Cant get enough fuel

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

I can NOT for the life of me get enough fuel into my motor.

Saturn 1.9l twin cam, built, all forged goodies
Borg warner S256 turbo right now running 10psi
Walboro in tank fuel pump
Aeromotive Boost referanced FPR
1000cc injectors
Tec3 purple box

Here are my settings

Setup for Phased
UAP 7.4
POT .4
MIT 1.3

3 bar map sensor, everything is reading correctly. I have the AEM wideband gauge, wired into the tec on the AD4 I belive. Every connection is soldered/heat shrinked.

With these settings, idling/part throttle im at about 12.8. Once boost starts coming on 13ish afr, tried upping the VE and I still cant get below 13afr.

I need to verify proper fuel pressure under boost, currently its raining out, so that really cant happen right now.

The FPR does Boost referance, idleing in the garage, hooked up my compressor to the vac line, and pushed in 10psi of air, and the FP gauge on the FPR went up accordingly.

This is a fresh build. First time with the tec, now its all broken in, and starting to get into boost more, but i just dont have enough fuel.

Hopefully the weather will let up this week, and I can verify FP under load, and get a datalog for you guys.

Also ALL enrichments are off right now, car is just running off the UAP and POT.

Any insight?

Thanks in advance
JW

**Jon@EMI** · EMI Joined: 26 Feb 2008 Posts: 144 Location: Manassas, VA

Make sure your fuel pump can keep up under load. Once you check your fuel pressure under load, you'll know if it's good enough.

Don't know how much horse power you're expecting or how much boost you're going to make it with, but 4 1000cc injectors should be good for almost 600 HP (with some overhead). Your injectors should be good enough. Also make sure that the pump can keep up under the pressure you will be running. With a manifold referenced pressure regulator, and 15lbs boost, you will have almost 70lbs of pressure absoulte. Don't forget that the flow ratings on a fuel pump are usually at only 3 bar. As the fuel pressure goes up, the flow will drop.
_________________
Jon
Project Engineer
Electromotive, Inc
jon at emi.cc
www.distributorless.com

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

Well gotta chance to drive it tonight.

Had the fuel pressure gauge sitting under the wiper so i can actually see what its doing.

And sure enough, for whatever reason, it loses pressure. I start to build boost, fuel pressure builds, then falls again to 40psi.

I ran a little different setup on my last build, i was using the stock fpr from saturn, that was supposivly boost referenced, but never really checked, because i always had enough fuel.

My last setup I was using the...ahem...megasquirt. After multiple engine failures, and headgasket issues, because of random parts of the board overheating. Trying to get a good tach signial etc, i finally had enough.

And that is part of the reason for the massive injectors, for whatever reason the MS thought the DC was higher than it was, so 1000cc injectors, were at like 70% DC only making 340whp...another reason its now in the trash.

So now i need to see if im getting a voltage drop going to the pump, or if its the pump itself.

However last time, using the same walboro 255 HO, it was fine, or so i thought?

So once I get another night off, and get a buddy to sit in the back with a multimeter...i guess we are at a standstill. I did get a datalog, but I think I already found some of my issue?

**Jon@EMI** · EMI Joined: 26 Feb 2008 Posts: 144 Location: Manassas, VA

Loss of fuel pressure certainly explains the lean condition. It is possible that you are making more horsepower than you were (it's been know to happen with switches to Electromotive), but i have my doubts that it would be that dramatic.

If your voltage is ok, one other thing to consider: you may have a clog or other restriction on the fuel pump inlet. If it's an in-tank pump, this seems unlikely, but it may be worth a look. Especially if the car sat for a while waiting for the engine and TEC.
_________________
Jon
Project Engineer
Electromotive, Inc
jon at emi.cc
www.distributorless.com

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

Ima check voltage first for sure, seeing as i have to drop the tank to even look at the outside of the pump...But if thats the case, it IS sometimes nice to have a lift at your disposal

Thanks for your input so far!

