5.3 starter issue, and parasitic battery drain.

[Fless]

Do you have similar voltage drop measurements with the key out of the ignition? Also check the PCMB fuse for voltage drop.

 

[xDan]

I'll have to see. I don't have electrical probes that get to the mini fuses well, so I've been using some 0.040 lockwire, making sure I'm not touching one lead. What works well for probing those fuses? It's not the most consistent dmm at 2Vdc setting, waving the leads around causes voltage spikes.
Which circuit powers the fuel pump? I might jump the starter when I get a chance... Just to disprove that as an issue. Also besides the engine ground wire, where is the engine grounded to the frame?

 

[Fless]

I'll have to see. I don't have electrical probes that get to the mini fuses well, so I've been using some 0.040 lockwire, making sure I'm not touching one lead. What works well for probing those fuses? It's not the most consistent dmm at 2Vdc setting, waving the leads around causes voltage spikes.

Just standard voltmeter leads, probing the two test points on top of each fuse:

 

[xDan]

Wow. I've never noticed those, ever. They are on regular blade, m-axi fuses too. I've got a chart but it doesn't have glass tube fuses. I've rarely needed to check voltage drop over multiple circuits before so I've only been watching battery voltage drop and amperage bridging with fuse pulling. With modern stuff and their complexity, fuse pulling doesn't work so well.

Ok, why is m-axi censored?

 

[xDan]

I did a lot more circuit testing today.
With the battery charged at 12.8V, only a couple circuits were drawing power:
SUV locked, unarmed, no key in:
Engine compartment fuses:
IPC/DIC (10A)= 2.0mV= 270mA
Radio (15A)= 0,1mV= 22mA
No instrument panel fuses or anything else was drawing power. The battery is still draining down to dead within two days.

I also was able to turn over the engine with the starter (it was refusing at first, but I short circuited it with a large wrench through the wheel well. At first the new solenoid did nothing, then after hitting it with power enough times it engaged the gear, then started to turn over the engine decently well, not great but enough.) I started it by jumping with another vehicle using the key after that. It ran well, alternator charging at 14.35V. I tested the hell out of everything you can turn on. While running with the alternator charging away, nothing misbehaves and the engine idles fine. Every interior light works, HVAC is 100%, instrument panel, radio, subwoofer, locks, windows, mirrors, seat, rearview mirror crap, 4WD controller, wipers, washers, electric defroster, 7-way trailer plug, all the exterior lights work.
On to the circuit draws:
Engine compartment fuses:
IGN A (40A)=1.2mV =316mA
IGN B (40A)=3.2mV =842mA
LBEC 1 (50A)=1.5mV =625mA
LBEC 2 (50A)=0.1mV =42mA
Blower (40A) OFF=0mV, 5=16.7mV =4.47A
HI-HDLP-LT (10A) OFF=0.1mV, =13mA ON=53.6mV =7.28A
HI-HDLP-RT (10A) OFF=0.1mV, =13mA ON=54.6mV =7.41A
LO-HDLP-LT (10A)=2mV (controller power used as signal for xenon low beams) =270mA
LO-HDLP-RT (10A)=0mV
FRT-PARK (10A)=11.9mV =1.62A
RR-PARK (10A)=2.4mV =323mA
LR-PARK (10A)=2.5mV =337mA
PCM (15A)=4.8mV =1.048A
PCM B (20A)=16.7mV =5.30A
FOG LAMPS (15A)=28.3mV =6.11A
ETC/ECM (15A)=0.7-1.3mV =153mA to 284mA
INJ 1 (15A)=0.9-1.1mV =197mA to 240mA
INJ 2 (15A)=0.8-1.1mV =175mA to 240mA
O2A (15A)=6.5mV =1.419A
O2B (15A)=6.5mV =1.419A
B/U LAMP (20A)=0.5mV =156mA
BTSI (10A)=1.3mV =175mA
IPC/DIC (10A)=3.5mV =472mA
HVAC/ECAS (10A)=0.6mV =81mA
SIR (15A)=1.9mV =415mA
RADIO (15A)=3.2mV =699mA
TREC (30A)=0.1mV =54mA
Instrument Panel fuses:
DMM (15A)=1.1mV =240mA
IGN 0 (10A)=7.3mV =984mA
IGN 3 (10A)=0.8mV =108mA
HTR/AC (30A) 0=0.0, 1=4.4, 2=8.2, 3=13.8, 4=21.0, 5=0.2mV =0mA =2.378A =4.432A =7.57A =11.35A =108mA
HVAC 1 (10A)=1.1mV =148mA
BRAKE (10A)=0.8mV =108mA
PDM (10A)=2.7mV =364mA
TBC 2A (15A)=10.6mV =2.40A
TBC 2B (15A)=12.2mV =2.62A

Any fuses not listed had no draw. My DMM on 200mVDC is sensitive to 0.1mV, +/- 0.05mV.

