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View Full Version : My stumbling woes (LONG due to explanation of my suspicions)


phillysrt4
05-30-2006, 09:59 PM
The other day I got some Sunoco GT104 at a place local to me. When I went to put it in my car, I noticed I stopped getting flow from my fuel bottle. I looked in my fuel bottle and noticed a lot of "flakes" of some substance. My screen on my fuel bottle is very fine, so I dont think any of those pieces got into my engine. I also had the fuel strained at the garage through a wire mesh to catch the big particulates. Turns out that their fuel drum is relatively old so they guessed the "flakes" were the lining of the drum coming off. :gcry:

Before figuring this out via the screen in my fuel bottle getting clogged up and not letting any fuel through, I already had close to 4 gallons of the fuel in my car in order to get the octane level close to, if not over, 100. I then stored 4 more gallons since it had been through their wire strainer and would go through the finer strainer in my fuel bottle, plus I couldnt see any flakes in the fuel.

Before heading to the track, I put in another 1.5 gallons of fuel. No issues. I drive to and from Philly on pump gas (about 1.5 tankfuls give or take) plus the putting around philly was all on pump. During my long weekend stay in philly, I stored the race fuel on a porch under a tarp so there would be no direct sunlight.

On the way home from Philly, I put in the last 2.5 gallons of race fuel and kicked HOM on for the final leg of the drive. I noticed as I got close to home I start getting a "stumble" at the upper end of the band (I forget where it kicked in). Its that kind of stumble where the car just refuses to go any higher than that RPM, and its a real struggle if it does manage to do so. This prompted me to buy some fuel system cleaner and I dumped it in with an extra 1.5 gallons of fuel. I drove the final 4 blocks home unable to notice a difference.

Today I got into the car and kicked on HOM. It held HOM the first 10 miles, but the stumble remained. After that I kept getting kicked out of HOM. The stumble seemed to happen right about 4.5k RPM on WOT all gears (with a LOT of popping coming out of my exhaust when I tried it in 2nd). So I decided to fill the tank to half full since I was pretty much down to about 1.5 gals left in the tank, and as I drove away I still had the stumble in 2nd gear pulls (local streets... all i could do) but it moved up to about 5k+ RPM and I actually had a shot at hitting redline.

I think its two possible causes, either:

A) dirty injectors. I say this because I had a stumbling issue at about 5.2k RPMs before after using about 10 gallons of "home depot" race fuel. A tank of regular fuel with injector cleaner in it fixed the problem. I think subtle particles have clogged up my injectors, and the fuel system cleaner plus the half tank of gas is helping to flush them out.

or

B) I need new spark plugs/wires. I've had the same plugs in since stage 2 went in (about 20k miles ago) and the same wires (magnacore IIRC) for about 40k miles.

or maybe its a combination of both? Some other cause? Either way Im going to run another bottle of cleaner through just to make sure when I go to philly (again) this weekend.

Discuss...

PS - No, I am never going there for fuel again. Not only did the "flakes" in the fuel piss me off, but I wound up dumping about a liter of fuel into one of their VERY dirty fuel cans to show them all the flakes they caught in the strainer of their funnel which they never bothered to replace when they refilled my can.

jhempstead
05-30-2006, 10:30 PM
It could be a clogged fuel filter. As a side note, its a good idea not to get on it with less than a quater tank, sometimes the gas moves off the pickup and causes lean spikes. Good luck philly holmes!

phillysrt4
05-30-2006, 10:34 PM
yea the fuel filter was another thing I was thinking of. Let me look at the service manual to see if its something I want to fuck with or if they should do it since its in for warranty work tomrorow.

uberingram
06-02-2006, 10:59 AM
yea the fuel filter was another thing I was thinking of. Let me look at the service manual to see if its something I want to fuck with or if they should do it since its in for warranty work tomrorow.
The fuel pump and fuel filter are serviced as one and it requires you dropping the fuel tank.

psi chick
06-02-2006, 11:03 AM
well you should probably replace the plugs and wires anyway since they've been in there so long.

if there were flakes in the gas then it probably clogged the filter. good excuse to throw a 255 in there......

and another reason to add to the list of why i only buy race gas in cans......

phillysrt4
06-02-2006, 11:16 AM
well you should probably replace the plugs and wires anyway since they've been in there so long.

if there were flakes in the gas then it probably clogged the filter. good excuse to throw a 255 in there......

and another reason to add to the list of why i only buy race gas in cans......

well I ran fuel system cleaner through it and it seemed to fix the issue. The pump gets replaced with the S3 install so when the old one comes out I'm going to have it cleaned.

But yea, lesson learned. If I'm not buying the drum I'm not going to buy it.

EDIT- and yes, new plugs and wires are on the way for S3 :thumb:

psi chick
06-02-2006, 11:18 AM
if fuel cleaner helped then it was probably a clogged injector. didn't know you were getting s3 in so then you're good.......

why clean the old one? s3 gives you a whole new assembly....

phillysrt4
06-02-2006, 11:37 AM
if fuel cleaner helped then it was probably a clogged injector. didn't know you were getting s3 in so then you're good.......

why clean the old one? s3 gives you a whole new assembly....

I have someone who wants to buy it and I want to make sure its 100% tip top