odd TBI problem

i have begun to open track my TBI project. it really does quite well, but im having a problem that i cant figure out. coming out of hard right hand turns, like out of turn 14 onto the front straight at CMP, the thing lays down. just no power, no throttle response, no acceleration. will so it more or less depending on the turn sharpness, and also on left hand turns. will not do it on the street.

as far as eliminating variables, i have tried a new fuel pump and filter, rebuilt the TBI, and tund it up. full tank or empty does not make a difference. does not do it in the rain, only after the track dries out and i can drive it harder. it gets worse the further into the session i get. im stumped on this, to be homest. i left this thing injected so i wouldnt have to worry about these kinds of things.

the vehicke is an 87 s10, five speed, 2.8 TBI. stock 92 ECM, stock PROM, stock motor. the motor has had th EGR removed, the air pump removed, timing bumped to 12 degrees initial, no cat, and 2/25 exhausts. no CEL happens to light, and no backfiring. seems like it is running lean at these points. i have not verified fuel pressure, nor do i belive i can do so safely.

if you have any ideas, let me know.
thanks
Michael

Sounds like fuel starvation.

you can get a inline shrader valve.  they sell them on ebay and you can get them with a fuel pressure tester that is sold at most parts stores.  just tweak your pressure line to get it in and just leave it there.  that way if you want you can leave your gauge hooked up and stick it up by the window.  odd question but what is your voltage doing at those times?  your getting a high enough voltage drop be it from ignition draw or the alt belt slipping because of the rpm.  you may be getting a lean condition because the power isnt there for the pump.  something to think about.

Do you still have the stock fuel tank? I can't remember that well, but my old first gen had a ground wire that was riveted or bolted to the fuel pump/ sending unit cover. the wiring on that truck was really messed up too.

One other thought. Your problem only happens when pyhsical things are being forced to move because of inertia. Look for loose or not secured wires. open up the tank again and find out the orientation of your fuel pump pick up. if it is a stock pump, see if you can pull the strainer off and make a pick up tube that the strainer will fit on. For a pick up tube i would use the right sized ruber fuel line with a couple nuts on it that are big enough to fit around the strainer end of the line, Use a couple of zip ties, one above the nuts and one below to keep the nuts on the line. This way when you are cornering, the fuel pick up will slosh with the gas.

PS. I only do this to fuel tanks/cells with rubber bladders, not sure if it is safe with stock tanks.

i used to be big into TBI at one point i was running ported vortecs, 2114 intake with TBI converter, 422 comp cam and 6lbs of boost on a supercharger. I went through hurdles with fuel leaking out during boost and hard turning from fuel shafts, injectors not firing from climbing fuel pressure during WOT voltage spikes only because i was running 1:1 FRP and pushing the 350 TBI injectors to the max.

Long story short.. Datamaster is how i found all my issues. I know laptops are heavy frowned upon in any motor sports but i never had an issues getting someone to let me make a run with an old laptop secured under a seat. My new trucks going to have a built in tiny computer mounted in the cab with LCD mounted somewhere for BS3 tunning/data logging.

http://www.ttspowersystems.com/

Also Brian at TBIchips is a good guy he did allot of tunning for work me and kept my mess going down the road.

I've been using WinALDL with good success for monitoring. I've also talked to brian twice, he'll be getting my money when I need to re-tune my ECM for V8 goodness.

i actually found the problem when i gutted the truck and stuffd the 3.4 in there. both injector wires sared a common solder joint, and a cold solder joint at that. the harness was unsecured in that location, allowing a slight amount of shif and breaking the circuit. the injectors were never firing when it was falling on its face.

no longer a concern, though.