I then turned the SUV off, key out and left it unlocked:
TBC BATT (10A)=0.9mV =121mA
RADIO (15A)=0.1mV =13mA

I don't know what half those circuits power exactly and nothing jumps out at me as abnormal but if anyone with more knowledge about it sees something way off, let me know. The slower starter is bothering me but the main power wire at contact points and everywhere I can see it looks to be in good shape from battery, through the breakout box to starter. Something is drawing down an insane amount of power when the engine is not yet running, it always takes two batteries and a running alternator to get it to start. Once it's turning over, it fires up within half a rotation. It revs up fine with no hesitation as well, no codes present. Is there anything in the tech2 that could help?

 

[bigdog9191999]

i have ran into once before on a 2001 grand prix i had several years ago, had a draw that would kill the battery in a day or so. could not find the issue. checked fuses, to the point i started unplugging things under the dash and under the hood to try and isolate the issue, still died! the issue ended up being the fuse box itself! i had a couple extras laying around and it was the only thing i had not tried short of testing individual wires out the back of the box, but swapping the box fixed that issue. but i could not tell what or why. but something in that fuse box was messed up inside and allowed drain.

these can be very frustrating issues to find, good luck!

 

[Fless]

I did a lot more circuit testing today.
With the battery charged at 12.8V, only a couple circuits were drawing power:
SUV locked, unarmed, no key in:
Engine compartment fuses:
IPC/DIC (10A)= 2.0mV= 270mA
Radio (15A)= 0,1mV= 22mA
No instrument panel fuses or anything else was drawing power. The battery is still draining down to dead within two days.

I also was able to turn over the engine with the starter (it was refusing at first, but I short circuited it with a large wrench through the wheel well. At first the new solenoid did nothing, then after hitting it with power enough times it engaged the gear, then started to turn over the engine decently well, not great but enough.) I started it by jumping with another vehicle using the key after that. It ran well, alternator charging at 14.35V. I tested the hell out of everything you can turn on. While running with the alternator charging away, nothing misbehaves and the engine idles fine. Every interior light works, HVAC is 100%, instrument panel, radio, subwoofer, locks, windows, mirrors, seat, rearview mirror crap, 4WD controller, wipers, washers, electric defroster, 7-way trailer plug, all the exterior lights work.
On to the circuit draws:
Engine compartment fuses:
IGN A (40A)=1.2mV =316mA
IGN B (40A)=3.2mV =842mA
LBEC 1 (50A)=1.5mV =625mA
LBEC 2 (50A)=0.1mV =42mA
Blower (40A) OFF=0mV, 5=16.7mV =4.47A
HI-HDLP-LT (10A) OFF=0.1mV, =13mA ON=53.6mV =7.28A
HI-HDLP-RT (10A) OFF=0.1mV, =13mA ON=54.6mV =7.41A
LO-HDLP-LT (10A)=2mV (controller power used as signal for xenon low beams) =270mA
LO-HDLP-RT (10A)=0mV
FRT-PARK (10A)=11.9mV =1.62A
RR-PARK (10A)=2.4mV =323mA
LR-PARK (10A)=2.5mV =337mA
PCM (15A)=4.8mV =1.048A
PCM B (20A)=16.7mV =5.30A
FOG LAMPS (15A)=28.3mV =6.11A
ETC/ECM (15A)=0.7-1.3mV =153mA to 284mA
INJ 1 (15A)=0.9-1.1mV =197mA to 240mA
INJ 2 (15A)=0.8-1.1mV =175mA to 240mA
O2A (15A)=6.5mV =1.419A
O2B (15A)=6.5mV =1.419A
B/U LAMP (20A)=0.5mV =156mA
BTSI (10A)=1.3mV =175mA
IPC/DIC (10A)=3.5mV =472mA
HVAC/ECAS (10A)=0.6mV =81mA
SIR (15A)=1.9mV =415mA
RADIO (15A)=3.2mV =699mA
TREC (30A)=0.1mV =54mA
Instrument Panel fuses:
DMM (15A)=1.1mV =240mA
IGN 0 (10A)=7.3mV =984mA
IGN 3 (10A)=0.8mV =108mA
HTR/AC (30A) 0=0.0, 1=4.4, 2=8.2, 3=13.8, 4=21.0, 5=0.2mV =0mA =2.378A =4.432A =7.57A =11.35A =108mA
HVAC 1 (10A)=1.1mV =148mA
BRAKE (10A)=0.8mV =108mA
PDM (10A)=2.7mV =364mA
TBC 2A (15A)=10.6mV =2.40A
TBC 2B (15A)=12.2mV =2.62A

