Fuel Filters? Loss of power...supercharger

[johndjmix1]

Is the "sock" style fuel filter thats on the pickup on the in-tank fuel pump the only filter in the fuel system?

I installed my supercharger about a year ago, and the only way to get the pump back together was to remove a hard plastic piece from that sock filter Radix sent me. In order to do this I had to cut a small slit in the sock. (I know guys, but it was 2am and it was the only way).

Lately ive noticed a loss of performance, mainly by since when I put the SC on the h2 would easily spin the tires off a start. Now it doesnt even come close. Its still way faster than stock, but somthing has definatly changed. Still runs perfect, just a bit "slugish" espically out of the hole.

Im thinking maybe clogged injectors? But if that was true wouldnt it just run a bit lean? Someone help me on this, I dont know where to start.

Its proboly not a bad thing since this last transmission is holding now -).

--John

[johndjmix1]

Anyone?

[HUMMERcustoms.com/TAZ]

I thought there was another filter. The sock in the tank is really to prevent large trash from getting into the system. I want to say the filter should be along the fame rail on passenger side.

It has been a while and memory may be tricking me but, do not think so. Maybe someone else will recall if not check to be safe or just give service manager a call and he should help.

Sorry I can't be more positive but, wanted to try and help if I could.

TAZ

[MVR 155]

There should definately be a filter in line somewhere..... keep in mind if you are having a fueling issue that driving aggressive will exponentially increase your change of melting a piston due to leaning out. Until you figure out your issue I would strongly suggest driving it easy.

[LEcustoms]

There is a fuel filter mounted to the front of the fuel tank on the drivers side. At least thats where it is on my 03.

[HummerMann]

GM lists FF864 as the only fuel filter for a 2003 and 2004 H2. It's the in tank unit and they don't list any other fuel filter at all. They don't even list one for 2005 on up. I was on the line with my Hummer dealership this morning ordering a lug nut and the parts guy said there is a special tool you can order from GM for changing the in tank filter more easily.

[johndjmix1]

They changed the fuel system in the later H2's. I remember when installing the SC the parts were different from newer to the older. Im sure im on the newer fuel system.

Yea, i was figuring the sock was just to stop large debris....cant imagine that would be the only filter.

Im not running real lean, im figuring this since the thing doesnt ping....and I run 85 or 87 octane (Always have).

The real question here is, would I notice a power loss if i had a clugged injector or would I notice lean behavior such as pinging...? Im sure someone on here thats ran lean can let me know the answer.

--John

[LEcustoms]

Thats wierd cause i just replaced mine not too long ago. Heres a picture you can only see one of the lines cause both lines run right behind one another. This is the part number i got: AHG9344

[ttkresurfacing]

Do you have any guages? Wideband, fuel pressure, boost? Could be alot of things but I would guess that if you have good pressure then thats not a fuel problem. Better gas will usually equal more timing/power. Any belt dust? Maybe slipping belt, spinning crank, vacuum leak, etc. Have you thrown any codes?

Alot of the fuel filters are located above the crossmember under the center of the truck. Mine is atleast.

Tim

[H2 Bill]

Try going to premium fuel (which is recommended with the SC) and use an injector cleaner like Techron. I had the same problem and it turned out to be bad fuel. Now I only run Chevron or Mobil premium.

[johndjmix1]

Yea, true....maybe because of the 85/87 ive been running its been backing way off on the timing causing a power loss., since when i first installed the SC i ran 91 and it ran good enough to kill a transmission in a few weeks.

Next tank ill run preminum and see what happens.

--John

[MVR 155]

Running a supercharger on 87 octane in my opinion is just crazy, even conservatively tuned its still a bad idea. You have all that money invested why not spend another few bucks per tank and have the piece of mind.

[IRA51]

you don't run cheap gas in a supercharged or turbo charged vehicle ,step up to 91 or 92 octane. throw a can of Seafoam in the gas tank and it will clean the injestors and remove carbon deposits,nothing I have ever used works as well as Seafoam .you might consider a Walbro fuel pump ,it will deliver all the fuel you need .

[MVR 155]

I forgot to add also that just because you dont hear it pinging that does not mean that your not running too lean. If the premium fuel with higher octane does not do the trick I would suggest getting a fuel pressure gauge hooked up to see if your getting pressure under throttle load, if pressure is good the next step I would take is getting a wideband A/F on that thing and see what the true air/fuel ratio is, with a forced induction set up I would be scared of anything in the neighborhood of 13:1 or higher. Another thing you may want to do if its not done already is get a plug that one heat range cooler along with tightening up the gap by .010

Im not just giving you this info blind..... I have owned a couple of supercharged cars along with having alot of nitrous experience, under artificial asperation you want to be on the rich side vs. lean for safety.

