momentary leaning out
08-29-2014, 12:09 AM
#1
Le Mans Master
Thread Starter
momentary leaning out
i'm working on my stock 2000 LS1 that just rolled over 60kmi last week. well, the engine's stock, but i've got ARH long tubes/X & a TVS2300 blower since 45k.
a few weeks ago, i all of a sudden started getting a momentary lean condition when rolling into the throttle. it starts out fine for 1-2 seconds, leans out for roughly 1 second, then the A:F catches back up until i let out. that timeline is roughly the same every time for these events & the severity is based on how open the throttle is.
for example: when just putting through town, accelerating at 10inHg or less, it'll lean out to roughly 16-16.5ish. when getting on the interstate, passing, etc near 0inHg or in boost, i've seen the wideband jump to 18-19+. even saw 21 a time or two. i'll let off when it starts hesitating & either shift or lightly roll back into it, and it seems to catch back up by that point & maintain 14.5-15 (or lower if i'm still accelerating).
the only thing that changed on the car when this started happening was when i swapped my pulley configuration, but i ran the numbers & the new setup is less than 2% faster. that's less variation than day-to-day atmospheric differences, so i doubt that could be causing my problem. when i asked my tuner (who's now half a country away since i moved), he instantly thought slow front O2 sensors - i'm pretty sure mine are OEM (15yrs old with 60k). it made sense even though i ain't got any codes, so i grabbed a couple new AC Delco 19178930 sensors & put them in tonight.
the old ones looked like normal used sensors - not excessively black or gray, and the wires looked fine from what i could tell. the funny thing is that it's a little better now but still doing the same thing.
thoughts/opinions/suggestions?
a few weeks ago, i all of a sudden started getting a momentary lean condition when rolling into the throttle. it starts out fine for 1-2 seconds, leans out for roughly 1 second, then the A:F catches back up until i let out. that timeline is roughly the same every time for these events & the severity is based on how open the throttle is.
for example: when just putting through town, accelerating at 10inHg or less, it'll lean out to roughly 16-16.5ish. when getting on the interstate, passing, etc near 0inHg or in boost, i've seen the wideband jump to 18-19+. even saw 21 a time or two. i'll let off when it starts hesitating & either shift or lightly roll back into it, and it seems to catch back up by that point & maintain 14.5-15 (or lower if i'm still accelerating).
the only thing that changed on the car when this started happening was when i swapped my pulley configuration, but i ran the numbers & the new setup is less than 2% faster. that's less variation than day-to-day atmospheric differences, so i doubt that could be causing my problem. when i asked my tuner (who's now half a country away since i moved), he instantly thought slow front O2 sensors - i'm pretty sure mine are OEM (15yrs old with 60k). it made sense even though i ain't got any codes, so i grabbed a couple new AC Delco 19178930 sensors & put them in tonight.
the old ones looked like normal used sensors - not excessively black or gray, and the wires looked fine from what i could tell. the funny thing is that it's a little better now but still doing the same thing.
thoughts/opinions/suggestions?
Last edited by _zebra; 08-29-2014 at 12:15 AM.
08-29-2014, 12:11 AM
#2
Le Mans Master
Thread Starter
or am i maybe looking at a problem with my MSD boost-a-pump? i ain't got a way to monitor fuel pressure, so i don't know how i could check that one for sure.
08-29-2014, 05:57 PM
#3
Le Mans Master
Thread Starter
alright... from what i understand, the BAP either works or it don't, so now i've done what should've happened first - sprayed out the MAF & made sure the MAP didn't pop out.
that's all done, but i've still got the same issue.
any ideas yet?
that's all done, but i've still got the same issue.
any ideas yet?
09-03-2014, 02:37 AM
#8
Burning Brakes
Hi bud
Crap problem
, just a thought I used my iphone to vid the throttle body plate to make sure is was smooth in operation , pulled the air bridge and propped the phone aiming at the plate hit record then pressed the go pedal .
o2 sensors would have been my choice as well .
I got a pretty good fuel gauge of ebay can take a pic of whats involved if you need it.
Cheers mate , oh and no I don't come to this section much
Crap problem
, just a thought I used my iphone to vid the throttle body plate to make sure is was smooth in operation , pulled the air bridge and propped the phone aiming at the plate hit record then pressed the go pedal .o2 sensors would have been my choice as well .
I got a pretty good fuel gauge of ebay can take a pic of whats involved if you need it.
