Sequential ignition with Rev MS3 and Fab9 CoPs
 

I just had an FM turbo, Reverant-built MS3, and Fab9 Coil-on-plug kit installed by Tork Motorsports in Kent, WA on my 1995 with the stock 1.8L engine. John at Tork is a very experienced Megasquirt tuner and he's worked diligently to get everything running.

John sees a couple of issues that would keep us from running anything but wasted spark. I'm hoping somebody with a similar setup can chime in on how to get sequential ignition working.

Issue 1:
Before starting all this, I asked Dimitris (Reverant) about running sequential ignition with his ECU, and especially whether I'd need a crank trigger wheel. He said everything would work fine with only the CAS and I wouldn't need the crank wheel. John believed that you *do* need a crank trigger wheel to run sequential ignition because you need to know exactly what the crank is doing to manage timing. He thinks there's a way you could fake out the CAS signal to make this work but it would be a bit of a hack. Is that correct? Can we do sequential ignition with only the CAS or do we need a crank trigger wheel?

Issue 2:
The Fab9 website says you can run their CoP kit with sequential ignition. John says that the ignition controller included in the kit can only run a wasted spark configuration even if I had a crank trigger wheel. That doesn't add up since I see others on this board running sequential ignition. Can you help me understand how to wire the CoPs for sequential with the MS3?

And as an aside, John was seeing spark blowout when tuning the car with the standard .032 gap and the Denso IK22 plugs. I'm running less than 15psi so those plugs should be fine. But John had to knock down the gap to .022 to keep the ignition firing. The car seems to be running OK except for the idle, which is rather rough. John attributes that rough idle to the smaller gap. Does anybody have a thought on this too?

Many thanks in advance...

The cas is both a crank and cam trigger, at least on a 1.6. I doubt the early 1.8's are different.

I know this for a fact, because I run sequential injection off a cas alone.

Miata aren't wired for sequential spark, so you will need to modify the stock harness by adding wires. If the cop set was sold as PNP, well, it now needs modifying too. Rev should be able to tell you where the extra two channels are outside your box, then you extend those to the cop kit.

Normally 1-4 and 2-3 are wired together on the coils, you'll need to split those and wire in the extra wires you just ran, new spark triggers. Keep them in order, Rev can tell you how.

Your megasquirt tuner don't sound so good to me.

Yes, you can do sequential ignition on the CAS alone. I've done it on more cars than I can remember.

Do your FAB9 coils have the upgrade module?

Rev, can you share some instructions for running sequential ignition running only with a CAS? My tuner says he doesn't know how to do that.

Braineack, do I need a different (upgraded) module to run sequential ignition with the Fab9 kit? I see on their website that an AEM twin-fire module could be required if running more than 19psi. I'm not doing that so I figured the standard module would work for me.

Is the issue that the standard module can't be wired for sequential ignition or that it's not strong enough to keep the spark from blowing out? I saw another thread about spark blowout on this site. It appeared to be happening because that module wasn't adequately heat sinked, which was causing it to overheat. My module is connected to the body of the car so I'd expect heat control to be OK.

The wire for ignition on cylinders 1 + 4, becomes cylinder 1.
The wire for ignition on cylinders 2 + 3, becomes cylinder 3.
Connect cylinder 4 to the DB-37, pin 6 (Ign C).
Connect cylinder 2 to the DB-37, pin 7 (Ign D).

Oh, so it's just a matter of wiring up the ignition and then switching to sequential ignition? The ECU figures out the rest of it?

Correct.

I talked with John and he's extremely hesitant to run sequential ignition without a crank sensor. He says that OEM applications always run their ignition signal off the crank since you need to know exactly where the crank is to accurately fire the plug. He also says that firing off a CAS is asking for trouble because the timing belt could break, stretch, or skip a tooth and cause a catastrophic engine failure.

From my perspective, I'm thinking that all pre-1996 Miatas ran without crank sensors and the ignition timing had to come from *somewhere*. That somewhere has to be the CAS, which means it has to be good enough, right? That's unless sequential ignition fundamentally changes something about engine timing.

As I understand things, the difference between batch and sequential ignition is that you're not firing one of the cylinders when it's not needed. That is to say, you're only firing the cylinder that's ready for its power stroke. That extra efficiency seems like it would tax the ignition module less, which could lessen the possibility for blowout.

