Big lope on cold starts

**Olee_Poole** · #1 (**permalink**) 12-27-2011, 07:47 AM

I have a 2003 just changed the ICP sensor.. There was no ICP voltage had codes clear them with IDS the voltage now with key on is .22v

On cold starts it has a big lope idle.. Real bad this morning after it's hot idles fine? No codes as of yet.

Thanks

fixxxer-upper · #2 (**permalink**) 12-31-2011, 07:44 AM

You did check the ICP pigtail for oil contamination when replacing the ICP...right? As you probably already know about these engines, tons of stuff can go wrong that cause identical conditions. Do you have anyway of monitoring any other engine data at idle?

**Olee_Poole** · #3 (**permalink**) 12-31-2011, 08:01 AM

Harness/ plug was dry.. No oil was leaking from ICP sensor just no voltage from old sensor.

There is no codes and yes i have a IDS can scan.. I did check fuel pressure it's 50psi at idle stays solid with the crazy lobe.

Not sure what to check next?

fixxxer-upper · #4 (**permalink**) 12-31-2011, 08:12 AM

Well, if the FCIM voltages all check out (main power 48v, logic power, and key on power), HPO system checks to be fine with correct ICP pressure/voltage, correct IPR%, crank and cam signals are in sync to the FICM and PCM, fuel delivery has been verified with steady pressure....All of the above parameters were met when diagnosing my truck too. When I did the cylinder balance test, it showed cylinders 2 3 5 8 were off. These were all on the X2 connector at the FICM. Even though the FICM voltages were correct, the logical side of the FICM was still corrupt.

Have you performed a cylinder balance test? Buzz test the injectors at KOEO? With engine warmed up, turn off the injectors one at a time and see if the condition changes. It may help narrow down your problems.

**Olee_Poole** · #5 (**permalink**) 12-31-2011, 09:08 AM

Ficm is 48. Idle is fine once hot.. I thinking air in oil system?

fixxxer-upper · #6 (**permalink**) 12-31-2011, 09:18 AM

Did all of the other items I pointed out check out to be fine? If you have IDS, you shouldn't have a problem getting those numbers. Post them up.

KOEO readings?

Engine warm at idle.

FICM Main Power
FICM Logical Power
Battery Voltage
VREF- reference voltage
MAP
Mass Fuel Desired
ICP
ICP Desired
ICP voltage
IPR%
VGT

Balance test?
Buzz test?
Look for wire chaffing?

This is the way to eliminate possible causes and get to your root issue.

**Olee_Poole** · #7 (**permalink**) 12-31-2011, 09:50 AM

I did a power balance when cold.. lines were crazy man like a kid with a crayon for all 8 injectors.

fixxxer-upper · #8 (**permalink**) 12-31-2011, 04:30 PM

That may very well be an FICM issue. Try it when warm. Oil temp and coolant temp up to 190 degrees. I had issues on 2 3 5 8 cylinders, all of which are on the X2 plug at the FICM. Did an FICM swap, problems went away. Let us know what you find.