i have issues

.... and this time they arent personal issues, its problems with the truck.....

so a while back i had a race lined up (i think it was early november) and did my usual routine of changing the plugs, changing the oil, going out and purchasing some 108 unleaded to throw in the gas tank before i head out... run the tank kinda low to where the gas light comes on, and then make a couple WOT drives up and down the street to make more room and then toss in 8-10 gallons of 108....

make the drive out to rockwall, which is about 15 miles from my house, get out and go watch a movie with a friend for a few hours... jump back in teh truck and head out to go race a mustang... turn out of the neighborhood and give it about 3/4 throttle and BAM its like someones shooting a machine gun out of the tailpipe....

it was spitting, sputtering, popping loudly when i would put my foot into it... cruising it was totally fine like a regular truck... get more than 1/2 throttle and its like a big block with an angry cam that doesnt want to run...

so go and do what i hate to do and tell him i cant race, then head home and immediately drain all the gas as low as i can just in case i got a bad batch or something... hell i dont know...... and changed the fuel filter...

i noticed the next few days (and still to this day) on my aeroforce gauge that the O2 voltage would drop down to 0-45 and stay there instead of jump 35/800 46/766 etc etc... you know what i mean.... anywho... since then i have changed the MAF, both O2's, TPS, and fuel filter....

still the same problem....

i have had a few people offer to hook up a fuel pressure gauge and scan it with hptuners, but my schedule has been hectic the past few months (and only gonna get worse) so im pretty much SOL for the time being

i still daily the truck and it does fine going across town, and on some colder days i can even get some good WOT runs around.... but on the top end it still acts like its starving for fuel or something....

any ideas.. thoughts... comments.. suggestions.... witty banter that any of you could share....

oh and greg had mentioned maybe the fuel filter sock... so i may drop the tank and check it... i need to get with V and toss a fuel pressure gauge on it too, to possibly knock out that possibility, or fix it if it is an issue...

any other ideas?

You need to check the fuel pressure for sure. I know you already know that but I bet you find the problem there.

why isnt virgil online.... he isnt doing anything today.... he (or someone else with a FP gauge) should drive to rockwall while im at work doing nothing

It's a two hour drive for me.

chop chop, ill be here till 630

I'll be there in a minute. :LOL:




















J/k
14 hours away. Sorry


Gotta be in the pressure and I am thinking its the pump or something in the area of da pump.

but what would make the O2's lose voltage??

Dude Alan....

Really?

The O2 voltages will generally stick low (less than 200 mV) when the mixture is LEAN and high (above 750mV) when rich. When I say stick, I mean stay there as long as you're doing what you're doing (spraying or full throttle duplication of complaint). They range from around 0 to 950 mV (depending the the PCM, sensor type and brand, tuning, software, scanner, or scan gauge) with "bias" voltage at 457 mV. If you hammer one and the mV goes to 5 or 39 or 0 or 17 (you get the idea) and stays there the entire time you have it matted, especially if it's pooping fire turds, it LEAN.

Get a gauge.

BTW, you can drive from Rockwall to Sanger and race the truck but you cannot drive it 15 more minutes to have it looked at? LOL

i havent raced in a LOOOONG time

Me neither. Prolly since that night I met you....:LOL:

im on here now sunshine:D

Dude, you didn't mention you were running 108 octane. Isn't 108 leaded? Lead is no bueno for caca with 02 sensors. Thats a sure fire way to ruin them.

He said it was 108 unleaded but I'd really like to know...

I am having the same issues.. I was going to change plugs when I leave the office to see if that would help.. If that doesnt work, I am going to check the sock in the gas tank. I will also change my fuel filter.

I may not be able to get to all of that today though, I have jobs working at the time being and I will post what I find when fixed.

it was unleaded....

I still have not been able to check anything, I will hopefully know more today.. A friend thats a GM mechanic had told me he had gone through the same issues with his Camaro and it was a plug wire.

change plugs again bro, you might have one jacked up, i seen this happen on a brand new set of plugs, switched and it was good.

I changed mine (plugs) and I noticed one of my wires not on there good.. I went to the store and did a small hit and I had no issues. I can not really get on it around here, too many houses and people. I am using the NGK t55 plugs and MSD wires.

i plan on swinging by and picking up V's FP gauge and testing it out...

what is the pressure supposed to be at during certain RPM? steady regardless or more pressure at WOT

if yours has a FPR, I believe its supposed to be 52 at idle and 58 with the vacuum line removed. Otherwise its 58 psi, if I remember correctly.

52-55 idling and 58-60 with the vacuum off...i think thats what i remember

55-62 psi with the pump running and engine off. Should go up 3-10 with the vacuum line removed and engine running.

Alan--you still having these problems?

well yesterday we were working on the fuel pump on an airplane and were using a FP gauge.... took a look and it was the same size fitting as on the fuel rail

so after work tossed it on the truck and it idled right at 50psi.... went driving around and at WOT from 1000-2500 it was right at 55 and then as the rpm's came up the pressure dropped to 40, then to 30 then down to 20psi and at 20psi is where the truck started acting up and giving the symptoms that i described....

welp guess its time for a walboro 255 now

Good girl! Yup, FP is dying a slow death. Your FP replacement should be pretty easy--isn't your FP along the driver's side frame rail?

hahaha i wish it was that easy... its an in tank pump.. so im gonna pick one up from Nelson's on either thurs evening when i get in town or if thats too late friday morning... im bringin tools with me so i should be able to swap it out in my buddy's parking lot

if i get it changed i guess ill finally get some 1/4 times in patches.... dang now i gotta fill the bottle

So Alan...the FP was the culprit, huh? Run a lot better now that it is actually getting gas?

i dont know if it was slowly dieing out or if i just dont remember what it feels like going WOT again....

either way it feels alot better, starts alot quicker, and i dont have to pull over fo 20 minutes at a time when traveling long distances :laugh:

so now its time to toss the bottle on it and see if i can blow it up

Mine ended up being the fuel filter... LOL