[CobraNutt]

EDIT: Just noticed this in the forum header: "99-04 Forum - For the 1999 to 2004 Ford Mustangs with the PI (Performance Improved) 4.6L modular engine." Moderator...please move if necessary... DOH!

Wow...my first post wasn't supposed to be in regards to a problem already!! Sorry for the long first post!!

Howdy! I'm a NOOB to the modern Mustang arena. In June, I picked up a nice little (bone stock) '01 GT convertible to run around in. Been loving it ever since...for the most part...

ISSUE:
It's been running great all around town and on the short little runs I've made around the local freeways. Just after I bought the car, I went on a 350+ mile run with a couple members of the Utah Cobra Club ('65 based roadsters, not Mustang Cobras....). About 1/2 way to our initial destination, I started having some issues with the GT. It felt like it was running our of fuel. Power was way off, and I couldn't get rpm to rise unless I feathered the go-pedal. If I put my foot into it, it would just lay down on me and bog. It ran decent, for the most part, but if I needed/wanted power, it just wasn't there. If I shut it off, and waited a few seconds, it would run normal for a few miles, and then revert to the same issue. Fuel level was fine, temp was fine, no dash lights, no CEL, no other obvious signs of trouble. I've noticed that it does this typically after I've been driving for ~45 minutes or more, and it's hot out. It also happens more frequently as the fuel level drops.

When I picked up the car, the previous owner told me that he had one of the injectors replaced (#7), and the rest were serviced/cleaned at that time. I inquired about the fuel filter and he said he hadn't changed it and didn't know the status since he only owned the car for about a year.

So...my first thought was fuel filter. Replaced it, and still have the same problem. When I replaced the filter, the fuel on the tank side (inlet) was pretty nasty looking, so I decided that there may be enough crap in the tank to be plugging up the pick-up sock, and maybe the pump was headed south anyway. I picked up an SVT Focus pump and and will be installing it tonight. I dropped the tank last night...filler tube was the worst part!!
One question that I have is this. I was told that the SVT pump is a plug-n-play swap, but that pertains only to the pump itself. From what I am hearing on other forums, I need to take the baskets apart and simply swap out the pumps...the plug and wiring is the same between the two...Does that sound right?

The 4.6 is still sort of a stranger to me, especially with all the computer stuff and returnless fuel system! I'm sure I'll have more questions later on, but I really want to get this thing back on the road! I hate going back to using my Dodge Intrepid as my daily driver!!

Any tips or suggestions are welcome!! I'll post pics of my GT in awhile!

~Gary~

[CobraNutt]

Ok...so I pulled the pump out tonight. Here's what I've learned so far.

1. Dropping the tank isn't really that difficult. I did it by myself with a floor jack to support the tank while I unplugged everything. Having it near empty was a big help!

2. The top of the tank collects LOTS of sand and dirt. I wore safety glasses while underneath the car dropping the tank. Glad I did! Also, before cracking it open, I took my air nozzle and blasted away as much dirt as humanly possible. I used a parts cleaning brush to get the stubborn stuff.

3. The SVT Focus pump (3S4Z-9H307-BC) is plug-n-play...sorta. It comes with a different cover than the stock Mustang one, so that needs to be remedied. I took the old and new buckets apart and essentially swapped the tank covers along with the fuel level sender, wiring, and in-tank fuel line.

Old bucket and pump assembly...


New bucket and pump assembly...


Here are the empty buckets side by side. Yes, the socks on the original pump and bucket are NASTY!!!


Inside the old bucket...no problems in there, just a little dirt! That's actually about 1/3 of what was in there when I cracked it open!


Here it is all assembled back together with the new bucket and pump with the original tank cover and fuel level sender.


So...the new SVT Focus pump is plug-n-play...for the most part.

I'll have this all back together in the morning. Hopefully this will take care of my issues! From the looks of the filter socks, I'm betting on it! I'll keep ya posted!

