Service engine soon

[iamdub]

It's probably a minor, one-time thing. There are a few possibilities for it to throw a code when the engine's under heavy load/high RPM- detonation, miscorrelation between the MAF and MAP sensors, something in the trans...

Don't have them clear it if you have it read. It may be something Justin should look at and consider before tuning it. Actually, since it's getting tuned, I hope the code(s) is/are still stored so Justin can look at the freeze frame(s).

 

[02_Tahoe]

It's probably a minor, one-time thing. There are a few possibilities for it to throw a code when the engine's under heavy load/high RPM- detonation, miscorrelation between the MAF and MAP sensors, something in the trans...

Don't have them clear it if you have it read. It may be something Justin should look at and consider before tuning it. Actually, since it's getting tuned, I hope the code(s) is/are still stored so Justin can look at the freeze frame(s).

Will he not tune it if there is something wrong with it? If so I hope I can get my deposit back

 

[iamdub]

Will he not tune it if there is something wrong with it? If so I hope I can get my deposit back

That's up to him and what the problem is, but at this point I'm doubting it'll be an issue. Generally, tuning for power includes advancing the timing. If your truck has an issue with detonating (preignition) at higher loads and/or upper RPMs, advancing the timing would make this worse. You may have just gotten some bad gas. Fill up with a top-tier gas of whatever grade of octane you're getting tuned for before you go for the tune. Don't put high octane gasoline in as a diagnostics to this issue if you want it tuned safely for a lower octane level.

There again, your SES light may not have anything to do with detonation or the knock sensor or even the engine. It could be a transmission thing. The ideal thing is to get the code read ASAP, before it is self-deleted. It may go away and the light turn off before you get to Justin, but it would be nice to at least be able to mention the recent issue to him. It could save you a motor and him some headache.

 

[02_Tahoe]

That's up to him and what the problem is, but at this point I'm doubting it'll be an issue. Generally, tuning for power includes advancing the timing. If your truck has an issue with detonating (preignition) at higher loads and/or upper RPMs, advancing the timing would make this worse. You may have just gotten some bad gas. Fill up with a top-tier gas of whatever grade of octane you're getting tuned for before you go for the tune. Don't put high octane gasoline in as a diagnostics to this issue if you want it tuned safely for a lower octane level.

There again, your SES light may not have anything to do with detonation or the knock sensor or even the engine. It could be a transmission thing. The ideal thing is to get the code read ASAP, before it is self-deleted. It may go away and the light turn off before you get to Justin, but it would be nice to at least be able to mention the recent issue to him. It could save you a motor and him some headache.

My trans shouldn't have a problem as it was rebuilt less than 20k miles ago, hopefully this is just something to do with emissions, and I'm on my second tank of gas while having the light on from 2 different stations, so does that rule out the detonation issue?

 

[iamdub]

My trans shouldn't have a problem as it was rebuilt less than 20k miles ago, hopefully this is just something to do with emissions, and I'm on my second tank of gas while having the light on from 2 different stations, so does that rule out the detonation issue?

Not to induce fear or doubt, but transmission techs can and do make mistakes. I highly doubt this is the case, though. I was just listing examples of how things may or may not be related or even pertinent to your tuning.

If you've driven enough miles to burn 2 tanks of gas, then that should be enough drive cycles to clear the code if it was a "soft" failure. If you were having steady detonation issues, especially since driving it easier lately, then you'd definitely have a problem that you'd feel. The problem may not even be a knock sensor issue. It's just the best guess since the light came on during a high load scenario and you say the motor feels normal afterward.

 

[02_Tahoe]

Not to induce fear or doubt, but transmission techs can and do make mistakes. I highly doubt this is the case, though. I was just listing examples of how things may or may not be related or even pertinent to your tuning.

If you've driven enough miles to burn 2 tanks of gas, then that should be enough drive cycles to clear the code if it was a "soft" failure. If you were having steady detonation issues, especially since driving it easier lately, then you'd definitely have a problem that you'd feel. The problem may not even be a knock sensor issue. It's just the best guess since the light came on during a high load scenario and you say the motor feels normal afterward.

I put it under heavy acceleration twice the day before and no light came on. I've had it come on when it was cold after I started it too. Could it just be bad spark plugs?

 

[HiHoeSilver]

I put it under heavy acceleration twice the day before and no light came on. I've had it come on when it was cold after I started it too. Could it just be bad spark plugs?

Stop thinking until you see the codes. You'll just be running in the dark. Don't drive yourself nuts.

 

[iamdub]

^^^ Pretty much what I was gonna say. lol

Also, if you're in doubt about your spark plugs, then you should replace them before the tuning. If they're not old and are the correct ones for your rig, then you shouldn't doubt them. Get your PCM read but not cleared ASAP so you can fix whatever needs to be fixed (if it needs it) before getting it tuned. You gotta at least know why your SES light is on.

We could speculate and guess all day long but all that's gonna do is stress you out.

 

[02_Tahoe]

Stop thinking until you see the codes. You'll just be running in the dark. Don't drive yourself nuts.

Too late

 

[02_Tahoe]

^^^ Pretty much what I was gonna say. lol

Also, if you're in doubt about your spark plugs, then you should replace them before the tuning. If they're not old and are the correct ones for your rig, then you shouldn't doubt them. Get your PCM read but not cleared ASAP so you can fix whatever needs to be fixed (if it needs it) before getting it tuned. You gotta at least know why your SES light is on.

We could speculate and guess all day long but all that's gonna do is stress you out.

I have enough time after work so I'll go get that checked