daniel6718

iTrader: (36)

ok i been looking into thing after thing and replacing parts with other parts i have sitting around and im prety knowledgable on lt1 just cant get this figured out

bought this car with no motor/ tranny and i completely rebuilt it and out it in with a 6 speed, cars a 95

the car was stock a ran great, but it had the knock sensor bypassed with a resistor for a solid roller, so it had no down low but alot of up top power, stock pcm btw,

so i had some longtubes and out them on and removed the resistor for the knock sensor, and the fuel gauge was wrong so i removed the pump and replaced the whole bucket assembely and put in a new walbro pump since my sock on the old one fell apart and trached it all up, i replaced the filter and boom car was back on the road, but now it seems to have no power...fuel pressure is good, car runs smoothe (idles at about 1000 and kinda rough) but midrange is perfect just at about 4k and above it doesnt pull very well

i know as long as its smoothe it can only be 2 things right? loss of fuel pressure, or timing related

well i checked the knock sensor and its reads within speck, replaced icm, changed to another opti check for vacume leaks, changed fuel filters ect, i cant figure it out

next is when the car gets to half way idleing for a while it will spudder idle up and down and up and down then finally die, anyone have these 2 symptoms before?

ThoR294

iTrader: (6)

check your throttle body and IAC passage for any carbon or **** in there. that might help the idle

as far as mid range and no top end, check your timing, might be a problem.

daniel6718

iTrader: (36)

yeah but you cant change timing? weird

ThoR294

iTrader: (6)

you can, thats why you have to check to make sure its on timed correctly

daniel6718

iTrader: (36)

how can you change timing on a lt1? its computer controled for one...and distributor only goes on 1 way

Ralls

iTrader: (32)

When you say idling for a while, is it going into closed loop? I bet if you get a scan tool on it, you will see something act funny once it decides to fluctuate then stall.

You said your fuel pressure is good, I assume you checked it at WOT? I would run some fuel injector cleaner in case it's clogged injectors.
If fuel and fire is working correctly, then compression would be next. Do a compression check.

ThoR294

iTrader: (6)

the timing chain can jump or tooth or so. that'll effect your RPM ranges.

daniel6718

iTrader: (36)

the motor is fresh rebuild with new parts, about once a week/2 weeks it runs GREAT (if the car sits a few days) until i kill the car then when i restart it runs like crap again....
its something getting hot and shutting down, i tried looking at it on a scanner i was throwing high res pulse and low res pulse failures, and ground circuit fault, then i changed optis, and found the ground wires next to the coil was loose (i think was the problem the whole time) and codes went away but problem is there...

infinitebird

iTrader: (11)

Could be the ICM over heating. Have you done the cooling mod?

ThoR294

iTrader: (6)

the ECM could be heating up. A loose ground will do a lot of **** to you. Get those infrared temp guns and check out how hot your computer gets. Make sure all of your grounds are good around the car.

clamato96lt1

iTrader: (2)

yeah check your icm or coil

daniel6718

iTrader: (36)

checked out grounds they are good...
the icm was changed to a differant one with the cooling mod and its still doing it

i just went and checked fuel pressure weird, the other day it was 45 at idle and 40 at full throttle....now its 30 at idle 35 with no vacume line and 25 at full throttle...so i know why it has no power, problem is i have a walbro in the tank(no hotwire kit) i think it should support a stock motor with bolt ons...i have 2 other regulators on extra fuel rails sitting around...im goana try them...but i dont think thts the problem, i put a new filter on it about 5 days ago...so yall guys think i need a hotwire kit? or somethign else?

Ralls

iTrader: (32)

You should check the voltage and amps at the fuel pump to see if you need a hotwire kit. Racetronix says the factory harness will give ~13.24 volts and ~7.7 amps.

daniel6718

iTrader: (36)

i do have a volt metter and amp meter...see if i can rig somethign up tonite...

ThoR294

iTrader: (6)

This could be a problem with fuel flow (GPM which is Gallons per Min) instead of PSI.

http://emi-tech.com/fsa/

This is the tester we used at school, it showed the FLOW of the fuel AND the PSI of the fuel. We diagnosed a shitty running ford ranger because of a pump pickup that was going bad.

Ralls

iTrader: (32)

Pretty much the only thing that will cause low fuel pressure is the fuel filter, pump, fuel lines, and regulator. You replaced the pump and filter, now try your other regulator like you said and see if any lines are kinked. If you dropped the tank, you could have squished a line above the tank when putting it back.

Let us know on the fuel pump volts and amps.

SEXICAN

iTrader: (1)

i really doubt its any of that considering it was running fine before any mods. umm i would put it on the scanner and drive around to watch the knock retard or look for lazy sensors, but if you already know the fruel pressure is low i would start there, cause theres only one thing that controls fruel pressure, vacum right? other than that it would be 1) mechanical or 2) electrical, but i don't think you need the hot wire kit cause the stock pump would hold bolt ons but i would look into a frayed wire but i doubt it cause your **** about your car and you woulda noticed it when we wired the car up! so how about any thing that would send signal to the pump like under the dash, lose connector or bured wire?

daniel6718

iTrader: (36)

thanks alot scott...its either old worn out wire not being enough, or regulator...or leak inside the tank...i can test regulator easily with another spare rail i got here...if it changes then ill simply change regulators...if not its back into the tank for time number 7