Power steering pump = dead engine

[cstfs]

In a strange situation.
07 yukon 5.3
Power steering pump needed replaced, easy enough. I noticed the wire harness look was cracked and missing in some spots, wiring exposed but nothing unusual, get to that in second
Lift tires off ground, start vehicle, get air out of the hydraulic line/rack.
Notice a rough idle.
Strange, it ran fine the day before.
Maybe I bumped plug wire. Check. Restart, seems, better but not great.
Later I go to leave, she's idling rough.
Pop hood, push plug wires in, thinking I may have broken the plug wire for some reason, idle sure felt like bad cable. no change.
Grab the wire harness that runs behind/beside power steering pump.only thing that stood out, that I bumped while trying get pump back up into the bracket. Well, Engine dies the instant I move those wires.
Now I'm in a crank no start situation. The crank is also different. If I engage starter and release key, the engine will continue to turn over for 4 or 5 revolutions before it stops or unless I turn key to off.
So the wiring I touched, seems be a good culprit, Removed loom from where it T's into main harness behind alternator, down to Cam sensor. No visible wire damage.
Test cam connector wiring, key on I was getting 3ish volts on 2 wires and less than half volt on 3rd wire. No idea what it should have read but that tells me those 3 wires aren't broken. Although reference volts should been 5v and signal wire back to PCM shouldn't show anything, as it's disconnected from sensor or so I would think.
There are 3 black ground wires in that bundle and all 3 shown continuity.
Just for my own curiosity, I tested driver coil pack main connector, wiring to the coil pack..
I was getting power on pink wires and orange. Key on.
The common black wire, I could not get any continuity.
I've read that should go to g102. I'll trace it back.
I did get a code p0300 random misfire, no surprise there.
But I also shown a U0073 and U0102,
One is tccm, transfer case module, other is no canbus communication.
Seems like ground issue but what hell do I know, replacing power steering pump led unusable vehicle. Ha
Any input appreciated.

 

[Doubeleive]

In a strange situation.
07 yukon 5.3
Power steering pump needed replaced, easy enough. I noticed the wire harness look was cracked and missing in some spots, wiring exposed but nothing unusual, get to that in second
Lift tires off ground, start vehicle, get air out of the hydraulic line/rack.
Notice a rough idle.
Strange, it ran fine the day before.
Maybe I bumped plug wire. Check. Restart, seems, better but not great.
Later I go to leave, she's idling rough.
Pop hood, push plug wires in, thinking I may have broken the plug wire for some reason, idle sure felt like bad cable. no change.
Grab the wire harness that runs behind/beside power steering pump.only thing that stood out, that I bumped while trying get pump back up into the bracket. Well, Engine dies the instant I move those wires.
Now I'm in a crank no start situation. The crank is also different. If I engage starter and release key, the engine will continue to turn over for 4 or 5 revolutions before it stops or unless I turn key to off.
So the wiring I touched, seems be a good culprit, Removed loom from where it T's into main harness behind alternator, down to Cam sensor. No visible wire damage.
Test cam connector wiring, key on I was getting 3ish volts on 2 wires and less than half volt on 3rd wire. No idea what it should have read but that tells me those 3 wires aren't broken. Although reference volts should been 5v and signal wire back to PCM shouldn't show anything, as it's disconnected from sensor or so I would think.
There are 3 black ground wires in that bundle and all 3 shown continuity.
Just for my own curiosity, I tested driver coil pack main connector, wiring to the coil pack..
I was getting power on pink wires and orange. Key on.
The common black wire, I could not get any continuity.
I've read that should go to g102. I'll trace it back.
I did get a code p0300 random misfire, no surprise there.
But I also shown a U0073 and U0102,
One is tccm, transfer case module, other is no canbus communication.
Seems like ground issue but what hell do I know, replacing power steering pump led unusable vehicle. Ha
Any input appreciated.

all those wires by the power steering lead up into the fuse box, check that all of them are up in there nice and snug, if you pulled on any them it could have came loose up under the bottom of the fuse box

 

[j91z28d1]

isn't there a ground wire for the coil packs bolted to the block right around the ps pump? possibly you removed that to get the pump off and missed putting it back on?

 

[Fless]

All good suggestions.

G102 has many circuits near the front left of the engine and it's common for one or more to go bad. See diagram at the link below.

G102 — 2007 GMC Yukon 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2007 GMC Yukon 2WD V8-5.3L.

charm.li

G102 — 2007 GMC Yukon 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2007 GMC Yukon 2WD V8-5.3L.

charm.li

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[cstfs]

Thanks for the welcome.
So far Ive tested coil wiring, its in fact getting ground continuity on black and brown wire. Pink is battery voltage key on. Was unable test signal wire to coil from pcm, multimeter doesn't do Hz but it's fair to say it's not sending a signal, as there is no spark.
Do have fuel pressure.
I don't think the injectors are doing anything either, when it crank no starts, weren't audible. Don't have noid light handy, yet.
So that leads me to the cam sensor, maybe. I changed the pigtail as a quick and easy test, no change.
Not having much luck finding troubleshooting info for gen 4 5.3 cam sensor. Or sensor wiring, as far as, what should be seen at the connector. Haynes manuals aren't as useful, as they once were back in the day.
I'm sure all 3 wires from cam sensor, go back to the PCM, so testing continuity is best I can do when time and weather allows.
I'll keep searching for actual values to test but should one of you find fellers have link that'd be great too.
Thanks

 

[Doubeleive]

