help!! with idle and spuddering prob. after swap

LSvtecboi

New Member
ok this is my situation...
i bought a 96 gsr shell and a auto LS motor(convert to manual) to go into the shell. i did the conversion and the swap my self and had no problems starting it up but.... i can get it started but the it idles at like 100rpm and spudders and backfires when i press the gas.... when i release the gas pedal it stalls out... it will drive but it has absolutely no power and will only rev to a max of 5500rpms with the pedal to the floor.. before i did the swap the motor ran perfectly fine and had no problems before i pulled it... even though the car runs it only runs well enough for me to get to barely get down my road in my neighborhood and back...
things i have tried to do to fix it...
fresh gas
fuel system cleaner
move the dizzy to fix timing

does anyone have anymore suggestions...?

when i didnt the auto2manual conver. did i have to get a new ls ivac for my TB.?

please help i really want to get my project on the road and i have been searching and searching online for help and can't find any..
 

Kuchtaboy

Unregistered User
make sure the spark plug wires are going to the correct cylinders?

I had that problem on my first teg.

also, is it the gsr/auto computer? I'm not sure what a gsr computer would do on a ls motor, or if it would even bolt up for that matter.. and the auto would at least throw a code for the torque converter, but I don't know anything else.

I say check the wires first... just make 100% sure you are on the right spots on the distributor.
 

mteg

Automatic Lover
Map sensor not plugged in or going out? Are you throwing a code?
 


LSvtecboi

New Member
all my sparkplugs are in the correct position...

i do have a CEL on but it might be from an o2 sensor because i have a plug after my cat that doesnt have a place on the exhaust for another o2..
 

Kuchtaboy

Unregistered User
that shouldn't regulate how the engine runs, tho it could explain not reving past 5500. Your car isn't seeing that second signal and it might put it into limp-home-mode because it thinks it's in danger.

Try and see what code(s) it is throwing. It's going to be at least a cat-code (because of the second o2 sensor), but it could also be something else.

check to see if the dizzy is making spark to all the cylinders. you might need to replace that... it sounds like some sort of mis-fire... now if its fuel, or spark related is the question..

do you know how to check for spark?
 

LSvtecboi

New Member
yea i know how to test for spark with the screw driver.
 


LSvtecboi

New Member
ok i tested for spark on all my wires and all of them were getting spark.... i removed my sparkplugs and checked them and it looked like the #2 and #3 cylinder plugs were black and the #2 looked like it was wet... #1 and #4 didnt look that even half as black as the others...


thanks for everyones help in advance...
 

Kuchtaboy

Unregistered User
did you do anything to the motor with the swap? like, take anything apart before swapping it in?
 

Kuchtaboy

Unregistered User
check your spark plug seal tubes. If oil leaked thru that when you took the valve cover off it can cause a miss fire just like that. (happened on 2 seperate friend's neons. lol)

I'm willing to bet that's your problem. take the vc back off, check the seals. if you really want to you can put some rtv on the seals to make sure they don't move when you put them back on.

When you have the vc off make sure you get all the oil out from the spark plug holes and what not. see if that helps.
 

LSvtecboi

New Member
would that also be the cause for it only reving to 5500 with the gas on the floor or by hand with the throttle spring?
 

Kuchtaboy

Unregistered User
might. :shrugs:

lets get her runnin on all 4 first tho. then we can dive into the next problem.
 
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