What do you guys think?

Your tuner is a fucking moron. Find someone else.

Seq. Ignition is a diminishing returns gains. Typically, the reason you want sequential spark is so you can let your coil packs charge up for longer times. If they fire in batch, they've got half the total charge time available, plus they heat up double.

It's not much a problem with good coils and stock redlines, running wasted spark that is.

The timing belt will stretch, and your ignition will become less precise. This is inherent to the cam-angle-sensor-only based approach, and is one of the reasons why you can't run as much timing on those motors (because you need to leave a larger safety margin before detonation). It can also break or jump a tooth, yes.

None of these things is likely to cause a catastrophic engine failure, and even if they were, there's nothing magical about running waste-spark that makes it safer than sequential. The only difference is that you're firing the cylinders in pairs, and the other one that gets fired is on the exhaust stroke, so that spark does nothing.

--Ian

John is correct in saying that proper sequential isn't possible on the 95, but yes it can technically work as "sequential" with the CAS. You can run it with the CAS if you run 2 extra wires, unless the igniter on the FAB9 cops are only in wasted spark. If it has an individual output for each coil, then you can do it, but personally I wouldn't

If you want a real way to add sequential spark, you can always grab a:
crank pulley and timing wheel
crank sensor
intake cam wheel
cam sensor
valve cover
associated connectors for the sensors

off a 99-00 miata and wire those in. Then just wire up the crank and cam sensors into the CAS wiring, run the 2 extra wires to the igniter/coils and choose 99-00 miata settings in megasquirt. Not hard, but it's more work than just using the CAS

also, running in wasted spark is just fine. It might help extend your coil life, but it won't give you better performance

What do you mean "true sequential?" It's either sequential ignition or it's wasted spark, no sortof partially sequential. As stated, it's not as precise, but running sequential with just the CAS is still sequential. And doing it that way really is not practically different than what the factory did with the wasted spark configuration as far as I understand it.

yes, it's sequential, but it's more of a bandaid. Full sequential fuel and spark needs a crank and cam signal. The CAS gives both the cam and crank signal, but both signals are going off the exhaust cam, and not the actual crank. I think when I took a datalog and looked at timing error when going through only the CAS, I had around 15% timing error. With a proper crank sensor and timing wheel, along with a cam sensor, my timing error went down to 3%

the whole point of doing full sequential is to get fuel and spark to happen exactly when it's supposed to right? so if you're using a sensor with that much error, what's the point if it's off by so much?

maybe I shouldn't have used the word TRUE, but the word proper

I think John's a pussy.


Running sequential off the CAS is not a bandaid.

It's not "fake sequential".

It's not "untrue sequential".

It's simply "not-quite-as-precise-sequential as with a crank sensor".


If you're not upgrading to a crank sensor, you're still using a sensor that has that much error, regardless. There's still plenty of benefits going TRUE sequential over batch fueling -- even with the erroneous CAS as your CMP/CMK signals.

Timing Error % in MS logs is the "% off from expected" -- and unless they've reworked the code it's not even that useful a log.

Thanks for the feedback, guys. The main reasons I want sequential injection are:
1) I got the CoP to avoid spark blowout as I switched from supercharger to turbo. But to my surprise I'm still getting it. It seems like the spark blowout in the Fab9 CoP kit could be caused because the module is firing two plugs instead of one. I'm figuring if one plug is being fired as in a sequential setup then there will be more energy, which means a bigger spark and less blowout.
2) The precision of sequential appeals to the engineer in me.
3) The computer supports it so I figure I might as well take advantage.

The Fab9 kit has outputs for each cylinder and the website has a sequential option for the wiring harness, which basically means it doesn't come with a PnP connection. That strongly implies the kit supports full sequential ignition and I believe I've seen others on this site who are running it that way.

FWIW, I don't think John's a pussy. He just hasn't run sequential ignition with a Megasquirt this way before and he wants to make sure it works. As my tuner, he feels (justifiably) responsible to ensure my car runs well and does it safely. Since neither of us have done this before, I'm happy he's challenging my requests instead of simply following my potentially stupid instructions.

