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Top Swap w/codes P0463 & P1643

dbextreme

dbextreme

New member
Ok, got the motor installed and running. The thing fires right up and idles smooth (strange for a XP cam) LOL but it is idling at 1100 - 1200 RPM. All my vacuum is correct, I had an issue with my fuel pressure regulator vacuum I had running to it was wrong but have since fixed. Now when I shut the car off I hear hissing under the hood for a few seconds like pressure is being released. I started the car back up, sprayed carb cleaner around the vacuum joints, nothing. Cut the car back off, sounds like the hissing is coming from where the EVAP quick release plugs into the EVAP sensor. Anyone have this problem? Aeroforce pulled the two codes P0463 and P1643. If it was just the P0463 I'd think the sending unit was bad, but with both codes I'm thinking I have a bad leak at the EVAP hose to sensor. Also would this cause a vacuum "leak"? I hear it hissing, but I don't smell fuel... :-/ bit confused.

Fuel gauge is acting like a bad sender per the P0463 code. But I've researched that the EVAP has something to do with function of the level indicator....
 


:D From what I've gotten the past few days is I seem to have a wiring issue/bad ground. I did not have this code with my L36 motor. I am using the same wiring harness with the L26 top swap. Everything hooked right up OTHER then the: MAP sensor (bought the L36 to L67 adapter), Rear O2 deleted/tuned out of the PCM (plug is hanging for now), EGR deleted/tuned out of the PCM (plug hanging for now), LQ4 had the 5 to 3 wire adapter WITH the IAT wired into the adapter (ordered from Intense), TPS adapter (also ordered from Intense), Front O2 sensor I had to extend the wiring harness which I had a spare harness here, I just cut the long pig tail off and cut the plug off the Rear plug on the same harness. I matched colors/letters on plugs, one splice taadaa factory plugs on each end... Unless those adapter harness have issues with connection, I am assuming I have a bad ground like stated above, or pinched wire. But wanted to know if anyone else had this issue and would know more where to start!!

Thanks

P0463 Fuel Level Sensor Circuit High Input
Symptoms of a P0463 DTC may include:


  • Mil (Malfunction indicator lamp)
    illumination
  • Fuel level gauge may fluctuate abnormally
    or read empty or
    full
  • Fuel light may illuminate and sound alarm
Potential causes of a P0463 code
include:


  • The signal circuit to the fuel sender is
    open or shorted to B+ (Battery voltage)
  • The ground circuit is open, or ground path may have high resistance due to rust or missing ground strap on
  • Damage to the fuel tank could cause problem in fuel level circuit
  • There's an open in the fuel lever sensor's resistor to ground
  • Possibly faulty instrument cluster
  • Less likely is the possibility that the PCM, BCM, or Fuel pump computer module has failed

P1643 Engine Speed Output Circuit (nothing more really... But I read it's more of a TPS, EVAP, MAP type issue...)

P1635 5 Volt Reference Circuit Refer to A/C Presure, Fuel Tank Pressure, TP, MAP, IAT, ECT Sensors
 
Also from hooking up a Vac/Boost gauge I am holding at 16 (whatever units) of VAC at idle which is ~1300 RPM.. Thought I might of had a vacuum leak but I am thinking I don't... I heard a hissing sound AFTER I cut the car off like pressure was being released, but today after several startup's no sound what so ever... BUT I am not building boost. I throttle it and the gauge goes to 0.. :( Awful confused at the moment...

I know that these run ~19 - 19.5 (whatever units of vac) at idle, but from building muscle cars I know larger cams mean less vac. Is this normal for and XP cam to run where it is showing on the gauge since it's a higher lift cam?

Vac routing is:

Nipple at the LIM under the supercharger snout is T'ed. One end going to the MAP T which runs to MAP and Boost gauge.
Other end of the T from the LIM goes to the T at the FPR.
Other side of the T at the FPR is capped ATM.
Nipple at the TB runs to the EVAP Sensor

Supercharger tree has:
Brake booster hooked up
Acc hooked up middle nipple
Lower nipple goes to BBV
Other end of the BBV is capped (I think I should leave this one open to Atmosphere...)

My aeroforce (might have the wrong parameter setup to read Vac/Boost) but it's only showing like 0.8 for Vac... Could the MAP sensor be causing all my problems??

 
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I will check. Looks like the ones in question are: MAP, O2, TPS, IAT (which I'm wondering about. I don't have my IAT sensor in the air tube anymore I am using the LQ4 dual plug adaptor), EGR (which I don't have), ETC, EVAP, and all grounds.

I'll also search for pinched wires, but everything is pretty free moving as far as wiring goes. Expect for the chunk between the ICM bracket and valve cover... It might have gotten pinched while I was tightening up that bracket.

Sigh, I hate gremlins.....

How does the VAC reading look for where it's idling and the cam? Normal, should it be higher?
 
Wow.... It was the MAP sensor harness from ZZP causing all my problems!!! The end that plugs into the existing L36 plug was wired backwards... :-/ I tested all my 5V references and they were all ok except for my fuel tank one and the MAP. The MAP was reading NOTHING at the grey wire. I went back to the original L36 plug and I had 5.04V there so I guess the wiring for the adapter was bad.. no.. I went to plug it back in and noticed the outter wires were swapped. I flipped them, all done...
 
dbextreme said:
Wow.... It was the MAP sensor harness from ZZP causing all my problems!!! The end that plugs into the existing L36 plug was wired backwards... :-/ I tested all my 5V references and they were all ok except for my fuel tank one and the MAP. The MAP was reading NOTHING at the grey wire. I went back to the original L36 plug and I had 5.04V there so I guess the wiring for the adapter was bad.. no.. I went to plug it back in and noticed the outter wires were swapped. I flipped them, all done...
Click to expand...

Glad you figured it out. My brother and I had the same issue with the adapter. I had to completely remove the internal notch to get it to mate properly.
 
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