I filled up the car with e85 a few days ago and a minute after starting it , it started running rough again.
Hooked it straight up to the pc and she was running super lean. The flex fuel sensor mustn’t be working. I drained most of the fuel out and filled with petrol and back to running well. I don’t know if this was part of the problems I’ve been having. Will get new flex fuel sensor and try runnin e85 again

 

Im still having problems, I replaced both o2s again, checked earths, dont know whts gpoin on
in the scan , it will show im cruising at 1900rpm then out of no where the o2s read -21%, so the ecu feeds it.
When i accelterate from a stop itll chug a bit then all of sudden itll come good and away i go
I checked fuel pressure and the reg showed it at 60psi when key on but once turned of itll bleed down in a few seconds
I think its electrical due to it being good one minute then trouble the next.
ive attached the log

 

Mick, hook up fuel pressure gage and fix it to windshield. Monitor fuel pressure while driving to see if fuel pressure is steady when engine runs lean to eliminate possibility of pump going bad or issue with B+/ground wiring to pump.

 

I’ll try that.... I don’t hv an issue with it running lean , my stft shows it’s 20% rich..... I’m at a loss at whts causing it...

 

Have you checked your intake manifold bolts, could be a small erratic vacuum leak from the intake gaskets. I've never bother torque the plastic intakes as they just end up getting loose and need retightening a bunch of times. I just snug them down carefully by feel with a 1/4" drive ratchet. They're such a small intake bolt size on the LS i'm always been afraid i will snap them or strip the threads if tighten it all at once so i just tighten snug then i go back and do it again several times as the rubber gaskets sit and compress. By the time the engine is in the car and has done some street time i probably end up tightening the intake 5 times over. They are not like an old school alloy intake manifold with paper gasket where you torque it down once or twice at the most and it's done. After racking up some miles and some heat cycles the LS rubber intake gaskets compress and always end up loosening and need retightening. For me it ends up at the point where the plastic intake surface is pushed hard up against the head surface to the point there's no gap between it then they always stay sealed after that.

Not sure how strong the MSD intake is compared to the factory one piece intakes, you could put a crack in it maybe so go easy on it.

Also check your TB gasket that a part of it hasn't been sucked into the intake. Remove air filter and open the TB full throttle by hand and look inside around the perimeter make sure there's no gasket hanging over. Happened on my 102tb as i ported the opening on the factory ls7 intake i'm running and the factory green o-ring gasket got sucked in a little in one spot and caused high idle. I made my own paper tb gasket and used rtv on it haven't had a problem since.

 

I check manifold bolts regularly. Im confident thereall tight. It has to be a sensor, or something in engine harness. Itll be 20% rich at odd times , then ill stop the engine and next time i restart itll be 20% lean. It did do something odd yesterday , i started it and it died a few times, the map started climbing and kept going till engine died, i was at idle , my son was keepin an eye on fuel pressure. It did that tw.ice. Bank 1 o2 seems to oscilate normally, bank2 seems to hover around 450mv only going up or down by 20 mv either way
Ill try a new map sensor and see if tht helps

 

Problem solved!!!!!!! After seeing the map sensor act erractically , i thought id check my grounds. Pulled them all off , checked them, I didnt find any ground wires broken, gave them a bit of a clean , bolted them all up , no more problem... Dont know why but who cares ,

 

Just disconnecting/reconnecting takes care of it quite often. I have a taillight that pulls that crap on me on occasion.

 

Sounds like the old Bud Dry commercial: Why ask why?!!!

 

Why dont we see any slide manifolds used on builds?

 

Im getting a whining noise from rear end when coasting/not on the throttle, it doesn’t happen when I hv the clutch pushed in….Am I rite in thinking that it’s my gearbox and not the diff?
Could it be Tyre’s?

 

So it was the pinion gear, I had it replaced and while in there put 3.73 gear in it. So much better than the 3.45, can actually use 6th now.
here’s a pick of the gunk you get in a good catch can setup. , after 2 months I got half cup, 80% is water, 20% oil… why would you want tht going thru your intake n thru your engine

 

I lost 3rd gear so I pulled the engine and gearbox out together put new gearbox on the engine and dropped it back in the car. I only disconnected the engine harness from the ecu and left the harness on engine when I pulled it, so when it went back in I just had to plug it into the ecu and do a few grounds
now when I go to start it I’ll hear the dbw throttle body making strange noise which stop when I push on the throttle pedal then when Itry start it , it will fire straight off but won’t catch and keep going , it won’t spark after the 1st time it sparks if u get my drift
i pulled the spark plugs and they were wet, checked grounds, checked to make sure all wiring was hooked up correctly , don’t know what’s going on

 

So i dropped a lifter 2 days ago. Im thinkin of going back to hydraulic. Seems i get about a yr out of it before i hv problems... I crank out to many miles ....If it was just springs once a yr thtd be fine but it wwent 11 months so i didnt get to yearly spring change, so now instead of costin me $800 iull be up for $3500, cam, springs, head gaskets, lifters rebuilt

 

If this is your daily driver you need a more conservative build.

 

So how many miles are you doing a year? You went through the springs and rockers? a year ago or so…did you mess with the lifters back then?

 

What lifters were you running? Problem is probably a combination of the lobes/spring pressure/lifter combo.
What oil also? There are guys putting miles on solid rollers, I've talked with them, but it's all in the combination.

 

I run crower lifters and use driven 10w40semi synthetic oil. In December last yr it had new lifters , new cam motion llsr cam, new pac 1209x springs. New yt rockers
I would hv done 15,000miles

 

As much as I love Crower stuff, I think the BAM or Isky Red Zone lifters are better suited for what you are doing. Che70velle/Darth can comment more from experience, but me personally I would run a thicker oil. I am huge Mobil 1 15-50w fan for street cars getting beaten on. Cam Motion knows what they are doing, I don't think that's the issue. I know you had a spring wear issue, how did this set hold up?

 

I will check my spring pressure so I know how they went.
my mains clearances are .0028 so I don’t know if I should go to a 50 weight and I’m using driven because a semi synthetic is supposed to be better when running solids.
I will be changing spring manfacturer . I talked to mamo last month and he’s going to spec me a cam specifically for the nationals dyno comp. I’ll decide after that if I’ll stay solid or go hyd