GodzillaMF Posted April 7, 2023 Report Share Posted April 7, 2023 Hello, I am having trouble finding why the Linkecu PNP G4 is suddenly reading lower voltage while driving causing issue to go into throttle sometimes to voltage loss. Has done this before and now starting to do so. Equipment on Car electronic loads: 125amp Alternator Hotwire relay kit to a 525lph hellcat FP/ Spal dual electric fans/ AEM wideband/ Link G4+ PNP On a cold start and into idle, the ECU reading os 13.38 or more volts. On a hot start after driving it will be 13.02 volts. Linkecu reading 12.3 to 12.8 volt cruising and then stopping to come to an engine idle it reports 13.01 volts. The big 3 wires are new and are 0-1 gauge in sizing. My whole wiring specialities engine harness is new and have a new 125amp alt and new AGM battery. What I did, while having IGN on : Pin 49 shows battery Voltage of 12.4-12.5 probe with ECU connected and Link PNP reading 12.21 volts. With engine run its 14 volts and Link PNP reading 13.38 volts Now moved to testing battery etc: I have a charge and battery test and all passed. Cranking Voltage at 11.8 and charge test at 13.8 volts. Both Battery and Alt. are new. I fixed an issue a while back for PIN 16 fixing pin 45 for Voltage loss which help the PNP stay on while cranking. Wiring Specialities harness used a different ECCS relays other than stock. But I haven't had this problem before. What advise can anyone help with. Is this not normal for battery to be different than what Link is reading. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 9, 2023 Report Share Posted April 9, 2023 The ECU voltage measurement is accurate within 3%. The power supply is pin 49 or 59 and 116, so put your voltmeter across those pins and it should match what ecu shows. Quote Link to comment Share on other sites More sharing options...
GodzillaMF Posted April 9, 2023 Author Report Share Posted April 9, 2023 Ok, I get 12.4 Volts on the pins which is the battery at its solid state with IGN on second position. The ECU is at 12.19 volts. Seem right? I'll look over some harness grounds on the looms for the engine in case one is loose Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 9, 2023 Report Share Posted April 9, 2023 Thats less than 2% so would be within tolerance. Are you measuring between the pins I suggested? Quote Link to comment Share on other sites More sharing options...
GodzillaMF Posted April 10, 2023 Author Report Share Posted April 10, 2023 I tested and yes it's within the spec. What I did find that since the Fuel Pump and Staged second pump on a relay which is hotwired for max Voltage to the Pumps and I run 2 two Fans; there is to much amperage needed to drive everything. I was able to install a 250amp alt and took out my 125amp. Now, at idle the ecu reads 13.6 volts with everything running and battery volts at 13.84 . So I think we got it solved! I just don't think the 125amp alt could keep up. Thank you AdamW Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.