High HP SR Spark Blowout....Discussion/Solutions

[jspaeth]

Originally Posted by Darius

First, tune the car. There is no excuse for running AFRs in the 9's and 10's at 18 psi. Any ignition system will have trouble firing through that. As for dwell, you can play with the settings a little bit to see if giving the coils a little more time to charge will help. But doing this will only serve as a band-aid at best. Start planning a better ignition system today.

Second, the symptoms scream coil packs.

I agree with you that those AFR's are WAY to rich.

It does NOT explain why with the same AFRs, everything was fine for 9 MONTHS.


Anyway, this weekend I am going under the car and taking a once over on my alternator/battery/starter wiring and grounds.

I think alternator is okay, as I see around 13.8 V output at all RPMS and loads.


New plugs came in.....


Plans are:

1) Replace spark plug well gaskets and valve cover gasket to eliminate minor leaking of oil (very minor amount).

2) New spark plugs go in (v-power now rather than regular tip)

3) Pull some fuel across the board in the boost portion of the map, to get rid of silly 9.8-10.4 AFR's under boost and try to get it at least into the high 10/low 11 range which is still rich, but should at least be ignitable.

4) THEN, after doing all that, install my new Spliftires, which comes with ignition amplification unit to increase the voltage by about 50%.



I am hoping that doing the first 3 steps fixes the problem!




The other thing I was thinking.....when the car does this, it literally barely wants to keep pulling at all....is it possible that it could feel THAT crappy even with only 1 coilpack not doing it's job?

[GSXRJJordan]

Originally Posted by jspaeth

4) THEN, after doing all that, install my new Spliftires, which comes with ignition amplification unit to increase the voltage by about 50%.
...
The other thing I was thinking.....when the car does this, it literally barely wants to keep pulling at all....is it possible that it could feel THAT crappy even with only 1 coilpack not doing it's job?

Sell the Splitfires. Increasing voltage by 50% does not increase charge current 50%. Go LSx coils and save a bunch of money.

1 coilpack going out will be noticeable because that plug will be rich as balls while the others are better.

[Z U L8R]

man this week was crazy, had to make up for taking memorial day off, mama needed a new pair of shoes!

aiight. where were we

Jordan: i knew you had the elaboration of the lsx coil pack under control, great job, great research, and great posts + reps sir, i agree with everything you said.

Jspaeth: Justin

fwiw, i used fc edit on my rb25 in my sig and it worked great! i loved it! i wasn't insinuating anything negative when i said "australian knockoff"

great job on testing your charging system, that eliminates that. ahh the power of deduction, so good when you're only wasting time instead of wasting money.

always test never guess (if at all possible)

v-power rox teh casba bkr7e @ .028 shouldn't blow spark on stock ignition up to 20-22psi if the tune's straight, good choice.

i'm struggling not to go
1.
2.
3.
with my points/suggestions because i don't want you to think i'm being condescending or a jerk, honestly i do that for my own benefit so i can keep my thoughts in order so don't take that personal please.

you should have no problem running a flat 12.0 a/f ratio across the board which is still considered too rich by some well known tuners here in GA...

me personally, i feel 12.5 is the limits, therefore going to 12.0 and 11.7 up top gets the most power and is still PLENTY rich for those cold days and bad tanks of gas here and there....

with that said, there's no reason to be afraid to get your a/f in the 11.5's , i charge thee to not stop tweaking until every cell you get into whilst driving in boost is above 11.0

10's are not acceptable. if i see 10's i see a problem, and blowing out spark is definitely gonna and should happen.

that point is a dead horse and i'm done beating it, you get the idea.

i have a problem though. i know i don't know you that well, but from what i can tell (and i feel i'm a pretty good judge of character)

there is absolutely no way on God's green earth that someone like you OR ME would be able to drive a car that gets into the 9 and 10 air fuels for 9 months and not have/or know that there's a problem...

