SOLVED: Another misfire chasing threads (2008 express van)

[Tonyv__]

Pulled the intake manifold today. Found all this gunk… should I clean it out? And if so what do I clean it with?

 

[Tonyv__]

Months of headache may of finally come to an end. Replaced the intake manifold gasket on a whim. Then drove it for a day or so. Code reader picking up misfire 7 again and now a new code evap leak…. At this point WHAT THE F***!!! I was so close to throwing in the towel. I even called 2 local mechanics to try to schedule my van. Weirdly enough. Neither one called me back…. I popped the hood a few days later and noticed the evap hose was not connected to the purge cylinder thing! Hooked it up nice and secure. Cleared the codes and were we are about 2 weeks later nice smoooth idle. Hope I don’t jinx myself

 

[Tonyrodz]

Months of headache may of finally come to an end. Replaced the intake manifold gasket on a whim. Then drove it for a day or so. Code reader picking up misfire 7 again and now a new code evap leak…. At this point WHAT THE F***!!! I was so close to throwing in the towel. I even called 2 local mechanics to try to schedule my van. Weirdly enough. Neither one called me back…. I popped the hood a few days later and noticed the evap hose was not connected to the purge cylinder thing! Hooked it up nice and secure. Cleared the codes and were we are about 2 weeks later nice smoooth idle. Hope I don’t jinx myself

Can you post a pic what/where you're talking about.

 

[Tonyv__]

Can you post a pic what/where you're talking about.

So directly behind the alternator is this vapor purge thing. I think. It’s mounted on the intake manifold. The hose wasn’t clicked in all the way and fell off. So I had to secure it.

 

[Tonyrodz]

So directly behind the alternator is this vapor purge thing. I think. It’s mounted on the intake manifold. The hose wasn’t clicked in all the way and fell off. So I had to secure it.

Thx. I'm still chasing my low idle issue. Idles around 425-450 rpms. My P0300 went away when I swapped out my plugs--I also gutted one of my cats. They're both clogged some, but the gutted one was the worst. Strange because when I bought it at 110k, driving it home the P0300 popped up--did plugs and wires, and that damn code was still there. I did buy the plugs--1st time--on Amazon. Might've been bootlegs. 2nd set I got from Advance, at changed it at 152k. Has 153k on it now. Low idle is going on 2 yrs now. Annoying.

 

[Tonyv__]

Thx. I'm still chasing my low idle issue. Idles around 425-450 rpms. My P0300 went away when I swapped out my plugs--I also gutted one of my cats. They're both clogged some, but the gutted one was the worst. Strange because when I bought it at 110k, driving it home the P0300 popped up--did plugs and wires, and that damn code was still there. I did buy the plugs--1st time--on Amazon. Might've been bootlegs. 2nd set I got from Advance, at changed it at 152k. Has 153k on it now. Low idle is going on 2 yrs now. Annoying.

I’m sitting in mine right now. Mine idles at 500 consistently. Which I think is a tad low. I cleaned the throttle body. Fuel injector cleaner. I think a few other things about a year ago. And I just let it go. I was more concerned about the misfire


I do know that replacing the throttle body on my Tahoe fixed the low idle issue I had on that… I bought new sensors and cleaned the TB. Didn’t fix the problem. So I wen to junkyard and pulled one off a Yukon and slapped it on my Tahoe just like that with the used sensors and all fixed the problem

 

[Tonyrodz]

I’m sitting in mine right now. Mine idles at 500 consistently. Which I think is a tad low. I cleaned the throttle body. Fuel injector cleaner. I think a few other things about a year ago. And I just let it go. I was more concerned about the misfire


I do know that replacing the throttle body on my Tahoe fixed the low idle issue I had on that… I bought new sensors and cleaned the TB. Didn’t fix the problem. So I wen to junkyard and pulled one off a Yukon and slapped it on my Tahoe just like that with the used sensors and all fixed the problem

So far I've done the map, maf sensors and swapped a known good throttle body. Intake gaskets were done maybe 3 years ago. I tried spraying around the intake with brake clean with no results. Really ****** me off. I saw on yt a supposed common issue for a messed up idle is broken internal wires that plug into the maf sensor--just like on the Tahoes.

 

[Tonyv__]

So far I've done the map, maf sensors and swapped a known good throttle body. Intake gaskets were done maybe 3 years ago. I tried spraying around the intake with brake clean with no results. Really ****** me off. I saw on yt a supposed common issue for a messed up idle is broken internal wires that plug into the maf sensor--just like on the Tahoes.

That spray with carb cleaner didn’t work for me either. I even smoke tested it. Couldn’t find the leak on the intake

 

[Tonyv__]

Back again…. I really really thought the intake manifold did it but 3 solid days of running then BAM misfire is more noticeable than ever. Truck shakes at idle. Never did this before just minor rumbling…. I’ve read here and there that sometimes gunk from the fuel rail seems to settle at the number 7 injector area so I’m probably gonna pull the rail and the injectors out to see if it’s clogged? If nothing there I think I have no choice but to pull the heads and inspect the valves, lifters, and cam. I find it hard to believe that it would be mechanical because it’s still only at idle. But i feel like I’ve explored all avenues and no results.

One more question about vacuum… is the valley cover under vacuum? So when I pulled the intake I stupidly used the valley cover as leverage to pry the intake off and dented the cover… i don’t know if this cover is crucial to the function of engines performance or to just keep crud out of the internals…. The worsened misfire did not happen right after this. It ran perfectly fine for a few days (which I thought was fixed) then the worsen misfire occurred in the same cylinder. So I’m wondering if I caused a leak there

 

[Tonyv__]

FINALLY HAVE SOME ANSWERS!!!
Caved in and tore the cylinder head off. I have an eaten up lifter on cylinder 7… so now I have to weigh my options.

