gm. service eng.soon light

[13 heritage]

01silverado, 4.8l. It has a hi flo specter air tube. It codes lean on both banks. Can I remap with out buying programmer? Or just find a stock air box? Had light off for 20 miles then back on. NYS won't inspect. Plus I don't want to damage engine. I checked & cleaned all clamped connections. Input please. Thanks

[Jsdirt]

Probably could use a commercial programmer, like Hypertech. I don't know of any way to program the unit without that, or a custom tune, like Black Bear for example.

 

Welcome to the world of computer controlled cars. Used to be a cheap and easy test & tune, swapping jets and changing timing. If you got it to run strong on a day midway between the high and low temps for your area, it would run fine in every temp you encountered - no computers needed. Now the cheapest tuners (the ones worth a damn) are still well north of $200. I really miss the old days for alot of reasons, not just automotive.

[13 heritage]

Yeah I hear ya, Js dirt. I used to have a second home under the hoods of old Chevy trucks. Had a 69 4x4 with a nasty 350 me &my old boss built. So do ya think if stock air boxed this thing the prob with service light would go away? I've done the spray method of looking for intake leaks. I think its the hi flow breather as its lean on both banks. I think a non computer operated truck is happening soon. Thanks in advance.

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[Jsdirt]

Yeah if that aftermarket box is much more freer flowing than OEM, it would definitely make it run lean. Unusual that it's throwing a code, but these days anything is possible ...

 

If you correct the lean issue, it can take several key cycles to make the light go off without a scan tool, just FYI.

 

I've had motorcycles that wouldn't even run past 1/2 throttle after just installing a K&N filter - the filter flowed so much more air than the OEM filter, that it leaned it out to the point where it wouldn't take any throttle whatsoever. Had to go up a couple main jet sizes, then the bike hauled ass. Wanted alot more fuel.

[Stevens03]

If you have a K&N filter or similar oil filter clean your MAF sensor with MAF cleaner, clean your filter and see if the light comes back on. A dirty MAF sensor will cause that.

[Doug_Scott]

Carbureted motorcycle engines are far more sensitive to air box resonance than cars or trucks. Simply putting a one inch hole in the air box can cause issues that require rejetting to correct.

 

When did the codes start to appear? Was it after the changes were made to the air box and/or air filter? Try checking the intake manifold for vacuum leaks. Vacuum leaks can only happen after the throttle body, air flow is measured after the air filter, but before throttle body, so a vacuum leak will allow more air into engine than the MAF sensor thinks entered. Depending on where the vacuum leak is, it can cause both banks to register lean.

[Jsdirt]

I figured the differences were obvious. Just mentioned it as an example of what changes will do to any engine - definitely not an apples-to-apples direct comparison, but an example nonetheless.

[13 heritage]

Thanks you guys. I'll re check for any intake vacuum leaks again. I did the carb cleaner method. I'll check any hoses as well , again. Its a Spectre, big frigging basically straight jam of air getting blasted into the intake. It's got too many miles on it to be pounding on any how. 175,000. Everything was good till I drove it home. It had that set up in it when I bought it. No exhaust mods. No other codes either. I'll keep yous posted on the out come of this problem child.