I recently installed my Long Tube headers, and have noticed that the car smells super rich. So I have been doing some logging with Autotap. I have been watching my STrims for both bank 1 and 2, as well as my LTrims for both banks.

On all of my logs, the LTrims, bank 1 is at -.8% and bank 2 is at -1% ALWAYS, it NEVER CHANGES. Regardless of fuel cell.

At idle, the PCM is pulling fuel from the STrims (like -4% to -6% normally) but anything above idle usually shows the PCM adding up to 15% more fuel depending on the fuel cell.

Autotap shows two sets of LTrims for (2 bank 1's and 2 bank 2's), and I've logged both, with one set staying at 0 all the time.

My old logs with my stock exhaust showed the LTrims changing depending on the fuel cell the PCM was in at the time, so those numbers fluctuated somewhat during logging.

But the new logs, the LTrims are rock solid and never ever change...

My O2 sensors are scanning up and down from .010 to .9xx, and are brand new (were when installed into headers, 350-400 or so miles sense installation)...

The car is getting lower mileage too, 15 MPG with headers compared to 18.5 with stock manifolds.

Anyone have any ideas?

 

Could you possibly post a link to the scan files, preferably in .csv or .xls format? Kind of hard to follow the written description of what is going on.

 

Sure thing!

Before Headers

After Headers

It's the LTrims that have me puzzled.

Thanks for looking at them!

 

I've got literally hundreds of scans that people have sent me, and I've never seen one like that.

You mentioned "cells" but your logs don't include the cell #. Do you have a "after headers" log with cell #'s shown.

 

Sure Fred, here you go.

After Headers with fuel cell noted..

I really appreciate you helping me with this.

 

I'm not sure I'm "helping"..... I've never seen a data log that looked like that.

You mention in the first post:

"Autotap shows two sets of LTrims for (2 bank 1's and 2 bank 2's), and I've logged both, with one set staying at 0 all the time."

Are you refering to the fact that AutoTap can show both the "128" base multiplier, and the resulting "%" correction? They should be the "same" in that the "%" should represent the deviation from 128.

Gotta keep poking around on this one.... can't think of any logical reason for what you are getting.

 

I realize this will probably be of NO help to you whatsoever, but when I open the list of things to watch in Autotap, there are two LTrim Bank 1's and two LTrim Bank 2's.

They're listed like this:

Long Term Fuel Trim Bank 1
Long Term Fuel Trim Bank 1
Long Term Fuel Trim Bank 2
Long Term Fuel Trim Bank 2

The top one for each bank is the one that always stays at zero.
The 2nd one for each bank is the one in the log file.

When I first start the car (open loop), the LTrims both read -100. I presume this is becuase the o2 sensors are not warm, the timer has not expired, etc... Once it goes into closed loop, the fuel trims change to what you saw in my files.

I drove 50 or 60 miles yesterday and the car showed 1/4 tank used on the gauge.

Something else that's odd...

I park my car in my garage. It normally stays at least 50 degrees in there even on the coldest night so far. I parked my car Friday night and went in the house. Yesterday I changed the fuel filter, and went to go help a friend drop his engine out of the car. I started Autotap logging, and started the engine, but Autotap was not recording. So with the engine still running, I closed Autotap and backed the car out of the garage. I restarted Autotap and got it recording and backed up some more. I backed up some more and saw a small puddle where the car had been idling. I got out and look underneath for leaks at the fuel filter and had none, but looking at the clamp that is at the y-pipe to i-pipe junction I saw lots of fluid coming out of the clamp. Now I was probably stupid for not moving the car and smelling the fluid, but I didn't and I left. By the time i got where I was going, there was no more coming out of the exhaust. And later on, when I started the car after it had set about four hours, there was none coming out.

If you think it will help any, I can post links to the raw CSV files, that are unedited. I organize and color code to make it easier for me to see the data.

 

Just as a test, I reset the PCM before leaving work today. I started the car and started logging. The car ran about 10 minutes, then shut it off and put gas in the car. Afterwards, I started it up and drove it about 35 miles. The LTrims still haven't come off of 0 yet, so I'll have to keep an eye on it and see if it does any better this time.

 

Well, I didn't drive the car much yesterday or the day before.

I drove it for about an hour tonight. Over 60 miles, and my LTrims still haven't come off of 0 on either side.

How long does it take for the LTrims to start to come off zero?

 

My LTrims still haven't come off 0 (as of yesterday afternoon) even though the PCM was pulling fuel at idle and adding it above idle.

I've been watching my STrims (since my LTrims seem unreliable) and see that Bank 1 (driver's) is almost always richer than Bank 2 (passenger's). The difference is usually within 5%, is this acceptable?

One night (Thursday night last week) after driving the car a while, I let it idle in the garage with the door open and lights off and could see some sparking inside the boots on the plug tips (I could see the occasional blue glow THROUGH the boot of the wire), and one one wire I could tell spark is jumping from one wire to a metal bracket that it's close to. All the visible sparking is on Bank 1 (driver's side), there's none visible on the passenger side.

I'm working on getting some new wires, maybe that will help with
the driver's side being slightly richer than the passenger side as far as STrims are concerned.

I'm still trying to figure out why the LTrims are still 0 though. It just makes no sense.

 

I'd be tempted to swap out the PCM temporarily with one that you know is "good"...... otherwise, I can't figure out why it would do what its doing

 

I don't know anyone with an OBDII PCM that I can borrow for testing. At least, not with a stock tune.

I guess I could see about ordering one.

I was hoping to get myself a dyno tune here soon...

The car has only been programmed twice since I got it (once for gears, and once to correct converter lockup issues created by first load).

 

Pretty odd looking. Any chance that the person that programmed for your gears locked in the min/max BLM's for any reason?? Or maybe they changed the PE TPS enable table such that your in PE all the time and "learn enable" is inhibited. These are long shots! Definately wierd.

Steve

 

I have my stock and current LT1 Edit files here. I have opened them in LT1 Edit (I have the software but no cable, so I can see but not change anything) and have compared the two. I have looked at all the tables that I could find and they match 100%. The only ones that are different are the shifting tables I believe.

I have not verified in the area where you turn stuff like EGR and AIR tests and codes off, but I have looked everywhere else.

As far as I can tell, the only changes to the stock program were as follows: Set transmission and speed gear ratios to 3.42, and change the fan turn on temps to 170 low speed and 191 high speed.

The car does go into closed loop and it stays there.

I have only noticed this problem since the headers were installed as the before header file was recorded about after the gear install and programming change.

I don't think this is a tune issue, but I guess it could be.

If anyone thinks it will help, I'm willing to email them my LT1 Edit file.

 

When you had the headers installed, was any arc welding done directly on the car? If so, was the battery disconnected before welding? Did they try to make the ground connection reasonably close to the piece they were welding?

You can see where this is going......