Any fuses not listed had no draw. My DMM on 200mVDC is sensitive to 0.1mV, +/- 0.05mV.

I then turned the SUV off, key out and left it unlocked:
TBC BATT (10A)=0.9mV =121mA
RADIO (15A)=0.1mV =13mA

I don't know what half those circuits power exactly and nothing jumps out at me as abnormal but if anyone with more knowledge about it sees something way off, let me know. The slower starter is bothering me but the main power wire at contact points and everywhere I can see it looks to be in good shape from battery, through the breakout box to starter. Something is drawing down an insane amount of power when the engine is not yet running, it always takes two batteries and a running alternator to get it to start. Once it's turning over, it fires up within half a rotation. It revs up fine with no hesitation as well, no codes present. Is there anything in the tech2 that could help?

The key on, engine running values mean almost nothing when troubleshooting a parasitic draw. What matters is what is being drawn while the truck modules are supposed to be asleep.

The IPC/DIC is the Instrument Panel Cluster, and it's drawing too much while the truck is asleep. I think a previous poster mentioned the silver migration issue on the IPC and that could easily be the issue; it's very common. You could pull the cluster and disconnect it by pulling the connector, and re-testing to confirm whether or not the cluster itself is at fault for that 1/4 amp draw.

Do you have the auto HVAC control, where you can set the HVAC temp? Those can take 4+ hours to go to sleep, but it looks like your key off tests didn't show that as an issue. It would draw 50 or 60 mA until it goes night-night.


EDIT: the typical goal is to get the fully-asleep draw to be 50mA or less. My '04 runs consistently at about 27mA or less.

 

[OR VietVet]

The key on, engine running values mean almost nothing when troubleshooting a parasitic draw. What matters is what is being drawn while the truck modules are supposed to be asleep.

The IPC/DIC is the Instrument Panel Cluster, and it's drawing too much while the truck is asleep. I think a previous poster mentioned the silver migration issue on the IPC and that could easily be the issue; it's very common. You could pull the cluster and disconnect it by pulling the connector, and re-testing to confirm whether or not the cluster itself is at fault for that 1/4 amp draw.

Do you have the auto HVAC control, where you can set the HVAC temp? Those can take 4+ hours to go to sleep, but it looks like your key off tests didn't show that as an issue. It would draw 50 or 60 mA until it goes night-night.


EDIT: the typical goal is to get the fully-asleep draw to be 50mA or less. My '04 runs consistently at about 27mA or less.

It has been 15 years since I ran shops. At that time we used the 50 mA draw as a baseline. After I got out of that business I had heard that the new baseline was higher because of all the "keep alive memory" required for all the modules/computers on todays vehicles. I never heard what that higher baseline is or if it is higher.

 

[Fless]

It has been 15 years since I ran shops. At that time we used the 50 mA draw as a baseline. After I got out of that business I had heard that the new baseline was higher because of all the "keep alive memory" required for all the modules/computers on todays vehicles. I never heard what that higher baseline is or if it is higher.

I, too, have heard that newer vehicles would have a higher baseline for exactly that reason. I also think the newer year modules take longer to go to sleep. But thankfully not the case for the NBS.

 

[xDan]

Just putting the key in and switching to accessory is dropping voltage down to 9.5V, to run drops it down to 8.9V and to start it goes down to 5V.

I thought I found something to do with IGN B, but I insert the key and sometimes get a voltage drop from 12.6V to 10V but it's momentary drop.