Need help with stuttering

[5 Liter Eater]

Not me, I can speak fine. The car is another story.

If I'm cruising and slowly give it just enough gas enough to pass through 10"Hg the car stutters like I turned the AC on and off real quick. It has been doing this for quite some time but now it is starting to do it in boost as well!

I originally thought it was an ignition problem but when I sent my RC's off to get flowed and cleaned and I had my stock injectors in the problem seemed to go away. Could the injectors be freezing up?

[dbman96]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by 5 Liter Eater:

I originally thought it was an ignition problem but when I sent my RC's off to get flowed and cleaned and I had my stock injectors in the problem seemed to go away. Could the injectors be freezing up?</font></td></tr></table></td></tr></table></BLOCKQUOTE>


I have the same problem with 450s running at stock fuel pressure; I'm pretty sure the problem is the stock ECU can't pulse the larger injectors fast enough to make the transition between "no gas" when your foot is off the throttle and "a little bit of gas" when you're cruising at light throttle pressure. Only solution as far as I know is a standalone.

[5 Liter Eater]

But it's doing it in boost now.

[5 Liter Eater]

It did it real bad yestarday in boost. Stuttered like 5-6 times throughout the powerband in 2nd gear. I am seriously thinking about going back to the stock injectors! [img]mad.gif[/img]

[Holden]

Don't blame the injectors. I use bigger ones (320cc) and have none of the problems you're having.

Does the stuttering happen right when you floor it? If so, I'd blame the cartech restrictor and/or check valve.

If the stuttering happens even after max FP is achieved, I'd blame something in your ignition system.

[randomwalk101]

Bill, just get rid of it and get a TL...then you're cured of all problems [img]wink.gif[/img]

[iranman]

I know this isn't listed in your signature, but have you installed the MAP Converter?

[5 Liter Eater]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by iranman:
I know this isn't listed in your signature, but have you installed the MAP Converter?</font></td></tr></table></td></tr></table></BLOCKQUOTE>

No. Why?

[5 Liter Eater]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by Holden:
Does the stuttering happen right when you floor it? If so, I'd blame the cartech restrictor and/or check valve.</font></font></td></tr></table></td></tr></table></BLOCKQUOTE>

When it happens in boost it's after I have already floored it and it happens about every 500-750 RPS's or so, it's like it's cutting out, which is why I originally thought ignition like you say.

I associated it with the 10"Hg stutter but this may be a different problem than the stuttering at 10"Hg. I guess it may be ignition related as I haven't tested whether swapping injectors out makes the in-boost stutter go away but I know it does make the 10"Hg stutter go away.

Before I go swapping injectors I'll inspect the ignition components although they're all relatively new.

<font color="#a62a2a" size="1">[ February 27, 2002 11:07 PM: Message edited by: 5 Liter Eater ]</font>

[klintman]

check the spark plug wires . sometimes when they start going bad the engine will sputter under load , but run fine reving not under load . i went through 2 sets on my eclpise and one miatas that ended like this .