I just got done installing a new opti and have put about 100 miles on it and it already has a horrible stumble. It started as the car cutting out at about 5,000 rpms on me. It only did it once but it felt like it hit a limiter. Today I went to run it and it had trouble starting and it ran rough. If I punch it the car strugles to get up through the rpms. I replaced plugs and wires about 10k ago, my 02's have about 1k miles on them and opti is brand new. I can't really think of anything else and am really starting to get frustrated with my car. Should I just replace the coil and coil wire and go from there?
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1994 Firebird Formula, M6, Fan switch, 160 thermostat, Pacesetter LT headers, Morosso CAI, TB bypass, True duals. -
Coil, IC Module, corroded terminals on the Opti harness connectors and/or plug/coil wires, wires burned on the LT's, damaged O2 extensions, poor ground connections aroung the coil and ICM.
Check for codes. A loss of low res pulse from the Opti will cause the injectors to shut down, and it will set DTC 16, even if it only happened for an instant.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor -
I installed a new coil this afternoon and it is no better. I looked over my opti connections and they do not look corroded at all. The wires look fine and are not touching the primaries. I also installed a new coil wire. Where should I look next? I'll put it on my computer next weekend when I get back from school and see if that points me anywhere or if its throwing a code but am I missing anything simple? The entire ignition is basically replaced. Could a bad fuel pump cause this? The car shakes horribly at idle and under any load it gets much worse. It also has absolutely no power. I'm beginning to get very frustrated with this since basically everything has been replaced. It also showed very low oil pressure today but I think the shaking is making my sending unit read off because it was fine the other day and it does not read steady it will just sporatically jump from 5-25 psi.1994 Firebird Formula, M6, Fan switch, 160 thermostat, Pacesetter LT headers, Morosso CAI, TB bypass, True duals.Comment
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Does anyone have an idea or had something similar happen?1994 Firebird Formula, M6, Fan switch, 160 thermostat, Pacesetter LT headers, Morosso CAI, TB bypass, True duals.Comment
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I have a similiar problem after installing a new opti....but I am pretty sure my problem is the coil. It only stumbles when it gets hot and after spacing my coil away from the cylinder head, the problem got a lot better, but is still not fixed. I am going to a new MSD coil when spring arrives.....
You may have one of many possible problems as Fredd alluded to. It could be a fuel pump, but could be other problems as well. You need to get a fuel pressure gauge on it and drive it while watching the gauge. THere really isnt much point in guessing, so you really need to get some diag equipment together and go to work. A scanner and fuel pressure guage will be your friend.96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there
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Have you replaced the IC Module?Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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If you were asking me, then, yes. I have actually replaced both the coil and IC module. The problem got much better when I replaced them AND spaced them from the head. But, its still not right. I am pretty sure I need a better than stock coil......Originally posted by Injuneer96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there )
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No... I mentioned it for "94 formula" since I had already mentioned it before, but he never responded specifically whether he had replaced it.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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Sorry I missed that before. I haven't replaced that yet. Is that the part that bolts to the coil?1994 Firebird Formula, M6, Fan switch, 160 thermostat, Pacesetter LT headers, Morosso CAI, TB bypass, True duals.Comment
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Check this out. http://shbox.com/coil/coil.htmlOriginally posted by 94 formula2002 Electron Blue Vette, 1SC, FE3/Z51, G92 3.15 gears, 308.9 RWHP 321.7 RWTQ (before any mods), SLP headers, Z06 exhaust, MSD Ignition Wires, AC Delco Iridium Spark Plugs, 160 t-stat, lots of ECM tuning
1995 Z28, many mods, SOLD
A proud member of the "F-Body Dirty Dozen"Comment
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Thats what I was thinking it was. Thanks for the link. Mine must have been replaced by a previous owner it was screwed in I did not have to punch out any rivets and their was no grease on it. I'll replace the IC module and put some grease and go from there.1994 Firebird Formula, M6, Fan switch, 160 thermostat, Pacesetter LT headers, Morosso CAI, TB bypass, True duals.Comment
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if i have the crane hi-6 ingniton what type of coil should i get this is on a 95 fromula with some bolt ons1995 formula firebird
mods k&n fipk ,flowmaster catback, 52mm throttle body, crane hi-6 with lx92 coil,mad dog tranny with trans coolerComment
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The coil driver module or IC module is bolted to the same bracket as the coil. Heavy duty Dielectric grease is applied liberally to coat the backside of the module, then it is bolted to the coil bracket. The harness connector can provide an intermittant contact if the pins do not make a clean contact. This can cause stumbling, knock, etc. I would pull the connector and make sure the pins and receptors are even and straight, you might even spray some electrical contact cleaner and reassemble. Another thing you could be experiencing is voltage leak. Start the car in a dark environment with the hood up. Apply the throttle and observe if any blue glow can be seen around either the coil or spark plug wires. The blue glow will show the location of the leakage. I chased this problem on mine for weeks and found the coil driver module was making intermittant contact. I bent the pins just a little for a better seat in the connection and the problem was fixed. Ironically, this was just after doing the rest of the ignition including a new module. Evidently the pins were just a little off in the configuration.
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"Note: If you remove the ignition control module from it's mounting, there is some silicone grease between it and the mounting plate. DO NOT clean this off, unless you plan to replace the grease. It is there to provide a proper heat-sink bond between the two parts."
This is in Rob's web link......how important is the silicone grease between the parts? Could the lack of grease cause a high-temp stumble? Should I use regular dielectric grease for this?
Joe, you mentioned that the voltage leak was caused by misaligned pins at the IC module. Where did you see the blue glow? I saw the blue glow inside of the coil when the car was running in the dark......I figured the coil was bad.
96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there )
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I incorrectly typed dielectric grease as the application for the back of the module, in fact it is a silicone grease. It is very important! The replacement modules include a little tube of the stuff. Could that cause a high heat stumble? You bet. Is that definately your problem? Hard to tell. Modules aren't too much, it might be worth swapping a known good one and see what happens.Originally posted by N20LT4Bird
This is in Rob's web link......how important is the silicone grease between the parts? Could the lack of grease cause a high-temp stumble? Should I use regular dielectric grease for this?
Joe, you mentioned that the voltage leak was caused by misaligned pins at the IC module. Where did you see the blue glow? I saw the blue glow inside of the coil when the car was running in the dark......I figured the coil was bad.
The blue glow is a way to chase it down in the dark. In my particular case, I just hadn't got to that point yet..... the problem was intermittant and I figured out the problem before resorting to that. It's usually most common around plug wire boots and the coil. For the coil to glow, there was a voltage leak and should have been replaced. It may have worked OK for the moment, but it was starting to break down. I always use a swab of dielectric grease on the inside of each wire boot to keep the boot from sticking, keep out moisture and minimize leak.Comment
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