Totally Stock - Way Too Much Knock - UPDATE page 3 - Page 4 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


2000-2005 Discuss your 2000-2005 Bonneville SE, SLE, and SSEi Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 09-20-2007, 10:23 AM   #31
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default

Will do that Saturday.
bonnie94ssei is offline   Reply With Quote
Old 09-20-2007, 10:24 AM   #32
Senior Member
Certified Car Nut
 
Join Date: Oct 2003
Posts: 19,756
Thanks: 0
Thanked 0 Times in 0 Posts
1993 SLE is on a distinguished road
Default

the LTFT'* should fluctuate based on engine load and what the PCM calcualtes to add or subtract fuel to make the car run based on what it wants

we will check FP, on your and my car this weekend

we also need to check Vac leaks
1993 SLE is offline   Reply With Quote
Old 09-20-2007, 02:31 PM   #33
Senior Member
Certified Car Nut
 
Join Date: Jun 2003
Posts: 15,928
Thanks: 0
Thanked 0 Times in 0 Posts
BonneMeMN is on a distinguished road
Default

Quote:
Originally Posted by BillBoost37
Remember to check fuel pressure.
That was my thinking seeing the funky LTFT. Although if you're driving around with less than 1/2 a gallon, you're straining the fuel pump, and could really run into a lean condition if your tank got sloshing a lot.....
BonneMeMN is offline   Reply With Quote
Old 09-20-2007, 03:31 PM   #34
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default

Yeah, after I posted I quickly remembered I was very low in fuel. I'm almost certain that'* why I was getting those ridiculous readings. Today the readings were "normal." I'll check my fuel pressure this weekend and see what I'm really looking at.

I'm almost certain I have a slow coolant leak which could cause some misfires that I've been having. I plan on doing my LIM gaskets ASAP, which will probably not be for another 2 - 3 weeks unfortunately.
bonnie94ssei is offline   Reply With Quote
Old 09-20-2007, 03:34 PM   #35
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

You can't necessarily know for certain that a LTFT which moves frequently when not at WOT is caused by low fuel.

One of the things I've been doing since having a scanner/Aeroforce is to try and learn what the expected behavior of the various parameters should be at any given times. LT is one of those things that fluctuates. At least on stock pcms.

Currently my LT'* are anywhere from 0 to -13 since I changed some programming.
BillBoost37 is offline   Reply With Quote
Old 09-20-2007, 03:40 PM   #36
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default

Yeah, it'* basically a guess right now as the only different variable was the very low fuel and I never saw such high (and low) readings until that point. Since they're back to where they were before, it just seems that could be the cause.

But 15.6 at idle just seemed really bad.

A question I posed earlier in this thread but wasn't answered (probably not a real easy answer) was how 'bad' is 6.2 for my LTFT at WOT? If I understand correctly, there is a certain point when the PCM can't compensate and adjust fuel. What is that point?
bonnie94ssei is offline   Reply With Quote
Old 09-20-2007, 03:56 PM   #37
Senior Member
Posts like a Corvette
 
Join Date: Jan 2004
Location: Montréal, QC
Posts: 1,374
Thanks: 0
Thanked 0 Times in 0 Posts
Foghorn is on a distinguished road
Default

Quote:
Originally Posted by bonnie94ssei
A question I posed earlier in this thread but wasn't answered (probably not a real easy answer) was how 'bad' is 6.2 for my LTFT at WOT? If I understand correctly, there is a certain point when the PCM can't compensate and adjust fuel. What is that point?
Was it +6.2 or -6.2? The LTFT value is reported in % so if you see +6.2 that means the PCM added 6.2% extra fuel while in PE mode, that means the PCM learned your fueling as being lean and needed to add fuel.

From the O2 value you mentioned (885), while it'* not necessarily accurate it has become 'known' to be a value that is too lean. If your LTFT value was in fact negative, meaning it was -6.2, then if correct that assuming your fuel trims locked at 0 while in PE mode, then your O2 value would have been in the 943 range which is thought to be safely rich.

Hope that helps.

Cheers,
Foghorn is offline   Reply With Quote
Old 09-20-2007, 04:11 PM   #38
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default

My LTFT is at +6.2 at WOT which I understood was lean. And IIRC 10% is the point where the PCM cannot compensate anymore.

Can you explain how you came to the number 943? What'* PE mode...drawing a blank. lol I need to know what PE mode is before I understand what you meant by a –6.2 LTFT and "fuel trims locked at 0 while in PE mode" means:

Quote:
If your LTFT value was in fact negative, meaning it was -6.2, then if correct that assuming your fuel trims locked at 0 while in PE mode, then your O2 value would have been in the 943 range which is thought to be safely rich.
I thought I had read somewhere that the numbers were a percent, thanks for clarifying that!

Thanks!!
bonnie94ssei is offline   Reply With Quote
Old 09-20-2007, 04:12 PM   #39
Senior Member
True Car Nut
 
Join Date: Jan 2005
Location: Montevideo, MN MWBF '05, '06, '07 WCBF '06 '07 survivor
Posts: 3,882
Thanks: 0
Thanked 0 Times in 0 Posts
sonoma_zr2 is on a distinguished road
Default

Quote:
Originally Posted by bonnie94ssei
My LTFT is at +6.2 at WOT which I understood was lean. And IIRC 10% the point where the PCM cannot compensate anymore.

Can you explain how you came to the number 943? What'* PE mode...drawing a blank. lol I need to know what PE mode is before I understand what you meant by a –6.2 LTFT and "fuel trims locked at 0 while in PE mode" means.

I thought I had read somewhere that the numbers were a percent, thanks for clarifying that!

Thanks!!
power enhancement, or performance if you like
sonoma_zr2 is offline   Reply With Quote
Old 09-20-2007, 04:32 PM   #40
Senior Member
Posts like a Corvette
 
Join Date: Jan 2004
Location: Montréal, QC
Posts: 1,374
Thanks: 0
Thanked 0 Times in 0 Posts
Foghorn is on a distinguished road
Default

Quote:
Originally Posted by bonnie94ssei
My LTFT is at +6.2 at WOT which I understood was lean. And IIRC 10% is the point where the PCM cannot compensate anymore.
When you have +LTFT that'* because the PCM is corecting for a lean condition, so yes you're correct.

The PCM can correct +16.4 and -22.6

Don't ask how I got the value, I'd have to shoot you after...

Oh...PE = Power Enrichment...otherwise known as the mode you should be in while under boost, unless you want fuel economy

Cheers,
Foghorn is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
My Car Updated, Had Way Too Much Red!!! 94SSEgold Your Ride: GM Pictures & Videos 20 03-31-2008 02:14 PM
knock knock knock L27Buick 1992-1999 7 09-17-2004 04:23 PM
Knock Knock, engine knock? Spiral 1992-1999 5 05-23-2004 10:08 PM
Star Wars + Too Much Time + Too Much Money = ??? mremer Lounge 7 03-10-2004 01:54 AM
WAY too much time to kill... MOS95B Lounge 4 02-24-2004 11:15 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:19 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.