I NEED to clean my intake manifold. Backfiring again.
07-13-2021, 12:29 PM
#11
I haven't done any testing myself, but I am a fan of the stock intake boxes for these rigs. I feel like they do pretty well and the paper filters catch a lot more than the single or even pleated fiber filters
For the cost of the NNBS vs cleaning, I might be inclined to swap to NNBS. There are pockets and runners in the manifold that can accumulate **** and you will never get it out
Clean and performance gain- win win
For the cost of the NNBS vs cleaning, I might be inclined to swap to NNBS. There are pockets and runners in the manifold that can accumulate **** and you will never get it out
Clean and performance gain- win win
07-13-2021, 06:59 PM
#12
I don't think its grit. I ran my finger along a small portion last time I cleaned the tb, and its a fine powder that's built up to the point where its looks like grit, (the best I can tell, and by feeling it). This is also why I want to pull it off to clean it to see if it is powdery, oily, or if there is another issue.
I searched for micron size before I ever bought one. I found K&N was the ONLY one I could find that only filters a percentage (and a lower percentage of everyone else) of 3 micron sized particles. I have never and will never use K&N. I'm not trying to spend money on this engine. I'm more or less waiting on a better time to cash in on some investments. It may take me a few years, or until something major goes wrong with this engine, but I do plan on going 6.0 eventually.
I don't think I gained any on the CAI, and I learned that the hard way. I keep thinking I'll put it back to factory some day.
What I read, I was just going to take some purple power and try to get it clean. How or how tough it will be to get it clean, was something I was going to find out in the moment.
I started searching on the NNBS intake swap. I found a couple of good posts that explain it all:
Nnbss/tbss - PerformanceTrucks.net Forums
Nnbss/tbss - Page 2 - PerformanceTrucks.net Forums
This TB link is inactive. I see adapters for about $30. Chinese TBs for about $50. In the same thread there is a link for
Home - WARR Performance LLC
with the 92mm 4 bolt DBC TBs for $140. (This would be my choice if I do).
After spending most of the day reading up on this, and looking for parts to see if this could be in budget I found this:
:45 "What we found out was that if you had a stock 4.8 or 5.3, and its just got headers and an intake, it actually didn't pick up any power at all"
Nobody who did this could say that it helped in any way. I'm still close to stock, and this engine will stay that way.
Its good info to know for down the road, but for now, I'm just going to go back to cleaning the manifold.
I haven't done any testing myself, but I am a fan of the stock intake boxes for these rigs. I feel like they do pretty well and the paper filters catch a lot more than the single or even pleated fiber filters
For the cost of the NNBS vs cleaning, I might be inclined to swap to NNBS. There are pockets and runners in the manifold that can accumulate **** and you will never get it out
Clean and performance gain- win win
For the cost of the NNBS vs cleaning, I might be inclined to swap to NNBS. There are pockets and runners in the manifold that can accumulate **** and you will never get it out
Clean and performance gain- win win
What I read, I was just going to take some purple power and try to get it clean. How or how tough it will be to get it clean, was something I was going to find out in the moment.
I started searching on the NNBS intake swap. I found a couple of good posts that explain it all:
Your fuel system is return. I would buy any 4 bolt intake you want from a Trailblazer SS, 08+ 4.8/5.3, a C5 fuel filter and this throttle body:
GM GEN LS1 LS2 LS4 LS6 LS7 92MM INTAKE MANIFOLD THROTTLE BODY PLATE ASSEMBLY SL | eBay
GM GEN LS1 LS2 LS4 LS6 LS7 92MM INTAKE MANIFOLD THROTTLE BODY PLATE ASSEMBLY SL | eBay
Theres plenty of info out there regarding these manifold swaps and there is certainly more than one way to get it done. But for a brief summary, on a 99-02 year model, you'll need the following:
-Cathedral Port intake manifold from an NNBS truck or TBSS
-Matching fuel rails from an NNBS truck. If you're running NBS style injectors then you have to use non-flex fuel rails. The flex fuel rails have shorter spouts to accommodate the taller flex fuel 36lb injectors. I believe LS2 style injectors will fit the flex fuel rails though.
-Or, if you choose you can use your original rails but they will have to be cut and shimmed to fit. The crossover will also hit the intake so it must be cut and fittings must be welded on to plumb a new crossover. I personally feel that adapting the factory rails is more diffficult and does not look as "professional" or well done. You can normally tell that they've been cut up and made to fit.
-a fuel filter from a C5 Corvette. This allows you to retain your factory return style fuel lines if you choose to use the NNBS rails. Your feed and return line go into the fuel filter on one side and the filter accepts a female 3/8 quick connect on the other side as an output to the rails. The vette filter is internally regulated and has a static 58psi output. You will need to have your tune adjusted to accommodate this change.
