Chicago1

Well I literally got off the Dyno. My tuner worked on it all day and we made 668 corrected to the wheel and just using Meth for saftey. Long story. short he made almost 15 pulls and was tuning all day literally for hours. ll was good. I got the car back ran a gt500 3x and pulled easily. Picked up a friend and gave him a ride then dropped him off no issues. Drove around for awhile all was lovely. Got on it and it seemed flat then like it hit a wall. I noticed under boost my fuel pressure would go from mid 50 to the teens. Car does not like that at all but drives kills timing and just kicks and sputters so i let off...now normal idle and just cruising normal the fuel pressure is fine and in the mid to high 50. Just when I start getting into boost it drops down and fast to the high teens. I have 60lb injectors. KB Bap which is new aem 320 pump which is new and a caspers harness which is new. Wanted to get some ideas what to start looking at. My feeling is start with the Bap but what could be causing this? Fuel regulator on fuel filter took a dump? Just odd it only drops under boost

2001 coupe

Milan

Non return setup? The stock fuel filter/regulator has a tough time maintaining fuel pressure when making that kind of power regardless of what kind of pump you have

4DRUSH

Flip drive?

Log voltage?

Chicago1

Yes non return but why didn't it do that earlier on the Dyno when it was making pulls all day? I don't know what the numbers are uncorrected mid to high 500? Never heard of anyone having that issue at that power level. What about it just starting to fall at the 4k range just starting and already falling? This is all new to me so that's why I'm asking. I thought the Bap but it should still maintain a certain level if it just works off the pumps. Its all tied in together.

[QUOTE=4DRUSH;1586532159]Flip drive?

Log voltage?[/QUOTE

no flip drive 6 rib
Ill ask about the logs tommorow. I wanna see if in the am if it does the same thing like is it fine at first then once its fully warmed and driving will it do it and how long. Just so I can add more info. Is it possible the pump is bad or the fuel filter is clogged? I did have someone pour sugar into my tank and the car ran for 5mins but that was on the stock injectors. I did clean out both tanks and fuel pump outer sock.i did not see any sugar in the sock while cleaning it so I assumed none got in the fuel pump or in the fuel pump sock casing. I did not change out the fuel filter if it was clogged I assumed it would of shown up awhile ago or on the 15 Dyno pulls. A part of me wants to put a stock fuel pump and see if the same issues accour so I can start the process of elimination.

Chicago1

So uncorrected if I use a correction factor of 1.16 I'm making 575 or so. According to my tuner I still have plenty of fuel left especially running the Bap pump and harness and 60lbs. Gonna start with the fuel filter/regulator first.

skydiven4fun

I'd be really careful getting on It too much till your able to find the issues, definitely don't want a lean condition.

Chicago1

Yeah it won't let me as it it just kills timing and feels like someone is pulling me from the back the way the tune is set up. It just dies basically but this am my thoughts feeling where correct...I wanted t ogoose it and see what it would do and fuel pressure stays steady. I did a 2nd and 3rd gear pull and fp stayed at mid to high 50's. It was about 40 degrees out or so. So just curious why it would be fine this am? I know if I continued and getting the car nice and warm it would drop I bet. I am going to start with the fuel filter and regulator.

helga203

[QUOTE=Chicago1;1586532391]Yes non return but why didn't it do that earlier on the Dyno when it was making pulls all day? I don't know what the numbers are uncorrected mid to high 500? Never heard of anyone having that issue at that power level. What about it just starting to fall at the 4k range just starting and already falling? This is all new to me so that's why I'm asking. I thought the Bap but it should still maintain a certain level if it just works off the pumps. Its all tied in together.

Street tuning and dyno tuning are different. Theirs more load on street tuning then dyno tuning so it needs more fuel. So possible sugar got in your lines and making a restriction. Just thinking out loud. Keep us informed what you find out. GL

ajrothm

Get the volt meter out and start testing stuff... Stop hammering it before you melt it.

Maybe your signal to your BAP is dropping out... (where it be a map sensor or relay piggy backed off of some other map sensor).. Even without the BAP, your fuel pressure on the fuel pump alone shouldn't drop that low.


Is the system a return style with an external fuel pressure regulator?

Either way, you need to do some testing in the garage using your air compressor to supply "boost" or else this will be the shortest lived supercharged stock motor yet.

PEETYZ

Is the car rough to start? When my fuel pressure regulator went out it was. Milan is right the stock one has a hard time regardless. I had a new one fail but I'll admit it was a cheap one since it was only in stock at time... All the same right? Wrong...thats when my fp gauge saved me.

You will want to replace it anyway with AC Delco or Wix do not use the other cheap ones.

