Klaus

iTrader: (1)

So I have a 94 sc400- I had another thread that got way boogered up trying to get to even first base with this problem. I have replaced the ECU, replaced the MAF sensor, replaced ignition wires, replaced plugs, bypasses FP ECU, inspected cap and rotor (fine), inspected air intake tube (fine), and now here I am.

When I start the car it starts perfect, comes down to a smooth 900rpm idle, and idles great. If I leave it idling for about 5-10 minutes eventually the car will stall. It throws a MAF and IAT code. If I try to restart it, the car will start them immediately die. If I come back 30 minutes later to start, the car will start, idle, then die again in 5 minutes or so.

If I pull the car out and drive it, it also runs perfectly. Pulls fine all the way to redline, shifts perfect, runs perfect. Then stalls 5-10 minutes in.

The WIERD thing about this, is that the car runs exactly the same (perfect for a while, then completely cuts the engine) whether or not the MAF is plugged in. With a new MAF and ECU, what else should I try?

Codes are:

15 - Ignition number 2 signal (still not sure what would be triggering this?)
24 - IAT signal
31 - Air flow meter signal

gunyvw

exhaust blockage maybe.... catalyic convertors

T4-Teg

iTrader: (2)

Code number 15 could be caused by an intermittent loss of signal from Cam sensor, crank sensor, bad ign coil, bad distributer.. These type of sensors are known (basically in any make/model) to fail intermittently when they get hot. They get hot and basically short out internally. You best bet is to find specs to test your sensors out, MAF, Cam/crank sensors, ign coil, etc. You just need to test them when the problem is occuring. The only way to test the sensors them selves is to ohm them out. If you ohm them and there is no reading indicating an open in the sensor itsself, then you found 1 of your problems. Also, too high of a ohm reading, and the sensor is bad too.

From when your explaining, your problem sounds like a ignition coil going bad. Again, these usually fail intermittently after they get hot. The best thing to do is pull a plug wire and check if its getting spark when it dies out. You really need to check for spark and fuel psi when the engine dies. If both of these are fine, even when the engine dies, your looking at a timing problem most likely, not mechanical timing either. You cam/crank sensors tell the ECU when to fire plugs, and tells the injectors when to open/close(pulse width).

Let us know what you find, in your basic checks and we can go from there.