John's objection is the CAS's diminished accuracy relative to the crank angle sensor, just as you all note. He made a similar argument to bmxfuel007 that the timing variability could be large enough to cause problems. I made the point that we're already running off the CAS, which ipso facto must be sufficiently accurate to run, even with the timing variability we know about. As I see it, sequential ignition wouldn't affect - or be affected by - timing accuracy from the CAS since it would be exactly the same as the current batch fire setup. The only difference would be that we're firing one plug instead of two, which provides the benefits I mentioned above.

I'm hearing very clearly that a crank sensor would be better than running exclusively off the CAS, not least because that adds the accuracy that appeals to my engineer's mind. Let's say I run off the CAS now and add a crank sensor later as bmxfuel007 suggested. Would I really see a difference? What would that be? And why would I need a new intake cam wheel and cam sensor (which is a CAS, right?) to replace the CAS I've already got?

Define "A difference." If you plug in the computer and log shit then yeah, you'll probably see a difference in the logs. Will you see a difference in drivability? I don't know. Will you see a difference on the dyno? possibly, if you tune at the higher accuracy as mentioned -- you can tune more on the edge since you can control things more precisely.

^All this? It's all regurgitated from reading other people's posts. Just saying.

JOHN (the tuner) is NOT a $%!^** moron. What he is suggesting the OP is to rewire the ECU with an engine that has a crank sensor and crank wheel capabilities in order for the MS3 ECU to read the most accurate timing available which will yield the most power when the car is tuned. Pre-95 engines do not have this feature which most of you know is not a good thing due to the fact factory 89-94 OEM crank pulley design is defective in first place.

The addition of 2 wires to run sequential ignition in the MS3 sounds like piece of cake.

Nope, He's a moron.

I understand entirely why he thinks a crank wheel is necessary, but it's not a requirement, and the car won't spontaneously explode because of whatever slight error might be introduced.

Same tuner also let this guy leave his shop with his tune in batch fuel injection still megasquirt and car all pre-wired for that, the tuner is a fucking idiot.

Is "bandaid untrue" sequential fuel injection off a CAS going to cause an engine to explode off a bit of timing belt stretch? According to this tuner, probably.

OP

If you want to keep things simple, consider upgrading the crank pulley to like ATI and or the Supermiata but with the OEM crank pulley on your pre-95 miata you are not 100% safe.

If you want to keep things simple, do nothing at all. It's worked for thousands of turbo 1.6 miata and countless other early 1.8 miata.

The only time it don't work is with this pro level tuner. Then you are 100% unsafe.

You don't absolutely need the 99 cam wheel and cam sensor, and use the CAS for the cam sensor signal.

Can get the 99 crank pulley with timing wheel and crank sensor and wire that into the respective wire for the crank signal to the megasquirt. the stock 4 tooth wheel is pretty accurate and a 36-2 or -1 isn't quite necessary unless you want to brag about it.

The CAS o-ring does leak a lot, so deleting it by going with a cam sensor would solve that headache. Would keep the back of the engine a lot cleaner

Yes, now lets loose the cam trigger, or buy another extra valve cover, or weld a cam trigger in.

All because this tuner is a moron, and the cas might leak.

Great!

why would you loose the cam trigger? it'd eventually fall out....

Deezums, why do you have so much animosity towards this his tuner? Were you a previous customer that got burned or something? He sounds like someone who runs a business and isn't willing to do a job where he considers it a compromise, whether you consider it one or not

Oh, I didn't realize that a cam trigger is different than a CAS.

FWIW, I already had a SuperMiata crank pulley installed as part of this build. So I'm all set there. I refrained from getting a crank wheel and sensor based on Dimitris's suggestion I didn't need it.

Because it's part of the CAS you stupid freaking knob.

I have animosity towards this tuner because from what I've seen and read from him thus far, He's a fucking idiot.

You've clearly no idea what's going on, either. It'd be super easy to mislead you to believing anything, as I believe this shitty tuner is to cover his own incompetence.

Instead of just admitting that a CAS trigger for crank and cam is fine, yet not the pinnacle of automotive triggering, this tuner has chosen to either lie or make shit up about the consequences of not wasting more money for performance that may not be required.

That's why I don't like him.

Holy shit, this thread is bad. :hatecat:

Your tuner is incorrect. The CAS outputs both cam and crank sensors. Every single 1994-1997 Miata uses the pattern from this sensor to run sequential fuel, and every 1990-1993 Miata is capable of doing the same.

