90 stanger gt

Hey guys I'm having a problem with my motor cutting out when I'm getting on it hard anywhere from 3500 to 5500 I've replaced everything in the ignition system new msd box and wires new accel high performance header plugs can't seem to get it to stop any help would be great thanks

Tirefryer

Just a thought.... Fuel pump getting week or not keeping up....

AlsCobra

I've seen this happen too many times in fox bodys and it's usually a fuel filter. Try that first.

bob

I'd imagine its pretty easy to check with the port on the pressure side fuel line and fuel pressure gauge. Screw the gauge on observe the fuel pressure at idle and while revving it, a dramatic drop in fuel pressure will indicate if there is a problem with the fuel system.

skunk21

Check teh easy stuff Like Al stated. the fuel filter ( if dirty will starve the car at higher rpms) is easy but you can also put a temporary remote fuel pressure gage on the car where you or a pass. can see it and see what readings you get at the higher rpms. another issue could be the sock on teh fuel pump is partly clogged or has issues and can cause high rpm fuel starving problems and a weak pump.

90 stanger gt

Would the fuel pump getting weak cause carbon deposits on the spark plugs? I checked the plugs and they look like they have been burning good except they have carbon deposits around the bottom of plug that normally means a bad tune mine had the sct chip in the computer! I also have a fuel pressure gage on the fuel line i wool check that to

skunk21

Not really. how many plugs we talking? I would need a pic ( a good pic) of a few plugs to get an idea. you need to pull them all and mark which cylinder they are from to get a good idea. only a few, like one or two could be a sticky valve. carbon deposits ( fouling) of an entire set could be a host of things... running rich, wrong heat range, dirty injectors/malfunctioning, weak ignition voltage,etc. you can trouble shoot and how bad they are can also lead you in a direction.

90 stanger gt

It was all the plugs i changed them i was using stock heat range plugs can send a pic of them when i get off work

skunk21

thats fine I'll take a look at them. I'm wondering if it is a rich condition, have you pulled codes at all yet ?

90 stanger gt

Its not displaying any codes! All the plugs look like this one

AlsCobra

Fuel filter yet?

90 stanger gt

I haven't checked the fuel filter yet

90 stanger gt

I just checked the fuel pressure out was idling a Lil bit under 35 psi when you rev it up it jumps to 40 psi then settles at a Lil over 30 psi while running

90mustangLX

Did you let the car warm up a little then do a WOT a couple times while watching the gauge? Now easing into WOT but full on stabbing it WO?

90 stanger gt

No i didn't let it warm up very long! I didn't hold it all the way open but i opened it up a Lil bit

AlsCobra

It requires more fuel when the car is under a load also. I'm still calling fuel filter. If not, I only costed you about $12.
Fuel pump upgrade never hurts either.

skunk21

I'm with Al, start with the fuel filter so you can rule it out. then if you are still having the issue you need to get a fuel press. reading under cruising loads. 35 psi is in the range with vacuum connected to reg. if the problem is still happening after the filter change we need to see what the FP is doing under a load, ie a weak pump, ir even a faulty reg. etc.

90 stanger gt

It has a bbk adjustable fuel pressure regulator so out couldn't be that i will try the fuel filter if that don't help then i will upgrade the fuel pump it has a 190 lph now i guess i will go with the 255 lph