I dont know what to do here guys. Im posting this here cuz frankly you guys seem to be more helpful than the DIY guys at least at general questions. So heres the problem. I just built a 383 Stroker with a LT4 hot cam (218/228 .525/.525 112ls) The motor has the stock computer... Which I plan on fixing I know this will effect things drastically... But the problems remain... When driving at around 1000-2000 rpm the car SOMETIMEs runs very poorly... I would say when running in closed loop (when cold I think thats closed loop right?) When cold though the car will run great awesome throttle response not sluggish at all... However, after just a bit of driving the car becomes a ford pinto... The thing just bogs and bogs its sluggish and at steady throttle actual acceleration is uneven.... Until again like 2k where it begins pulling hard. So... Whats going on here... I have timing at 8* advanced last time I checked I have an adj fuel regulator no gage (yet one in the mail) I adjust the nut on the regulator down too far, the car just will suddenly die... So I tried setting it just before that point, same problem I can also smell access fuel that makes me think its running rich... If I back it way off to where it barely touchs the spring in the regulator (or doesnt at all) The car still runs with the same problem... Ive tried in between but again no gage to fine tune.... Anyone have thoughts here... Could the fuel pressure have changed my timing??? No way right so could I just need to get the pressure within literally like a quarter turn to make the change I want... Or is this in the chip.... I dont have much tech info yet... Just the smell of excess gas Ill get some sort of scan tool as well as equipment to start making my own chips but can someone please please help
Paul

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90 Red Convertible
100k running great
ZAINO!!!
383 Stroked.... LT4 Hot Cam... Forged Elgen Pistons Scat 9000 Crank Elgen 5.7" rods New Lifters w/ 1.6 Rockers and hardened Pushrods Super Ram Intake Hooker Headers and Y pipe into Gutted Cat with Monza Mufflers (WAY TO LOUD!!) Adj Regulator K&N Shift Kit High stall converter 160 termo, ZR1 Rims.... Red Calipers....Alpine head unit, Kenwood 6x9 4 ways, Polk DX 6 1/2 compnents, MTX 240 amp, Viper 550 alarm,


www.corvetteforum.net/c4/nomar116/

 

What kind/size injectors are you running? Without a doubt, you will need to make or purchase a custom PROM if you ever want it to run correctly. Your part throttle fuel and timing characteristics have changed and the ECM can only compensate so much. If it's still running too rich even with the pressure backed all the way off, then the injectors are too big and the constant will need to be changed in the prom as well. But also, be sure to check for basic things like a misfire caused by the ignition system first. Hope this helps.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

I like the thought of the injectors being to big, However they are stock and are barely large ENOUGH.... I would think anyway... However, I did think that my O2 sensor could be causing problems... I had added a heated sensor to my car by following some tips and installing one wiring up the ground and electrical connector, but never connected the power (couldnt locate an ignition one...) Anyway, I hooked that up tonight and it seemed to smooth things out quite a bit....

Does that make sense?? It would to me if the O2 sensor wasnt working, wouldnt the ECM read 0mv and think a pretty damn LEAN condition, and over compensate with additional fuel... So no matter the setting at the regulator it just pumped it up.... Im going to continue to check into this whats everyones thoughts???

 

nomar,
your injector size should be between 22-26lb
throttle body 52mm, ignition timing start @
8-10*. the O2 problem... hook the power wire
into the fuel pump relay. to cold O2 start
is 200-300sec before it even engages. on warm
O2 starts 50-75sec.
to find out the culprit, get a scanner and some
one on the other end of to read your tps, O2
BLM/FI and map voltages. id bet your running
12-18% to fat in fuel, fuel pressure who knows.
that same scanner person should have a pressure
gauge, turn it to 42# idle. and rescan.
you are in the unknown territory because too
many things have changed...