the car would buck, sputter, and foul the spark plugs every week if not after a couple times of just boosting.

it's like putting 550's in your stock sr or rb then starting the car. it idles fine and drives fine but if you try to boost, you're gonna be in the 9-10 afr's and it's gonna break up/foul plugs

i will bet you money that your car was not in the 9 to 10 air fuel ratio's for 9 months giving you no problems.....now hold up a second

i'm not calling you a liar at all whatsoever, and i don't care about that, that has nothing to do with my point or my suggestions to try to help you so don't get stuck on trying to defend yourself because i don't care what you say, there's no way the car could have been running that rich and been "driveable" by OUR standards...

therefore, i must ask you, have you monitored your real time coolant temperature that the ecu sees and is it normal?

i can't see jeff evans tuner or whatever his name is guy that's in your area have a good reputation as a tuner and let people leave his dyno with air fuels like that.......nor if i just paid some guy to tune my car and my air fuel ratios were in the 9-10's i would either ask for a refund or tell the man that my car's not done yet.....why??

because a boosted car whether it be any nissan or a built stroked magical 2j would be sputtering like crazy and blowing spark out that rich, ESPECIALLY with the stock ignition.... so there's just no way

so my theory is that, your tuner gave you a safe tune in the 11's, nice, safe, semi-rich for safety, and you've been driving the car for the last 9 months with no problems so you haven't really payed attention to much cause there's been no need, everything's been working correctly...

however, your coolant temperature sensor for the ecu recently has been taking a dump and is sending your ecu bad information which is causing your ecu to fatten up your whole map....now how you didn't notice this makes me doubt this theory because i'd assume you would have noticed that by now....

however if i don't assume and i simply ask you to check what your ecu is seeing as coolant temps from the sensor, then i get my question answered, and we deduce one more possibility.

don't ever think i'm trying to insult your intelligence or chastise you. i sincerely want you to remedy these issues you're having and maybe learn a little in the process.

i'm in your thread to help you,

Dave

[jspaeth]

Dave,

I fully appreciate your help.


My wideband has been calibrated from day 1, so I know it is accurate. I have always had a fuel pressure gauge, so I always know that the fuel pressure hasn't changed since day 1 when he first tuned my car.


That being said, i HAVE NOT TOUCHED any of the fuel map relating to the boost portion of the map EVER.

For the past 4-5 months that I have had the wideband, I have been monitoring the AFRs...

Under boost greater than abut 7 or 8 psi, the AFRs across the board have ALWAYS been at least as rich as 10.5, usually in the LOW 10s.

I agree with you that this retardedly rich.


However, the car HAS pulled fine, never misfiring....clearly I am losing torque, but never was misfiring EVER.

I had a correction in there to richen things up a bit for the warm weather, and in some spots it made the AFRs drop into the high 9's even...


That being said, even in the cooler weather, where i left the air temperature correction UNTOUCHED, the AFRs have always been in the low 10s.


Don't get me wrong, I am not trying to "call anyone out".....but I have been to Jeff's shop quite a few times, and have never witnessed him calibrate an O2 sensor.

If you are doing 100s and 100s of pulls at WOT under AFR < 12 conditions, the O2 sensor is gonna foul and not read accurately.


Makes me wonder how accurate the wideband sensor that was used to tune my car is.....




As far as coolant goes, I monitor this constantly, and it never deviates from 81-84 C.

In my water temperature correction, the correction from being 78 vs 85 C is at MOST only 1%....nowhere near enough to make it overly rich like this.


One last thing........


I agree with you that it should be 11.5-12.0............however, the reason I say high 10s/low 11s is because of timing.

Although I look at the timing map and it "looks" okay to me based upon the timing I have seen coming off of Enthalpy/JWT maps and word of mouth, I refuse to just "trust it" without having it on a dyno to measure the torque and listen for knock and what not.

