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Fueling Issues

4K views 32 replies 9 participants last post by  johnt 
#1 ·
I have been running into some fueling issues ever since my power adder has been on.

My current fuel setup is as follows:
-techedge hotwire kit
-Kenne Bell boost a pump
-GTP fuel pump
-60lb flow matched injectors

What has been happening is that my fuel pressure will drop off in the top of each gear. It doesn't happen when I run my car NA, but as soon as I add the minimal amount of boost I can (16-17lbs) my fuel pressure will drop off up top. The boost a pump helps but makes tuning a PITA! Any suggestions on where to go with this would be appreciated, I am to the point now of possibly putting in a fuel cell, some fuel rails, aeromotive pump and whatever else will be needed (If anyone has a diagram of a fuel cell system that would be appreciated).

As far as what I have tried to do to fix this is below:

-replaced my fuel pickup hose on the fuel pump 3 times now (same results everytime)

-replaced my FPR (same results)

-reseated all my fuel rail connections and pump connections (same results)

-replaced fuel filter (same results)

I see no leaks and everything seems fine, but I won't be going WOT anymore until I fix this!
 
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#5 ·
Adam,

The symptoms you're describing are classical fuel delivery issues. This is happening because you're literally running out of fuel at the top of every gear. It's either your pump or your lines. I saw the same things late last year when my fuel requirements pushed my pump/lines beyond their limit. Our lines become an issue as you approach 400 WHP.

I notice in your sig though, that you're running 13.0@107. That's a great time, but not enough for you to be seeing this. Have you replaced your fuel pump yet? I would look at that, or possibly a kink somewhere in the feed line. BTW, What's your static FP?

John
 
#6 ·
johnt said:
Adam,

The symptoms you're describing are classical fuel delivery issues. This is happening because you're literally running out of fuel at the top of every gear. It's either your pump or your lines. I saw the same things late last year when my fuel requirements pushed my pump/lines beyond their limit. Our lines become an issue as you approach 400 WHP.

I notice in your sig though, that you're running 13.0@107. That's a great time, but not enough for you to be seeing this. Have you replaced your fuel pump yet? I would look at that, or possibly a kink somewhere in the feed line. BTW, What's your static FP?

John
Yup, I have tried the pump, a kink may be a possibility because we pulled everything out for the engine rebuild, I guess I will have to go dive into the deep, dark hole tomorrow and start removing wire loom from the lines and see what I come up with. Is there any way to just replace the stock lines with AN line and fittings? My only worry would be adapting to the plastic lines, then I could completely rule out lines down the road.

Thanks Much!
Adam!
 
#7 ·
Yes, you can replace the plastic portion, but it's a PITA. You'll have to get tubing adaptors to tie into the metal lines. You should also flare them.

John
 
#8 ·
maybe this was suggested above, but have you tried upgrading to a better than stock GTP pump like the walbro? sounds like you may have topped the pump or the lines.

You are running a lot of boost through that thing, more than most anyone with an M90. I havn't been able to go WOT with my Whipple yet either, it's got some spark issues.... then I'm sure I'll have some fueling ones too!

Rocky
 
#9 ·
Well, I think I am set now on the fuel cell, enough dealing with this stock stuff because it may become a issue down the road again.

John - Do you happen to have a diagram of what you did to put a cell in your car?

Basically this is what I am looking at right now.

-custom set of PRJ rails (Paul said he can do whatever I need)

-aeromotive A1000 fuel pump

-aeromotive A1000 -6 AFPR, run after the rails with a return line to the cell

-AN line (whatever size is needed, Im thinking run 1 -10 then splice off to 2 -6 lines and hit the rails with those.

-inline fuel filter

-fuel cell

-Fuel level pickup (can you retain the stock one? If not what else is a option?)

-Evap (vent into air from the cell?)

Does this sound proper? Just figure might as well just set it up right and be done with it. I am no where near what I wan't to be yet with my setup and don't really care what this will cost, I just wan't to do it once on the fueling and be done (getting sick of using bandaids). If theyre is anything you can think of that I missed let me know, and any suggestions are appreciated.

Thanks!
Adam!
 
#10 ·
We have -10 from the cell and split to -6 at the rails. I will get you detailed pics Monday if you like. I will be in Columbus until then.

It sounds like the 13.0 is an old time John. I believe Adam has a novi 2000 etc.... now and could probably use a new fuel setup.

If you wanted new plastic lines, I will send you them. I rather see you do it right personally. That setup may very well be making some power and need all the fuel you can get it. Dont make the car beg for fuel or you will have problems. do it right.
 
#11 ·
GTPMORAD said:
We have -10 from the cell and split to -6 at the rails. I will get you detailed pics Monday if you like. I will be in Columbus until then.

It sounds like the 13.0 is an old time John. I believe Adam has a novi 2000 etc.... now and could probably use a new fuel setup.

