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Yes, there is something else. There's a driver for the coil in the ECM. It is time to replace the ECM for sure and see if that resolves the issue. It is also possible there is a bad (intermittent connection) pin in the connector to the ECM.
I have seen myself a failed ECM in a GS F, so it's not beyond the realm of possible at all. In this case, it was the power to the heater circuit on one of the O2 sensors, and I isolated it to the ECM by validating the wiring integrity and validating the sensor was good.
Questions: the ECM is the ECU? How much do those cost?
if it is the ECM, wouldn’t a specific code pop up for it?
Questions: the ECM is the ECU? How much do those cost?
if it is the ECM, wouldn’t a specific code pop up for it?
No grasshopper. It might be the ECM. It might also be the pin in the connector. I had this problem with my Supra two decades ago, and the issue was the pin in the connector was not making good contact with the pin in the ECM. Swapping the ECM will pinpoint the problem, and since you're not the one doing the actual repair, they're going to insist on replacing the ECM first. If it were mine, I'd take out the connector, pull the pin in question, backshell it to raise the petal inside the pin, and put it all back together to test. If that failed, then I'd say it's time to buy a new ECM, and I'd be very confident this is the root cause, but I might also pull the board out of the ECM and check the solder joint on the pin in question to make sure this isn't a bad solder joint before spending somewhere around $1100 for a new one.
We tried all this with the one I ended up replacing. It was a bad component on the board, and I don't do board level repair anymore.
Sorry if I missed it, have mechanical problems been ruled out here? An ignition scope can give you a lot of information as well to lead you down the right path.
Sorry if I missed it, have mechanical problems been ruled out here? An ignition scope can give you a lot of information as well to lead you down the right path.
Update:
Per text from mechanic:
“Took a boroscope into the cylinder
Tip of Injector looks fine
Minor carbon buildup inside
Piston top looks incredibly clean
Valves have super minor buildup.
Switched around some coils, still misfiring. Tested a brand new plug, NGK. Still misfiring.
No grasshopper. It might be the ECM. It might also be the pin in the connector. I had this problem with my Supra two decades ago, and the issue was the pin in the connector was not making good contact with the pin in the ECM. Swapping the ECM will pinpoint the problem, and since you're not the one doing the actual repair, they're going to insist on replacing the ECM first. If it were mine, I'd take out the connector, pull the pin in question, backshell it to raise the petal inside the pin, and put it all back together to test. If that failed, then I'd say it's time to buy a new ECM, and I'd be very confident this is the root cause, but I might also pull the board out of the ECM and check the solder joint on the pin in question to make sure this isn't a bad solder joint before spending somewhere around $1100 for a new one.
We tried all this with the one I ended up replacing. It was a bad component on the board, and I don't do board level repair anymore.
Thank you for the explanation. I asked mechanic about the ECM and this was his response:
“We're trying to rule out everything except the ECM / ECU. Pretty much same thing. What I sent to VF Tuner in order to get the file to tune the car.
What boggles me is, if it was the ECM,
1. How were we able to drive the car great for over a month? Granted you took some time off.
2. How come the issue didn't appear as soon as we put the ecm back into the vehicle?
3. I put the stock file back in, how did it accept the new file?”
A tuning file has no impact on faulty drivers. The ECM interrupts the ground to the coil to make it fire. If it isn't doing this exactly right, the cylinder will have problems. But if the piston top is clean, that's a whole different can of worms.
I'd let the tech do some diagnostics before jumping to any conclusions. You'd most likely see lots of white smoke if you were leaking coolant into the cylinder to the degree that would suddenly cause a misfire, not to mention you'd have coolant loss.
This should be treated the same as any other car that has a misfire. Just make sure your tech is up to the task, he should be using an oscilloscope to check the ignition circuit. Replacing the injector, spark plug, coil etc without knowing the root cause first doesn't give me good vibes. He shouldn't need to parts cannon the thing.
It doesn' take a lot of water to clean a piston top. I do this before tearing down any engine I'm planning to rebuild if I can, just to make clean up easier.
Car is fixed. No misfire or rough idle. Per text from mechanic-
”Random piece of foreign material in the intake valve, causing valve not to close properly. It was possibly sucked in through the intake, we don't know what it was or where it came from.”
Car is fixed. No misfire or rough idle. Per text from mechanic-
”Random piece of foreign material in the intake valve, causing valve not to close properly. It was possibly sucked in through the intake, we don't know what it was or where it came from.”
I'd let the tech do some diagnostics before jumping to any conclusions. You'd most likely see lots of white smoke if you were leaking coolant into the cylinder to the degree that would suddenly cause a misfire, not to mention you'd have coolant loss.
This should be treated the same as any other car that has a misfire. Just make sure your tech is up to the task, he should be using an oscilloscope to check the ignition circuit. Replacing the injector, spark plug, coil etc without knowing the root cause first doesn't give me good vibes. He shouldn't need to parts cannon the thing.
Well the only actual part I bought was the sole direct injector. The other parts that they tried, they swapped from a wrecked GSF they have in shop. So they were just doing process of elimination.
Well the only actual part I bought was the sole direct injector. The other parts that they tried, they swapped from a wrecked GSF they have in shop. So they were just doing process of elimination.
But I’m no mechanic so 🤷🏻♂️
Definitely makes more sense if they have spare parts to test with, as long as they aren't charging you for replacing parts left and right.
Glad they figured it out though. I wonder what the debris was.