That being said, I feel that in the short term, moving the AFRs into the hi 10/low 11 range is a HUGE improvement over what is currently going on, and will still be rich enough to assure that it's not getting too hot in there or pre-detonating.

Like I said, my timing map LOOKS okay and pretty conservative, but I wouldn't feel comfortable running the "optimal" 11.7-12.0 until I am SURE the timing is safe enough by directly testing that.


Thanks for your help.

Justin

[Z U L8R]

Werd.

Can you compare your current tune to the default tune apexi puts in your power fc? i'd compare everything but mainly emphasis on the transient settings and timing map.

also...just worth mentioning...what's your injector % set at and injector lag "latency"

Jordan: lol now you got me thinking of doing LSx coils on my 2j ^_^...lol i was even thinking about a way to set it up on my stock ka funny

Dave

[jspaeth]

Originally Posted by Z U L8R

Werd.

Can you compare your current tune to the default tune apexi puts in your power fc? i'd compare everything but mainly emphasis on the transient settings and timing map.

also...just worth mentioning...what's your injector % set at and injector lag "latency"

Jordan: lol now you got me thinking of doing LSx coils on my 2j ^_^...lol i was even thinking about a way to set it up on my stock ka funny

Dave

Dave, all of the corrections are essentially default.

I made some minor changes to AirTemp and WaterTemp effects on fuel and timing, but very minor changes.


Injector % is set at 55%.....running 740cc injectors....technically, it should be 50%, but it doesn't really matter.

For building my initial map, Jeff started with 55% to have some global inrichment and just went from there.

As you know, it really is just a correction, and doesn't matter....as what matters is that % times the base map value.


My injector lag correction is +0.06.

This is correct, as the Tomei 740cc injectors are a bit slower than the OEM 370cc's. ( i forget the exact lag times, but I looked it up a while ago and they differ by 0.06 ms).

[jspaeth]

Okay I am ready for the flaming....

I just pulled my plugs, checked compression....145 145 145 142....very happy with that.


Then I checked my plug gap for the THIRD time.....previously I had been using a set of OLD flat feeler gauges.


Well I checked them this time with one of the "disks" that has the readings going around the outside....

Gaps were 0.035 0.027 0.027 0.030.


I am wondering if the first cylinder has been blowing out or not sparking, bc that is huge gap for 9/10 AFR with stock ignition.


I swear on my life when I checked it with the feeler gauges, they were all below 0.025.

Fuck feeler gauges.

[GSXRJJordan]

Originally Posted by Z U L8R

Jordan: lol now you got me thinking of doing LSx coils on my 2j ^_^...lol i was even thinking about a way to set it up on my stock ka funny

Dave

You should, it's not as much of an upgrade as old SR coils->LSx coils, but it should still be good for ya. Extra spark energy with a huge gap is good for fuel economy too, so Obama likes using LSx coils.

Originally Posted by jspaeth

Okay I am ready for the flaming....

I just pulled my plugs, checked compression....145 145 145 142....very happy with that.


Then I checked my plug gap for the THIRD time.....previously I had been using a set of OLD flat feeler gauges.


Well I checked them this time with one of the "disks" that has the readings going around the outside....

Gaps were 0.035 0.027 0.027 0.030.


I am wondering if the first cylinder has been blowing out or not sparking, bc that is huge gap for 9/10 AFR with stock ignition.


I swear on my life when I checked it with the feeler gauges, they were all below 0.025.

Fuck feeler gauges.

So did it fix the problem, or was that just a side issue? How are the A/F's now?

[jspaeth]

Originally Posted by GSXRJJordan

You should, it's not as much of an upgrade as old SR coils->LSx coils, but it should still be good for ya. Extra spark energy with a huge gap is good for fuel economy too, so Obama likes using LSx coils.



So did it fix the problem, or was that just a side issue? How are the A/F's now?

Didn't take it out yet. THe AFRs will certainyl be the same, I need to datalog and make changes to the fuel map to clean them up, which I won't ahve time for until next weekend.

