[General Stalin]

Got a question for an automechanic or anyone who has done a lot of their own backyard wrenching and may have experienced this:

I have a high mileage 07 Yukon Denali (195k) and about 3 months ago at the tail end of a long day of driving it bogged down and stalled while on on the highway. I was able to pull it off the road and tried to restart but it would not stay running. Would fire up, idle rough for about 5 seconds, then stall. I thought it might be an oil pressure issue as the piston rings are worn and it burns a lot of oil. Called a buddy to bring me a couple quarts to see if that would get her running. After waiting for about 45 minutes my buddy showed up, I dumped some oil in it, and it fired up and ran fine. Drove it back home and hadn't experienced the problem again until a couple months later. Was driving back from an event and same thing - this time it stalled while in stop and go heavy traffic on the highway. Was able to limp it off the road and into a gas station. I put a bunch of oil in it again right away but that did not fix it this time. Still rough idle when starting then stalls soon after. Had it towed home and replaced the battery as it was old. Next day it started fine and had been running fine since the other day.

Had the same issue just a few days ago sitting in a parking lot letting it idle for a while. Was waiting for someone in a grocery store and wanted to have the AC on because it was hot so I was sitting with it running for a while. Started to bog down just sitting in the parking lot so I shut it off. Had the exact same issue... rough idle/stalling at low RPM didn't want to stay running. Let it sit overnight and next day drove it home fine.

Now here's the nuts and bolts:

It has two relevant codes - Fuel pump relay, and Catalytic Converter. The fuel relay I'm actually pretty sure is NOT the issue as this popped up only because I removed the relay when doing a wet and dry compression test on the motor. I bought a new fuel pump but have NOT installed it yet as I don't think that is the issue - as the problem is not consistent with a bad pump. Wouldn't make sense that the pump would only have issue when running for a long time, and would magically work after it sits for a while.

Here's my big question: could the cats be causing this?

As I mentioned my truck burns a LOT of oil. This has likely ruined the catalytic converters (which is why they are throwing codes) and since this rough idle/stalling issue only happens when the truck has been running for an extended period of time, I'm wondering if the cats are clogging up the exhaust when they get hot. Thoughts?

[Jay Gatz]

(03-07-2018 01:53 PM)General Stalin Wrote:  

Got a question for an automechanic or anyone who has done a lot of their own backyard wrenching and may have experienced this:

I have a high mileage 07 Yukon Denali (195k) and about 3 months ago at the tail end of a long day of driving it bogged down and stalled while on on the highway. I was able to pull it off the road and tried to restart but it would not stay running. Would fire up, idle rough for about 5 seconds, then stall. I thought it might be an oil pressure issue as the piston rings are worn and it burns a lot of oil. Called a buddy to bring me a couple quarts to see if that would get her running. After waiting for about 45 minutes my buddy showed up, I dumped some oil in it, and it fired up and ran fine. Drove it back home and hadn't experienced the problem again until a couple months later. Was driving back from an event and same thing - this time it stalled while in stop and go heavy traffic on the highway. Was able to limp it off the road and into a gas station. I put a bunch of oil in it again right away but that did not fix it this time. Still rough idle when starting then stalls soon after. Had it towed home and replaced the battery as it was old. Next day it started fine and had been running fine since the other day.

Had the same issue just a few days ago sitting in a parking lot letting it idle for a while. Was waiting for someone in a grocery store and wanted to have the AC on because it was hot so I was sitting with it running for a while. Started to bog down just sitting in the parking lot so I shut it off. Had the exact same issue... rough idle/stalling at low RPM didn't want to stay running. Let it sit overnight and next day drove it home fine.

Now here's the nuts and bolts:

It has two relevant codes - Fuel pump relay, and Catalytic Converter. The fuel relay I'm actually pretty sure is NOT the issue as this popped up only because I removed the relay when doing a wet and dry compression test on the motor. I bought a new fuel pump but have NOT installed it yet as I don't think that is the issue - as the problem is not consistent with a bad pump. Wouldn't make sense that the pump would only have issue when running for a long time, and would magically work after it sits for a while.

