high rpm stutter (6k and above) are the plugs the culprit?
07-26-2007, 03:17 PM
#21
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the wires are about 2 years old, they are 8.5mm MSD wires, I have them routed over the valve cover in a set of mr. gasket looms. they all appear to be in great shape, the closests they get to the headers or anything but the block is about 2". the opti-stub harness is a new one from Casper's Electronics that I bought 3 or 4 months ago when I put on the next to last opti (I realized i had the check valve, on the vacuum line going to the opti, on BACKWARDS) but the terminals inside the harness looked good, I sprayed them down with CRC 2-26 contact cleaner anyway, just to be sure.
I'm running a comp 503 with pro-mag 1.6's, comp 918's, beehive retainers, comp welded-tip pushrods, and LS6 spring shims, stock 90k mile lifters.
this problem has occured over night. I ran the car at the track about a month ago, and never had the first bit of a problem. hell, 2 weeks ago I stomped a turbo'd civic hatchback and it ran flawlessly, as well as when I raced a friends 230/236 cammed '97 trans-am.
don't get me wrong, I never pulled it much higher when I race anyway, the highest I pull it to is 6400 before I shift, after that, it starts losing steam.
there is one thing I forget to mention, RIGHT before I went to dyno the car, I was running pretty low on gas (one of many times I've done this
) about 100ft from the gas station, the car ran out of gas across the street. I filled it up and went about things.
I'll see what I can do about getting a copy of the run.
I'm gonna go back up there tomorrow and put it back on the rollers after I change plugs. we're gonna hook up a fuel pressure guage, and hook his wide-band o2 up this time and see what makes it tick... if it's fuel or plug related, I'll know for sure!
I'm running a comp 503 with pro-mag 1.6's, comp 918's, beehive retainers, comp welded-tip pushrods, and LS6 spring shims, stock 90k mile lifters.
this problem has occured over night. I ran the car at the track about a month ago, and never had the first bit of a problem. hell, 2 weeks ago I stomped a turbo'd civic hatchback and it ran flawlessly, as well as when I raced a friends 230/236 cammed '97 trans-am.
don't get me wrong, I never pulled it much higher when I race anyway, the highest I pull it to is 6400 before I shift, after that, it starts losing steam.
there is one thing I forget to mention, RIGHT before I went to dyno the car, I was running pretty low on gas (one of many times I've done this
) about 100ft from the gas station, the car ran out of gas across the street. I filled it up and went about things.I'll see what I can do about getting a copy of the run.
I'm gonna go back up there tomorrow and put it back on the rollers after I change plugs. we're gonna hook up a fuel pressure guage, and hook his wide-band o2 up this time and see what makes it tick... if it's fuel or plug related, I'll know for sure!
07-26-2007, 04:49 PM
#22
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Originally Posted by ThoR294
you have to realize, that ONE COIL is trying to fire EIGHT cylinders at 6000+ RPMS. a distributor type ignition was not really built for that. If I was you, I would look into that LS1 coil-over conversion for the LT1s.
as far as i know, the nascar guys are using distributors, and what are they turning, like 9000 rpms?
and sorry i didnt see that u replaced the opti
07-26-2007, 11:42 PM
#24
I had a problem sililar to this a few years ago on my 1996. It dropped at about 6100, but then came back up again 100rpms later. You could see this on most of the dynos I had done back then. It ended up being the plugs.
07-27-2007, 03:34 PM
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I think I may have found the problem!
I started changing the plugs earlier, all look great. but when I went to remove the wire from the #6 plug, it just fell off! not because I didn't click it on right, but the POS NGK TR55's have the screw-on terminal end. well, somehow it "stripped" the threads on the terminal, and was just sitting on there by a prayer.
I pulled the wire off (without any force) and the inside of the wire was covered in some white corrosion dust???
anyway, I went to my other box of MSD wires, grapped a new terminal end, and plug wire boot (I tore the existing one a little when I tried removing the terminal from inside) I trimmed 2 inches off of the wire and re-crimped the terminal.
no test drive yet, seeing as it requires WOT to act up, and it's raining like **** out of a boot right now.
I started changing the plugs earlier, all look great. but when I went to remove the wire from the #6 plug, it just fell off! not because I didn't click it on right, but the POS NGK TR55's have the screw-on terminal end. well, somehow it "stripped" the threads on the terminal, and was just sitting on there by a prayer.
I pulled the wire off (without any force) and the inside of the wire was covered in some white corrosion dust???
anyway, I went to my other box of MSD wires, grapped a new terminal end, and plug wire boot (I tore the existing one a little when I tried removing the terminal from inside) I trimmed 2 inches off of the wire and re-crimped the terminal.
no test drive yet, seeing as it requires WOT to act up, and it's raining like **** out of a boot right now.
07-28-2007, 01:18 AM
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well...changed the plugs, went to start the car, and it wouldn't hit a lick!
no spark, injectors weren't firing, NOTHING. I thought I'd junked out another opti.
I had bluecat (my tuning wizard) come over to the house, and he poked around on it for a while.
for over a year now (ever since I swapped in the 6spd) I've been having an intermitent stalling problem at high revs (miss a gear, or over-rev doing a burnout, it would just quit) never would hit the rev-limiter.
apparently the wiring harness from the donor car has had some wiring issues. I pulled all the wire loom off the harness from the opti to the computer. I then notice that the 12-volt power wire going to the opti, had been cut, and re-spliced about 3" from the computer plug-in, in the past. they did use heat-shrink tubing, but moisture (from where? IDK) had gotten to it, and corroded the wire from the splice to the pin in the connector.
on top of that, one of the power wires going to the computer had been chafed against something, and too had corroded- enough to where there was no wire contact!
I de-pinned the opti wires from the computer connector (the black one) and pulled th wires from the harness. I'm going tomorrow to go do the same thing from another donor harness.
I think this might also be one of, if not the main reason why I've been killing new opti's every 2 months.
wish me luck!
no spark, injectors weren't firing, NOTHING. I thought I'd junked out another opti.
I had bluecat (my tuning wizard) come over to the house, and he poked around on it for a while.
for over a year now (ever since I swapped in the 6spd) I've been having an intermitent stalling problem at high revs (miss a gear, or over-rev doing a burnout, it would just quit) never would hit the rev-limiter.
apparently the wiring harness from the donor car has had some wiring issues. I pulled all the wire loom off the harness from the opti to the computer. I then notice that the 12-volt power wire going to the opti, had been cut, and re-spliced about 3" from the computer plug-in, in the past. they did use heat-shrink tubing, but moisture (from where? IDK) had gotten to it, and corroded the wire from the splice to the pin in the connector.
on top of that, one of the power wires going to the computer had been chafed against something, and too had corroded- enough to where there was no wire contact!
I de-pinned the opti wires from the computer connector (the black one) and pulled th wires from the harness. I'm going tomorrow to go do the same thing from another donor harness.
I think this might also be one of, if not the main reason why I've been killing new opti's every 2 months.
wish me luck!
