OK, so here is the situation. I'm working on a 1995 ES300 that wants to die out off idle. If you ease into the throttle it will usually pick up some, but the exhaust manifolds start glowing and it's still very under-powered, to the point of being un-drivable.
The CEL is on, but I can not pull any codes from it. I have tried jumping the diag terminals at the port under the hood, but the CEL doesn't flash. I tried the one under the dash, but there is no terminal in the Te1 slot, and I've tried hooking a generic scanner to the obd2 port by the fuse box, but it will not communicate with the scanner.
I replaced the cat, since the pipes/manifolds glowing usually indicates a clogged cat, but the difference, if any at all, is very minimal. I have also checked fuel pressure (35psi at idle, picks up to 40-45 when you press the throttle) and ruled out any vacuum leaks. Pulling and plugging the vacuum line to the fuel pressure regulator results in a consistent 45psi, but still no change in how this thing runs.
I have not checked the timing yet, but seeing as the problem started off as an intermittent problem, I can't see it being in the timing. If it had jumped, it would always be off.
I am thinking either MAF or ECM at this point, but any advise would be greatly appreciated.
pulled the front three spark plugs, and it's been running extremely rich (opposite of what I suspected) and backprobing the MAF while throttling it, the MAF appears to be working (rising from ~1.2v at idle to 3.0v peak around 3k rpms)
with the new cat, you can floor it now, and while it will fall on it's face (drops to around 400-500rpm) it doesn't die completely. I can slowly pick the rpms up in neutral or park to a max of just under 4k, but there isn't enough power to drive it above 10mph no matter what I do.
BTW, BOTH banks are glowing, and the problem starts as soon as you start it, so I'm pretty sure O2 sensors are not the problem since it is still in open loop at the time.
this one is being a real problem child.
Fixed!!! Wound up being a fried capacitor in the ecm. Woulda never found it if it wasn't for this forum.
Nice work. I know it always seems obvious after you already know the solution, but I think not being able to see a CEL is a big red flag for a computer issue. Although it may not always be a bad ECU, it can also be caused by a bad Ground. How did you find the fried capacitor?
__________________ 1998 ES300 Diamond White Pearl/Tan
After a lot if searching here and finding a link about the bad caps I decided to take the ecm apart. It was the only thing left that made sense. It took a bit to find it, but there was one cap leaking. Altgough it seems obvious now, ecms are normally the last thing to condem. They don't go bad often up north.