Here's my big question: could the cats be causing this?

As I mentioned my truck burns a LOT of oil. This has likely ruined the catalytic converters (which is why they are throwing codes) and since this rough idle/stalling issue only happens when the truck has been running for an extended period of time, I'm wondering if the cats are clogging up the exhaust when they get hot. Thoughts?

Your guess of it being the catalytic converters sounds quite likely to me as you are burning a lot of oil.

But personally I always try to do the easiest thing first: Which here would probably be giving it a good wash, charge the battery and check that nothing else is broken or is hanging loose.

After that is done, and no other problems have been spotted I would try to address the two fault codes.

Perhaps not very useful advice, but I am only a pushbike mechanic.

[roberto]

(03-07-2018 01:53 PM)General Stalin Wrote:  

Got a question for an automechanic or anyone who has done a lot of their own backyard wrenching and may have experienced this:

I have a high mileage 07 Yukon Denali (195k) and about 3 months ago at the tail end of a long day of driving it bogged down and stalled while on on the highway. I was able to pull it off the road and tried to restart but it would not stay running. Would fire up, idle rough for about 5 seconds, then stall. I thought it might be an oil pressure issue as the piston rings are worn and it burns a lot of oil. Called a buddy to bring me a couple quarts to see if that would get her running. After waiting for about 45 minutes my buddy showed up, I dumped some oil in it, and it fired up and ran fine. Drove it back home and hadn't experienced the problem again until a couple months later. Was driving back from an event and same thing - this time it stalled while in stop and go heavy traffic on the highway. Was able to limp it off the road and into a gas station. I put a bunch of oil in it again right away but that did not fix it this time. Still rough idle when starting then stalls soon after. Had it towed home and replaced the battery as it was old. Next day it started fine and had been running fine since the other day.

Had the same issue just a few days ago sitting in a parking lot letting it idle for a while. Was waiting for someone in a grocery store and wanted to have the AC on because it was hot so I was sitting with it running for a while. Started to bog down just sitting in the parking lot so I shut it off. Had the exact same issue... rough idle/stalling at low RPM didn't want to stay running. Let it sit overnight and next day drove it home fine.

Now here's the nuts and bolts:

It has two relevant codes - Fuel pump relay, and Catalytic Converter. The fuel relay I'm actually pretty sure is NOT the issue as this popped up only because I removed the relay when doing a wet and dry compression test on the motor. I bought a new fuel pump but have NOT installed it yet as I don't think that is the issue - as the problem is not consistent with a bad pump. Wouldn't make sense that the pump would only have issue when running for a long time, and would magically work after it sits for a while.

Here's my big question: could the cats be causing this?

As I mentioned my truck burns a LOT of oil. This has likely ruined the catalytic converters (which is why they are throwing codes) and since this rough idle/stalling issue only happens when the truck has been running for an extended period of time, I'm wondering if the cats are clogging up the exhaust when they get hot. Thoughts?

It worries me that you're just throwing oil in like you would diesel. Are you even checking the levels? If it's a diesel, with worn rings you've a very real risk of ending up with the engine running away on oil and blowing up.

When this odd behaviour happens, do you get any warning or service lights on the dash? Ie. is the ECU limiting the engine, or is it possible that the engine is so worn and that the oil has gotten so thin with the ambient temperature combined with extended running so as to be unable to maintain compression? I'd try a shot of something like Lucas heavy duty oil stabiliser in there.

I used to have an old Pugeot that was pretty knackered. When I started running it on chip oil the extra top end lubrication immediately gave it extra torque you could notice

[General Stalin]

I check the oil levels, yes. And I change the oil and filter every 3k miles like clockwork. It is not a diesel engine, otherwise the lost of compression from worn rings would likely be causing a very serious issue. This rough idle/stalling issue I've ruled out is NOT an issue with the oil. It's gotta be a fuel/air/spark/exhaust issue and given the symptoms that's why I suspect it could be the exhaust/cats.

