Why am I running so rich???

[jcfreeman0]

Ok so i'm trying to figure out possible reasons my truck is running so rich. Its a 4.8L engine. i've done the following to it:
220/222 110lsa comp cam
SLP valve springs
LS1 intake manifold w/ 28.8 injectors
Return style fuel setup
Walbro 255 fuel pump
Professional Products Fuel Pressure Regulator
SLP shorty headers w/ no cats into magnaflow round mufflers
Only front 02 sensors
Blackbear tune
Removed EGR and EVAP
Electric Fan
MAF right in front of the throttle body w/ cone filter in front of it (sticking right off the front of the engine)

Ever since I did this motor work its not run right. Its very rich. If i get on it if bogs out / shuts off briefly. It backfires really bad too. I'm already on my second set of plugs and thats just loading and unloading it on a trailer to go to maybe 4 shows.

It smells very hot when its running but it is probably the exhaust from all the extra fuel dumping out.

The fuel pressure goes down to almost 0 within a minute of turning the engine off.

I'm not 100% i have all the vacuum lines in the correct placement. I used the LS1howto.com as reference though.

I did have to extend the lines to the injectors, MAF, throttle body, 02 sensors.

What should I check? I plan on having a friend scan it tomorrow or friday but i'm affraid it wont help me here.

[casey23]

Does it even have a re tune?????....... at least set up for the new injectors?.... MAF needs to be further from the TB if possible.... and make sure you didnt soak it down in K and N oil already.........

[oleshifty]

turn the fuel pressure regulator down a lil

[casey23]

turn the fuel pressure regulator down a lil

At least make sure u hooked up the Hose to the FPR !!!

[96/chevy/pu]

At least make sure u hooked up the Hose to the FPR !!!

How much fuel pressure do you have? and will need a tune

BB

[ducky]

see below

Ok so i'm trying to figure out possible reasons my truck is running so rich. Its a 4.8L engine. i've done the following to it:
220/222 110lsa comp cam
SLP valve springs
LS1 intake manifold w/ 28.8 injectors
Return style fuel setup
Walbro 255 fuel pump
Professional Products Fuel Pressure Regulator
SLP shorty headers w/ no cats into magnaflow round mufflers
Only front 02 sensors
Blackbear tune
Removed EGR and EVAP
Electric Fan
MAF right in front of the throttle body w/ cone filter in front of it (sticking right off the front of the engine)

Ever since I did this motor work its not run right. Its very rich. If i get on it if bogs out / shuts off briefly. It backfires really bad too. I'm already on my second set of plugs and thats just loading and unloading it on a trailer to go to maybe 4 shows.

It smells very hot when its running but it is probably the exhaust from all the extra fuel dumping out.

The fuel pressure goes down to almost 0 within a minute of turning the engine off.

I'm not 100% i have all the vacuum lines in the correct placement. I used the LS1howto.com as reference though.

I did have to extend the lines to the injectors, MAF, throttle body, 02 sensors.

What should I check? I plan on having a friend scan it tomorrow or friday but i'm affraid it wont help me here.

[farmtruc]

like the guys said, but to be more specific.

make sure the injectors were tuned for, stock is 24lb, you upgraded to 28's, that'll make it run richer.
be sure the fp is set about 58psi. you'll get different opinions on this, but i like a constant 58psi of fp, not 45psi at idle and 58psi at wot, so for me, i leave the hose off the fpr.
be sure the maf isn't wet or dirty, that'll cause drivability issues.
the intake is throwing off the ltrims as well. be sure they are no more than -10 value, they are probably -20 to -25, if you're saying the truck is that rich and the pcm is ready to set a code.

your truck really doesn't have enough mods for an sd tune, but if the maf is bad, it might be a route to take.

good luck,

[jcfreeman0]

like the guys said, but to be more specific.

make sure the injectors were tuned for, stock is 24lb, you upgraded to 28's, that'll make it run richer.
be sure the fp is set about 58psi. you'll get different opinions on this, but i like a constant 58psi of fp, not 45psi at idle and 58psi at wot, so for me, i leave the hose off the fpr.
be sure the maf isn't wet or dirty, that'll cause drivability issues.
the intake is throwing off the ltrims as well. be sure they are no more than -10 value, they are probably -20 to -25, if you're saying the truck is that rich and the pcm is ready to set a code.

your truck really doesn't have enough mods for an sd tune, but if the maf is bad, it might be a route to take.

good luck,

I double checked with him and he did set it for the 28.8 injectors. The fuel pressure is at 58psi at idle (with the ref hooked up) When i rev the engine it drops to about 52 then back up. I'll check the MAF to see if its dirty when i get home. I did unhook the MAF and the TB last night and it runs the same hooked up and unhooked.

Now since i put that new walbro in it wont stay running either. (just put it in the other day to replace the MSD pt# 2225). If i keep my foot on the pedal just barely it does but wont idle on its own.

[farmtruc]

Sounds like the fpr is fine and set, the maf is good, tune is good.

Just needs some fine tuning.

With the ls intake and relocated maf, the tune probably needs to be tweeked, which is normal.
Plus, you're regulating the fuel better than factory, so that's one variable on why the truck is a tad rich.

Just have your tuner lean it out, give him the ltrim values, that'll help.

[casey23]

see below

Thank for you for the Correction.. DID YOU HAVE A RE-TUNE done from your BLACKBEAR TUNE Since your motor work ??? SINCE YOU INSTALLED A CAMSHAFT, and BIGGER INJECTORS and a new FPR that will all effect the tune.... but what do i know... I will stay out of the tech support and leave it for you Pro's !