HELP!!!! P163a

So I’ve got a doozy, 2018 colorado 3.6, we did a used engine swap and it has turned into a disaster. 23k on engine and used the original wiring harness from the original engine, the fuel rails, injectors and injector harness and high pressure sensor are all from the salvage engine. After the first test drive we got a p163a with no CEL, we have had these codes also but not consistently, p0090, p00c8 and p228c, those codes only occurred once at different times the p228c occurred by itself with no other codes and put me in reduced power, the p0090, p00c8 and p163a all occurred together and gave me reduced power at one point also but it seems the only codes that returns with consistency is the p163a but does not trigger a reduced power situation, the vin is-1GCGSCEN5J1118135, we’ve changed the high pressure fuel
pump with a GM unit, called identifix and went through the diagnostics and replace the ECM, no good, then identifix suggested I run a new circuit straight from the ecm to the high pressure fuel
pump, I used new pins on the x3 ecm connector and new 2 pin connector at the hpfp regulator and after about 60 miles the code come back, occasionally I’ll get a p228c with reduced power and the p163a, I’ve watched fuel pressure while driving and low is always between 50 and 60 and high is always over 550psi, freeze frame showed rail pressure at 61 psi when the light flagged, but there was no drivability change. The p163a always returns and the p228c occasionally flags and puts me in reduced power. I’m truly at a loss now it is very strange. Help

there is TSB on that , i think clls for changing fuel rail and connector good luck

I would make sure the grounds are good for those circuits. especially the small ones that bolt to heads. they are easy to miss.

I found a related tsb but it was for the Diesel engine, thank you

I 2nd a ground issue. I believe there is a ground on the back side of each cylinder head. I've had several gm vehicles kick my butt because of poor engine grounds.

Checked all the grounds several times, thank you though

then i would say to pull the injectors, rails, and harnesses and swap them out.

I was thinking that also I just can’t seem to see the correlation to the p163a code, the code refers to regulator control circuitry, the only things on the circuit according to the diagram is the high pressure fuel pump regulator, wires and ecm, all of which are new, I ran 2 new control wires from ecm x3 connector straight to the regulator with a new 2 pin connector, I just don’t know what else the ecm is looking at in the diagnostic strategy for setting the code

This circuit is fairly simple, ecm to hpfp regulator, my other thought was maybe the voltage to the ecm for the driver was an issue but the diagrams do not show me what lines coming into the ecm power which drivers, I don’t know, it’s probably far more simple

Have you load tested powers and grounds at ECM? Any electrical concerns with old motor? Have you had a scope on regulator power and ground?

There were no previous issues that I’m aware of, we did check for codes before we started the job and there were none. How would you suggest I load test the powers and grounds?

Are you familiar with voltage drop testing?

I am a little bit, definitely not as much as I should be, how would you suggest I go about it? I did have a new development though, I removed my new circuit from the ECM to regulator and found that if I pound this truck and lay it in the floor I can get it to store. P0090 and go into reduced power, it’s still a circuit code but I watched desired and actual on a graph and it is off comparatively

Here is a link to voltage drop testing.

www.google.com/url?sa=t&source=web&rct=j...hPRyxm8UQU_yYdUykv5D

Is the high pressure pump you have installed for sure good?

This is a pretty simple system, if you have a good High Pressure Pump, good ECM, and new circuits. I would verify ECM inputs are all good.

Mike

you say the pump has been changed , i would make sure nothing got left out or the cam actuater and then when engine replacemnts some time the connector pins of sensor get opened where we get shorting problems GOOD LUCK

Did you ever figure this out? I’m dealing with the exact same thing right now!