OK, I just had 75% of the mods in my sig put in my car, and its having problems. Here is what happens: right between normal driving and when you gas the car the fuel cuts out. It has been watched on a gauge and the fuel curve spikes badly. The data says its the EGR valve but that has already been replaced. They also made a blockoff plate to disable the EGR but the data still says its the EGR My tuner has been working countless days trying to figure it out. He also went and got the newest TunerCat tech out to make sure he is not making any errors.It seems to be electrical not mechanical. We are running out of options..actually we already have. All these parts have been replaced: OPTI, fuel pump, plugs, wires, ignition, coil, (no 02s on the car) EGR valve, EGR valve solenoid,injectors, timing chain etc. They have went through and checked all the ohms on the wires and all of them read fine. These are local experts working on my car and they are stumped on this issue as am I. What else could it POSSIBLY be???


Please, Please, Please Help me!!

 

Always helps to provide a signature

 

A crap dont have on on this site. brb

 

Were they looking at the A/F ratio using a wide-band sensor?
What data tells you its the EGR? Do you mean it has a DTC code for EGR? That would simply indicate the EGR system is not functioning, which also makes sense.

And without so much as the year of the car, tranny type, major mods, etc, its very difficult to help.

 

'94 Z28-built 4L60E, tuned, Strange 3.73's w/ ThunderRacing girdle, Trans-Go shift kit, FuddleRacing 3400 stall, FIPK II CAI, Pacesetter Longtubes, 3" X pipe, 3" true duals, Dynomax Bullets, MSD Optispark, 8.5mm wires, 6AL, ignition coil, Holley 50# injectors, Racetronix fuel pump setup, Comp Cams Pro Mags 1.6 RR's, NGK Tr55 plugs,fully built ported and polished heads, custom grind cam, Black Z06 Rims

These are the mods

Yes they were using a wide band sensor, I'm not sure if i was a DTC code. Any ideas?

 

You titled this thread "vacuum issues", sounds like you have fuel issues! Measure the voltage to the fuel pump under load; if you're voltage is dropping that would explain the loss of fuel.

 

Did you change the fuel filter?

Are you running open loop all the time? You say there are no oxygen sensors?

 

Yes I already did, no sensors.