If you wanted new plastic lines, I will send you them. I rather see you do it right personally. That setup may very well be making some power and need all the fuel you can get it. Dont make the car beg for fuel or you will have problems. do it right.
Thanks Ed, pics would be great, that time was from GPG with belt slip and stock tranny/diff/convertor :mad: ! Any info will be appreciated!
 
#12 ·
I just want to add that Adam did trap a 108.9 at that junk of a track we were at...

To add to this, the fastest times of the day were 12.4's at 105mph.. the track wasn't fast for MPH and he was almost always over 106 and was turning 2.2 60's.. that car is disgusting fast and the times for sure do not back up how the car is when you drive it. I fully belive the fuel issues... I wouldn't say he is hitting 400whp though.. not yet anyway hehe ;)

Methinks the trans isn't very happy either as it feels like a bit of slip at the top of the gears too. I'm sure your puking power to that trans also..
 
#13 ·
John - Do you happen to have a diagram of what you did to put a cell in your car?
I have a cell in the trunk. A single -8 line feeds a Weldon 2015 pump with a pre-filter and post-filter. Under the hood, the -8 Y's into dual -6 lines. Each -6 feeds one rail. Each rail then feeds a fuel solenoid (nitrous), and each of those T off to go into a dual input regulator. I'm using an Aeromotive A1000-6 like you're intending on using.

-aeromotive A1000 fuel pump
I looked at this, but still decided to go with the Weldon unit.

-Fuel level pickup (can you retain the stock one? If not what else is a option?)
I bought a fuel cell with a sender. You'll need one that goes from 40 ohm to 240 ohm. Only one problem. It will read backwards. If and when it bothers me enough, I'll design a circuit to reverse that.

-Evap (vent into air from the cell?)
Yes, but you'll have a smelly garage. I don't know any way around that. Don't forget to use an anti-rollover vent valve.

Does this sound proper?
Yes it sounds good. I had the same attitude when I did mine. I wanted to put in the last fuel system the car would ever need. Famous last words....

John
 
#14 ·
Thanks for the info John, after looking I think I will pickup a 0-90 ohm autometer fuel gauge so I know where I am with fueling exactly and just ignore the stock one.

I guess two other question also:

1 - When mounting the tank in the trunk, I realize a firewall will be needed, which I figured I will just remove the back seats and fab a sheet of aluminum to cover it and cut to size, but is there a thickness requirement on the firewall?

2 - For tank mounting in the trunk did you just cutout the spare tirewell, and weld in new sheet metal so you had a flat mounting surface?

Ed - If you could post those pics still when you get back in town that would be great. Mainly looking for some trunk pics for tank mounting ideas, and a good location for the fpr so I can get equal length runs for the AN line, just trying to get some good ideas before I dive into this.

Thanks again John and Ed, this info is greatly appreciated!

-Adam
 
#15 ·
1 - When mounting the tank in the trunk, I realize a firewall will be needed, which I figured I will just remove the back seats and fab a sheet of aluminum to cover it and cut to size, but is there a thickness requirement on the firewall?
That's what I did. IIRC, the thickness requirement was .032 if using aluminum.

2 - For tank mounting in the trunk did you just cutout the spare tirewell, and weld in new sheet metal so you had a flat mounting surface?
No I didn't cut anything. The front edge of the tank sits on the flat part of the trunk, just ahead of the well. This puts the sump in the well itself. The rear of the tank is supported by aluminum bracing attached to the bottom of the well. My fuel line then exits the well through one of the big rubber grommets at the bottom. I cut the stock spare tire cover and placed it under the cell so it fills out the well hole so the trunk floor looks flat.

John
 
#16 ·
John,
At what size pulley did you start to notice you were starving for fuel? With what injectors?
-Scott
 
#17 ·
I started going static with a 2.8" pulley, and it worsened with the 2.7". I was able to put off the starvation problem for a while by lowering the fuel pressure as a band aid, but the proper solution was to put in a real fuel system that could handle the demands. Now, I couldn't be happier.

John
 
#20 ·
John,
With your car properly tuned, and on premium pump gas, what pulley can you run asa a daily driver. im trying to make a goal to acheive based on your results ;)
 
#22 ·
John,
What boost do you max out at with the 3.1"? I just pu my 3.1" on about week and half ago.
 
#24 ·
I'll have to check, but i think I am only seeing about 15-16 with my 3.1"
 
#25 ·
Do you have stage 3 heads? It's also possible that my LT1 TB flows better. Another possibility is that my street exhaust may be more restrictive than yours.

John
 
#26 ·
Iv'e got 3" back to the Y then 2-2.5" to a pair of borlas. Not cat, just a 3" resonater pipe. Heads are a set of total flow out of Michigan, they have 2" intakes and I do not know any flow specs on them. They came off Mike Balz's Regal I beleive. I feel bad were hogging all of Adams thread, we might have to start a MP112 Catagory? ;)
 
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