-you will have either fabricate a throttle bracket using an adaptation of your original or modify one of the aftermarket brackets to accept your truck cables.
-the MAP sensor wiring will need to be cut out of the factory harness wrap so that it will allow the connector to reach the new MAP location.
-you will have to determine what throttle body you will utilize or adapt your original. Adapting your original is counter-intuitive because your negate the main reason for the intake swap, the 90mm throttle opening.
-you will have to adapt your original EVAP lines to the NNBS Evap solenoid. There are several ways to do this, but it doesn't have to be hard, just do so how ever you feel works best for you. I personally just ran a short run of vacuum line from the solenoid to my original line that I had shorted partway along the straight portion next to the intake.
The rest of the install is pretty straight forward. It's not terribly difficult to accomplish, but it's also not something that you can just purchase a list of part numbers offline and send out to your mechanic. Things will need to be customized, fabricated, or modified to fit. But if youre planning to cam the motor, it's well worth the swap. My cammed 6.0 simply could not breath above 5k with the factory NBS intake. I picked up a noticeable and quantifiable amount of power from the swap.
-Cathedral Port intake manifold from an NNBS truck or TBSS
-Matching fuel rails from an NNBS truck. If you're running NBS style injectors then you have to use non-flex fuel rails. The flex fuel rails have shorter spouts to accommodate the taller flex fuel 36lb injectors. I believe LS2 style injectors will fit the flex fuel rails though.
-Or, if you choose you can use your original rails but they will have to be cut and shimmed to fit. The crossover will also hit the intake so it must be cut and fittings must be welded on to plumb a new crossover. I personally feel that adapting the factory rails is more diffficult and does not look as "professional" or well done. You can normally tell that they've been cut up and made to fit.
-a fuel filter from a C5 Corvette. This allows you to retain your factory return style fuel lines if you choose to use the NNBS rails. Your feed and return line go into the fuel filter on one side and the filter accepts a female 3/8 quick connect on the other side as an output to the rails. The vette filter is internally regulated and has a static 58psi output. You will need to have your tune adjusted to accommodate this change.
-you will have either fabricate a throttle bracket using an adaptation of your original or modify one of the aftermarket brackets to accept your truck cables.
-the MAP sensor wiring will need to be cut out of the factory harness wrap so that it will allow the connector to reach the new MAP location.
-you will have to determine what throttle body you will utilize or adapt your original. Adapting your original is counter-intuitive because your negate the main reason for the intake swap, the 90mm throttle opening.
-you will have to adapt your original EVAP lines to the NNBS Evap solenoid. There are several ways to do this, but it doesn't have to be hard, just do so how ever you feel works best for you. I personally just ran a short run of vacuum line from the solenoid to my original line that I had shorted partway along the straight portion next to the intake.
The rest of the install is pretty straight forward. It's not terribly difficult to accomplish, but it's also not something that you can just purchase a list of part numbers offline and send out to your mechanic. Things will need to be customized, fabricated, or modified to fit. But if youre planning to cam the motor, it's well worth the swap. My cammed 6.0 simply could not breath above 5k with the factory NBS intake. I picked up a noticeable and quantifiable amount of power from the swap.
This TB link is inactive. I see adapters for about $30. Chinese TBs for about $50. In the same thread there is a link for
Home - WARR Performance LLC
with the 92mm 4 bolt DBC TBs for $140. (This would be my choice if I do).
After spending most of the day reading up on this, and looking for parts to see if this could be in budget I found this:
Nobody who did this could say that it helped in any way. I'm still close to stock, and this engine will stay that way.
Its good info to know for down the road, but for now, I'm just going to go back to cleaning the manifold.
Last edited by adriver; 07-13-2021 at 07:09 PM.
07-13-2021, 07:02 PM
#13
TECH Veteran
Didn’t mean to say K&N don’t know where I got that lol
07-22-2021, 11:22 PM
#14
Well, I finally got a chance to start on this tonight. Got the intake and TB off, and took a better look inside. It was no where near as dirty as I thought it was. In fact it looked pretty clean. I really have no idea how I thought I saw it looking gritty to it actually being clean. The only thing I noticed was about a teaspoon of fuel sitting in the intake manifold when I pulled the TB off. I'm going to hold off on pulling the intake for now.
I'm using a generic 91 tuner, and have been for a while. If I let it go longer than the suggested interval time to clean the intake, MAF, and TB, I will occasionally get a backfire If I let off quick, when its cold. I don't think its just the air temp warming up, but the point of this in the first place was; lately it has been feeling like it is just a hair or two sluggish on the response, and two hairs shy of its usual WOT. Combined with getting a backfire so soon this time, since I had just recently cleaned that, maybe I WANTED to see the intake dirty. Everything looked good, but since Its off, I went and cleaned it again, changed the PCV, and added an oil catch can.
