LT1 24x RH bank too rich, fuel plugs 6,8 and 7!

[Christian GM]

hello guys,
my setup is 96 LT1, Eagle 383, Golen LT4 heads and ported intake manifold, EFI connection EARLY design 24x with 58mm DBW throttle body, Ford 30 lbs skinny red top injectors, Hedmann shorty headers, 3" magnaflow exhaust. fuel pressure regulator with new diaphram set at 58 PSI. GM LT4 hot cam kit, comp camp 1.6 rockers
car can't be driven on the open road since there are no hood, fenders, door, interiors and so on - just a small 150 meter trip on the backyard when no neighbours around.
I'm just trying to have the engine running good at idle to send the car to the body shop ASAP. I had hard time starting the engine due to various issues.
already check all wiring (3 times!) from ECM to injectors and coils and O2 sensor for proper connection, firing order, correct continuity and so on. everything ok
already swapped side by side all injectors, no changes, all coils no changes, O2 sensor no changes
already plugged vacuum source to Brake booster, no changes. 3 times checked MSD wires, all at 35-40 OHM of resistence, checked also inj impendance all at 15.9 Ohm
crank and cam signals are OK with scope and timing is ok dot to dot. rocker arms adjusted one by one and checked 3 times
2 weeks ago replaced intake manifod gasket adding a small lip of RTV Permatext 80003 (resistent to fuel designed for intake manifold too) because it not match perfectly the head on the bottom.
bank assignment on HPtuners is ok.
I try SEVERAL setup adding and removing timing or tweaking VE. I ALWAYS have RH bank reading really rich at start up above 900mv, then the fuel trims starts to work ... but clearly something is wromg. the engine react to the changing in the tune, but it's something else....
see the latest tune, log, and photo of the plugs. I put NEW plugs were fouled to check everytime I change sometthing 15 minutes at idle and same results.
I SUPPOSE plugs 7 and 8 can be fouled at idle due to manifold design, it is stock ported.
but no sense on plug 2 and 6.
any experience to share guys?
thank you so much
bye

[IARLLC]

Hi Christian. HAPPY NEW YEAR!

Maybe this is not it if it is running that rich before the oxygen sensors get to start affecting things but under Fuel>Oxygen Sensors>Rich/Lean vs Airflow Bank1 is set to run leaner than Bank 2 throughout the whole airflow spectrum. Maybe that affects LTFT learning once it is warmed up.... then when it is cold LTFT adds more to bank2? Might be worth it to even the two tables out unless there is another reason for it.

Side note: The timing at idle seems much higher than I am used to which could lead to a miss at idle. Actually I am surprised it can take that much timing all of the way up (34 up top). I was thinking that the LT4 heads were already starting to use the "fast-burn" technology by then...but I don't remember well. Maybe the L31?

[Christian GM]

Hi Christian. HAPPY NEW YEAR!

Maybe this is not it if it is running that rich before the oxygen sensors get to start affecting things but under Fuel>Oxygen Sensors>Rich/Lean vs Airflow Bank1 is set to run leaner than Bank 2 throughout the whole airflow spectrum. Maybe that affects LTFT learning once it is warmed up.... then when it is cold LTFT adds more to bank2? Might be worth it to even the two tables out unless there is another reason for it.

Side note: The timing at idle seems much higher than I am used to which could lead to a miss at idle. Actually I am surprised it can take that much timing all of the way up (34 up top). I was thinking that the LT4 heads were already starting to use the "fast-burn" technology by then...but I don't remember well. Maybe the L31?

thanks!
I try to put different values on bank 1 and 2 to see if this can makes any difference, but it's not. I have the same issues with equal values with LS1 values or Vortech Express values, no changes.
also no changes regardless of timing.
I suppose I still have issues on sealing the intake manifold... but going to a machine shop is not an option...

[DGS]

https://www.grandsportregistry.com/lt1vslt4_intakes.htm

[Christian GM]

it's a damn intake manifold leak from the bottom.
I pulled it out during launch
will upload pictures and more info ASAP, hopefully late evening or tomorrow
bye

[anniversaryss]

Interested. I think I might have somthing similar. How did you figure this out?

[IARLLC]

No fun...but at least you got it figured out.

anniversaryss wrote, "Interested. I think I might have somthing similar. How did you figure this out?"

With the PCV valve blocked there will be a strong vacuum on the dipstick, sometimes the front crank seal will even whistle as air is sucked in past it.

[anniversaryss]

So your saying hook up a guage to the dipstick and look for vac?

