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Blowing out the spark....
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<table border="0" cellpadding="1" cellspacing="1" width="99%" align="center"> <tr bgcolor="#000000"><td> <table border="0" width="100%" cellpadding="3" cellspacing="0"> <tr bgcolor="#000099"> <td colspan="2" align="left"> <font size="2" color="#ffffff" face="Verdana, Arial"> <b>T O P I C R E V I E W</b> </font></td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,3,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Guys I am at a loss, I've got a 93 Cobra with a Vortec SQ, FMU, custom auto logic chip, MSD coil, distributor, wires, plugs @ 1deg colder than stock, full BBK exhaust etc etc. Aside form the blower and exhaust the engine has never been opened up and is bone stock. I'm pretty sure that my ignition is running hot enough but I could be wrong seeing as how this problem is persisting even as I shorten the gaps. Originally the gap was at .035 and then I dropped it down to .032 and this is where it has stayed. I'm worried that if I go any lower "like .030" I might do more harm than good.<br />I have been having persistent problems with my spark blowing out around 5200-5300 RPM and other than closing the gap some more I don't have any idea as what to do with it. As you all are aware, centrifugal blowers don't even hit peak boost until around 4800 RPM and I'm missing out on my power band. Can anyone recommend a fix for this.....should I cut the gap down some more? What should I do? <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>mtbaughs</b> <br /><small>Member # 4052</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,10,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Well you won't hurt anything going down some more but why not just buy an ignition booster instead and be done with it. I assume this is a case where the spark is blowing out and not another issue. Crane HI-6 boxes are nice with the built in rev limiter. Easy to install. Good luck. <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>wilit</b> <br /><small>Member # 3367</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,15,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> How much boost are you running? I've run 18psi in my old SVO with .035 gapped plugs and the stock ingnition and never had a problem. What exactly leads you to believe the spark is actually getting blown out? <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,27,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Sup Mike <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" /> <br />The only reason I'm avoiding the ignition booster is #1 the money and #2 all the people I've heard that haven’t needed a booster with setup similar to mine.....I guess what I'm getting at is why should mine be any different?<br /><br />BTW running 8 pounds of boost<br /> <br /> <small>[ March 02, 2004, 10:27 PM: Message edited by: Liv4Spd ]</small> <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>ray95</b> <br /><small>Member # 752</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,33,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> i don't think you're blowing out your spark plugs but i would buy an msd or crane ignition box anyway. i like my msd and can notice a big difference with & with out it. <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Blu50Stang</b> <br /><small>Member # 489</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,38,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Are you sure you are having spark blowout? Can you describe the symptoms? <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>9lbpony</b> <br /><small>Member # 3510</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,43,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Keep in mind - spark blowout feels exactly like valve float... <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>wilit</b> <br /><small>Member # 3367</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,48,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Can you describe the symtoms a little better? Also can you describe your setup? It sounds more like you've got a lean spot rather than the spark blowing out. Unless there's something majorly (is that a word?) wrong with your ignition, 8psi should not blow the spark out. <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,54,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> </font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by Blu50Stang:<br /><strong> Are you sure you are having spark blowout? Can you describe the symptoms? </strong></font><hr /></blockquote><font size="2" face="Verdana, Arial">I'll do my best...<br />For example, WOT my car runs like gem up through about 4500 RPM by this point I'm at about 5 to 6 pounds of boost. Around 4900 to 5300 I notice that my power band starts too feel like it's starting to fall flat, albeit slightly. Come 5300 the first signs of "hesitation" arrive, almost like a hiccup.... Anyways at this point I have arrived at full 7 to 8 Psi. The remainder of my RPM "6250" the car persists with the same hiccup that arrived at 5300 RPM. It also seems like in this last 1000 RPM my power band starts to fall flat on its face, or in other words it feels like my power stay the "same" through 6250. <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,22,58,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> </font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by wilit:<br /><strong> It sounds more like you've got a lean spot rather than the spark blowing out. </strong></font><hr /></blockquote><font size="2" face="Verdana, Arial">Pretty sure lean is not the problem. Without an FMU it seems feasible, but wouldn't it compensate for the engines demand for fuel? It's not like I've got a 500HP beast on my hands. Also, there is absolutely NO detonation or pinging.