ECSB4X2

Hi, just got done replacing the cylinder heads on my 2000 Silverado 5.3. Head gasket was leaking coolant into engine. I replaced heads, gaskets and lifters, and knock sensors while I was there. Went to start engine and it’s barely running with popping noises and what sounds like a supercharger whine from the engine. It’s showing p0200 injector circuit and p0108 map sensor set high. I’ve replaced the map sensor and still nothing. Checked all the wires for shorts and nothing. Really scratching my head on this one. Before the head swap it was running good with no codes. Any help will be greatly appreciated.

zz454Chevelle67

Is each injector plugged into the correct connector?

ECSB4X2

I’m pretty sure, I’ll check again tonight. I’ll take a look at the pcm too. I put hp tuners scanner and the map sensor is stuck on 102 kpa. It might move 1 to 2 kpa while barely idling. With the engine off the kpa is the same even if I depress the gas pedal. It’s weird….I checked for vacuum leaks and everything looks good.

RDF1

Did you miss a ground wire?

ECSB4X2

Grounds are good, every wire is where it should be. It’s just the map reading is maxed out.

RedXray

If you have HP Tuners disable the MAP (volumetric efficiency) and try running MAF only. If it runs ok on MAF only... you'll know it's the MAP sensor, MAP sensor wiring or the PCM.

RDF1

P0200 will be a injector test where it's not seeing resistance thru the injector coil. I've seen a missing/bad ground cause this.
On the MAP I would check for ground and voltage on the connector. See what you get.
also check voltage at injector connectors.

I dont have the pinout on my phone so not sure what fuses feed those.

ECSB4X2

K, I’ll check the fuel injectors. I checked the map and it’s getting 5 volts. Which maxes out the map of course. I’m going to take off the driver side coils and check all the wiring there. Thanks for all the ideas.

ECSB4X2

Well I checked all the wires and found nothing. I even readjusted the valves just because. I did have a loose fuel injector plug though. The map is still at 102 kpa engine on or off. The only check engine light is high map pressure. I’m really thinking it’s the pcm but I would be just guessing. I’m all out of ideas.

FFDP

iTrader: (2)

If you unplug the MAP sensor the voltage should drop to zero on the scan tool. If KOEO, & the MAP sensor unplugged, the scan tool shows a voltage reading, then there may be a short in the harness to the MAP sensor. Turn the ignition off. At the PCM unplug connector and remove the MAP signal wire from the connector. Re-attach the PCM connector and see if with KOEO, the scan tool MAP reading shows voltage. If it still does, replace the PCM. If not, check for voltage on the signal wire you just removed from the PCM. If there is voltage on the signal wire, find the short in the harness and repair.

Did you try that above yet?