As others said check signal to BAP, pressure switch etc too. When the fuel is hot the pressure will drop mine is about 66psi cruising on cool days and 60 or so on warm days. It dips down to about 54 under boost then BAP brings it right back up. I have my warning set for anything less than 48 psi.

Chicago1

I plan on starting with the bap to see if it's always on but how do I apply the compressed air to the motor to make it think it's boosting? I assume I use the brake booster but not sure what I need to do...Thank you for your responses greatly appreciated.

How do I go about checking the signal? I don't plan on running it anymore so unsure how to activate it while it's not running. As always thanks man!!

danieloneil01

Stock pump? Sorry didn't see if you mentioned this or not.

Chicago1

aem 320 pump , kb bap, caspers harness fuel pressure drops when car is ran for awhile and get warms after a few runs.

things I am starting with

replace filter/regulator(need it anyways)
test bap
check voltage at the pump

can't get logs till Thursday am the earliest Troy is coming over

MVP'S ZO6

Is it possible you are experiencing vapor lock? How far are your fuel lines from heat? Is the regulator bad?

Pick up an aftermarket regulator.

Chicago1

I thought I mentioned that. So my tuner also thinks that it is vapor lock it's the stock fuel lines on my 01. So the regulator/fuel filter is in the back under the car by the tank. it's incorporated into one so you have to buy the "expensive one" that are together you can't by them separate. I know rock auto has them for 36 shipped(wix) as opposed to the 90 dollar from dealer.

yes I know I probably should be going return style but I don't have more money for a fuel system and I know at my power level I should be able to run this setup...from what what I seen of others. I think my numbers break down to about 560-570 up here. There is a lot more in it if I want but I said that was good and that's without tuning with the meth...just using meth to keep things cool..Correct me if I'm I am wrong.....also a/f was in the 10.4 range idc at 80%..no knock conservative timing..

BLOWNBLUEZ06@RKT Performance

I was visiting with Troy about your issue today. You don't really have to boost the hobbs switch to test the BAP, although it's a more complete test if you do.
You can simply short out the 2 leads on the hobbs switch.

How I would start the testing:
remove the factory relay and create a shorting tool using a fuse link to short pin positions 87 and 30 together. When standing at the passenger fender, facing the driver side, remove the fuel pump relay from the upper left side and short the upper left and lower right pins. The pins are labeled (numbered) and there's a diagram on the side to confirm that 87 and 30 are the pins to short if you forget.
Turn the key on. You'll hear the pump start working.
Short the Hobbs switch wires together and you should hear the pump kick up a notch.

There's an output adjustment dial that comes with the BAP. I always ditch it and short the two wires together to make it go wide open when it's activated.
With the pump running, test the wires at the pump head at the driver side. Without the Hobbs running and without the car running, you should have maybe a 1/2 volt drop at the hot wire from up front. Next, measure the voltage with the BAP activated.
Next, touch your meter lead to the pump head cover and the other meter lead to the frame. It should read less than a few tenths of a volt. If it reads more, you lost your ground path in the plug. make a 10 gauge ground strap and ground the pump head to shiny metal on the frame to solve that problem.

If both the hot and ground show good, then my next suspect is an internal leak bleeding off pressure from a broken or loose line inside your pump assembly. Pull it out and you'll quickly discover that issue.

If the voltage is good outside the pump head and you have no internal leaks, the only remaining items are the connections at the pump itself and a pump that **** the bed.

If you need a better explanation of anything get my # from Troy and hit me up.
I'm working nights, so if you're up really late, hit me up.

MVP'S ZO6

Awesome!!

Gotta love bbzo6. Always helping out!!

Milan

Not sure if you checked this yet, how much fuel is in it? Did you start the day at a full tank and then after racing everyone end up with less than 1/4 tank? The way your new pump is setup it might not be getting enough fuel if the tank is low. I know it seems like a "no duh" situation but it's worth mentioning, seen it a million times before.

RoccoC5

Just spitballin here, but I wonder if the pump could be cavitatating? (Is that even possible with an in-tank pump?) If I remember correctly you installed a pump and screen that didn't quite fit right in the oem fuel bucket? Anyway, hope you get it figured out soon!

Arun@Dasilvamotorsports

Now it is normal to have the pump pressure drop to around 54-55 psi at demand.

Pressure should be 58 psi then jump to around 64 psi when the hobbs switch is activated.

One thing-did you make sure the plastic convoluted tubing that goes on the pump did not get cut or damaged when doing the pump? Did you get new clamps? Your not supposed to use worm style hose clamps on those.

It could be something as simple as the above.