Hello, Im at a loss as where to go from here.
We put a 350 into our jeep from a 90 tpi using a howell stand alone harness.
Motor rebuilt from block up using stock internals cam etc. New sensors all around. fuel pressure is good, brand new south bay bosch III injectors as well. Problem is when starting it cranks for a long time before finally firing then when it fires it runs ok. when accelerating in park,neutral or drive the rpms bounce all over if i hold it at around 2200 rpm, once past this it seems to rev up to normal ranges. if i start it with the EST wire unplugged it will rev up as desired. then while running I can plug EST back in and the computer takes over and I am able to rev it with no issues. all sensors check out. Im stumped as where to go from here and why it is like this with est plugged in from the start. have spent hours looking for answers on here and cant seem to figure it out. Sorry for the long post.
Thanks for your time,
Cody

 

Did you ground the motor to the chassis?

Double and triple check all your wiring set ups. Since it runs you have everything installed mostly correctly or it wouldn't, it's going to be something you've over looked or is so simple you haven't thought to check it.

 

Hello. I Have ground straps from negative batt to frame, one from back of head to body, engine to frame and negative to block