When I recently cleaned it, I had oil on the threads on #5 It looks like I have a BUNCH of crud and signs of fluid on top, of the valley cover and I think I need to replace the head or valve cover gaskets. I just bought a compression check tool, so I can see if that gives me a better idea if that cylinder is slacking. I am guessing that will be the problem, and read up on dry and wet compressions if it is. I still plan on putting a 6.0 in place some day (hopefully soon, but probably years down the road or when something major goes wrong). If I could find a cheap, real low mileage 5.3, that could be installed with a cam, and maybe a little more, I would probably go that route. I'm really not trying to put any money into this 4.8, other than maintenance. I don't like that I have to rev the hell out of it, and neither does my pressure plate (which is now starting to make some noise too). I don't need a lot more power, I would be happy with a little more, and a better powerband until I can get the suspension finished.
Assuming the compression check tells me what I am expecting it to. Is it is basic as, rings probably isn't worth it for me to replace for how I'm looking at it, but if its a valve it might be (if I can do the work)? Is there anything else I could check? (I'm not getting any codes).
I'm using a generic 91 tuner, and have been for a while. If I let it go longer than the suggested interval time to clean the intake, MAF, and TB, I will occasionally get a backfire If I let off quick, when its cold. I don't think its just the air temp warming up, but the point of this in the first place was; lately it has been feeling like it is just a hair or two sluggish on the response, and two hairs shy of its usual WOT. Combined with getting a backfire so soon this time, since I had just recently cleaned that, maybe I WANTED to see the intake dirty. Everything looked good, but since Its off, I went and cleaned it again, changed the PCV, and added an oil catch can.
When I recently cleaned it, I had oil on the threads on #5 It looks like I have a BUNCH of crud and signs of fluid on top, of the valley cover and I think I need to replace the head or valve cover gaskets. I just bought a compression check tool, so I can see if that gives me a better idea if that cylinder is slacking. I am guessing that will be the problem, and read up on dry and wet compressions if it is. I still plan on putting a 6.0 in place some day (hopefully soon, but probably years down the road or when something major goes wrong). If I could find a cheap, real low mileage 5.3, that could be installed with a cam, and maybe a little more, I would probably go that route. I'm really not trying to put any money into this 4.8, other than maintenance. I don't like that I have to rev the hell out of it, and neither does my pressure plate (which is now starting to make some noise too). I don't need a lot more power, I would be happy with a little more, and a better powerband until I can get the suspension finished.
Assuming the compression check tells me what I am expecting it to. Is it is basic as, rings probably isn't worth it for me to replace for how I'm looking at it, but if its a valve it might be (if I can do the work)? Is there anything else I could check? (I'm not getting any codes).
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tjmath (07-26-2021)
07-26-2021, 12:25 AM
#16
I definitely do. The sad part is I have a new hptuners with 2 credits sitting right here. I have parts for several upgrades waiting to go in, just need to stop being so damn lazy and get it done.
The only real concern I have beside being my first time trying to figure out tuning is, I have the generic tune on it, but don't have the handheld tuner to remove it. The dealer told me they would charge $200 to set it back to factory, and I don't know if that really matters.
When I pulled all this intake off again, my rubber intake couplers were... "peeling". The rubber was just rubbing off as if I had poured goo-gone on it, and it was shredding like it was melting. I'm really hoping none of that got in the engine, and not going to risk driving it until my replacement couplers come in tomorrow.
The PCV valve seemed a little gummed up. The innards were moving, but it wasn't clean sounding, and only "hitting" in one direction when I shook it. I should get a chance to see if I notice anything tomorrow.
My compression gauge came in today. I want to see how the pcv valve change is before I remove the spark plugs back out.
The only real concern I have beside being my first time trying to figure out tuning is, I have the generic tune on it, but don't have the handheld tuner to remove it. The dealer told me they would charge $200 to set it back to factory, and I don't know if that really matters.
When I pulled all this intake off again, my rubber intake couplers were... "peeling". The rubber was just rubbing off as if I had poured goo-gone on it, and it was shredding like it was melting. I'm really hoping none of that got in the engine, and not going to risk driving it until my replacement couplers come in tomorrow.
The PCV valve seemed a little gummed up. The innards were moving, but it wasn't clean sounding, and only "hitting" in one direction when I shook it. I should get a chance to see if I notice anything tomorrow.
My compression gauge came in today. I want to see how the pcv valve change is before I remove the spark plugs back out.
Last edited by adriver; 07-26-2021 at 05:12 AM.
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