In other words:
.022 plug gaps will cause shitty idle. If .022 plug gaps are required to avoid spark blowout, something in the ignition system is malfunctioning. You aren't the first person to have issues with that particular ignition system.

Yes, which is why sequential ignition is used particular in high-RPM and high-boost applications. Your car is neither, and you should be able to batch-fire your coils without issue.

Every 94-97 Miata uses the CAS to run sequential fuel. It's not "fake" sequential or "bandaid" sequential or whatever - it's true sequential fuel. You can use a Megasquirt to run full sequential spark off the 90-97 CAS as well. No qualified statements, no asterisks, no BS. It can be done safely, and people do it.


The OEM harmonic damper has absolutely nothing to do with the inaccuracy of the 90-97 CAS.


In short:
:party:

OP, I rarely run cars with sequential spark. On a race car that sees sustained high-RPM use, or on a car that's running coils that require a lot of dwell (like 6ms+), then yes, it can be beneficial, because you want to give the coil time to cool down between charging/firing cycles. For most street cars, it's just not necessary.

Thanks again for the help. It turns out I was incorrect about the plug gap. We're at .032, not .022. John said he knocked down the gap to .032 to help prevent the spark blowout. The idle quality got a lot better once I switched to sequential injection and I'm satisfied with how it's running now.

Regarding the Fab9 kit, perhaps in retrospect I should have gotten Savington's Toyota-based CoP system since that avoids the ignition controller. But since I've got this one I'd like to try and make it work.

I'm hearing that sequential ignition isn't really that important at the power levels I'm making. Honestly, that's not too surprising since Dimitris said from the very beginning that it's totally optional. Still, it sounds cool for the reasons I mentioned before. Maybe it helps, maybe it doesn't, but I think it's an interesting experiment. I'm glad to hear the CAS will be sufficient. Perhaps I'll add a crank sensor at some point if I want a project to play with.

Thanks also for the confirmation that the crank pulley isn't going to make a difference with timing. I got that since I was led to understand it'll help dampen crankshaft vibrations. I figured that was also optional based on my relatively low power levels, but I thought it would be a good move for safety.

http://members.rennlist.org/951_race...atchFiring.pdf

FUEL-DELIVERY AT HIGH-RPM
Under high-RPM operation, the fuel-injectors have longer duty-cycle periods. At redline, they are close to their maximum capacity and the differences in fuel-delivery is only 20% for a complete 720-degree 4-stroke engine cycle .

Another interesting tidbit is that the sequentially-fired injectors spend just as much time firing fuel at the back of a closed intake-valve as the batch-fired arrangement.

CONCLUSION AND DISCUSSION
Upon viewing a graphical display of the fuel-injector duty-cycles, one can see that the two methods of fuel delivery are not all that different. At low-RPM operation, the volume of fuel metered is minimal given the time available that these two systems have identical performance. At high-RPM operation near redline (where maximum-power is generated), the two systems are even more similar in fuel-delivery characteristics.

The only difference is really at which time during the closed-intake period to squirt fuel at the back of the intake-valve. Therefore, we can conclude that the differences in maximum power output is similar as well. This is supported in real-world cases of minimal differences.

The last scenario is not often used due inefficiencies in controlling the injectors at idle and low-RPM operations (because of minimum injector duty-cycle). High-RPM operation is also compromized because double the fuel has to mix with the same volume of air flowed making atomization difficult. Race cars that employ this configuration have resorted to pre-heating the fuel prior to injection and some even aim the injectors upstream to face the full brunt force of the incoming air for violent turbulence and maximum vaoprization.

These factors (and others) are probably the reason the majority of fuel-injection systems use batch-fired or semi-batch-fired fuel-injection(pairs staggered 360-degrees).

Another very simple explanation on the Cam/Crank angle sensors: https://www.hpacademy.com/technical-articles/how-does-an-ecu-know-what-cylinder-is-firing/

For a change, I agree with Savington. This thread makes my head hurt. So much half-correct information...

It's already been said, but I'm going to re-state for clarity:


All Miatas from 1990-2005 are capable of running fully sequential injection and ignition on just the stock sensors, provided that the ECU knows how to interpret the signals produced by the sensors. The output pattern of the NA CAS is a little unusual if you come from the old school of a crankwheel and a one-pulse-per-rev cam sensor, but it's just a different way of expressing the same information.