[IARLLC]

That is one way (to the dipstick tube). Usually it will be pretty obvious if the dipstick is harder to pull out with the motor running than turned off (important to plug off the PCV to be sure there is only one reason for vacuum in the crankcase).

[Christian GM]

I already know my intake manifold was not working good.
I found a machine shop to remove 0.040" from the china wall plane on the manifold, enlarged the bolt holes and now looks is everything ok
will be months before the body shop will finish it....
but now I can take it to him!
tnx
bye

[anniversaryss]

Are your heads milled? Christian

[DrLoch]

Are your heads milled? Christian

and/or the deck cut? I cut my deck to 9.00 on my LT1 to get my pistons to zero at TDC in which case I had to cut the china wall and the intake face of the intake manifold to get it to fit correctly.

[anniversaryss]

and/or the deck cut? I cut my deck to 9.00 on my LT1 to get my pistons to zero at TDC in which case I had to cut the china wall and the intake face of the intake manifold to get it to fit correctly.

I believe I'm still at stock deck height on the block but my heads were milled .020. I was told that's as far as I can go before messing with the intake. My rear two passenger bolts were kind of a pain to get in but they went.
This makes wonder if I have some sort of leak issue.

[cobaltssoverbooster]

Sorry its not important but i saw the intake and shaved heads comment and remembered this ass hat i had to deal with in the past. Maybe you all can get a good laugh.

i used to work for a race parts supply chain. our policy on returns was pretty lenient but i remember this one time a self proclaimed "ls master", really a total ass hat, started returning parts for ls stuff claiming they didnt fit correctly and the total was in the like $8000 range. My best salesman who has a rx7 with a twin turbo ls1 swap running high 8s and tuned it himself sold this guy everything. I knew this was all the right shit but couldnt figure out why. So, naturally my boss and i got curious and tried to figure out what the hell was going on to try and resolve a customers issues, but more importantly make sure this guy knew what he was doing.

The company employing me was big in the race parts industry and i needed a new non-running floor display motor for a huge annual car show event. Just had all these returned parts we didnt know exactly what to do with so i decide to slap together an empty ls engine as a show piece while using the returned parts to verify the fitment claim. I assembled it in a few hours, everything fitted perfectly. He came back into the store and we showed him the motor and pulled him into the managers office to discuss the high dollar returns. Turns out this ass hat shaved the heads really hard to get a compression ratio of ~13:1 and now had major alignment issues. The heads sat so low the brackets for the front drive wouldn't bolt up. More importantly, the intake wouldn't even come close to sealing. With light of the parts not having any manufacture errors and this completely being his fault we gave him two options. Option 1 was to pay for all the parts and we would give him everything back at 15% off because we had used them all as a show pieces which means they were not going new in box quality. The second option was to decline option 1 and loose his shop account status for 1 year. Option 2 didnt mean he couldnt purchase anything under his shop account, it just meant he wasn't granted the certified shop discounts.
This guy, needing the discount to make the most of his business takes option 1. As he left we told him he needed to go back to a stock or off the shelf new head because he shaved wayyyy too much off.

At the next car show i see this guy and a new ride i had never seen from his shop before. Lo and behold its the motor he returned stuff for. Everything was modified to fit and the damn intake manifold had 3 intake gaskets under it....you know the felpro LS3 composite ones (Felpro 1222-2)....yeahhhhh i laughed so hard it was audible a few cars away which got an instant rise out of him. I told him he was stupid for not listening to my advice and that i gave his motor 3 weeks or less before it blew up. He comes in 2 weeks later and avoids the shit out of me. I ask my co-worker who sold him some stuff what he was looking for....turns out one of those intake gaskets let go and leaned the motor out on the dyno which caused it do burn a piston and wipe out 3 cylinders making the engine a total loss. He asked for a gm crate ls engine and a plug n cruise kit to go with it.

that dude is exactly why i listen to my engine builders comments and always supply manifolds when i get machine work done.

[DrLoch]

I hear ya, been there, done that. I've run into that situation a number of times, enough to have purchased the correct fixtures needed to hold the parts for machining. Big thing is to make sure the machine is dialed in or you're going to have a whole new set of problems.

When I cut the intake to cylinder head sides of my LT1 intake manifold it was a pain in the ass, took 3 separate cuts to get it right since I'm boosting and didn't want to take off to much and do the multi gasket thing or make spacers.

Engine 1.jpg

There is a LT1 under all that stuff.

[cobaltssoverbooster]

Clean install. Wish I had that kind of room

[Christian GM]

yes they're. Chad Golen Engine Stage II

[anniversaryss]

yes they're. Chad Golen Engine Stage II

How much are they milled?