5.3l 4l60e issues NEED HELP!

[littlevictories]

well I've been playing with OLSD so currently my AFR is like 16.5 at cruise, low load and the total advance is around 40*. yes it is jumpy. the truck computer uses a bunch of different factors to create a "final spark" number if you will.

At the time I first noticed that the timing would go way out to 45* at highway cruise I was basically stock, closed loop with MAF. maybe a few basic VE edits (in addition to new injectors) to get my LTFTs in line.

[BR3W CITY]

Originally Posted by littlevictories

well I've been playing with OLSD so currently my AFR is like 16.5 at cruise, low load and the total advance is around 40*. yes it is jumpy. the truck computer uses a bunch of different factors to create a "final spark" number if you will.

At the time I first noticed that the timing would go way out to 45* at highway cruise I was basically stock, closed loop with MAF. maybe a few basic VE edits (in addition to new injectors) to get my LTFTs in line.

Yes, but they can all be manipulated. If your getting timing that you didn't add yourself (or whoever tuned it), you can take a look and see WHY. 16.5 is very lean at cruise, I barely go that lean on decel.

Under the condition you mentioned, you want to be a hair fat, as that particular range is prone to knock. 40* is still a large amount of timing IMO, spark tables shouldn't show much over 32.

What injector are you running? Did you rely just on VE, or was PE used also?

[chevyman70]

Originally Posted by BR3W CITY

Yes, but they can all be manipulated. If your getting timing that you didn't add yourself (or whoever tuned it), you can take a look and see WHY. 16.5 is very lean at cruise, I barely go that lean on decel.

Under the condition you mentioned, you want to be a hair fat, as that particular range is prone to knock. 40* is still a large amount of timing IMO, spark tables shouldn't show much over 32.

What injector are you running? Did you rely just on VE, or was PE used also?

Okay, finally I got the MAF sensor installed. It took me awhile since I ordered the MAF that had lifetime warranty, rather than one year. Just a few dollars more. Anyhow, after installing the MAF, the truck idles much better. After a few drive cycles, at idle, LTFT% is around 7% to 10%. At cruise, it varies between 16% to 21%. So far, no p0171, P0174 codes. It will read 25% while accelerating. I am not sure if that is normal.

What I do notice is that bank 1 reads higher LTFT% by 3% compared to bank 2. Bank 1 is where I hear it missing through the exhaust at rpms higher that 1500. That is when it shuffles between 1500 to 1700. I did check the ignition timing, at cruise speed and it does read 32 to 34 degrees, unless I drop it to 3rd gear, then ignition timing rises to 40 to 45 degrees.

I am using stock injectors that came with the engine. When I had the PCM reflashed, I just gave them the engines information, transmission information, rear end ratios, and tire size. Nothing more. Everything on the engine is stock. I do have a transmission question, but I'll take your advise and tackle one issue at a time.

[chevyman70]

So got a chance to play around with this continued issue. Ltft still at 25% at part throttle, 10 to 18 at idle. I get p0171 and p0174 codes. Replaced intake manifold gasket as well. Replaced fuel pump and fuel filter. What I did noticed is that when I plug the pcv the ltft drops to 0% during iddle and isolates from 0-10% during part throttle. The original pcv is the one that has a small hole on the pcv. I installed the one with the check valve to see if it made a difference and it worked the same as the original one. What could cause that vacuum leak through the pcv? I replaced the grommet as well, but to no avail. Any suggestions?