[ShotgunUppercuts]

@General

Check the fuel injectors man

I had some similar symptoms with my vehicle like that.

[ShotgunUppercuts]

Might be the pcm went bad also. Causing the fuel pump not to work .

[Dalaran1991]

I'm thinking about buying a house and certainly there will be some work required on it. Repaint the wall, rewire some electronics stuff, installing shit etc.

I would like to know if it's possible to do most of these handyman stuff yourself, and if it's possible to learn these in 2-3 months? If so, do you have some online sources you recommend? What stuff that's better left to the professionals? (Repainting the wall is no brainer, but plumbing and electrics stuff?)

Something tell me that a ton of stuff that would cost you 5000+€ could easily be done with a little patience yourself.

Thanks gents,

[realologist]

(03-08-2018 11:36 AM)Dalaran1991 Wrote:  

I'm thinking about buying a house and certainly there will be some work required on it. Repaint the wall, rewire some electronics stuff, installing shit etc.

I would like to know if it's possible to do most of these handyman stuff yourself, and if it's possible to learn these in 2-3 months? If so, do you have some online sources you recommend? What stuff that's better left to the professionals? (Repainting the wall is no brainer, but plumbing and electrics stuff?)

Something tell me that a ton of stuff that would cost you 5000+€ could easily be done with a little patience yourself.

Thanks gents,

It depends on how easy the electrical and plumbing work is. Fixing/installing a toilet, sink, etc are all easy but replacing pipes I would call a plumber. For electrical something easy would be rigging an outlet to a light switch but rewiring the whole house I would leave to a pro.

[Laner]

Some of the things best left to professionals:

- Major wiring. You should learn how to do sockets, lights, etc but anything inside the walls or at the breaker leave to a pro.

- Plumbing if it requires any soldering. PEX is great for this reason, but if there is any running of pipe into tight areas, or retrofitting, hire a pro.

- Shower tiling. Basic tiling can be fine, but schluter systems and anything that needs water tightness or visual perfection is better left to a pro.

Almost everything else is fine on your own. General contract your own show and save even more.

[roberto]

Most of the easy money a plumber/sparky makes comes from charging out an apprentice at mega money to do donkey work. Stuff like chasing out walls etc.

Like Laner says, manage the project yourself. If you present as a guy who knows his shit and have a labourer working for you, the tradesperson will be more ammeniable when you say "OK, my guys have routed it all, I want to pay you for a day to come and make the final connections and sign it off"

Engage the spark and plumber from the start. Give them a little job and pay them well, good cups of tea. Tell them the score, that you're re-doing it all and get a written spec for the rewire/re-plumb. What you really don't want to do is run all the cables and then find when they come back to connect and certify that the stuff you've run isn't up to code.

[porscheguy]

(03-07-2018 01:53 PM)General Stalin Wrote:  

Got a question for an automechanic or anyone who has done a lot of their own backyard wrenching and may have experienced this:

I have a high mileage 07 Yukon Denali (195k) and about 3 months ago at the tail end of a long day of driving it bogged down and stalled while on on the highway. I was able to pull it off the road and tried to restart but it would not stay running. Would fire up, idle rough for about 5 seconds, then stall. I thought it might be an oil pressure issue as the piston rings are worn and it burns a lot of oil. Called a buddy to bring me a couple quarts to see if that would get her running. After waiting for about 45 minutes my buddy showed up, I dumped some oil in it, and it fired up and ran fine. Drove it back home and hadn't experienced the problem again until a couple months later. Was driving back from an event and same thing - this time it stalled while in stop and go heavy traffic on the highway. Was able to limp it off the road and into a gas station. I put a bunch of oil in it again right away but that did not fix it this time. Still rough idle when starting then stalls soon after. Had it towed home and replaced the battery as it was old. Next day it started fine and had been running fine since the other day.

Had the same issue just a few days ago sitting in a parking lot letting it idle for a while. Was waiting for someone in a grocery store and wanted to have the AC on because it was hot so I was sitting with it running for a while. Started to bog down just sitting in the parking lot so I shut it off. Had the exact same issue... rough idle/stalling at low RPM didn't want to stay running. Let it sit overnight and next day drove it home fine.

