I think this is a 7747 ECM but not for sure. Anyway it has a ASTK chip in it and the owner thinks it wrong for the truck. The truck is a 1991 grain truck with a 366 tall block in it. Does anybody know if that code is right? He keeps getting backfire up through the tbi unit with the timing connector connected but it runs ok with it unconnected. I have not seen or heard this run i'm just asking for him, this aint my baby!
CK5
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Anybody know this broadcast code?
- Thread starter GMC Truck
- Start date
ASTK is for 1991 16147525 ECM Engine RPO LS0 6.0L manual So it's sounds right for a commercial 366 engine truck.
If the timing is set correctly with wire disconnected, then clear codes by disconnecting power as setting the timing sets an error code.
But that does not normally cause a back fire. Disconnecting the wire changes how the EST advances timing. The EST is a known part to still work when it fails, Glitchy. Replace it, clean mounting surface and use the heat transfer grease when installing new one. It is also critical to make sure bolts holding it in are clean tight because they ground the sensor.
If the timing is set correctly with wire disconnected, then clear codes by disconnecting power as setting the timing sets an error code.
But that does not normally cause a back fire. Disconnecting the wire changes how the EST advances timing. The EST is a known part to still work when it fails, Glitchy. Replace it, clean mounting surface and use the heat transfer grease when installing new one. It is also critical to make sure bolts holding it in are clean tight because they ground the sensor.
Not that I know of? TunerPro definitions are mostly community built, there's not much of a call to tune 366 commercail motors... have you tried to read the chip with $42? Last one I saw had same wiring and plugs as a 1227747.
If you have TunerCat $20. is cheap... but I don't think your going to tune out this issue...
If you have TunerCat $20. is cheap... but I don't think your going to tune out this issue...
I agree with you! However he wants me to see if there is suppose to be a 02 sensor in the program. He says that there is not one on the truck nor any place to install one or any wires for it, but there is codes for it? I did just find out from him that the ECM was replaced trying to find the backfiring issue. (god help us they are throwing parts at it) So I have no clue what they have done???
dave w
1/2 ton status
I think the problem is mechanical:
Worn down camshaft lobe?
Kind of blows exhaust gases up the intake manifold runners when the intake valve opens when the exhaust valve didn't open. Usually backfire worse at low RPM?
Crank the engine with the injectors unplugged, maybe the backfire still happens?
Hook a vacuum gauge to engine while running ... fluctuating vacuum readings means the problem is mechanical, not TBI / ECM related.
dave w
Worn down camshaft lobe?
Kind of blows exhaust gases up the intake manifold runners when the intake valve opens when the exhaust valve didn't open. Usually backfire worse at low RPM?
Crank the engine with the injectors unplugged, maybe the backfire still happens?
Hook a vacuum gauge to engine while running ... fluctuating vacuum readings means the problem is mechanical, not TBI / ECM related.
dave w
I think he's BSing you. Ones I have seen have O2, only vehicles I know from GM that don't are boats and exports. Some exports even have them but turned off in PCM.
Bingo! Thats exactly what I told him to start with. This guy has put 3 EST modules on and replaced the ECM twice. I hate "mechanics" that just throw parts at problems cause they don't understand.