Just changed oil, regapped plugs.


bleeding brakes now....

Also, pulled the ignitor chip and tested it per the FSM and it checks out beautifully.

I promise to follow up on this. I hope that the tigther (correct) gap PLUS better AFRs cures the issue.

Again, I emphasize that the spark is blowing out also at 6000+ RPM under heavy vacuum, where the AFR is in the high 14s/low 15s.......


This proves that it is not simply a super-rich AFR caused problem...

Thanks for your help.

[jspaeth]

Tighter gap helped a BIT (idle and driving and response seem a little better/smoother) but the car is still missing really really really badly above 5800-6000 RPM.


I am not sure if this sheds any light.....but, after I let the car warm up to temp 80C or so, which took about 5 minutes, I slowly took it out to 6500 once, and it was okay....I remember this happening the other day too.

However, once the car is being driven for a while, it just nevers DOESNT miss above 6K or so.


Could this be a heat issue? Something maybe getting physically too hot?

[GSXRJJordan]

Originally Posted by jspaeth

Didn't take it out yet. THe AFRs will certainyl be the same, I need to datalog and make changes to the fuel map to clean them up, which I won't ahve time for until next weekend.

Just changed oil, regapped plugs.


bleeding brakes now....

Also, pulled the ignitor chip and tested it per the FSM and it checks out beautifully.

I promise to follow up on this. I hope that the tigther (correct) gap PLUS better AFRs cures the issue.

Again, I emphasize that the spark is blowing out also at 6000+ RPM under heavy vacuum, where the AFR is in the high 14s/low 15s.......


This proves that it is not simply a super-rich AFR caused problem...

Thanks for your help.

They will not certainly be the same if there was a gap problem... that's the whole reasoning behind the coilpack/gap questioning, because the rich AFR's suggest that you're not igniting the mix. If you are now correctly igniting the mix, you'll see AFR's more on target.

That being said, the fact that you're getting breakup at 6k rpm under vacuum leads me to believe the problem could be CAS or coilpacks.

[jspaeth]

Originally Posted by GSXRJJordan

They will not certainly be the same if there was a gap problem... that's the whole reasoning behind the coilpack/gap questioning, because the rich AFR's suggest that you're not igniting the mix. If you are now correctly igniting the mix, you'll see AFR's more on target.

That being said, the fact that you're getting breakup at 6k rpm under vacuum leads me to believe the problem could be CAS or coilpacks.

I agree with you, but the AFRs I mentioned were observed while in boost, but prior to break up/misfire.....

I KNOW they are the way they are simply bc the map is too rich, not because of failure to ignite.


In bold....THIS is what I think.....I really do think it's the coilpacks.

I don't think it's CAS.....I mean it COULD be, but the car ran perfectly fine for 9-10 months without me touching it....as far as I know, they don't usually just "go".....but coilpacks....that is another story.


Voltage at battery or alternator at high RPMs.........okay, check
Tested ignitor chip.............................................o kay, check
Resistance tested all 4 coilpacks....about 1 ohm......okay, check
Good ground to head from chassis..........................check
Good coilpack harness ground to head.....................check
Spark plugs (now) gapped okay..............................check



It doesn't leave much else, to be honest, other than a coilpack or 2 or 3 that are not firing at high RPM for some reason.

[Def]

I didn't read the whole thread, but I'll save you an assload of trouble.

Ditch the copper plugs and get some 7 heat range NGK iridiums, or Densos(IK22 I think?). NGK p/n is BKR7EIX (2667).

Coppers work fine at higher pressures when they're brand new, but they require a huge amount of voltage to jump the gap and current to make a strong enough spark. Get a little carbon after about 500-1000 miles and they require an even larger amount of voltage/current to ignite stuff over 16-17 psi on our engines.

