Not to hijack another posters thread I'll make my own.

402 block completely forged with a small blower cam. Procharger D1 now w/ 4.5 pulley, Fast90 w/90mm t/b. Dynatech 1 7/8" LT, Magnaflow 3" catless setup with cutouts. Im running custom fuel rails now w/60# injectors, 255 walbro pump.

Once the car was strapped in and ready for dyno tune, upon getting into the wot part, around 5k rpm they said fuel pressure was dropping from 60s down to the 20s. They recommended a bap. Had a bap installed, and its still not supplying enough fuel.

They added a second pump externally made by aeromotive, and with the bap on fuel pressure would sit at 90.

What would cause a car with the 255+bap combo w/60#ers to drop in pressure when it was making just around say 550 when fuel cut came on? Yet on 255 pump alone and 42# injectors it would hold 60#s making 504?

Im only hoping to push just over 600whp, keeping torque at safe limits on the A6 torque wise. This isnt a track car either, its been there once and itll never go back, so the car never see's hard launchs, car was made to be a hwy roller.

 

You need to call Brandon at IPSMotorsports.net they had this issue on FI cars in the past and have a solution.

 

are you still using the stock intank pump to feed a surge tank? Tell me more about your system... I had the same issue, and we went though hell trying to figure out the right fix... But we have an awesome system now, after much trial and error...

 

From what I just saw. Its using a in tank walboro 255 pump, connected to a aeromotive fuel filter, then into a aeromotive fuel pump(both aeromotive pieces are external mounted). Then upfront im running revxtreme fuel rails with 60# injectors. With the kenne bell boost a pump. They figured the fuel issue out, now its my procharger tensioner bracket (again) thats causing my belts to come off and get destroyed.

 

who made your kit?? I see it's a Procharger D1, but who made the blower brackets??
are the brackets flexing?

 

Well thanks for sharing what the fix to your fuel problem was!

 

The bracket is the one supplied by ATI. The arm I suppose is only to supposed to rock side to side to allow the belt to "bounce" ? Well my bracket was wobbling from front to back and side to side, it was that loose. The replacement one they sent is still tight, but idk. The shop its at now is working

The fuel issue was solved. Since the aeromotive is in there, its been set to kick on under full boost if needed. On the dyno it made 604whp and right around 520tq i think. I havent seen the sheets just the phone call. The car held 70+ #s of fuel through the pull so im happy. But at the release of the throttle the belt was thrown and torn to shreds heh. I can count the amount of belts ive gone through prolly on both hands and possibly a foot.

 

LS2POWA,

Generally on this forum when someone posts a thread up asking for help (and folks invest time in trying to help said thread opener), then the thread opener usually takes the time to detail what the problem was so we can 1) know if we were right in our recommendations to you, and 2) if we weren't, we'll be better equipped to help the next guy.

Would you mind telling us what was wrong with your fuel system?

 

Lets see, I was told to call someone who hasnt seen any of my car, nor has any knowledge of the build or the tune. If I call the person it will be a waste of time more then likely cause it could be a number of problems.

Then I was asked if I was using a stock pump in tank, in therefor i replied I was using a walboro 255+external aeromotive. I then explained everything I knew of the fuel system.

Someone asked if my bracket was flexing, I then informed them its the tensioner bracket.

I know your all here to help and inform, trust me its greatly appreciated. The problem was more then likely wire was loose not supplying enough power to the pump to cause fuel cut at full boost. Now the same system at full boost holds 72#s across the board.

 

Not exactly as definitive as we had hoped for - but if that's all we get, then we'll say thanks!

Glad your issue was resolved!

 

Thats all I have right now. I havent been able to make it to the shop within the past few days of when the issue was resolved. When the shop called, didnt have much time to talk between work and school back to back.

Supposed to pick the car up today, and Ill find out the details of why fuel pressure was dropping off so quick, and what they did to remedy it.

 

If you would like an "end all my fuel problems" fuel system, feel free to call the shop. 609-752-0321

 

Ok update with a another fuel issue.

Last month the car was running a single intank walboro 255, with a external aeromotive 1000 pump and inline aeromotive fuel filter, with aeromotive fuel pressure reg.

The car would idle 72# of fuel, if you reved the car it dropped to 42#. They got it work out a day before a car show and a simple dyno run it made 607hp/518tq. I just wanted it safe enough to drive for a show. I arrive less then 12hrs later from that run to pick t up and it doesnt wanna run. Car stalled out couple times to the point where the aeromotive pump would whine and watch the fp needle climb from 0-40 still not start.

Now to current time, The car is running a dual walboro 255, inline aeromotive fuel filter and the fpr upfront.Fuel pressure idles at 62#s but when you blip the throttle fp jumps to 72#. In 4th gear from 2k rpm to 5.2k rpm AFR is 10/10.1 but by 5.7k its already at 12.2 an climbing, fp drops from 62# down to 50#. The car sounds healthy as hell, but it was only making 526hp/high 400 tq. After 3 test runs to check afr, boost pipe blew off the throttle body.

Anyone have a clue why the fuel is pig rich all the way up to say 5.4k then just goes leaner then a ****, or lossing 12# of fuel at topend? The shop thinks there might be something clogging the fuel lines cause when they dropped the tanks they found a bunch of crap at the bottom of the tank and the intake filters were clogged tight.

If anymore info is needed let me know, Ill find out what I dont know, i wanna get my car back...2mths without it is killing me.

 

A&A has a Procharger bracket assembly that will take care of your belt slipping issues. Costs about $500 for the bracket. Do you have a 6 or 8 rib pulley? If you have a 6 rib, you may want to get A&A's assembly and convert to an 8 rib set up at the same time. Had belt issues in the past, but not anymore thanks to A&A.

 

Belt slippage?....

 

As you stated it will not be easy to tell without being able to physically diagnose in person but should be able to determine with a few simple tests.

You state that your car is at a shop, what are they saying the issue is?

 

The only thing he could think of along with the tuner, is some of the crud in the tanks are in the fuel lines and building up at the end, cause fuel to clog and lose pressure top end. Monday hes tearing out the stock fuel lines and replacing them with stainless lines.

 

So you are saying that there is no fuel filter in your system anymore? The factory pump has a filter in the tank. If this was the case you better remove your injectors and send them out to be cleaned while you are at it.

 

There is a inline aeromotive fuel filter. Ill call the shop in the morning, and ask them how the injectors look. The tuner cant understand why its running pig rich (in the 9s) all the way to 5.5k rpm, soon as it hits that boom its at 12 an climbing.

Ill find out tomorrow. I do appreciate the help so far.

 

So is it dropping fuel pressure after 5.5K? You are not giving enough detailed, accurate information to help here.

But what I really want to mention is that if you trust your "tuner" enough to work on your car, he/she should have it under control already and just let them work. If you don't and you think you can find the answer before they can you might want to look for a new tuner... Just trying to help.