car sputter at 100% throttle

[kamikazee47]

you should be fine with 6in6out

[kamikazee47]

i don't have a FPR would that cause the problem?

[coolbone28]

ummm....why dont you have a fpr??? and yes...its going to cause A problem....damn kids

[kamikazee47]

i found a great deal on a MR FPR for 50 bucks, but is that the reason why my car run like sht b/c i don't have a FPR?

[frsh13]

That could be your problem, you may have only been sputtering at WOT because the engine wasn't getting enough fuel with the higher amounts of boost pressure. You defiantly need a fpr so I would get the one you were talking about and hook it up. It may not be the cause of your problem, but either way you should install one.

Low Fuel Pressure = Cold boosted air > Fuel Required = Detonation

[WDRacing]

Yep, you need a FPR. Might as well get a decent unit that's adjustable. Then you'll need to reset all the safc settings to zero since you may actually have fuel pressure.

[kamikazee47]

i will give it a try this weekend, is 50 bucks a good price for a barely used MR FPR, and how are MR FPR are they any good?

[C-Kwik]

i don't have a FPR would that cause the problem?

Are you talking about the OE FPR? Or a rising rate FPR?

[kamikazee47]

rising rate

[C-Kwik]

Assuming the tune is decent, the injectors you are running should be more than adequate without having to raise fuel pressure beyond the factory FPR's 1:1 rate. The problem is not likely your fuel system. It still sounds like a spark issue to me.

[frsh13]

Other than having too large of a plug gap, the wrong plugs, or bad wires... What might be the cause of a spark issue or "weak" spark?

[C-Kwik]

The wrong plug in that of itself won't cause an inability to spark. Too hot a plug and it may simply become a hotspot where detonation can start. Too cold a plug and it may foul, which will simply become a failed plug.

Weak sparks can also be caused by a bad coil, or perhaps one that isn't able to handle the additional resistance in the compbustion chamber casued by turbocharging. It can also be caused by a worn distributor cap and rotor.

[crzycav86]

Did you try gapping down the plugs?

I can't believe that only one person has suggested this as the likely cause. Blowing out the spark is the most common reason for sputtering in boost, and it will follows the symptoms exactly as you describe (sputters at full boost/WOT, but accelerates smoothly at low throttle)

I would not consider the fpr as a likely problem. First of all, a small or restrictive fpr would increase the fuel line pressure, causing a rich condition - not lean as has been suggested.

[kamikazee47]

i bought new plugs and gap them to .032 inch and nothing changed

[C-Kwik]

i bought new plugs and gap them to .032 inch and nothing changed

Try a lower gap. At some point, it will either solve the problem or be clear that the spark isn't the issue. It doesn't cost anything to try it so in an effort to rule out one possible cause, this should be a no brainer.

Bear in mind though, this is almost always the cause of the symptoms you describe. Many people experience it and don't consider the spark to be the issue. And it is a problem that gets worse with more boost. I didn't see what kind of boost you are running, but with the inkjectors and MAF you are running, it's safe to say that you might be running a moderately high boost level. The more boost you run, the more resistance there is between the electrodes. If gapping the plugs down more solves the problem, I'd seriously consider upgrading the ignition. This way you can open the gap back up a bit more as well.

[WDRacing]

.028 is the lowest I'd go. After that I'd be looking at an amplifier for sure.

[C-Kwik]

.028 is the lowest I'd go. After that I'd be looking at an amplifier for sure.

If he's running moderately high boost, I'd recommend he gap it a little lower just to see if he can get it to run at WOT under boost to confirm or rule out spark blow-out as a cause. Frankly, if I was running more than 10 psi, I'd be running an ignition amp regardless.

[eazye2000]

I've never had an issue with spark. I've ran 26psi with a .042" gap and the only thing I have is a MSD Blaster coil on stock wiring. Although I do have the Nology Plug wires. Maybe they actually 'do' what they say they do..

Pic in Sig.

[kamikazee47]

problem solved, upgraded my ignition.

thanks a lot for all the help

[frsh13]

What did you do to upgrade your ignition? So spark blowout was the cause of your problems?

[kamikazee47]

bought msd btm, new ignition coil, and new distrub. rotor and cap.

[frsh13]

Doesnt a MSD btm change your timing? and not apmlify the ignition?

[kamikazee47]

"The 6 BTM is ideal for engines with a turbo or supercharger. Not only will the engine benefit from MSD’s full power CD sparks, but there is also an adjustable boost/timing retard circuit to prevent detonation. "

my car seem to running better now under boost.

[C-Kwik]

Glad to hear you've resolved the issue.