Ill keep you posted as to my findings

**nefarious** · Posted: Fri Oct 10, 2008 11:09 am Post subject:

JW, is the fuel pump wired into the TEC3?

im using a Walbro as well, before the GT switch, with the TEC 2, i was also using 1000 cc injectors, and i had no issues at all, thats with the saturn OEM FPR, the reason i ask is that i've had alot more success letting the TEC control everything but the fuel pump, our cars can keep up, the only problem lies with the saturn OEM crank positioning sensor i you can believe it, thats why im asking how the pump is wired in, if its with the TEC, thats one thing, if not, i have prolly exhausted every possibility between the 98' returnless and 97 return style systems
_________________
97' Saturn SC2-Turbo
TEC2 + T3/T4 + FMIC
once again under construction
[img:7099059568]http://militarysignatures.com/signatures/member3983.png[/img:7099059568]

sixpak · Posted: Fri Oct 10, 2008 11:57 am Post subject:

Are you using the stock fuel pick up in the tank? If so, does it have one of those "socks" inside? Is the suction side of the pump sized too small causing the fuel starvation? If you are using an aftermarket pump could it be mounted too high or too far away to properly draw fuel from the tank. My pump feeds the pump from bottom of the tank, is lower than the tank, and is only 1 foot away from the tank. My car is nothing like yours but the fuel system should have the same design principals if possible. Just a few thoughts.

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

The fuel pump output on the tec, is the only thing that is wrong with it. I bought this used, and the fuel pump output doesnt work.

So right now, im running a toggle switch to the stock relay. So key has to be on, and the switch has to be on for the fuel pump to work.

Its a drop in 255ho pump. Im going to drop the tank in a couple minutes and pull the pump to make sure that it didnt suck any crap up. Also to make sure that the sock isnt all clogged.

So i think im going to run different wiring, like 12 ga to the pump and make my own circuit for it. And hopefully itll work.

**nefarious** · Posted: Tue Oct 14, 2008 10:01 pm Post subject:

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

I got the fuel pump re wired.

And the reason is that when i hooked everything up, the stock pcm would not see a tach signal because of the tec. So the pump would prime, but wouldnt run.

That is why im doing it this way, do you have the stock ICM still hooked up?

And pressure is good now, and still the same stuff, alittle richer, got some datalogs, going to try and find somewhere to post it

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

Well re checked all the wiring last night. Somehow its running about 12.7afr, still to lean.

Tomorrow found a place local that cleans, flow tests injectors, so dropping off my injectors tomorrow, and if thats the problem, everything hopefully will be good.

Untill i find out the status on the injectors, this is kinda at a standstill seeing as the car cant move now.

Thanks again for the help so far

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

Got the injectors back, they where fine. Was messing around with it and found that the fpr was leaking boost in the air chamber of it. Fixed that, and now the fuel pressure is good, however still not rich enough, and running that high of a UAP?

I think im going to send in the tec unit and have them check it to make sure its good.

**nefarious** · Posted: Mon Oct 20, 2008 12:22 pm Post subject:

yeah man, the stock PCM is still hooked up, and i was under the impression that the crank trigger for the fuel pump comes from the CPS, i had the same issue when the cps was disconnected, i had the IOT set at like 10ms to get the car to run, until i hooked it back up and that was the problem, but you'd know it because you'd be fouling plugs every time you started the car up
_________________
97' Saturn SC2-Turbo
TEC2 + T3/T4 + FMIC
once again under construction
[img:7099059568]http://militarysignatures.com/signatures/member3983.png[/img:7099059568]

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

I have the cps hooked up. That goes directly to the ignition control module...i thought?

At any rate though, injectors are fine, fpr is fine, fuel filter is new, no crimps in the fuel lines. And getting steady pressure now. And still to lean.

Its just mind blowing because of only 10psi not getting enough fuel, and how high i have to have these numbers to get it somewhat close

phat95nosdsc2 · never say die Joined: 17 Jun 2008 Posts: 19

Talking with Uba (sp??) From electromotive, he was saying i should try running these injectors in full seq.

So I wired them up like that tonight, and the same thing, need alot of UAP, but not as much, but still cant break that 13afr mark under WOT.

Im going to try a different WB gauge just to make sure that its not that. Once i try that, the tec is getting sent in.