All research and searches exhausted. 02 TB LTZ

cruz8

Original poster
Member
Nov 28, 2014
7
I have exhausted all efforts in finding a solution to my TB woes. I've read tons of posts, recommendations, and performed maintenance just to rule out the basic things.

Here's the story:
My TB has 114k and usually until now has always been reliable, except for a few things....starter, alternator, and basic wear and tear items. A few weeks ago, went outside in the morning and fired up the truck to let it warm up a little (it was a cold Minnesota night) but when I came back outside 5 minutes later the truck was not running. I jumped back inside and tried to fire it up, but it took a bit of cranking to even seem like its firing, yet though, it would not run. It was trying it's hardest to, but just sputtered and died. Tried this over and over, but never got any further so I left it until I could come back home from work. When I got home, I made a little more progress keeping it running. I would get it to start, but it would immediately die. Over and over again, giving it gas would kill it so I just had to let it recover on it's own to stay running. A quick key turn, it would fire up a few seconds and die. Eventually, It stayed running but the rpms would surge on its own until it eventually leveled out and stayed running. I let it warm up and drove it just fine, no problems whatsoever, not even a CEL. Coincidence perhaps? Nope, the problems all start here.

I took it to work the next day, and after about 20 minutes and getting stopped at a light, it feels like a sputter to the engine but the throttle is responsive with no hesitation at highway speed. This starts becoming a new behavior for this truck for the next few days. On the way home from work one night, I am doing 70mph on open highway and all of a sudden the rpms drop, hitting the gas pedal does nothing so I drift over to the shoulder. The truck is not stalled, it's still running. After a few seconds, the throttle starts to respond again and rpms will climb. No CEL either. I decide to just kill the motor and try starting it again. It fires right back up with no problems back home, still though it sputters a bit at idle and you can hear it from the tailpipe when near.. At this point I think I need a mechanic to look at it. I'm good with the little fixes, but don't have the resources to really dive into these problems besides just the internet to educate me on other's experiences. The shop finally gets a code of p0014 and p1345, so they replace the cpas, run an oil treatment, and give it an oil change. I pickup the truck on a Sunday evening to drive my son back to his mother, once warmed up and at a stoplight, the sputter is back with rpms around 550-600. Drop my son off and have my wife meet me back at the shop to leave it for them on Monday. No CEL at this point either.

The shop calls me the next day and I explain that all this happens after the truck is warm. So, they test it out and feel the sputter, but no codes are producing. It hasn't been dropping rpms while driving for them, so they tell me to take it for a few days and see if it clears up on it's own. Over the next few days the sputter remains, no CEL's, and no highway speed rpm drops.....yet. That third day on the way into work after about 20 minutes on the road, the rpms drop and I pull over. The truck is still running and after a few seconds, throttle is back and away I go....nope, drops again....still running I wait a few seconds...then go again, but this time the truck dies completely and the message "low oil pressure" displays. I turn the key to the off position and then try starting it again....fires right up. I decide to make a u-turn and head back towards the shop. A CEL finally appears, so on the way back I stop at Autozone to get that checked out. It's a p0014. Now, I decide to put some gas in it, what the hell, the gas pump nozzle clicks off when trying to pump in the gas!!! I have to gingerly piss the gas into the tank, any pressure, it just clicks off. I take a look around to make sure there isn't any little gnomes hiding under the truck screwing wtih me, this is crazy! Finally, I get to back to the shop and talk to the owner, and he sends out a mechanic to ride with me so he can see what is happening. Guess what, the truck drives like a dream, no sputter at a red light, no stall, flippen nothing, and the damn thing is more than warmed up!!! We go back to the shop and I figure that I might as well rule general maintenance out of the equation. I have them put in new plugs, yes AC Delco, and also have them remove the throttle body and fully clean that. Oh, and I made sure they disconnected the battery as well.

I pick the truck back up the next day, idles great so I decide to drive it towards work to give it a full test. On the road and at the exact point it has dropped rpm's in the past, it did it again and as I was pulling over, it stalled totally this time. Fired right back up and made it home with no issues, it's like once you recycle the ignition once when this happens, the problem doesn't rear it's ugly head until the next cold start. No CEL either. I decided to take a look online and found that the cam sensor has caused people problems in the past, it's cheap, so I replaced it. It looked pretty crusted up. That cam sensor replacement got me two full days of worry free driving. After a couple of dream driving days, a CEL appeared. Uh oh! Decided to drive the truck to the shop in the morning to see what the code is now. On the way slow driving speed and engine still not fully warmed up, the damn thing dropped rpms on a road with no shoulder. Decided to try turning it off and back on again to see if that cycle would work again.....nope, not this time. I'm stuck in the middle of a lane with nowhere to go. The truck is trying to fire but won't stay running just like when this whole problem started from day one. A police officer wasn't far behind me, so they pushed me off the road. After a few minutes of thinking this is a nightmare that won't end and picking up my phone to call a tow, I try to fire the engine up.....it starts. I put it in gear and cruise a few blocks to the shop.