Do I rebuild the top end while in the truck? Need some opinions on the valves? Do I just get the heads rebuilt since I have them off the truck anyway? Assuming the dead lifter is gonna cost me a cam? While I’m in there do I do the timing chain as well? Planning on doing a high output melling oil pump while in there since I have low oil pressure.. after I price this all out I need to consider if it makes sense to fix the top end and freshen up a few other things or do I just spend the money on a long block and replace the whole thing

Opinions and advice please.

The lifter pictured is the 2nd lifter from the back of the engine on cylinder 7. The valves pictured are cylinder 7 and the picture of the cam doesn’t show much

 

[OR VietVet]

At under 60k miles I would redo the top end and do the cam, every time I find bad lifter(s). I would have the heads freshened up. IMO, I would drop the pan and check for any debris in the pickup and do the o-ring while in there. Also, a new oil pressure sensor with the filter, right.

 

[Tonyv__]

At under 60k miles I would redo the top end and do the cam, every time I find bad lifter(s). I would have the heads freshened up. IMO, I would drop the pan and check for any debris in the pickup and do the o-ring while in there. Also, a new oil pressure sensor with the filter, right.

Thoughts on this O ring? Was it improperly seated? I can’t find any damage on the o ring itself. But the red marking on the o ring are uneven on the tube

Also top end rebuild it is. I’m calling a few machine shops around me to see how fast I can get them done. Also trying to pull the cam as early as tomorrow morning to make sure the cam bearings didn’t get wiped out. That will be my deciding factor if I just buy a long block or rebuild the top and keep going because apparently the engine has to come out anyway to do the cam bearings

 

[OR VietVet]

I see no problems with the o-ring. Replace with new though and wash out the pick up tube or replace. Make sure the tube mount bracket is in great shape with no cracks. Check for ANY debris in the pan and clean as well. Do the oil sensor and the filter. When you do the heads, freshen up the valve seats and valve guides and seals. It is apart and is perfect time to do that, even with the low miles. GM or Fel Pro gasket kits, IMO. While you have it apart, freshen up anything that looks suspicious.

 

[Tonyrodz]

Not sure if you'd want to go this route, but I saw a guy on CL in Montville NJ who's selling a 6.0 from a 2013 for $850. Doesn't mention the mileage. https://newjersey.craigslist.org/pts/d/montville-2013-chevy-express-van-3500/7396672522.html
I think the 4.8 in my 05 is on it's way out too. Pretty positive there's a crack in the 862 head. I used some Blue Devil in it, but I know it's just a matter of time before it goes. Only has 153k on it too.

 

[Tonyv__]

Not sure if you'd want to go this route, but I saw a guy on CL in Montville NJ who's selling a 6.0 from a 2013 for $850. Doesn't mention the mileage. https://newjersey.craigslist.org/pts/d/montville-2013-chevy-express-van-3500/7396672522.html
I think the 4.8 in my 05 is on it's way out too. Pretty positive there's a crack in the 862 head. I used some Blue Devil in it, but I know it's just a matter of time before it goes. Only has 153k on it too.

I’m not totally opposed to buying used. But I’m just so stuck on my van only having 42k miles when I bought it and apparently was either neglected or the high engine hours killed it. Or the fact that I didn’t address the oil issue a while ago….makes me weary of buying someone else’s engine with unknown history.

The experience of working on this van makes me want to get a new motor and never ever have to touch it again lol. But thanks for the link.

 

[Tonyv__]

I see no problems with the o-ring. Replace with new though and wash out the pick up tube or replace. Make sure the tube mount bracket is in great shape with no cracks. Check for ANY debris in the pan and clean as well. Do the oil sensor and the filter. When you do the heads, freshen up the valve seats and valve guides and seals. It is apart and is perfect time to do that, even with the low miles. GM or Fel Pro gasket kits, IMO. While you have it apart, freshen up anything that looks suspicious.

I was considering the melling high output also comes with a new tube but im getting mixed reviews. Some say go high output and some say it won’t fix my problem. A local machine shop is even telling me that my heads will fail prematurely because the oil will shoot too hard and not oil my heads properly.

As far as where I’m at now. I’m pretty much replacing everything that I’m taking apart. As I never want to have to dig into this engine again. Working on the van is awful

 

[OR VietVet]

If you think working on it is awful, try pulling the engine and reinstall another one. The whole front area comes apart to get it out. PITA. I personally pulled a small block 350 out of an older Chevy van years ago in one of my shops. I freakin' hated that beast.

 

[Tonyv__]

If you think working on it is awful, try pulling the engine and reinstall another one. The whole front area comes apart to get it out. PITA. I personally pulled a small block 350 out of an older Chevy van years ago in one of my shops. I freakin' hated that beast.

I’m not so much worried about taking the rad support out and srufff. It’s the fact that I really don’t think a cherry picker fits between the engine and the body of the van…

 

[OR VietVet]

It will fit but you have to be creative. I had to jack up and set the front end on small jack stands and stretch the picker arm out and then lift of the frame mounts and then remove the motor mounts on both sides and then roll out and coax with pry bars to wiggle it out and then back in. Again, PITA!

 

[Tonyrodz]

Def gonna be interesting.......
I think I'll be in the same boat in a year or 2.