The iridiums build up the potential much easier since it's in a much smaller cylindrical zone, and they will absolutely work for the life of the plug at whatever boost you want to run.

I went through 20 BKR7E's many years ago(stock S13 SR, problems at 16-17 psi of boost, fine below that, stock coils, stock igniter). Swapped to BKR7EIX and put about 7k miles on them with zero problems. Swapped to some Denso IK22(I think, the equivalent to the NGKs), just for preventive maintenance, but the NGKs were 100% fine when I pulled them out.

Trust me, the $4-5/plug extra you spend is well worth having a plug that doesn't suck after 500 miles. Don't buy into the copper hype. It's a bunch of people just repeating "forum group think" from the 90's.

Also, don't go to an 8 heat range. That is too cold for these motors and that power level, even for track usage. I wouldn't go to an 8 until I was making about 450+ rwhp and using the motor almost exclusively on the track.

[Def]

BTW - Rockauto.com has the best price on spark plugs in my experience.

[jspaeth]

Originally Posted by Def

I didn't read the whole thread, but I'll save you an assload of trouble.

Ditch the copper plugs and get some 7 heat range NGK iridiums, or Densos(IK22 I think?). NGK p/n is BKR7EIX (2667).

Coppers work fine at higher pressures when they're brand new, but they require a huge amount of voltage to jump the gap and current to make a strong enough spark. Get a little carbon after about 500-1000 miles and they require an even larger amount of voltage/current to ignite stuff over 16-17 psi on our engines.

The iridiums build up the potential much easier since it's in a much smaller cylindrical zone, and they will absolutely work for the life of the plug at whatever boost you want to run.

I went through 20 BKR7E's many years ago(stock S13 SR, problems at 16-17 psi of boost, fine below that, stock coils, stock igniter). Swapped to BKR7EIX and put about 7k miles on them with zero problems. Swapped to some Denso IK22(I think, the equivalent to the NGKs), just for preventive maintenance, but the NGKs were 100% fine when I pulled them out.

Trust me, the $4-5/plug extra you spend is well worth having a plug that doesn't suck after 500 miles. Don't buy into the copper hype. It's a bunch of people just repeating "forum group think" from the 90's.

Also, don't go to an 8 heat range. That is too cold for these motors and that power level, even for track usage. I wouldn't go to an 8 until I was making about 450+ rwhp and using the motor almost exclusively on the track.

Thanks for the advice.

Originally Posted by Def

BTW - Rockauto.com has the best price on spark plugs in my experience.

Just ordered 2 sets of BKR7E from there....I REALLY don't think it's the plugs....they look perfectly clean and unfouled.


Update/ New Question

Also....Def...pay attention to this statement!

AGAIN, I emphasize that the misfires are at 6000 RPM plus INDEPENDENT of load....even at very LOW loads (foot BARELY on the gas) at 6000 RPM, it is missing.

I am worried that tis may be CAS related now....it is eerie that the problem is RPM dependent but NOT load dependent.

You can't "blow out" spark at 6000 RPM with like 25 inches of vacuum in the manifold.....that is so little airflow.....


I am going to check my ECU to make sure that one of the CAS-related wires isn't messed up or loose or something.


I don't know much about how the CAS works (I know it uses 2 different signals 1* and 180*).....I am wondering if one of them being okay but the other being messed up could cause this "high RPM load independent" misfiring issue....like maybe the 1* signal is messed up?


Justin

[Def]

Oh, yea, that isn't a plug problem. I thought the "blowing out spark" was leading towards a high boost spark problem.

It could be anything from an igniter/coilpack or the CAS. I'd think the CAS would make it not really run if something was wrong with it.

[jspaeth]

Originally Posted by Def

Oh, yea, that isn't a plug problem. I thought the "blowing out spark" was leading towards a high boost spark problem.

It could be anything from an igniter/coilpack or the CAS. I'd think the CAS would make it not really run if something was wrong with it.