[IRA51]

GSS340 Hi Flow Fuel Pump

(Click to enlarge) Product: #Walbro GSS340 - GSS340 Hi Flow Fuel Pump
Price: $119.99
Category: Fuel & Cooling
Availability: In Stock
Manufacturer: Walbro
Weight: 2.00


Great in tank pump for forced induction



The Walbro high output in-tank electric fuel pumps are available in flow ratings of 255 liters of fuel per hour. These particular pumps flow significantly more fuel at higher pressure. For example, at 80 PSI the standard 255 lph pump will flow around 132 liters (35 gallons) per hour. At that same 80 PSI the equivalent HP (high pressure) fuel pump will flow over 210 liters (50 gallons) per hour.

Walbro in-tank electric fuel pumps utilize a proven gerotor design. The outside dimensions, however, are compact enough to fit existing hanger assemblies, without modification. Coverage includes most popular Acura and Honda, and many other Import applications.

These are complete fuel pump kits and include all drop parts, accessories and installation instructions. Also included is an inlet filter that meets or exceeds original equipment specifications and provides improved filtration and durability.

http://www.gonicd.com/intankinstall/intankpumpinstall

[MVR 155]

I ran a walbro 255 in my previous corvette, it was an aggressive heads/cam set up with a 150 shot of nitrous, with 30lb SVO injectors and this pump it was enough to safely run over 500 rwhp and get the car into the high 10's on pump gas. It never hurts to have too much fuel on tap.

[johndjmix1]

Ive had 4 supercharged vehicles, so im not new to this either, but more into noticing lean/rich conditions on ATV's and such.....

The fact that it was running great when i put the SC in means the fuel pump was sufficent, and since no other mods are done, that would mean MagnaCharger has made a mistake and not include the correct pump....on every kit they have sold for the H2.

I had some financial conditions change, mostly due to the economy, so i have been forced to use the cheap fuel. The SC cost me less than $3000, got it used so i really didnt make a big investment in it.

Anyone know anyone in Northern Colorado with a wideband we could run a test with?

--John

[IRA51]

you keep useing 87 octane in that engine and you will be rebuilding the engine in the not to distant future ,your rings and bearings are takeing a beating.

[HUMMERcustoms.com/TAZ]

It is a proven fact that your voltage can fluctuate allot depending on all the acc. you run. Drop in voltage means drop in fuel flow because pump will not pump rated volume. You can manage this with a Keene Bell Boost-A-Pump which will actually allow you to run fuel pumps at above rated voltage at a perminate increase as long as you are not asking for to much. You mainly set it to increase voltage at a consistant level then add a switch that allows for increased voltage thus higher volume at WOT only.

One thing on octane someone runs. There are many more text book knowledgeble people than me so I can only offer advice from so many years of experience than I want to mention. I have learned that you can tune almost any engine to run on any octane at alot of HP. Now you do not do this without running real time wideband A/F meter as well as fuel pressure and it would not hurt to add in there exhaust temp gauge and boost is manditory. The more info the better so do not stop with just the above mentioned.

I could continue on about other reasons I know I can run a 6lb. boost supercharged 6.0L on 87 oct. and make more HP with no knock then drive it every day. Everyone has there opinion and rightly so but, I know my experience and what to do to run 87. I know many can explain in great detail as why I should not do what I do. I have learned from the time back in the day of 70's when my tune was a feeler gauge for points and plugs then timing was set by my ear close to engine and my hand moving the dist. till I knew the right sound at throttle opening still listening carefully for that sweet spot. Then I knew my engine did my thing and win alot of pink slips or large cash wagers that would take me as well as all the friends I could get together to pool our money.

To do non-comforming things you had better no what you are doing and have the equip. installed on engine to get it done safely then have everything you need to monitor what your doing whether it justs runs on the street or nothing but, the track. If you can't put all these things together at once then make sure you follow conventional wisdom suggested by manufacturers.
Run higher octane if you do not know how to tune and monitor that tune from every angle possible which will allow you to be safe doing radical stuff.

TAZ

[pdsq99f4]

If the vehicle you're asking about is the 06 in your signature, it doesn't have an external fuel filter. GM got rid of fuel filters on the H2 in 04 when they went to the returnless fuel system.