1BAD_LS1

iTrader: (36)

Ok bought this motor/pcm/harness off a guy.... ran good when i bought it.

Put it into a project car... first tried to start it nothing but cranking... diagnosed the problem, it was no spark... found out i forgot to hook up the crank sensor!! lol

Now the car starts but the idle jumped immediately to 3000rpm (does this about half the time) and just sits there. Sometimes it will start and idle fine, at WOT about around 4000rpm it breaks up bad and wont hardly accelerate anymore. I also noticed the dash lights, dome light, headlights fluctuate bright dim bright dim.. even at an idle!

Here is what i have tried:
Different TPS
Different IAC
Cleaned TB
fuel pressure is good
checked all grounds (frame to block, back of heads, battery to frame)
alternator seems to be putting out good voltage according to guage in car
no codes are being set off
No vac leaks that i can find, even sprayed starting fluid oeverywhere trying to find one lol


thinking maybee:
stuck injector
broke sparkplug
bad plug wire (although im running new msd's)
possible CASE relearn needs to be done since i cranked it without sensor hooked up)
a power wire possible shorting out somewhere
alternator bad (shows like 15 volts on the guage in the car, but doesnt fluctuate)
coil is bad
bad battery


idk just wanted to get some more ideas, maybee im missing something...

Thanks guys!

1BAD_LS1

iTrader: (36)

Bump!

LS6427

iTrader: (2)

Go get the battery and alternator checked first for free somewhere.

Also, the PCM-to-block ground wire being loose will cause problems too.

.

1BAD_LS1

iTrader: (36)

K, i have a new alternator on the way... I needed one for my other car anyway so ill throw it on the project and see if it fixes it.

Will try a different battery also...

I have checked all the grounds i can find... ill check them over again..

This has me stumped pretty good.... i have swapped 6 motors in these cars without an issue then this one came along lol....