I was thinking the same thing, but I was wondering if a good 180* signal may be good enough for it to get timing right at lower RPMS, but perhaps it is absolutely dependent on the 1* signal at higher RPMs.


About to do some reading.


If someone could shed some light or hypothesize why a coilpack would fail in an RPM dependent (not load dependant) way, I would feel at ease, with the new Splitfires being on the way and all haha

[GSXRJJordan]

Originally Posted by jspaeth

Thanks for the advice.



Just ordered 2 sets of BKR7E from there....I REALLY don't think it's the plugs....they look perfectly clean and unfouled.


Update/ New Question

Also....Def...pay attention to this statement!

AGAIN, I emphasize that the misfires are at 6000 RPM plus INDEPENDENT of load....even at very LOW loads (foot BARELY on the gas) at 6000 RPM, it is missing.

I am worried that tis may be CAS related now....it is eerie that the problem is RPM dependent but NOT load dependent.

You can't "blow out" spark at 6000 RPM with like 25 inches of vacuum in the manifold.....that is so little airflow.....


I am going to check my ECU to make sure that one of the CAS-related wires isn't messed up or loose or something.


I don't know much about how the CAS works (I know it uses 2 different signals 1* and 180*).....I am wondering if one of them being okay but the other being messed up could cause this "high RPM load independent" misfiring issue....like maybe the 1* signal is messed up?


Justin

The coil needs to effectively discharge (quickly) in order to be able to be charged again, to discharge. Old coils take longer to charge and discharge so it can still be a coilpack problem. See below for CAS info...

Originally Posted by Def

Oh, yea, that isn't a plug problem. I thought the "blowing out spark" was leading towards a high boost spark problem.

It could be anything from an igniter/coilpack or the CAS. I'd think the CAS would make it not really run if something was wrong with it.

In general, it's true that "bad CASs" won't work at all, and the SR won't start.

The CAS (any optical pickup) depends on it's ability to accurately pick up that notch and the ECU needs a clean square wave to effectively control ignition. The SR20 is especially dependent on the CAS (as opposed to many other motors which use cam and crank position together). The CAS is not hermetically sealed, and the electronics do go bad. It's worth re-stabbing/retiming with a friend's "good" CAS to eliminate the possibility.

[jspaeth]

Originally Posted by GSXRJJordan

The coil needs to effectively discharge (quickly) in order to be able to be charged again, to discharge. Old coils take longer to charge and discharge so it can still be a coilpack problem. See below for CAS info...



In general, it's true that "bad CASs" won't work at all, and the SR won't start.

The CAS (any optical pickup) depends on it's ability to accurately pick up that notch and the ECU needs a clean square wave to effectively control ignition. The SR20 is especially dependent on the CAS (as opposed to many other motors which use cam and crank position together). The CAS is not hermetically sealed, and the electronics do go bad. It's worth re-stabbing/retiming with a friend's "good" CAS to eliminate the possibility.

Okay, well I am waiting for the splitfires to get here on Monday....next step is to try those....if it goes away, I know it's the coilpacks.


I AM still going to fix the richness under boost, but it is clear that that is not the cause of the problem, due to the misfiring under heavy vacuum at high RPM, where the AFRs are in the 14.7 range or leaner.


I dread it being the CAS.....when it comes to "sensitive" electronic parts like that, I HATE buying used ones, so I would probably wind up wasting lots of money buying a new one

[jspaeth]

VERY interesting and enlightening thread on NASIOC....this guy was having high RPM "misfires"

It turned out to be an issue related to the crank angle sensor not being close enough or something like that....worth the read:

High RPM misfire/stutter - Page 3 - NASIOC

[GSXRJJordan]

Originally Posted by jspaeth

VERY interesting and enlightening thread on NASIOC....this guy was having high RPM "misfires"

It turned out to be an issue related to the crank angle sensor not being close enough or something like that....worth the read:

High RPM misfire/stutter - Page 3 - NASIOC

We don't use magnetic pickups, doesn't apply.

