Hello All

I am still trying to figure out whats going on here.

Basically ever since I got the car out this year its running way lean as soon as I get on it. Fuel pressure was not going up as needed on the dyno as we verified.

403ci with YSI

I have the A&A fuel sytem with an intank Lingenfelter pump and a BAP attached to the secondary inline pump. 80lb injecters. Methanol as well.

I have made the following changes to the car in hope of a fix:

- replaced both inline pump filter and regular fuel filter
- changed to -8 line for the secondary system
- added a check valve to the secondary sytem
Change the Hobbs switchs for the inline pump to come on at 2psi and then the BAP to come on at 4psi
- tested the Fuel regulator and it seems to take pressure when I hook a pressure pump up to it.

I tested the car today and it literally goes way lean when I just put my foot to the floor in 4th. It used to do the exact opposite and go way rich in the past. I am talking lean at 5100rpm and barely any boost..4lbs at most.

SO now I really need your help people. I have a brand new inline pump I can install but I am thinking this is not the issue as due to the fact I put my foot to the floor in 4th and it goes lean right away..like 15 AFR + that it would make me think the internal pump may be weakening? This sound right?

2 years ago this car made 770rwhp with 12lbs of boost @6800rpm 11.3afr with 60lb Injectors, 18 degrees of timing. Zero Issues.

We noticed the issue at Champion motors sports about 2 months ago
there was an issue as the car made 778rwhp @5900rpm 14degrees of timing and spiking way lean @ 13lbs of boost. Fuel pressure never went above 64lbs.

Please let me know what ya think pro's !





thanks

 

When you roll into it in 4th is your pressure dropping?

Do you have a check valve stopping pressure flow from your secondary fuel system into your stock when it kicks on?

Fuel issues just plan suck.....

 

simple you have a dead pump in the tank ,

 

Is your check valve on the feed line to ur second pump if so check it out. I had the same issue after pulling the fuel system piece by piece i made it to the check valve and figured it out. The brand new check valve was broke the ball in it was stuck closed not allowing fuel to flow. So i took the guts out of it and put it back inline. Just a tought for ya.

 

I have a check valve going from the tank to the secondary (inline) pump.

thANKS

 

I have been having issues before I put this new check valve in. I added it to seee if it would help fix my issue. Good food for thought though !

thanks

 

think this is a possibility.

thanks

 

thanks Ken for the PM !

 

If the intank pump was dead the car would not start. The external pump is boost referenced only to come on at wot.
Drew, make sure you have a check valve installed on the oem fuel line right at the firewall. When your external pump kicks on it can overpower the intank pump and the oem intank regulator will bleed off pressure not allowing fuel pressure to rise. LPE sells block off plugs for this very reason, but a check valve will do the same thing.

 

Have you made sure that one of the hose clamps or one of the hoses in the tank does not have a pin hole leak or bypassing around the worm clamp that attaches the hose to the pump. I had the same problem a while back and that was the problem...

 

Hey bud..My thought was the pump may be dying. Its fine under normal driving conditions. Correct... the the BAP is hobbs switched to come on the 2 pump only after 2psi through the vcuum lines.

The check valve is installed right before the second pump on line comming out of the tank (not stock line)....this is not correct?

 

thanks for the info. I have not had the pump out of the tank to check for any of that yet. I was hoping it was an issue external to anything in tank so I may be doing this sooner now

thanks

 

oh...you need to come to Ottawa and do this with me

 

Sounds you have some of that crazy Canadian stuff going on. What were you drinking when this problem occurred?

Try disconnecting power from your in-tank pump (pull the fuse) and temporarily bypassing the Hobb switch and setting up your A&A system to run all the time. See what happens. That will help isolate this problem.

While you're doing that, measure the voltage to the pump. A bad connection will cause this. (Bad connections include bad relay contacts. )

 

thanks bro... don't really drink anymore but these fuel fumes may be gettin to me

 

I would also isolate the stock system (disconnect A&A) and record results, and then force the A&A on (bypassing the Hobbs) with the stock system and compare these results. How sharp does FP drop when you are spiking lean?

 

All this does is help build pressure when cranking the car over at start up. You need one on the oem line because the intank regulator will bleed off pressure. I'm almost certain Andy sells this with his fuel system, but better to confirm with him.

 

Do you have a check valve in the stock pressure line before where the secondary pump pressure tees in. As talked about above, the secondary pump could over power the stock pump causing backflow throught the stock pump into the tank

 

thanks everyone...I have a fuel pressure gauge but its under the hood so I cannot see if FP is dropping when driving. On the dyno we noticed that it wasn't dropping but just wouldn't rise at all. I don't know if that has changed since 2 months ago when we noticed the issue. At the time though we noticed FP was just not rising.

With the car off I can pump air into my vacuum distrubution block which will at 2psi kick the second pump on then at 4psi kick the BAP on....the Fuel pressure go to 64lbs. Now..i was able to get pressure to rise if I kept pumping the pressure gun a couple weeks ago before I made the changes stated in the first post but have tried since.

I am so sick of working on this F*&king car ! I just want it to work. I can gaurantee this is the last modified car I own. I have spent way too much time and money. It seem like its always something.

thanks for the help guys.

 

It looks like I do not. My kit never came with one. I see on a pick for 2003-2004 vettes on Andy's site they may have. Mine is a 2001 Z06. I guess there is no harm install one. I will call A&A tomorrow. See picks below of my setup.






This is a pick of A&A site..looks like it has a check valve