Adding a crank sensor improves the accuracy of the spark by eliminating the flex inherent in the cam belt (in EE terms, it decreases jitter), but this is a totally separate matter from running fully sequential vs. wasted-spark ignition. The spark will be just as accurate (or inaccurate) on a '90-'97 CAS whether you're running wasted-spark or sequential.



The aforementioned tuner is sadly misinformed. The '90-'97 Miata CAS produces both a crank reference and a cam reference. What the tuner is saying makes no sense at all. It's like he's thinking backwards. It would be impossible to run fully sequential on an engine with on cam sensor (eg: Ford EDIS-equipped engines), but whether an engine has a discrete crank sensor or one integrated into a cam sensor is irrelevant. Saying "you need a crank sensor to run sequential" doesn't make any sense at all. The fact that the engine ran in stock form at all (without a distributor) means that it must, by definition, already have a crank sensor or something equivalent to it.

I'm sure the guy is skilled with some piece of software, but he doesn't seem to know much about how engines work.








Doesn't really matter whether the ignition controller is built into the coils (eg: Toyota) or in an external box (Fab9). In terms of wiring and configuration, the two are basically the same.









Pretty much. The theories have already been covered, but the fact is that until you're running such high RPM that your cycle time is less than 2x the required dwell time, there's no signifcant advantage to fully-sequential ignition. If the coils have enough time to dwell, they're going to fire properly. Assuming a 4.5ms dwell time (stock coil), you'd have to run a wasted-spark engine at over 13,000 RPM before the cycle time impinges on the dwell period.



(Fully-sequential injection is a different story. The benefits there are real and observable, and are most significant at idle and low-load cruise. )










This thread is about ignition coils, not fuel injectors. Totally separate discussion.

https://www.miataturbo.net/attachmen...ine=1445910901

OTOH, there's no real disadvantage to it either. You need to run a couple extra wires, but unless you're cutting the connectors off the factory harness (ick) you're doing that anyway.

Yeah, and the linked page appears to be about some weirdo 944 Porsche thing that doesn't work the way the megasquirt does either.

--Ian

Correct. No disadvantage, unless it causes you to needlessly spend money.




It also contains bad advice. Here's an excerpt from the section discussing the conversion to fully-sequential injection:


https://www.miataturbo.net/attachmen...ine=1445911513


Notice where the end-of-squirt is relative to crank and intake valve position.

From my own experience, the fab9 coils worked great from NA up to about 10 psi. When I went up to 15 psi, j would get really bad breakup at higher rpm, full boost. I was using MS3 and wasted spark. I tried both versions of the igniter, tightened plug gaps down to low 20s, changed dwell and related settings, 2 different sets of plugs of different heat ranges, and could not get rid of the problem. I ended up cutting the white and yellow wires on the fab9 harness and ran them to the MS, and changed the settings to sequential COP. It helped slightly, but definitely did not make a big difference. I was able to find a set of toyota coils and a pnp harness someone had made up and tried that out, switched settings back to wasted COP and changed the dwell to the generic recommended Toyota COP settings posted on this site, and that finally solved my issue.

I don't think sequential is really necessary for most applications, and I also believe there is a somewhat common problem with the compatility of fab9s COP kit and MS3. I know fab uses his kits on some crazy high hp builds, but he also uses AEM for engine management...

:idea: :idea: :idea: :idea: :idea: :idea: :idea:

Honestly, people would have a lot less issues if they stopped buying FAB9 coils*.


*I'm not saying this to bash a vendor, or to be an ass, but it's a clear fact they are more trouble than they are worth if they can't actually work correctly and provide better spark than stock coils.

you don't like to squirt fuel on a closed valve?

Ah, Mech5700 wins the prize! That was the information I was looking for. So the problem sounds like it's the Fab9 kit and not with batch vs. sequential ignition.

Mech5700, I'm sorry to hear about your trouble but I'm grateful you could help me avoid more of mine. I'm also happy if we can help others avoid this problem in the future.

I'll plan to remove the Fab9 kit and replace it with Toyota CoPs.

and like I asked before, are your FAB9 coils using the new or old module?

They made some sort of revision to the product after all the reports of simple coils not being able to work with MS (even though it can run any other coil on the planet)

I just bought this kit so I assume it's the "new" module. There are no markings on it so it's hard to tell exactly what it is.

I sent an email to Fab9 asking them to comment on this thread.