[jspaeth]

Originally Posted by GSXRJJordan

We don't use magnetic pickups, doesn't apply.

Ok thanks.

Tomorrow I am gonna check continuity from ECU to the CAS...I assume it is good bc the car runs fine usually....worth a check tho.

Sidenote: Can anyone explain why the J4 ECU (what I have...a 97-98 blacktop out of Type-X 180sx manual) only has a single wire for the 1 degree CAS signal, whereas it seems like all the other SRs have 2 wires each for the 180 and 1 degree signals?


I should also add that my CAS is NOT in perfect condition.

When I took it off , I trying opening the lid (don't know why) and there is a small "bend" in the disc.

I will post up a pic.

Again, I don't think this is the issue, as the car has run fine for about a year like this.

[GSXRJJordan]

Originally Posted by jspaeth

Ok thanks.

Tomorrow I am gonna check continuity from ECU to the CAS...I assume it is good bc the car runs fine usually....worth a check tho.

Sidenote: Can anyone explain why the J4 ECU (what I have...a 97-98 blacktop out of Type-X 180sx manual) only has a single wire for the 1 degree CAS signal, whereas it seems like all the other SRs have 2 wires each for the 180 and 1 degree signals?


I should also add that my CAS is NOT in perfect condition.

When I took it off , I trying opening the lid (don't know why) and there is a small "bend" in the disc.

I will post up a pic.

Again, I don't think this is the issue, as the car has run fine for about a year like this.

Normal SR harness has two inputs to the ECU for 1* and 180*, but they come from the same wire. If yours only has one each, that's fine, that's all it needs.

Bent CAS disc. You're kidding, right. Lol. Wow. Lets take the most sensitive sensor in the whole car, which uses a small metal disc spinning at thousands of revolutions per minute, and bend it. Then lets spin it for a hundred hours. Do you think the disc and it's moving assembly are going to stay perfectly normal? ANY misalignment between the disc and the sensor is going to cause problems with an optical pickup.

My money's on the CAS, they're fairly cheap, just replace it.

[jspaeth]

Originally Posted by GSXRJJordan

Normal SR harness has two inputs to the ECU for 1* and 180*, but they come from the same wire. If yours only has one each, that's fine, that's all it needs.

Bent CAS disc. You're kidding, right. Lol. Wow. Lets take the most sensitive sensor in the whole car, which uses a small metal disc spinning at thousands of revolutions per minute, and bend it. Then lets spin it for a hundred hours. Do you think the disc and it's moving assembly are going to stay perfectly normal? ANY misalignment between the disc and the sensor is going to cause problems with an optical pickup.

My money's on the CAS, they're fairly cheap, just replace it.

Jeff, it isn't anywhere near as bad as you make it sound.

Why is it that when I say "the car has been running perfectly for 10 months" that people just kind of overlook that or don't trust me?

Anyway, I will take pictures tomorrow.

There is a small kink near the edge of the disk basically.....

[2fast4y0u]

subscribed.

very interesting issue. i like it when you guys get all techy about the sr...just doesnt happen enough on here

[jspaeth]

Originally Posted by 2fast4y0u

subscribed.

very interesting issue. i like it when you guys get all techy about the sr...just doesnt happen enough on here

I also enjoy that. I am so sick of people talking about stretched tires and how slammed their car is or what body kit or paint they have.

Stuuuupid.

[jspaeth]

Checked continuity between ECU and CAS per the FSM and it checked out perfectly.

Took the cover off the CAS.....there was a SLIGHT brownish filmy look to the disk, so I sprayed some carb cleaner on a paper towel and wiped the surface of the disk.


I do NOT think that this is gonna fix the issue tho.

Also, the small "bend" or "wavyness" in the one spot on the CAS disk is far less than I remember it being.

