half throttle, car goes lean instantly...

[1turbo6]

fixed yet?

 

[bsdlinux]

Changed my sock on mine i will take a pic of it, it was FILTHY to say the least when i held it against the sun you could barely see through it, it idles awesome now haven't checked lean condition yet, but i am not going to the same gas station anymore, the sock was previously changed approx. 6 mos ago and 1500 mi.

I have to assume that the fuel pressure was dropping?? I'm having a similar problem but the fuel pressure is dead nuts on. But I was also told that you could have great fuel pressure but a volume problem which is still a pump or a sock problem??

 

[Jerryl]

I have to assume that the fuel pressure was dropping?? I'm having a similar problem but the fuel pressure is dead nuts on. But I was also told that you could have great fuel pressure but a volume problem which is still a pump or a sock problem??

To verify volume:
Connect the fuel pressure gage hose and grab a gallon jug.
Connect the hose on the Shraeder (SP??) valve, gage side open.
Add power to the pump connector under the hood.
You "should" see about 50 sec/gallon @ 43psi setting.

 

[bsdlinux]

To verify volume:
Connect the fuel pressure gage hose and grab a gallon jug.
Connect the hose on the Shraeder (SP??) valve, gage side open.
Add power to the pump connector under the hood.
You "should" see about 50 sec/gallon @ 43psi setting.

Ok will do. I already have a new 340 coming from FullThrottle. I believe the previous owner installed a Kirban intank pump. I have to replace the pump anyway, because the fuel pressure drops immediately to 0 when I shut the car off, either I have a bad pump or the fuel line that connects to the pump in the tank is leaking. So down comes the tank..damit

Even at 20 psi of boost I have hella fuel pressure though, 65 PSI all day long.... 45( Thrasher ) + 20 yep that math works Damn pressure never drops or jiggles while running. Always dead nuts on... go figure

I did not however take the EGR off to have a look see in the intake, thats next.

 

[bsdlinux]

are you asking him or me? I figured out what the problem is on my car. the intake side of the EGR is completely caked with grime. The only way to clean is to remove the intake completely.

Never heard of this being a problem?? What hell is the explantion for that one?? Guess I better check mine

 

[Chuck Leeper]

Huh???

To verify volume:
Connect the fuel pressure gage hose and grab a gallon jug.
Connect the hose on the Shraeder (SP??) valve, gage side open.
Add power to the pump connector under the hood.
You "should" see about 50 sec/gallon @ 43psi setting.

The gallon test is run at atmos PSI. Running the fuel out the shraeder valve bypasses the regulator...
If you want to see the flow at reg PSI, you have to install the hose to the jug on the return line fitting.

 

[Jerryl]

The gallon test is run at atmos PSI. Running the fuel out the shraeder valve bypasses the regulator...
If you want to see the flow at reg PSI, you have to install the hose to the jug on the return line fitting.

My bad :redface:............ you are correct!!!
Just the excess (if any ) will bypass the regulator.
Also, make sure you remove the Shraeder valve.

 

[t-typex1]

Im having a similar problem. If I hold the throttle less than half, it runs no problem. Anything over 10# of boost, it sputters. It wont go past 10#. At first I was thinking of changing the wastegate solenoid( I think thats what it's called, on the PS valve cover)should I be looking at the fuel pump as well? I bought mine from Full Throttle and have only put @50-75 miles on it since I bought it. I'd have to agree, its an annoying problem. I too am just hoping to resolve this issue.btw, dont have alky(yet)

 

[bsdlinux]

Im having a similar problem. If I hold the throttle less than half, it runs no problem. Anything over 10# of boost, it sputters. It wont go past 10#. At first I was thinking of changing the wastegate solenoid( I think thats what it's called, on the PS valve cover)should I be looking at the fuel pump as well? I bought mine from Full Throttle and have only put @50-75 miles on it since I bought it. I'd have to agree, its an annoying problem. I too am just hoping to resolve this issue.btw, dont have alky(yet)

All I know is forget everything you were told. Your fuel pressure can be perfect and the pump could still have a problem. Albeit.. this doesn't happen very often but a few on this board ruled out fuel pump problems due to correct fuel pressure only to go through everything and find that the damn pump is indeed the problem

Hell I've been through eveything to figure out this part throttle knock. If its the fuel pump so be it. The only other thing I can do is get rid of the stock injectors and put on my 83s with the modified ECM and my TT chip from the GN to see what happens. I've been through it all.... different ECM , chips, MAF Translator, stock MAF, different regulator... etc...etc you name it

The engine pulls 20 vacumn at idle, cam seems to be great. I'm not sure a wiped cam can pull that amount of vacumn at idle, I doubt it.