Thanks for the welcome.
So far Ive tested coil wiring, its in fact getting ground continuity on black and brown wire. Pink is battery voltage key on. Was unable test signal wire to coil from pcm, multimeter doesn't do Hz but it's fair to say it's not sending a signal, as there is no spark.
Do have fuel pressure.
I don't think the injectors are doing anything either, when it crank no starts, weren't audible. Don't have noid light handy, yet.
So that leads me to the cam sensor, maybe. I changed the pigtail as a quick and easy test, no change.
Not having much luck finding troubleshooting info for gen 4 5.3 cam sensor. Or sensor wiring, as far as, what should be seen at the connector. Haynes manuals aren't as useful, as they once were back in the day.
I'm sure all 3 wires from cam sensor, go back to the PCM, so testing continuity is best I can do when time and weather allows.
I'll keep searching for actual values to test but should one of you find fellers have link that'd be great too.
Thanks

if the charm li doesn't have it, then you can usually grab a $20-25 factory service manual .pdf off of ebay and it will be on there you just have to use keywords to search for it in the manual because they are not hotlinked. the manual is over 10,000 pages.......

 

[j91z28d1]

don't these trucks start without the cam sensor, just long crank before start and throw fault codes? seems like remember that somewhere, it's the crank sensitive it can't live without?

if you have a scanner, can go to live data and see if you have rpm while cranking?

 

[cstfs]

Doubeleive​

Interesting, never heard of charm li. Appreciate the info.

j91z28d1​

I do have torque pro, can watch live data, will see if there is rpm. Could watch injector output or lack there of as well. Good idea. Ive read mixed info on whether it needs cam input to run or start. I may be over focused on that area, as it was the wires I moved when the engine instantly stop running. Tried a tone generator to trace the wires/look for a break but its not been as effective as Id hoped. Thanks

 

[j91z28d1]

Doubeleive​

Interesting, never heard of charm li. Appreciate the info.

j91z28d1​

I do have torque pro, can watch live data, will see if there is rpm. Could watch injector output or lack there of as well. Good idea. Ive read mixed info on whether it needs cam input to run or start. I may be over focused on that area, as it was the wires I moved when the engine instantly stop running. Tried a tone generator to trace the wires/look for a break but its not been as effective as Id hoped. Thanks

try unplugging it and see if it starts. might be bad data keeps it from running but no data will default and run.

 

[cstfs]

j91z28d1​

Good idea. Cam sensor disconnected, no change.
Watching live data, crank no start. RPM was present, 90rpm to be exact. Was seeing injector pulse width. Plus the aroma of unburnt fuel would suggest shes getting fuel.

So theres fuel, cam signal, Coils are getting 12v key on, as well as ground(s). The pcm coil signal wire is untested but no spark would suggest its not being told spark.

After clearing codes, code U0102 has reappeared, which is lost communication to transfer case. No other codes at this time.

Narrowing it down.

 

[Doubeleive]

j91z28d1​

Good idea. Cam sensor disconnected, no change.
Watching live data, crank no start. RPM was present, 90rpm to be exact. Was seeing injector pulse width. Plus the aroma of unburnt fuel would suggest shes getting fuel.

So theres fuel, cam signal, Coils are getting 12v key on, as well as ground(s). The pcm coil signal wire is untested but no spark would suggest its not being told spark.

After clearing codes, code U0102 has reappeared, which is lost communication to transfer case. No other codes at this time.

Narrowing it down.

did you check the wire harness going to the ecm? those are also right there around the power steering area

 

[cstfs]

Physicaly but didn't see anything obvious. Only wires I touched, when engine instantly stop running, ran up behind power steering pump. Seems be couple ground wires, test good, 3 wires for Cam sensor. And few more from under engine block going transmission. Couple look familiar like vss wiring but there's couple more I'm unsure of. I've done stand alone harnesses for swaps but it's been while and they didn't use transfer case wiring.

Seems rpm comes from crank sensor, so at least we can rule that out.

So cam sensor or wiring may not be ruled out just yet. It tells PCM cylinder location. Which would explain no signal being sent coils. Then there's the signal loss to transfer case...further complication.

Charm li, only gave test procedure for oil sensor. Seems like interesting site, keep it for future use.

Weathers taking a turn for the worse, Yukons outside at moment.

I'm gonna see if alldata can shed more light on this.

Appreciate the help.

 

[Fless]

don't these trucks start without the cam sensor, just long crank before start and throw fault codes? seems like remember that somewhere, it's the crank sensitive it can't live without?

Yes. Without the cam sensor input the crank time might be long. Or not. It could be intermittent, but it should start.

Has the ground at the coil connector been verified? You stated 12v at the connector but was that using battery ground or the coil harness ground?

 

[cstfs]

Yes.
Tested harness at a couple coils.
Pink wire 12v
Signal wire unknown
Brown wire PCM ground good
Black chassis wire good.

Tested grounds by connecting multimeter to battery + and measuring voltage.

I did watch spark advance while cranking and there was no data.
So which may lean back cam sensor based on recent research.

 

[j91z28d1]

my thought was do you have a test light? something that can put a bit of a load on that postive and negative terminal in the coil plug. I've see a meter show voltage, but all a load and the voltage crashes from a bad connection.

the ecm ground and signal, I believe it's a 0-5v square wave and the coil fires when the pos goes to zero. if your meter happens have have hz on it, might get something across those 2 when cranking, or might even seen some voltage on the ac scale, like maybe 2v while cranking.

I still feel like this is a ground or power issue more than cam. but I'm not there, so just a feeling.