The diagnosis at this point is a bad cam phaser. They took it for a nice drive and it did the rpm drop on them, and they were also to see the cam phaser acting up. I bite the bullet and had it replaced. All I want is my truck back, but dang, their little Honda loaner car got some really good gas mileage!!! Okay, so they get the truck all back together and it's running without the rpms dropping. They drove it all around and the stalling is gone, but wait, now once it's warmed up the truck's oil pressure drops to 0 and the message "low oil pressure" comes on when at idle. If you tap the gas, it goes right back up. They checked it all out and tested the actual oil pressure....it's only showing 5psi at idle. I've never had a problem with the oil pressure in the past, why the hell now. It's like this truck is possessed!! Screw it, I pick the truck up until I can do some further research. The next morning, I decide to go out and warm the truck up. It fires right up and runs.....I even checked it a couple times to make sure. My wife walks out to start her Toyota 4-runner that has 312k miles on it (just a poke at GM). She comes in to tell me my truck isn't running, wtf???? Guess what, the whole thing that started this problem in the first place is back again. The truck will try to fire, but won't stay running. Called the shop and they came and got it. They've had it for two days trying to get it to reproduce the problem, but it works perfect for them... No CEL's either.

That's where I am at right now, even inquired a friend who got me in touch with a service manager at a GM dealership. All he said is if they can't reproduce the problem, there isn't much they can go on. Sorry for the long post, but really, should I hire a priest to exorcise the truck?? I just hope someone might be able to feel my pain and point me in some direction. I've heard the best of the best are on this site, and I am hoping they can help me. If anything, thanks for reading.

Joe
 

Einst-Hawk

Member
Jan 31, 2014
105
Wow.. I'm sorry that I can't offer anything useful for your situation. It really does sound like its possessed.

I'm sure some others will chime in with more knowledge and expertise.

Oh, and Welcome to the Nation. Glad you're here
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
Isn't there something on these trucks with the fan clutch affecting the TBW? I seem to remember a post from long ago about a fan clutch going out and causing drivability problems, and the cause was the fan clutch wiring harness having broken/frayed wires.
If not, it sounds to me like it's a throttle thing, gas pedal or throttle body.
 

Sparky

Member
Dec 4, 2011
12,927
NJTB said:
Isn't there something on these trucks with the fan clutch affecting the TBW? I seem to remember a post from long ago about a fan clutch going out and causing drivability problems, and the cause was the fan clutch wiring harness having broken/frayed wires.
If not, it sounds to me like it's a throttle thing, gas pedal or throttle body.
I remember something like that also.
 

cruz8

Original poster
Member
Nov 28, 2014
7
I've had the vehicle since 43k, and have had to replace the power steering pump, idler pulley, tensioner, ac compressor bearings, clutch fan, alternator, ignition switch, and 2 starters. Honestly, this thing looks brand new under the hood and not much mileage on all the newer parts.

Today I went outside to warm it up a little and it fired right up, but the motor was kinda knocking and the low oil pressure message displayed. After a couple of seconds, it quieted down and the message disappeared. The gauge was jumping up and down from 0 to 40, but then leveled out at 40. I walked inside to grab my bag, after a couple of minutes, jumped back in the truck to see the nice message "low oil pressure" and not bouncing, just sitting on 0. The engine was quiet as could be. I drove it into work, but when parked, the gauge just goes down to 0. I'm thinking this thing is a ticking time bomb, and I should have never had that cam phaser put in. It never had this problem before, so basically I spent good money to fix one problem to only get another horrible one in return. Would putting synthetic oil in help with that cold startup or am I just driving a grenade with it's pin pulled?

One other question, if the truck was warming up and received a signal that there was no oil pressure, would it stall out? I'm wondering if my oil pump has been the cause all along?
 

Matt

Member
Dec 2, 2011
4,019
I have a feeling the oil pressure switch has had the dick. It's only a low pressure switch, the oil pressure gauge in the dash is not representative of what the pressure really is...it's a lie. Only the V8's have a real gauge.
 