Cheers mate , oh and no I don't come to this section much
09-04-2014, 12:59 AM
#9
Le Mans Master
Thread Starter
sorry... spent the last couple days driving cross-country again.
checked the fuel pressure this evening.
original fuel pump because the shop manager who did the blower install decided on his own that a boost-a-pump would get it out faster than waiting on the backordered Aeromotive that i specifically said i wanted.
58psi as it primes then 56psi when the pump stops with the key on/engine off. 58psi with engine running & throughout any rpm in neutral. with part-throttle revs in neutral, i still got the same leaning-out with a constant 58psi
that'd be nice if you don't mind. is yours fully SD tuned? otherwise, wouldn't the A:F be weird with the MAF disconneted?
original fuel pump because the shop manager who did the blower install decided on his own that a boost-a-pump would get it out faster than waiting on the backordered Aeromotive that i specifically said i wanted.
58psi as it primes then 56psi when the pump stops with the key on/engine off. 58psi with engine running & throughout any rpm in neutral. with part-throttle revs in neutral, i still got the same leaning-out with a constant 58psi
Hi bud
Crap problem , just a thought I used my iphone to vid the throttle body plate to make sure is was smooth in operation , pulled the air bridge and propped the phone aiming at the plate hit record then pressed the go pedal .
o2 sensors would have been my choice as well .
I got a pretty good fuel gauge of ebay can take a pic of whats involved if you need it.
Cheers mate , oh and no I don't come to this section much
Crap problem
, just a thought I used my iphone to vid the throttle body plate to make sure is was smooth in operation , pulled the air bridge and propped the phone aiming at the plate hit record then pressed the go pedal .o2 sensors would have been my choice as well .
I got a pretty good fuel gauge of ebay can take a pic of whats involved if you need it.
Cheers mate , oh and no I don't come to this section much
09-04-2014, 02:31 AM
#10
Burning Brakes
Morning mate
Hope to get car back from tuner Saturday so will try and take pics then.
Yeah full SD tune 2 bar map , no maf . Did a street tune then wanted to take it up to 180mph so used the dyno . First pull and the drive belt shreadded on the two front ribs , so that was that 
Conservative tune 640 RW no meth.
Because of my 10% crank pulley etc not many belts lengths available
but the tensioner was in the tight side of the range .
Will have to go over it when I get it back.
Hope to get car back from tuner Saturday so will try and take pics then.
Yeah full SD tune 2 bar map , no maf . Did a street tune then wanted to take it up to 180mph
so used the dyno . First pull and the drive belt shreadded on the two front ribs , so that was that Conservative tune 640 RW no meth.
Because of my 10% crank pulley etc not many belts lengths available
but the tensioner was in the tight side of the range .
Will have to go over it when I get it back.
09-07-2014, 12:04 PM
#11
Burning Brakes
Hi mate.
This is the fuel gauge sensor 1/8th npt , you will need to put it in the rail , I have put mine in this hose , two wires go to gauge then its just
ground and key on +
Not sure how accurate these are but think at least their consistent in operation.
This is the fuel gauge sensor 1/8th npt , you will need to put it in the rail , I have put mine in this hose , two wires go to gauge then its just
ground and key on +
Not sure how accurate these are but think at least their consistent in operation.
09-08-2014, 02:29 AM
#13
Burning Brakes
No prob , another thing crossed off the list
I have a PLX wideband with a gauge and left and right bank sensors.
That might be handy in your situation ??
I have a PLX wideband with a gauge and left and right bank sensors.
That might be handy in your situation ??
09-09-2014, 04:12 AM
#15
Le Mans Master
Thread Starter
yeah, mine ain't quite as specific as yours, though.
i've just got the standard single in the X-pipe about 6-9in downstream of the front O2s.
it's an Innovate MTX-L
i've just got the standard single in the X-pipe about 6-9in downstream of the front O2s.
it's an Innovate MTX-L
09-23-2014, 06:47 PM
#16
Supporting Vendor
Pressure check everything. Cap off the inlet on the other side of the MAF, remove the brake booster line (leaving the check valve out of it) and hit it with some pressure to make sure you have no leaks.
I don't tune 99.9% of the boosted cars that I tune with MAFs. 2/3 bar SD is the way to go when done properly.
I don't tune 99.9% of the boosted cars that I tune with MAFs. 2/3 bar SD is the way to go when done properly.
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Offering products from A&A Superchargers, East Coast Superchargers, Mechman Alternators, Mantic clutches, RPS clutches, Kooks Headers, Lakewood, LG, Brian Tooley Racing, Comp Cams, FAST, ARP, UPP Turbo systems, Wiseco, Callies, K1, MAST Motorsports, Haltech and many more. PM me for details.