[HBK_2007]

nice write up. lets see pics of the finished car now, lol

and welcome to MM

[CobraNutt]

Thanks for the welcome!
Here's my "Official Intro" thread...with pics inside!

[CobraNutt]

UPDATE: Back on the road today. So far so good! Throttle response seems MUCH betr in the 3-4k rpm range...but that may be just what I'm feeling after driving my Intrepid for the past few days!

I'll be headed out to take a long drive tomorrow, so we'll see what happens!

[HBK_2007]

good luck with it

[ModularSteed]

Originally Posted by HBK_2007 good luck with it

+1

[CobraNutt]

Burned through about 1/3 tank of fuel today running 75-85 mph on the freeway around the valley, and then I took it up into the mountains around Park City. I pushed it hard in a few spots...ok...several spots ... after driving for about an hour in the heat. NO Hesitation, NO stumbling! Ran great! Hopefully it stays that way!

[~C~]

Good on ya! Glad you got it figured out. Welcome to the forums. I just did my pump as well for the s/c install. I swapped the cover, wiring, and hose. Kept the rest of the svt focus in tact.

[SGTPinder]

Do you gain any sort of performance with the SVT Focus fuel pump? you said it was better responce, is that better than what it was, or better than the stock pump?

[CobraNutt]

Originally Posted by SGTPinder Do you gain any sort of performance with the SVT Focus fuel pump? you said it was better responce, is that better than what it was, or better than the stock pump?

I doubt there is any performance gain over stock. My perceived better throttle response may be due to 1 or 2 reasons:
1. My 4.6 is now getting the fuel it needs to run. Both socks on the old pump and bucket are FULL of junk, so I know I wasn't getting adequate fuel supply.

2. It may just be my perception after driving my gutless Intrepid for a few days, and jumping back into the GT that is now getting enough fuel.

Either way, it's running like it's supposed to.

[00vabchgt]

cool. glad to hear everything worked out for you...

[SGTPinder]

Thanks for the insight!

[CobraNutt]

Ok...time for an update and a question.

As I mentioned in my first post above, the previous owner of this car replaced #7 injector and supposedly had the others serviced. After I changed the pump and filter, the GT ran like a champ! It's been running well for most of the past 6-7 months, even thought it's spent a lot of garage time over the winter. However, I'm starting to notice a bit of a miss once in awhile that hasn't really gotten any worse over the past few weeks. I've also noticed a bit of a lag like there is still a fuel issue. The power is a bit off, but it will pull all the way up on the tach without no problem...other than reduced HP. New plugs were put in about two weeks ago...didn't seem to make a difference. The old plugs all looked good when I pulled them. So...in my mind, I'm thinking that the plugged up/dying duel pump and filter that WAS on the car is still haunting me with the gunked up injectors.

So...here's my question.

I've got a set of new FRPP 24lb injectors available to me for a great price. The car is bone stock. Would I have any issues installing the 24lb injectors without adding a new MAF sensor that is calibrated for them?

Gimme your thoughts! Thanks!

[SWEET2KSTANG]

the tune is calibrated for the injectors, and you will need to tune if if installed.

[CobraNutt]

I guess that's what I'm trying to get clarification on. Do I need to upgrade the MAF as well, or will the new tune be all that is required? I'm getting conflicting input on this. However, my understanding is that the MAF calibration simply fools the computer. I believe that a good tune takes care of that issue without putting in a 24lb calibrated MAF. Am I correct?

[qwick04gt]

yes that is correct i am running 30lb with stock maf

[qwick04gt]

on a tune though

[BoCFes]

Jus chimin in, def one of the better threads ive seen in my short time here so far. love the detailed pics and updates. props.

[CobraNutt]

Very well...sounds like a new tune is in order! Thanks guys!


BoCFes...love the sig! That's friggin hilarious! Man...getting my license and first ticket was such a long time ago....