Ok, Now What?!

[HisandHerTurbo]

Anyone want to help stop a murder suicide? LOL, OK, not that I have your attention. Guess what, still hesitation/stutter/mis-fire under boost.
Fought this for many many months, finally got ANOTHER brand new 255hp and it was good for 4 days! woot!, Then last tuesday morning it came back AGAIN! Wednesday I found a decent size crack along the weld in my Magnus. Got that fixed and assumed that was why it came back, cause friday before the dyno I did a boost leak test and nothing found, it was perfect. Well, crack fixed, but didn't change anything. Looked at the plugs and they were a little big (.030) so I lowered them down to .025. FP seems to be good, it's holding pretty strong about 70psi at 30 psi of boost. WB along with front o2 spikes lean (only like 12.4 or so, on RACE GAS).
I just don't get this? I want/need this fixed! I am leaving in a couple weeks to go back to iraq and I am lost. Please please please help me!!!

TY

JOE

[matthewdesigns]

Is the list in the first post from your other thread, as to what has been tested or replaced, current? If not, can you bring it up to date and paste it into this thread so we can see everything you've tried?

My first thought is to look at simple things, since you've been through the car so thoroughly over the last 6 weeks, like the fact that it's been raining a lot lately. Is the car garaged? Did you run through any big puddles prior to this happening? From what I've read, maf's don't like to be wet, but I don't recall what the issues are if that happens.

Maybe now that it's running strongly, your plugs aren't gapped down tight enough and you are blowing out spark? Seems to me you'd go rich at that point, though, not lean, unless your lean spike does not correspond with the misfire/stutter.

[HisandHerTurbo]

6 months total been messing with this

Fuel pressure is now holding, where as before it wasn't...... List of what all has been done/checked

New fuel pump
re-Wire relay replaced (also ran pump straight off the batt.)
Fuel lines blown and ran without a filter
Injectors swapped out
AFPR swapped out
CAS switched
ignitor (drawing a blank can't remember if that's what it's called....... little black box that is normally with the coil pack) swapped out
Tried my MSD Dis II, stock ing., COP, and known good coil pack and every combination of the 4
2 different times put in new plugs (that are now gapped to .025, see above post)
BASE timing is 5*
Base FP is 43.5
ABSOLUTLY NO BOOST LEAKS!
MAF is pretty dead on with calibration
Tried a different known good ECU
Tried a different MAF

It's not a water puddle thing, and yes it's garaged.

When I was at the dyno on friday (last week) it was strong as he**, 30-32psi FP perfect, 28* of timing no knock......
I am not sure if this is related or not, but I get decel back-fire..... I was thinking when I found the MAGNUS crack it was because of that..... guess not

Soooooooo, what are your thoughts? This isn't the first time I "thought" it was fixed....... but I do know FP was an issue, but that is fixed now..... well, I think as good as it's going to get. Later on I will post both a log I will do this afternoon and also a log from last friday after the dyno.

TY
JOE

[Overkill]

Its probably safe to assume fuel still since the new pump fixed it temporarily. You could be right on the threshold of your fuel capabilities and your car may be telling you to upgrade.

I say try a supra pump, bosch, aeromotive, etc as Walboro's are junk in my opinion. Even the OBX pump is supposedly good to 500 hp and only cost $175. Seems like a bargain considering the loss of sleep and waste of time you are experiencing diagnosing this still.

If you want to come up and try a brand new supra pump your welcome to.

Just my .02!

[HisandHerTurbo]

That would be nice to try........... BUT, isn't there like crazy modifications you have to do to get one in? Unless you have one already mounted to a 2G AWD sending unit.
Also, if I didn't have enough fuel wouldn't my fuel pressure be dropping? Like it was before?

[HisandHerTurbo]

Here's 2 logs.......... 1st one is from last friday long 3rd gear pull with the dyno tune right after I left the dyno......... everything perfect

2nd log, just through 2nd gear, done today. After I subtracted 6 "clicks" of fuel across the board thinking maybe the race gas was too rich. I also went back to an old file, since I wasn't sure if the "dyno tune" had the crack in the magnus or not.

Last Friday put the new fuel pump in, went around the block, everything was good to go. So, I did a boost pressure test, found nothing, went to the dyno.

Then last tuesday morning (4 days after it was good) I got the mis-fire/stutter/hesitation, Wednesday did another boost pressure test, found the crack along the beeds on the magnus, got it fixed......... and here we are.

[Overkill]

If I'm not mistaken you have an electric fuel pressure gauge, which in turn is not as immediate as a mechanical gauge. Your pressure could fall off and it happen a second after the stutter has already happened.

Spark blowout is usually somewhat violent where fuel shortage is not from my experience. It's either spark or fuel and the symptoms point toward fuel in my opinion. Try a boost-a-pump and see if you can get some more fuel out of that pump. I know you have a rewire, but they are not the same.

You probably answered this, but does it happen if you turn the boost down 2lbs?

[HisandHerTurbo]

Can't turn the boost down that low.........lol, well maybe I could if I loosened up the arm all the way....... etc etc........ but that wouldn't help/do anything even if it did not mis-fire........ what would that tell us? I can't run 34psi, but I can run 2psi.........lol, not running only 2psi.......hahahahha

I do have an electric step sweep aeromotive gauge. It used to show in my logs that it was falling, now it isn't falling. Also, if it was falling, I would go hella lean....... seen it before the new pump, but I am not going lean, only the quick spikes. Also........ electric may be "slow" but it doesn't take seconds....... and doing a complete second gear pull..... that would be long enough....... And lastly...... before the new crank/clutch, I didn't need a boost a pump.

And this actually is pretty violent takes an 11 sec car and makes it run only 13's if I stay in it the whole way.....lol

AND IT WAS JUST FINE FOR 4 DAYS!!!! UGGGGGGGGGGGGGGGGGGGGGH

[Overkill]

I meant turn the boost down from 34psi to 32psi. Don't make me get out the crayons!

Your still not comparing apples to apples from last year. Your clutch is lighter now! :-P

[HisandHerTurbo]

hahahahaha yeah, I can try that..... that's about where I was at after the dyno (30-32) little higher right now..... even with the mis-fire. tomorrow I am going to buy yet another set of plugs, try that, then lower the boost.... then when neither fix it...... drive off a bridge..... hope my air bags work..... probably wont

[Cloud]

I would give the 8 heat range plugs a shot and gap them around .22 or so. I knew a few guys who swore that was the only way they could keep spark regular over 30psi.

[HisandHerTurbo]

TY ALL!!!

My less then 2 month old and less then 500 mile spark plugs were grap! I replaced them with some new BPR7ES at stock gap .030 and all it well! WOW, I know we are lucky that the best plugs for our car are cheap........ but damn....... I just put them in!
OH WELL, who cares I'm good!!!

PS CYA all at Bandi on Wednesday!