Now here's the nuts and bolts:

It has two relevant codes - Fuel pump relay, and Catalytic Converter. The fuel relay I'm actually pretty sure is NOT the issue as this popped up only because I removed the relay when doing a wet and dry compression test on the motor. I bought a new fuel pump but have NOT installed it yet as I don't think that is the issue - as the problem is not consistent with a bad pump. Wouldn't make sense that the pump would only have issue when running for a long time, and would magically work after it sits for a while.

Here's my big question: could the cats be causing this?

As I mentioned my truck burns a LOT of oil. This has likely ruined the catalytic converters (which is why they are throwing codes) and since this rough idle/stalling issue only happens when the truck has been running for an extended period of time, I'm wondering if the cats are clogging up the exhaust when they get hot. Thoughts?

If you don’t own a code reader, you need to get one. In addition to reading codes, it will allow you to erase them as well. It will allow you to clear off inconsequential stuff like fuel pump relay codes.

What’s the actual rate of oil consumption? How many quarts in 1000 miles of driving? Most engines can tolerate a certain amount of consumption with no ill effects.

What weight oil do you use?

I presume this is a gas engine which likely means the 5.3. Does it have active fuel management? Do the lifters rattle/tap when running?

Piston rings shouldn’t just wear out unless it was run without oil for a while. And if the rings do wear out, simply replacing them won’t fix your problem. I’ve done the AFM lifter repair so I’ve dug deep into the 5.3 engine. Many of them still have the cylinder honing marks clearly visible at 150K miles. If your rings are worn, look for a reman engine.

Heavy oil consumption can cause premature cat failure. It can cause blockages. But that kind of consumption should show up elsewhere. Your spark plugs should probably be fouled to the point of misfiring. When I say heavy consumption, I mean 1 quart of oil each time you fill with gas.

A failing fuel pump can cause it to run poorly or not at all. It can be intermittent as well.

Are you the original owner of the truck?

[General Stalin]

@porshceguy et al

Had a guy run the codes at the autoparts store. 6 catalytic converter below thresh codes (banks 1 and 2). Also had a lean code, and some older and inconsequential codes that weren't relevant (fuel pump relay code is gone). I also did an infared thermometer test to check the cats operation and from what I was looking at it seemed as though they weren't really working properly (basically no temperature change from the front of the cats to the back).

I probably go through a quart about every 1-2 tanks of gas. I use 5w30 full synthetic. Have used the same oil since I've owned the truck but I am not the original owner. I bought it @ 120k miles from a used dealership.

It is not the 5.3; its the 6.2 L92 (LS-based motor).

If/when I address the piston rings/oil burning issue I would likely just get a junkyard motor and rebuild it. For the money I'd rather do that than piss away $3500+ on a refurbished motor. I can pull a motor from a junkyard for around $200 then refurb, re-gasket, and clean everything up myself for well under $1000.

Here's an update to this issue: I decided it was definitely the cats (causing the stalling) so I went ahead and started the process of replacing them. It's been a lot of hard work as anyone who wrenches on cars knows that removing exhaust-system nuts and bolts are pretty much the worst nuts and bolts one will ever have to deal with. Had to cut one of the exhaust manifold flange nuts with a dremel as it was too seized up and got too rounded to be able to wrench off, and I broke both of the flange bolts on the flexpipe/muffler flange. Got the Y-pipe/cat assembly out finally and cut them out. They are pretty gummed up, but you can still see some light through them.

Anyway, I got two new universal magnaflow cats and have been welding them onto my old Y-pipe. I'm close to being done with the reassembly and reinstall so we'll see how she runs after this.

This does not fix the big issue which is surely my heavy oil consumption, but it will at least (hopefully) get my truck running reliably in the meantime.

I will report back once I have it all installed and go for a few test runs.

[glugger]

Does it run rough/ low rpm every time you idle, or only in one-off failure cases?

