ok well to start ill say what ive replaced. which was just some cracking vacuum lines and pcv valve. i use the truck to get to work and usually drive 30-40 miles each way and MPG hasnt been very good. all info needed will be on this video. also there is no black smoke or anything, and it does lack a little more power then my sonoma did, just wondering if i could do serious damage to, fuel pressure when primed is about 55psi and 50psi when i start it. heres the video...

JUST CLICK ON IT AND IT WILL PLAY!!!

 

any 1?

 

get that code read.

 

i know the code. its p0171 - p0174 bank 1 bank 2 lean. i need info on fixin it. i cleaned the iat maf, map looks oily, there is a hint of gas from the throtle body when i take off the air intake pcv valve is new, new vac lines all around, still baging at initial takeoff, sometimes wont bog and give good power other times its killing gas milage and i gota give more gas to the pedal. HELP!! and i used my buddies vac gauge and running its inbetween normal and early timing

 

ok well i replaced the fuel filter, the old one was dirty and i could shake it and hear the filter moving, seems like the fuel pressure dropped more now...so now what could it be? i would have drove it with the gauge hooked up but i didnt have the $150 deposit for Autozone to let me leave the lot with it... this test is from the shreader valve

WHILE PRIMING AND STARTING!!! CLICK IT TO WATCH!!!



AFTER LETING IT SIT FOR 5 MINS, LEAKDOWN!!!



Any help would be greatly appreciated

 

you dont have enough pressure. it supposes to be 60 not 55. there could be two things going bad here one fuel pressure regulator and two fuel pump. Does your fuel pump makes loud noise? but my guess would be your fuel pump since it doesnt put right amount of pressure. if you replace it you should replace it with ac delco. its expensive but worth it

 

ok i think i might have figured out what the problem is but wont be able to check till i get paid. i got in the truck and driving it will take off by itself and pull, when i shift to nuetral the gas gauge goes from 1/4 to under empty with stoping, i drop it again and when i started it, it showed a full tank which was rong, then i drive at 25mph and shift to nuetral and it drops to empty completly, and with the low fuel pressure thats most likely the fuel pump and sender unit right? now filter causes lower fuel pressure to 48 primed and 43 running. correct me if i am wrong, and thanks again guys for your help. and sorry for the long posts just tryin to give all the info i can.

also how hard is it to drop the tank with only 2 gallons of gas in it? how long does it take? and also ONDER i do smell just a hint of gas in the intake. and no the fuel pump is silent, my sonoma used to have a very loud fuel pump, i could hear it over my radio but pressure on it was 60psi running and 68psi primed and it ran well for 48k miles b4 i flipped the truck in snow.

 

As far as running lean, I would suspect you have a vacuum leak in the intake track. maybe the manifold?

As far as running with no thermostat, I would get one in there. The truck is not getting warm enough to get to a closed loop cycle. You probably have a code for the thermostat as well.

I tried a 180 constant flow thermostat and got codes, went back to the factory and have had no issues. With the stock tune, I would maybe go with a 185.

Justin

 

if you dont hear anything from fuel pump i wouldnt suspect it. replacing the fuel pressure regulator is easy and cheaper. try to replace that first and see what happens. if you need help let me know i have done it and im not a mechanic at all i just started to learn and i did it.

 

Well i work tonight ill try the PR tommarow if i can come up with the money. Also do you have any pictures on how to do it? Also about the thermostat i didnt have 1 on my sonoma and it never threw a code and so far only codes on the blazer is the lean condition. Is it bad to drive it like it is? It drives fine just initial takeoff sucks.