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cruz8

Original poster
Member
Nov 28, 2014
7
Matt said:
I have a feeling the oil pressure switch has had the dick. It's only a low pressure switch, the oil pressure gauge in the dash is not representative of what the pressure really is...it's a lie. Only the V8's have a real gauge.
The shop did a true oil pressure test and it read 5-6psi@600 rpm's. That's when the gauge shows 0 and the display lights up "low oil pressure." I'm just wondering if my oil pump has been sporadically having problems from sludge and coincidentally now has appeared after the cam phaser replacement. Always have run synthetic in it in the past, now has high mileage. I switched to see if I could reduce the oil consumption.
 

Matt

Member
Dec 2, 2011
4,019
Could be...is there a way of testing it or will replacing it be the only way to find out for sure?
 
Apr 26, 2014
53
Any chance that exact spot for the rpm drop off is uphill? Maybe your Cat is failing? Has it ever been done? Has your mechanic done a back pressure check? It may not give you codes.
 

bobdec

Member
Apr 19, 2013
233
They would have to temporally install a real oil pressure gauge to know that you pressure is 6-5 lbs at idle. OR maybe they took a shortcut and just assumed those numbers because the dash was going to zero ?? Give them a call to verify if they actually used a gauge.. It's important because if the later you just may have a crappy oil pressure switch. If the previous you may have worn bearings, a pump problem or a messed up pickup in the pan. Could be they put in new oil when the did the phaser ,maybe, it was a lower viscosity or poorer quality than what you were using.. that coupled with a worn engine would aggravate the low pressure indications.

As a worn bearing test ... My 20 year old Z28 started dropping to 5 lbs at idle and I took the viscosity up a notch. That usually buys you 5+ more lbs at idle if the crank or cam bearings are on the way out. However it's still a bandage only delaying a permanent repair/rebuild. (Been running it that way 3 years now)
 

mcfootballs

Member
Dec 20, 2014
2
I had simular issues with my RCSB 04 Sierra but my issues were stalling after short trips and gas filling issues ( still working on glass filling issue) but my stalling issues were fixed with a MAF sensor and throttle body cleaning. You can pickup MAF SENSOR cleaner for under 10 bucks and it only takes a few minutes. I think my glass filling issues are caused by the tank or evap cpu I replaced the evap canister my self but there was no change. I also agree with the earlier post saying throttle body if you. tB is 03 or newer because it would be the drive by wire version spouse to actually having a throttle cable.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
First of all, you MUST confirm with the shop that they used a separate oil pressure testing gauge as the one in the dash is fake. Depending on the answer to that, I would replace the oil pressure switch if the pressure checks out.

But, you have said that it makes noise at idle, that would be indicative of low oil pressure. Oil pump failures are extremely rare. First I would try an oil and filter change using a good quality filter (no Fram or other cheap brands) Mobil1, Wix or Purolator are good. There could be a problem with the filter, either clogged, collapsed or a faulty relief valve. Beyond that, it could be a problem with the pickup tube screen clogged, a leaky tube to pump seal or a defective oil pump. Any way you look at it, it will be major work because you have to Remove the intake manifold and valve cover , Remove the oil pan and Remove the timing chain cover since the oil pump and pickup are in the timing chain cover . It's probably easier to replace the engine.

To me, it makes sense if the oil pressure is low, it would cause all sorts of problems with keeping the engine running right since the VVT uses oil pressure to adjust the exhaust camshaft. Would also affect the valve lifters. The cam phaser may have been replaced for nothing if the oil pressure is to blame.
 

goombi

Member
Jun 23, 2014
11
I had to replace my oil pressure switch. The gauge would drop while idling and jump up while hitting the gas. It would run rough and want to stall. After replacing the switch it was fine. The part was cheap and my son installed it. Can't help with other issues. Good luck
 

cruz8

Original poster
Member
Nov 28, 2014
7
Mooseman said:
First of all, you MUST confirm with the shop that they used a separate oil pressure testing gauge as the one in the dash is fake. Depending on the answer to that, I would replace the oil pressure switch if the pressure checks out.

But, you have said that it makes noise at idle, that would be indicative of low oil pressure. Oil pump failures are extremely rare. First I would try an oil and filter change using a good quality filter (no Fram or other cheap brands) Mobil1, Wix or Purolator are good. There could be a problem with the filter, either clogged, collapsed or a faulty relief valve. Beyond that, it could be a problem with the pickup tube screen clogged, a leaky tube to pump seal or a defective oil pump. Any way you look at it, it will be major work because you have to Remove the intake manifold and valve cover , Remove the oil pan and Remove the timing chain cover since the oil pump and pickup are in the timing chain cover . It's probably easier to replace the engine.