Two things - You could very well have the old module, I don't recall ever having seen this issue with an MS3 car. As stated in my email, send me a quick photo of the module and I can shoot an updated replacement out.

The only reason sequential is beneficial for our kit is related to the module being to be hyper sensitive to the trigger input and when run in wasted spark with a couple of specific ECU's. We're splitting the signal between two drivers in the module. I was able to support just around 400whp on sequential with AEM using the same kit we ship each day. I've since swapped to a true CDI ignition box. That being said, we don't advertise it will support 400whp, in any configuration - it was intended to be a great PNP replacement system for those using the factory ECU (no dwell issues) or someone running 18/19psi. Regardless I'll do whatever we can to help you out on this, thanks for reaching out Andrew.

-Bryan

:bigtu:

Thanks, Bryan. My car is in the shop right now so I'll ask those guys to take a picture.

For the record, my car is running around 240hp and (I recall) around 14 psi. Considering that's a relatively mild configuration compared to others', I expect it's well within the performance envelope of your system.

Here is a picture of the ignition module. Per an offline conversation with Bryan @ Fab9, he says this is the updated version.

https://www.miataturbo.net/attachmen...ine=1446070694

Yup

FWIW, I have them in my car. 2000 with Rev built MS2E @ 15lb,. 032 gap wasted spark. Upgraded module.

No issues with spark that I recall.

3000 miles or so now.

I asked my shop for more details and they were seeing spark blowout above 10psi, which seems like it should be inside the performance envelope for a CoP system. My shop knocked the gap down to .028 to avoid the problem.

Bryan offered to send me another ignition module. I'm grateful for the support but I suppose the question is whether that's going to help. He suggested that running in full sequential mode, which was the original question in this thread, would help since we're firing 1 plug at a time instead of 2. But Mech5700's similarly unsatisfactory experience running full sequential makes me wonder about the compatibility of this kit with the MS3. Of course, bahurd's experience contradicts that, which is great.

Bryan, any thoughts on this?

I have the MS2E not MS3. That said, my plans are to change out to the GM truck coils over the winter. I already have everything but need to finish the harness. I'll end up selling them to someone with a stock setup who wants a low cost replacement for stock coils.

how much are those pencil coils? I'm wondering if your blow out is related to an ignition coil and not the actual igniter module. I've had experience with less than stellar performance from ebay coils (toyota cops and LS2 coils) blowing out when above a certain psi. The problem was only fixed after trying another set of higher quality ignition coils.

If you can find another set of coils for cheap, or even a spare known good working coil, you can try swapping out one at a time to see if the problem goes or changes

Thanks for the suggestion, bmxfuel007. The coils in the Fab9 kit are made by Denso, which I believe is the same manufacturer of the Toyota coils everybody likes.

I talked this through with Bryan from Fab9 offline. He said the ignition module could be bad but suggested some settings changes first. I'd appreciate any insights from the community.
• Set 3.5 - 4ms dwell
• Set 1.2 ms duration
• Under Number of Coils, change from Wasted Spark to Wasted COP

For the record, here's snapshot of my current ignition settings:

https://www.miataturbo.net/attachmen...ine=1446143562

For the sake of completeness, I wanted to bring everybody up to speed on how this turned out.

Bryan from Fab9 suggested a 3.5-4ms dwell and 1.2ms duration. John, my tuner, didn't feel comfortable with those settings because it increased the temperature of the coils.

The shop went ahead and ran sequential ignition based on my request and the engine runs much better now. They increased the gap to 0.32 and there's no blowout anymore.

It seems to me that the ignition module couldn't keep up firing two coils simultaneously as in batch mode, but it does OK with one at a time in sequential mode.

Many thanks to everybody who contributed to this thread and in finding a solution.

I wanted to give another update on this thread. I'd been troubleshooting random engine stalls since about March. Things got especially dodgy when the engine would stop running on the highway or at stoplights. I looked all over my config and wiring to find the problem and it finally disappeared after removing the Fab9 setup in favor of a Toyota CoP setup.

I don't know what caused the failure in the Fab9 setup. At one point the ignition module failed and I replaced it with a new one sourced directly from Fab9. They sent a generic Chinese replacement, which was interesting, but that made no difference either helping or preventing engine stalls.

Most importantly, I'm glad to have everything running properly so I can trust the car again.