Good Luck. I'll update as I go, just waiting for that pump :biggrin:

 

[bsdlinux]

Part Throttle Knock continues

Ok. I disassmbled my upper intake, power plate, EGR and couldn't find anything wrong in there all looks great. Put it back together, re-install my Translator, and LT1 Maf, BLMs are looking real good. BUT.. still have part throttle knock even when cruising up a hill or something like that. Low timing street chip, etc..

I did however have an oil sucking PCV valve that I have fixed via a catch can. The only thing I can think of is maybe the car had been sucking oil for a very long time before I even got it and mybe I just have carbon deposits in the cylinders. The previous owner DID use the GM steel headgaskets which raises the compression a bit and MAYBE just a little carbon could do it, who knows.

Still waiting on the new 340 Pump, I hope it fixes the problem but at this point I have no faith. The only other thing I could possibly think of is maybe I have an injector acting up a little. These are Tomco 33# stock injectors. Like I said in an earlier post I might pop my 83s in there and see what happens.
More later...

Ok where is that pump

 

[DynamicGN]

Sorry it took so long guys, I broke my finger and havent been able to drop the tank. Anyway, I realized my alky isnt working...don't know if this is the full problem...but it is a problem. The solenoid clicks, but nothing pumps, its a new pump and the fuse in the SMC black box is good. I got it to work a little when I took the box apart and used the test button, but it stopped working, i guess it has a mind of its own. Has this happened to anyone, the spray on light doesnt even turn on when it works or doesnt work...i think i need a new system.

 

[Chuck Leeper]

Hmmmnn..

If you set your boost where no alky is needed and turn alky kit off all together..... does it still pop like that at part throttle?

Maybe if this idea had been explored, you would be a month closer to scalding some tires??? :biggrin:

 

[DynamicGN]

I had lowered it to 15 psi before, alky off...still knocked...so like i said, I dont think it all has to do with the alky....i used to run 17 psi without alky and no knock. I am gonna lower it to 10 and see what happens..

 

[DynamicGN]

ok 10 psi, not as much knock but still knock....a/f doesnt drop below 770...i don't know why it's knocking at such low boost. I dont get as much knock...5-8 points, and it only knocks at WOT not half throttle. So i guess i gotta drop the tank and take it from there, its hard working with one hand.

 

[chrisgarrett]

What's the latest? I have a similar problem.

 

[Daniel Jost]

Have you watched FP yet? Watch it when you get into it and you could very easily figure out your problem!

,Dan

 

[broke1]

The knock could be a bad esc module...And im shocked that no one has asked if you had plenty of gas?Aftermarket fuel tank?

 

[DynamicGN]

sorry guys, I sent my alky control to steve and he said it wasnt malfunctioning...so my problem is elsewhere, I need to fix my alky, it doesnt spray...i also need to order a FP guage...the tank and pump are fine, the sock isnt bad, i changed the fuel filter...so lets see what happens when i get the guage ( something i should have done a while ago, i know)..meanwhile I'll see whats wrong with the alcohol, probably a bad connection.

 

[84BuickGNYorkPA]

I had a similar problem and after all the chasing around it was a bad pump. And the pump was about 1 yr old when it wouldn't keep up only under boost and yes it was a walbro 340, hot wired. One thing for all to keep in mind when getting into the tank, well a couple of things for the new guys. Watch the rotation of the sock when you do the install, keep it in line with the float for the fuel gage, if you dont the sock won't be flat, it will fold if rotated out of location. Also don't forget to get rid of the reducer in the pipe that the pump hose hooks up to, I used a little cut off wheel(of course deburr the pipe inside diameter and the outside diameter). And get some electrical grease, take your time and check all the connections (in the tank around the pump)for tight or loose fittings. I used a plier's on the female connectors and closed them ever so slightly, then lubed them up with electric grease also while the grease is out do the main connection at the bumper. The fuel sending unit did not come off willingly so I didn't fight it and the gas gauge works good. Also with the voltmeter my ground ohms where not there so I attached a small ground to the frame and spliced into the factory harness right before the connector for the fuel pump.(Basically at the connector)
Hope this helps someone,

Chuck

 

[j5ash]

DJ, Hey Jason here, I was/am having the same problems as you. My SMC alky kit is doing the exact same thing, just happened to notice the spray light not coming on, hit the test button and it still doesn't come on. Here's where it gets wierd, with car idling, hit the test button, car seems to load up and dies. BUT, we can not hear the alky pump running, so we remove the line and of course no alky is coming through it. So I kill the power to the alky kit altogether, instead of just unplugging it under the hood, turn the boost down and go down the road and wala! PROBLEM GONE I haven't contacted SMC yet about sending in my kit to have it checked out but someway or another, it's causing my problems. Hope this helps you in your search, I'll keep You updated on my situation. Jason