rpm goes up and down like up to 1500 and down to 900 and sometimes lower and then it stalls but after it was driven and warmed up the rpm stays idle. ive already change spark plugs, ignition coils problem still persist even checked for vacum leaks. sometimes the car misfires too plz help me thx.

Currently, I have been facing the same issue. I did a comprehensive check everywhere and no red flag.
My problem is fouling spark plugs.
I do premix and running Sohn adapter as well as increased OMP rate with d585 + increased dwell which makes plugs fouled faster.
If I drive aggressively I would have butter smooth idle, if I drive like I have to do in the city I would have shitty idle.
Also, I tried a hotter spark plug which is good but still risky as it could cause more harm for obvious reasons.
So, I need to clean my spark plugs more often.
Somewhere in the future, I will use better coils like ign1.

Another note to mention is about negative/ grounding issues. try to isolate grounds from battery to chassis and mind your coils grounds.
I see so often people ground their after-market coil to the battery which is wrong! it MUST be grounded to both housings.

https://cimg6.ibsrv.net/gimg/www.rx8...2ce7f4c601.png