Thread: PE nuts

Originally Posted by TDCRacing

Yeah the maf is used all of the time. If you unplug it the pcm is going to resort to the VE table. How are you tuning your fuel? VE Table? Injectors table? MAF? Lets say you were tuning the fuel on your car by the maf. You got it running right. then you unplugged the maf. Well then the pcm is going to be looking at the VE table. Wich has stock fueling...get it? the VE table never changes unless you change it. It's been up in the air but some people claim that there car doesent even use the VE table with the MAF unplugged.

Except for a few basic changes (nothing fueling related) I'm running a pretty much stock tune. If the PCM doesn't use the VE table when the MAF is unplugged, then what the heck does it use? I know my VE table affects stuff because after a VE tune my trims definitely changed in accordance with it.

I'm still going to unplug the MAF tonight and see what happens. We recently had a guy whose MAF was bad. No codes were thrown, but with the MAF plugged up it wouldn't even idle. No MAF and it runs just fine. Replace the MAF and it works.

So, just cause I have no codes I'm not ruling out the MAF. And I'm going to look at that o-ring soon, maybe next weekend. Installing a Plog and coated x-over anyway, so might as well.

Originally Posted by Sabrewings

Except for a few basic changes (nothing fueling related) I'm running a pretty much stock tune. If the PCM doesn't use the VE table when the MAF is unplugged, then what the heck does it use? I know my VE table affects stuff because after a VE tune my trims definitely changed in accordance with it.

I'm still going to unplug the MAF tonight and see what happens. We recently had a guy whose MAF was bad. No codes were thrown, but with the MAF plugged up it wouldn't even idle. No MAF and it runs just fine. Replace the MAF and it works.

So, just cause I have no codes I'm not ruling out the MAF. And I'm going to look at that o-ring soon, maybe next weekend. Installing a Plog and coated x-over anyway, so might as well.

I'm sorry I said that wrong. The VE table was zeroed out with the maf still plugged in. And the car still ran and FT's stayed the same.I sent bill an email to see if he had the link because i couldnt find it. I'm not sure what the conclusion of all of it was but i figured you may want to look at it.To be honest im not even sure if they did any testing on the impalas. But what the heck

Originally Posted by TDCRacing

Here ya go he got back with me - I actually see that Indeedss posted in there also




V6 VE Tuning Test - HP Tuners Bulletin Board

That pretty much showed me that different cars use the VE and some don't use it much. From what was said, I'm pretty sure my OS uses it.

I did my MAF/no MAF testing. I won't tell you what I think just yet, only post the scans. See what YOU think.

No MAF:

07122008_223856 from sabrewings -- Scan Depot dot net

MAF:

07122008_225311 from sabrewings -- Scan Depot dot net

No MAF:

07122008_230811 from sabrewings -- Scan Depot dot net

I did the "No MAF" a second time right after the MAF. Like, maybe a minute in between those scans. And I drove the same stretch of road as I did towards the end of the MAF session. I did this to rule out any temperature changes in internal components, IATs, etc from affecting the results.

Edit: Okay, those scans suck. Damn interface doesn't save right half the time.

Anyway, I saw less KR with the no MAF than I did with the MAF. Does this mean I need a MAF tune, or a new MAF?

Originally Posted by TDCRacing

Cupple questions. Why are you ft's locking in at 0 in your first scan twards the begining of this thread but not now? When was the last time you did a maf tune? What is your PE enable tps at?

Since I replaced my O2 sensor, I reset my fuel trims so any anomalies it created were gone. The FTs were probably still settling.

Never done a MAF tune on it.

PE is set to come on at about 60-65% (it's the stock data right now).

Originally Posted by TDCRacing

Could you flash a stock MAF table on there then do a MAF tune and see where you are at?

Well, it already has the stock MAF table.

...

Doh, it just hit me why some of the knock might've been worse yesterday. I reset the trims, duh. It was having to figure everything out again, all my trims, etc. I'm going to give it some time, then MAF tune it. If I can get my hands on a set of security torx bits, I'll try cleaning it.

I'm ordering a HVTB later this month from ZZP and they come complete, so I should have a new(er) MAF soon enough anyway.

Knock was so bad in the heat today.

This can be locked if you wish. I'm making a post out of the tuning section to get more ideas.