Resolved Fuel Pump kills the car

[sleeper1ga]

When cold the car doesn't seem to mind much about turning the fuel pump on, however once I drive the car for a few minutes it doesn't want to idle with the fuel pump on- it will surge and cause a rough idle- if I turn off the car then it wont run with the fuel pump on unless pedalling it... however if I start the car without the fuel pump and let it run it idles beautiful and doesn't have a problem...

Suggestions?

Car is a gvr4 v3 speed density
Engine:.020" wiseco pistons 8.5:1, std. eagle rods
Fuel: 1450cc FIC Bluemax Injectors, AEM 380lph External Pump
Turbo: Godspeed 20g

 

[A Sharp]

I'm guessing you are turning the inline pump on and off, while the in-tank walbro is always on. Does your fuel pressure jump way up when you turn the inline pump on?

EDIT: do you have a wideband (you really should)? If so, what is that reading with the pump on?

 

[sleeper1ga]

Went to a fuel cell so it's my only pump, I do have a wideband and when it's surging it varies a good amount

 

[gsxeclipse102]

If its your only pump and your turning it off how is the car running?

 

[sleeper1ga]

It can run off the fuel in the lines, at idle you don't burn through gas quickly... pretty sure it's my iac motor just was looking for a second opinion... coils were good but it doesn't move as much as I thought it should so ordered a new one, and hopefully that will solve the problem...

 

[sleeper1ga]

Iac did help stablize my isc position some, but still is surging... here's a log of while hot w/pump on

 

[sleeper1ga]

Well it runs much better now, the stock 1g base timing map was too aggressive around the idle area, once I smoothed/retarded the idle range of the timing map it idled great, the surge was just caused by an aggressive timing advance, thanks to dmertz on the ecmtuning forum I was reminded of this... dealt with it on a formula car last year and just forgot about it.... but now it'll be remembered, anyways for my first time tuning on my own I'm not doing too shabby...