check fuel pressure, might need to adjust the idle speed. im guessing the tbis come preset, but if they're anything like reman qjets theyre usually set wrong.
Thanks for the reply.
Does your scanner rpm match the vehicles tach, well mine has a tach but it reads way too high as compared to having a scanner hooked up. One day I'll get those replacement resistors in there.
Any CEL codes being reported? I'd start there if any.
Sensor reading is good doesn't tell us anything. Can you post pictures of the scanned data or perhaps a datalog from the Actron?
Vacuum leak presumably would give you a high idle accompanied by high MAP reading.
What's the IAC reading? 0 would indicate a vacuum leak or the throttle blade adjusted too far open and the ECM slams IAC shut losing control of idle speed.
What's your TPS volts at idle? If it's too high >1.2v, the ECM won't control the IAC.
Is the new TBI an exact match or did you buy a Holley replacement? Granted that the problem surfaced before you changed it, Holley replacement units do present some issues with revised IAC passages and need to use specific vacuum source to the MAP sensor. Wrong sized injectors could present wrong fuel delivery.
Did you follow the procedure to set the minimum idle speed???
Does your scanner rpm match the vehicles tach, well mine has a tach but it reads way too high as compared to having a scanner hooked up. One day I'll get those replacement resistors in there.
Any CEL codes being reported? I'd start there if any.
Sensor reading is good doesn't tell us anything. Can you post pictures of the scanned data or perhaps a datalog from the Actron?
Vacuum leak presumably would give you a high idle accompanied by high MAP reading.
What's the IAC reading? 0 would indicate a vacuum leak or the throttle blade adjusted too far open and the ECM slams IAC shut losing control of idle speed.
What's your TPS volts at idle? If it's too high >1.2v, the ECM won't control the IAC.
Is the new TBI an exact match or did you buy a Holley replacement? Granted that the problem surfaced before you changed it, Holley replacement units do present some issues with revised IAC passages and need to use specific vacuum source to the MAP sensor. Wrong sized injectors could present wrong fuel delivery.
Did you follow the procedure to set the minimum idle speed???
Thanks for the reply. I’ll attach a screenshot.
No vehicle tachometer. Base trim V6.
Code 45, Rich exhaust indicated.
Attaching screenshot. Good idea.
Assuming vacuum leak as posted.
MAP hovers just over 1V, ≈ 1.08-1.12
IAC works toward 0 as Coolant temp rises
TPS is set at .53 at idle.
TBI is an OEM replacement same body.
Injectors are same as before issue.
Wasn’t aware of Minimum Idle Speed procedure. If mechanical, wouldn’t apply here as issue started prior to hardware replacement. No change after. Electronic idle is maintained in closed loop by ECM, correct?
Again thinking vacuum leak but they don’t “magically” appear. This issue was acute, one day it just showed up. Have checked for vacuum leaks around the intake and brake booster with starter fluid, can’t find any.
ECM maybe?