Regarding the possible cat converter issue:

Quote:

The first question is, can an exhaust leak cause a rough idle? When you have a rough idle situation and it's being attributed to an exhaust leak, it is more likely that the reason for a rough idle caused the exhaust leak.

https://www.bellperformance.com/blog/can...rough-idle

[General Stalin]

It only has this rough idle/stalling issue once it's been running for a long time (45+ minutes) and it never had an exhaust leak; that cats are bad and clogged up which I believe was causing an exhaust restriction.

[ShotgunUppercuts]

check the coil packs too General

[ShotgunUppercuts]

I planned to take my mother wooden table but someone took it (and destroyed and perfectly good one) before i could get a hold of it.

So now i want to build a kitchen table with my own hands,anywhere in paticular i should get some wood from? Does home depot carry some decent wood? I want to go all out on this

[Sooth]

(03-13-2018 02:08 PM)ShotgunUppercuts Wrote:  

check the coil packs too General

This is a good point.

I know there were a bunch of older Mitsubishis that had the same symptoms, and it was that after a long period of the engine running the engine bay heat warmed the faulty coil, increasing its resistance and making it run rough.

[Sidney Crosby]

For those that need to do basic plumbing but are afraid of soldering copper pipe check these out. They really simplify things, I've used them and they are great.

http://www.sharkbite.com/

[Laner]

(03-13-2018 06:33 PM)Sidney Crosby Wrote:  

For those that need to do basic plumbing but are afraid of soldering copper pipe check these out. They really simplify things, I've used them and they are great.

http://www.sharkbite.com/

I have used those to connect an old system to a new pex system. Great product, but very expensive. I would not hesitate to use them on a small run but for a whole room or home it would be painful on the wallet.

[General Stalin]

@ShotgunUppercuts and Sooth

Good tips. Will do!

[realologist]

(03-13-2018 02:12 PM)ShotgunUppercuts Wrote:  

I planned to take my mother wooden table but someone took it (and destroyed and perfectly good one) before i could get a hold of it.

So now i want to build a kitchen table with my own hands,anywhere in paticular i should get some wood from? Does home depot carry some decent wood? I want to go all out on this

Yes. Just make sure to pick out each piece of wood individually. Sand each piece. Do you plan on staining or painting?

[Laner]

(03-14-2018 06:07 AM)realologist Wrote:  

(03-13-2018 02:12 PM)ShotgunUppercuts Wrote:  

I planned to take my mother wooden table but someone took it (and destroyed and perfectly good one) before i could get a hold of it.

So now i want to build a kitchen table with my own hands,anywhere in paticular i should get some wood from? Does home depot carry some decent wood? I want to go all out on this

Yes. Just make sure to pick out each piece of wood individually. Sand each piece. Do you plan on staining or painting?

Stay away from 'softwood' if you can. You will want a hardwood - cherry or walnut is popular - so you can make sure it seals well. You wipe down a dining table multiple times per day and you don't want the 'slivers' lifting up or stains getting into the wood pores.

[ShotgunUppercuts]

Staining for sure.

[ShotgunUppercuts]

Gotta do a major brake job on my van.been hearing them scream lately when im not on the brakes.

Front caliper is fucked (im changing both)

Both rotors are too thin to be machined

Drums are fucked

Axle seal is fucked on one side

One drum is fucked on the other

Might do some of this work myself if i have the time.

[roberto]

Whilst it's best practice to change brake discs and pads in pairs, I see no reason to change both calipers if only one has failed, unless of course you are replacing with uprated components.

Also, you say it's fucked? I presume you mean sticking, as you're still driving it. When you have the caliper free from the disc (but still connected), pump the brakes till it pops out. Clean it up, and polish it with a buffing wheel. Reassemble with copious red rubber grease (and only red rubber grease, it's expensive but nothing else will do), and you'll probably get lucky. That's all there is to freeing up a piston.

You might as well do all of the work, seeing as you will have the wheels off anyway.

I'm confused when you say rotors (american for discs?) are fucked, then drums are fucked, then one drum fucked one side. Surely you have two rotors up front and two drums at the back?