To me, it makes sense if the oil pressure is low, it would cause all sorts of problems with keeping the engine running right since the VVT uses oil pressure to adjust the exhaust camshaft. Would also affect the valve lifters. The cam phaser may have been replaced for nothing if the oil pressure is to blame.
The oil pressure has been verified, and it's low. 5psi@600 rpms I thought about changing the oil, but I think it's inevitable that this truck is done. The cold start mornings are too painful to listen to, gonna just cut my losses. I'm going to miss this truck it just rides soooo nice, but holy crap, this thing has absolutely no resale value!!!
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
If I remember correctly, the MINIMUM oil pressure at idle is 7psi. The reason your's is low is the main/rod bearings are a bit worn, allowing too much oil to 'seep out the sides'. It's also the reason for the cold knock.

The suggestion above to change the oil to a higher viscosity is a good one. Try going to 10-30 or even above, and use synthetic. At the point you're at oil additives aren't out of the question.

You may be able to buy yourself quite a bit of time with this. Vehicles are expensive, at least you'll have extra time to shop for one.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
I wouldn't go with 10w30 and here's why. There wouldn't be any difference between 5w30 and 10w30 when it's hot. As per http://www.upmpg.com/tech_articles/motoroil_viscosity/ :

When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.
So what you need to do is get a 5w40 or 5w50 oil to increase your oil viscosity when hot. You want to keep the 5w for the cold weather pumpability unless you're in a southern state (your profile just says United States).
 

swede

Member
Jun 22, 2014
1,576
I read the whole story and all the replies to it, but I found something interesting that nobody else thought about.

I'm just throwing in my $0.02 here and correct me if I'm wrong ok?

You sad that you couldn't fill her up, that the nozzle just clicked off all the time, to me that seams like the fuel tank vent is not working properly. You know when you fill up a tank with fuel the air inside the tank have to go some where to make room for the fuel. Well if your tank vent not working the fuel will fill up the filler tubein a hurry and shut off the fuel pump filler handle.

If you have any problem with the fuel tank vent system not working it's possible that your fuelpump while pumping fuel to the Engine creates a vacuum in the tank and then starve the Engine from fuel due to that the fuel pump can't deliverthe right amount fuel at the right pressure.

But like I sad, only my $ 0.02 what do I know??
 

Mike w

Member
Jun 24, 2014
287
Have you checked the intake manifold bolts? they have been known to be loose...
 

cruz8

Original poster
Member
Nov 28, 2014
7
Just an update. Still getting a p1345 code randomly. Noticed that the new cpas had oil in the connection, so I cleaned it up nicely and will see how it is over the next few days. It might be defective though. The only problem that remains is that I still get the "low oil pressure" warning after the truck has been warmed up a bit and at idle. I have found that if I park on the driveway or hill with the nose down, the oil pressure won't drop and display the warning. The truck also won't do the morning stall if it cold started with the nose down as well. I believe that all my stalls have been from my oil pressure problem all along.
 

Texan

Member
Jan 14, 2014
622
If it was my TB, I would be tempted to run a oil flush such as KW or Marvel Mystery Oil
for a few hundred miles and then change the oil & filter and use 5W-40 or 50 oil.
 
Apr 26, 2014
53
As crazy as it sounds,if you unplug the oil pressure switch the warnings will go away. Doesn't fix anything but may relieve a bit of anxiety if you are going to continue driving it. The readings will be false but might make you feel better.
 

cruz8

Original poster
Member
Nov 28, 2014
7
I think I am going to give the synthetic 0w30 a try. It's been below zero the past few days here in MN, and the oil pressure takes a bit longer to pickup after the overnight sit. I also have the GM block heater coming to help as well. I do appreciate all the help I've received here.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
The 0w30 won't help at all since it's when warm you have the pressure issues. The 30 means the viscosity when warm do both will be the same when warm. I would go with a 0w40 or 5w50. A flush is also a good suggestion.

Btw, was your CPAS a Dorman? If so, they're junk.
 

cruz8

Original poster
Member
Nov 28, 2014
7
I see, then the 0w40 will also help with that cold morning start and also help prevent the issue when warmed up and sitting at idle. Lately with the below zero temps, it has really struggled with the oil pressure until warmed up just a bit. I'm just trying to find that magic elixir to help with both ends of this issue. Oh, and I will do another oil system flush shortly here.

I'm not sure if the CPAS was a Dorman, but yeah, I have heard on here that they are bad. On the safe side, I will just get an AC Delco one in there instead. That darn p1345 just keeps coming and going.

Thanks
 

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