02BlueStepside

iTrader: (1)

Alright, a little background I suppose:

About 10-12 months ago now, I parked the truck as the stock 4l60 was finally starting to slip on me and become undrivable. The truck sat for 8-10 months, cranked a few times in between while I saved money, collected parts, worked out a time with the guy doing the work, etc. Anyways, the day I took it over to get the work done, I was able to drive it, just had to take it easy as it only had 2 gears, and revved high in those 2 gears. Anyways, make it over there with no issues. Only thing I did notice is my fuel pressure wasn't where it should have been, but watching my o2 trims, seemed to be supplying enough as long as I didn't get on it.

So the work gets done, swapped over to a 4l80, wiring, tune, exhaust modified, etc. Afterwords the truck has a misfire and is throwing a couple codes, only recall the p0300 code. I clear the codes, get it home and seems to be doing ok. Can tell there is a misfire on cold start up, and when under a decent acceleration stumbles a bit. Eventually park it again, about 2 weeks ago, to do a little maintenance (new plugs, back to stock wires, change procharger oil, relocate procharger idlers, new filter, and maybe 1 or 2 other small things I'm forgetting. Upon doing so I did notice the plugs where a little on the dark side, and I found that 2 of my wires (Taylor 10.4mm) had cracks in the insulation from the stupid old design dynatechs with the "hump" on the drivers side.

So after that, crank it up, take it around the block, and it feels so much better but still couldn't pinpoint what wasn't right. Felt completely new cause I guess there wasn't any belt slip with as tight as the belt was due to the relocated idlers and it gave it so much more power (seat of the pants anyways). That in addition to actually feeling the 4l80 and shift kit due its magic. I was enjoying the truck for the first time in about a year. Fast forward to today, crank up and idle is horrendous, check engine light flashing, throwing codes p0172, p0175, and p0300.

So now the question is, where do I go from here? I don't know what to do. I am willing to do as much of the work as I can, just don't have a clue where to begin.

Sorry it is so long winded, but figure I would get it all out up front instead of making you guys ask the questions later.

02BlueStepside

iTrader: (1)

Huh, is there where I posted this? Or did it get moved? I suppose this section works too...

Anyways, any thoughts on this?

mcfarlnd

iTrader: (15)

Go over your connections for the air filter and anything you replaced or removed while doing maintenance on the truck there could possibly be unmetered air entering the engine. What are your Mods? MAF, MAFLess? And do you have tuning software? Your computer is dumping fuel for some reason, I would start with the simple stuff. Did you do a search? Also, after using the nifty search function, this seems to be a common issue in boosted applications.....

1FastBrick

iTrader: (17)

Were did you get the Tune From after the 4L80E Swap??? You mentioned you changed a Filter??? If this was the air filter are you sure you put it back together properly??? as mentioned un-metered air could cause this. Have you checked for Intake leaks around the intake gaskets??? that is also another common problem on these engines with some age. Gm even re-designed the gasket to help with this.

P0172 Fuel Trim too Rich (Bank 1)
P0175 Fuel Trim too Rich (Bank 2)
P0300 Random/Multiple Cylinder Misfire Detected

02BlueStepside

iTrader: (1)

The only tubing connections touched were the filter to elbow, elbow to supercharger, and supercharger to the rest of the piping. Mods are the procharger itself, injectors, fuel pump, Nelson tune and dynatech headers. A few other little odds and ends, but nothing to the actual engine itself. The MAF is still on the truck, and is after the supercharger, intercooler, just about in the stock location. Nothing has been touched with it in over a year. I do not have tuning software, the tune originally was done by Nelson Performance, and has been updated by them. No one else has touched the tune.

The truck has been supercharged for well over 5yrs with no changes since, other than routine maintenance. Probably has 30k or so on the setup. I will check over all the elbows from the intake to the throttle body.

Is it possible an injector is stuck dumping fuel? Of maybe one of the coil packs has went out? FPR maybe? How do I need to check for leaks around the intake? By hand? Soap and water mist around it like checking for air leaks in fittings?

1FastBrick

iTrader: (17)

Its a vacume system so soap and water will dissapear. Use something like brake clean or carb clean and spray around the base were the gaskets are. and around all the tubing after the MAF. If it has a severe enough leak it will suck it in and either raise the idle or or lower the idle and make the Engine stumble.

A leaky injector would usually affect 1 cylinder. same with a coil you would have a dead miss.

A FPR is possible. Pull the vacume hose off the FPR while its ideling and see if its leaking. If the diafram inside is bad it will have fuel comeing out when you pull the vacume hose off. If not visually leaking You would have to put a fuel gauge on the rail and make sure you get a 10 PSI change in pressure when you pulll the vacum line off.

mcfarlnd

iTrader: (15)

If this was a single injector or coil issue, the truck won't be rich in both banks. It is something that will affect both sides. An intake leak would most likely fail to one side or the other causing a rich condition in one bank or the other. Not saying that they won't but, very unlikely. Could be a FPR as tated before, faulty map sensor, maf or a vacuum leak that would not be partial to one bank. Let us know what you find.

02BlueStepside

iTrader: (1)

Didn't even think about the coil/injector only affecting one bank, thanks for that. So here is where I am at for the moment, only had a quick couple of minutes to look at it...

Pulled the vacuum fitting to the fpr, no fuel coming out. Also looked at my fuel pressure gauge, didn't notice a drop in pressure. So what does that mean? Bad fpr?

I also check all fittings, they are all tight from filter to tb. Went ahead and pulled the maf connections to see if it seemed dirty, couldn't even feel the slightest bit of oil residue on inside of the maf. Should I clean it anyways? I did however pull the plug to it to see if there was a change, idle got much worse unplugged. When plugged back up, was better, but still not right.

From what I can see the vacuum fitting all look to be intact and not leaking

Next steps?

02BlueStepside

iTrader: (1)

Any thoughts?

livefast1

iTrader: (1)

Fuel pressure generally goes up a couple of pounds with the vacuum line off the regulator. You mentioned the idle changed dramatically with the maf unplugged, how many grams/sec is it reading at idle? I would try cleaning it first. Could definitly cause a rich condition if its not reading properly.