Basically, along one portion of the disk, if you view it along the edge, it is very SLIGHTLY wavy rather than a perfectly straight edge, and as I have said 100 times, the car ran fine for 10 months.

Coilpacks come in tomorrow!

UPDATE:

Just took the car out again. As soon as it hit operating temp (after like 4-5 minutes of warmup...) I floored it 1st and 2nd gear and it pulled strong all the way to redline in both gears, no sputtering.

Did it again 2 minutes later, slight sputtering

Did it again 5 minutes later, awful sputtering from 6K and up.



This seems heat related, like the heat is getting to the coilpacks....


Does this make sense at all? Can the heating up of the coilpacks as the engine and engine bay heat up cause them to stop working at high RPM?


I want to make sure there is not some "bigger problem" that is causing this.

I don't want to put in my new coilpacks, only for them to get ruined because there is another underlying problem (heat?).

[steve shadows]

What is your leakdown like?

What's your compression numbers like?

How are your grounds on your coil pack harness?

Not a fan of the split fires honestly man, if I were you I would just buy some new OEM ones, the OEM ones are solid up to 600+ whp all day long. And 30 PSI of boost.

Also def also makes a good point about the heat ranges, there is such thing as too cold, I guess you could say. Heat range 7 is plenty on the SR.

How is your fuel pressure under load? (sorry I havent read the whole thread either). Have you been able to watch it under heavy load by running a fuel presure gauge into the cabin to check?

What type of injectors do you have again? If they are D-werks then that's possibly an issue as well.

Don't just focus on Ignition, cut out issues could be related to a lot of different things

[jspaeth]

Originally Posted by steve shadows

What is your leakdown like?

What's your compression numbers like?

How are your grounds on your coil pack harness?

Not a fan of the split fires honestly man, if I were you I would just buy some new OEM ones, the OEM ones are solid up to 600+ whp all day long. And 30 PSI of boost.

Also def also makes a good point about the heat ranges, there is such thing as too cold, I guess you could say. Heat range 7 is plenty on the SR.

How is your fuel pressure under load? (sorry I havent read the whole thread either). Have you been able to watch it under heavy load by running a fuel presure gauge into the cabin to check?

What type of injectors do you have again? If they are D-werks then that's possibly an issue as well.

Don't just focus on Ignition, cut out issues could be related to a lot of different things

Leakdown.....no idea

Compression....145 across the board

Grounds are excellent from coil pack harness to head and head to chassis.

Fuel pressure is good......increases 1:1 but for some reason, it stops increasing past 58 psi (it increases 1:1 up to 15 psi of boost, but then stops going up past that.....doesn't DROP, just holds 58 psi constant past 15 psi of boost.....I am going to directly wire it to the battery soon....)....have an electronic FP gauge in cabin.

The FP is NOT the issue....the car was like this when it was tuned, so a little more injector probably needed to be used.....nonetheless, it is NOT lean....AFRs are VERY rich under boost....in the low 10s.


Btw the injectors are Nismo/Tomei 740s.


However, the richness is not what is causing the misfires....it misfires at 6K RPM even under massive vacuum (where the AFRs are in the 14.7 or slightly leaner range).

It is RPM dependent, not AFR or load-dependent....I have tested it under many conditions to draw this conclusion.


I will know as of tomorrow if it's the coils, which I think it is....

[Darius]

Coil pack problems increase with temperature. What is happening is the insulation in the tired, old coilpacks is deteriorating and cracking. These cracks widen as the coilpacks heat up making it easier for spark to arc across to the head than to be forced through the rich fuel and dense air mixture in your cylinder. This is when you feel the engine missing.

I 100% guarantee that the problem will go away with new OEM packs, Splitfires, or LSx packs.

And please stop messing with spark plugs. I know it is the cheapest route to try, but they have little to no influence on this problem unless they are in terrible condition, which most car guys' are not. Plus it clutters up a perfectly good coil pack thread haha