Mert Celet

Hi Everyone,

Finally hot summer days have arrived and it's time to get back on the road with my 74 Firebird (98 fbody LS1, A4, (did 411 swap) 98 LS1 f body steel tank fuel system adapted to 74 steel tank). BUUUT... This fueling issue has been haunting me for such a long time and just this morning, it has got worse.

For such a long time, i had been trying to tweak out the fuel related problem as the car was running pig rich but with LTFTs Crazy Positive around +12-25
No matter how much i had added to the VE it never got better. And it was stumbling as if starving for fuel at higher rpms (especially after a 10mins of spirited driving around the mountains)

As of this morning, The pump primes, the car starts, no problem, in 30 secs, the world turns upside down. The engine starts to desperately try to maintain idle and dies. I restart it, does not start unless you press the pedal to the metal. And dies again. Whenever i try to keep the rpms steady with the help of the pedal, still dies. Even with a steady foot at the pedal, the rpms vary as if running out of gas. I've got sufficient fuel pressure, 48psi cranking, 60psi idle, 59psi wot)


I am trying to find out if this will take me to a dying pump, but this is a new racetronix pump with it's hotwire (checked everything cables, fuses,relay all ok) and there's only like 500 miles on this pump at most.

The issue was present with my previous pump (which was an og 98 fuel pump assembly) and JUST that i thought that it was like a symptom of a dying pump, i had converted to racetronix but again same issue. I though it was fuel starvation and installed Hydramat (more $$$ dumped) still there it was.

Anyway, here attached You can find my Log from this morning with many counts of failing. The tune file & the log from last night too...
Sadly here in Turkey, no one knows **** about these cars and i'm all alone with my issue. If anyone can help me sort this thing out, i can not even express the amount of my gratitude. I have had this engine installed on this car for the past two years and never get to drive the **** out of it.

All the best
Mert

Mert Celet

Took out the spark plugs... Black as the night.( And covered with oil...****!) Oil smells gas... It is exactly a pig rich condition. However; If You can take a look at the log, the oxygen sensors and wideband reads LEAN. And the pcm keeps adding adding adding...

BTW, while the stumbling is happening, as soon as the fans kick in, as if the whole car's electricity is being sucked dry and it can not even continue with the stumbling...

Here are the spark plugs...

Mert Celet

Bump!

Old Geezer

iTrader: (3)

" It is exactly a pig rich condition. However; If You can take a look at the log, the oxygen sensors and wideband reads LEAN. And the pcm keeps adding adding adding."
Exhaust leak?

JoeNova

The wideband and 02 sensors will read lean if it's so rich that it missfires.

Mert Celet

Hi Guys!
No leaks anywhere. I'm dead sure.
However, You guys have steered me to the right path i guess. Here's how it is:
Since i had completed the 411 swap, at the vcm scanner, my O2sensors and O2sensor heaters always show up as ''incomplete'' Till today, i always overlooked that issue and tried to find the missing link in my tunes.
Actually i am so scared to get that pcm out again and get crazy inside those messes of wire bundles again but i'm dead certain now that has to be the only way.
At the moment i'm trying to find another 411 swap forum with excellent results in order to make a checklist for myself. Since I have no clue where the O2 cables should go or where have i attached them to. One thing i'm sure is that i've got some wrong pins...
I'll definitely get back with the results tomorrow but i'm sure I got this.

Ps: I have dyslexia (A.D.D.) so i always mix left / right , red / blue , etc...

Lsxford

iTrader: (6)

Doesnt LT1swap have these pinouts? Thats where i got the info to mod my harness and it all seems to work. He has a page with each pin, wire color, and what it goes to.

Mert Celet

I have all of them as well. And have used them. But this ADD thing is a real pita.

JoeNova

It could still be so rich that its tricking the O2s.

I figured up a cammed 5.3 last week and stuck the sniffer in the tail pipe. It was showing full lean on the wideband, and the O2 sensor mv were WAY low. The fuel trims were adding 25% fuel because it was showing so low. But it smelled like a rich pig. I also had a random misfire at idle every few seconds. Usually, it would stumble and die after cranking and firing. Sometimes I could get it to idle.

Pulled out 40% fuel at 400 RPM and 25% fuel at 800 RPM from the VE tables. Fired right up, idled like a champ. Started logging fuel trims and started on VE tuning from there.

Mert Celet

Think i've found the problem...
A year ago, i had bought new HO2 Sensors from Ebay. Installed them directly so i haven't checked them. Today i had pulled out one in order to compare with the takeouts.
The takeouts are grounded to the body of the sensor. But on the new ones, all four cables go into the body of the sensor...
Does any of You guys know the difference? Maybe those new ones are for LS3 or something?

Just Another Shitty Buy from just another ******* Ebay shop i guess...

jimmyp3353

iTrader: (3)

Your logs are reading lean. That isn't oil on the plugs, that's the look of plugs that are running suuuuper rich (black, sooty, oily looking). Which makes me think that your O2's aren't reading properly.

Edit:I just read your above post.

JoeNova

There are both case ground and isolated ground O2 sensors. You need the ones that match your PCM. The isolated ground sensors will all be ground to the PCM.

Mert Celet

No Problem Mam! Thnks for the help anyway!
But here comes another problem with KR. I had started a new thread on HpTuners Forum but i'll alsa post it here anyway also. Here it goes;

Hi Guys!

Seems that i've sorted out many issues with my LS1 & 4L60E swapped 1974 Pontiac Firebird.
The car has 1 1/78 LongTubes , Fast 92 intake with 92mm TB, 3inch tubes with X Pipe
(My Trick Flow 220 CNC heads are still at my garage)
Currently I'm running MAFless but i hope soon i will reengage it.

My problem is that i'm seeing knock (which i degraded sensitivity)
As far as i see my Commanded AFR and Current AFR do not match.

BUT I DON'T KNOW HOW TO LEAN OUT THIS RICH CONDITION!

Guys, this is my final step. I'll be more than appreciated if someone can just show me how to match my Commanded AFR to my Running AFR.
How can i lean the wot out?

Thanks in advance.