<br />Thanks guys! <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>wilit</b> <br /><small>Member # 3367</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,23,31,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Detonation and running lean are two completely different problems. Detonation is caused by the fuel combusting too early, and actually "pushes down" on the piston as it's trying to move up, causing the pinging sound. You won't always hear a lean condition. A lean condition comes from not having enough fuel, and can feel like you're engine is falling flat on it's face. Just having the FMU will not guarantee a stoich mixture. An FMU will only increase the ammount of fuel the injectors can "squirt", you still need the computer to be calibrated to make sure the injectors fire for the proper length of time, and at the right time. If I were you, I'd invest some time on a dyno with a wideband to make sure your A/F is correct.<br /> <br /> <small>[ March 03, 2004, 12:21 AM: Message edited by: wilit ]</small> <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,2,23,36,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> If I hook up a wide band that'll tell me what I want to know....at least fuel mixture wise, right? <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>wilit</b> <br /><small>Member # 3367</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,0,23,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> What size injectors are you using, what type of FMU, what type of fuel pump, what's your static fuel pressure set at, what is the ratio of your FMU? Also, what year car is this? 5.0? 4.6?<br /><br />Yes, a wideband will tell you your A/F, and at least narrow down the problem to whether or not it is a fuel problem or an ignition problem.<br /> <br /> <small>[ March 03, 2004, 12:24 AM: Message edited by: wilit ]</small> <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Blu50Stang</b> <br /><small>Member # 489</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,7,8,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> </font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by Liv4Spd:<br /><strong> If I hook up a wide band that'll tell me what I want to know....at least fuel mixture wise, right? </strong></font><hr /></blockquote><font size="2" face="Verdana, Arial">Yes. I want to point fingers at the FMU, but you should be able to tell when you get the wideband. It is probably cheapest to take the car down to be dyno'd with an a/f reading. <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>JohnB</b> <br /><small>Member # 969</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,8,18,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> Definitely sounds like an FMU problem. If you ease into the throttle, will the car make the desired RPM? If it does, you have a faulty FMU. All the FMU does is hold line pressure when there is an increase in boost. More than likely, the disc inside the FMU is sticking. I had this same exact problem with my 93. Tore the FMU apart, put a new 12:1 disc kit in, ta-da..no more problem. <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" /> <br /><br />Also, make sure your vaccum source for the FMU is from the tree, no other source is acceptable. <img border="0" title="" alt="[Smile]" src="smile.gif" /> <br /><br />Edit: the belt IS tight, right? The problem you're describing can be belt slippage also...<br /> <br /> <small>[ March 03, 2004, 08:22 AM: Message edited by: JohnB ]</small> <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>CobramanPhil</b> <br /><small>Member # 2170</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,10,58,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> It still may be spark blowout (even though you are gapped smaller and have a decent coil). Back in the days when I first start started modding the car, I would get spark blowout at around 5300rpm. I first thought it might be fuel related (fmu problems or the fmu just doing too good of a job by putting out too much fuel at high rpm). I did the smaller gaps, better coil, and replaced the fmu disk (even tried putting a bleeder valve on the fmu) and I would still get that hesitation. Once I put the crane ignition it...all the problems were gone <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" /> <br /> </font> </td></tr> <tr bgcolor="#dedfdf"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>2stangs69-91</b> <br /><small>Member # 1951</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,12,30,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> I will chase you all over the internet LOL Aotolite racing plugs gaped at .028 or .030. All the reaserch has been done for you by me LOL. so just do it. <br /> </font> </td></tr> <tr bgcolor="#f7f7f7"> <td valign="top" width="18%"> <font size="2" face="Verdana, Arial"> <b>Liv4Spd</b> <br /><small>Member # 3784</small> </font></td> <td width="82%"> <font size="1" face="Verdana, Arial"> <img src="https://californiafords.com/ubb/posticon.gif" border="0" alt=" - " /> posted <script language="JavaScript1.3" type="text/javascript"> document.writeln(timestamp(new Date(2004,2,3,13,48,0), dfrm, tfrm, 0, 0, 0, 0)); </script><hr /> </font> <font size="2" face="Verdana, Arial"> So do you think I should try regapping my plugs to .028 or .030, I've heard this helps.....j/k <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" /> <br />Thanks for your help everyone! <br /> </font> </td></tr> </table></td></tr></table> <br /> <br />
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