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The White Bug by pmbrunelle
Started on: 01-03-2019 10:14 AM
Replies: 289 (7784 views)
Last post by: ericjon262 on 05-02-2021 05:36 PM
pmbrunelle
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Report this Post03-05-2021 06:24 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:
The reason I want to install them back is because since the cam on the 3.7 wont make much vaccuum I'm wondering if by installing these back would give me a bit more bite if I run out of vaccuum assist.


Assuming that you're keeping the revs above 2000 RPM during braking, you'll have more vacuum than the "idle vacuum" of the engine.

Do you really need full vacuum assist when the engine is idling?
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La fiera
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Report this Post03-05-2021 08:19 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:


Assuming that you're keeping the revs above 2000 RPM during braking, you'll have more vacuum than the "idle vacuum" of the engine.

Do you really need full vacuum assist when the engine is idling?


With the cam I had on the 3.4L at idle it only had 8inhg. If I suddenly took off in 1st and shift to 2nd and then hit the brake twice then I had no brake assist.
The pedal would get hard and I had to REALLY press down on the brake pedal to slow it down. When I installed the vaccum assist pump that problem was cured.
If I can install these bigger bore calipers and I can slow down the car with less pedal effort without or very little assist then I have a "Plan B" in place to use when the vaccum pump decides to quit without giving me 2 weeks notice.

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pmbrunelle
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Report this Post04-28-2021 12:34 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I've been daily-driving my Fiero since the end of March, but in the last two weeks or so, the engine would stall a few seconds after firing up.

This happened after cold starts with the engine coolant temperature at 0°C... however, I had no stalling issues at the end of November last year.

I suspect that at the end of last year, I was running the more volatile winter-blend gasoline, and I tweaked my tune using that fuel.

That tune worked fine at the beginning of this year, but probably the combination of summer-blend gasoline AND 0°C coolant temps caused problems. The onset of my problems seems to coincide with the introduction of the summer-blend gasoline...

To address this situation, I increased the amount of afterstart fuel enrichment, and the stalling went away. My objective is to run the same tune year-round, just like any normal car.
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ericjon262
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Report this Post04-28-2021 05:46 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
Glad to hear you are driving your car regularly, I'm very tempted to throw something together stupid quick to get mine back on the road, but I think I need to take a step back and wait until after my move.

do you have a flexfuel sensor installed?

If so, did you notice any differences in output between the "winter" and "summer" fuels might be able to add some compensation that way to improve the tune without having a tune work better on one or the other. I doubt it would show anything useful, but it may be worth investigating.

------------------
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pmbrunelle
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Report this Post04-28-2021 08:00 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't have a flex-fuel sensor. E85 isn't a thing here in Canada; the most ethanol you're going to get is up to 10% mixed in with your 87 AKI regular gasoline. Some gas stations have 94 AKI, with an unspecified amount of ethanol, but this isn't widely available.

I run my car on 91 AKI premium gasoline, which is generally ethanol-free here (removing a variable).

The real way to distinguish the difference in volatility between summer/winter gasoline is with the Reid Vapor Pressure test. That's a lab test, not something that can be easily implemented in a car.

So apparently, to meet the RVP limit (depends on the season), almost no butane (4 carbon atoms, very volatile) is used in summer, while refineries may mix up to 2% butane in winter. I think it would be pretty tricky to have some sensor that could detect such a small amount of butane, not to mention that the recipe of gasoline in general is unpredictable.

I began tracking my changes at the end of last summer by saving "milestone tunes" (not necessarily every little micro-change or quick test) with descriptive file names. TunerStudio also has a file comparison function, which is handy.



Unfortunately, I haven't been documenting my reasons for each change; I only have records of the changes themselves.

I don't remember from tuning the afterstart enrichment last year if more enrichment had no effect (except wasting fuel), or if more enrichment caused driveability problems. So I'll just have to wait and see what happens in the fall.

Check this, I just decided to click around a bit in TunerStudio, and I clicked on the bubble icon of this window.



You can leave notes to yourself in the *.msq. I should have played with this feature long ago!
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ericjon262
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Report this Post04-29-2021 03:03 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
gotcha, I didn't think it would show anything, but I figured it was worth a shot. I installed a flex sensor on my car as a means of "future proofing" I've only seen a couple of E85 pumps in my life but having the sensor installed leaves the option open. An added bonus is the the flex sensors display % ethanol via frequency, but also display fuel temperature based on peak voltage of the output frequency, but I'm not sure how useful that would be so... lol.

the notes tabs are super handy, I really should be using them more. Hopefully before too much longer the new MS3 firmware will be released and I'll be able to go full sequential, right now, I'm limited to "semi sequential" due to compatibility issues between my crank and cam position wheels, theoretically, I could grind the stock cam wheel and make it work, but for now, I'll wait for the firmware corrections, and an engine with rod bearings... lol!

do you have your water injection setup operational again? seem to be working well? I need to start exploring charge cooling options for when I start turning the boost up, I like your 6 nozzle setup, but I don't have the same IAC passage setup. I think I would either do a plate behind the TB, or nozzles in the top of the plenum. eventually, it will get an A2W intercooler though.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

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pmbrunelle
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Report this Post05-02-2021 12:59 AM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
For me, I think that the most useful fuel temperature measurement would be at the rail.

I have noticed that on hot restarts, after letting the car sit 15 minutes or so (looks like a heatsoak phenomenon), that it would run about 10% lean (and sometimes rough running), tapering off over 30 seconds. I do not explain this with IAT heatsoak, because the IAT reading only increases 2 degrees Celsius or so; not enough to explain the 10% lean running. My only other suspect is the heating of the fuel in the rail itself; the heatsoaked fuel becomes less dense, so less fuel mass is injected into the engine during each squirt.

The hot afterstart enrichment patches this behaviour nicely. The extra fuel doesn't cause problems on a non-heatsoaked hot restart, besides wasting gasoline...

********************************************************************************

I still have my slipping clutch (Fierostore RAM HD) right now, so I haven't been playing with WOT or heavy loads (situations requiring water injection). I haven't yet had the opportunity to install my Spec Stage 3+.

I still managed to do a lot of cold driveability tuning on the failing clutch, though I've pretty much zeroed in on that now. By cold driveability, I mean hopping into the car with a cold engine, turning the key, and driving off immediately without too much weirdness.

My truck is currently in pieces in my parents garage; during weekends it's my priority to go there and get it running, because I need the truck for my move which is coming soon. Since my truck isn't running, the Fiero has to assume the DD duty. Half-throttle in the Fiero will still get me from A to B...

I'm not actually planning on renting a cube van for the move. Since the new place is only about 1 mile away, I'm just going to drive my truck back and forth a dozen times or so, with friends at either end helping me load/unload.

********************************************************************************

I am quite happy with my overall tune, but I don't know how much of it is because of the sequential injection. As a future experiment (like in November when it's cold), I should revert to batch fire and see what difference it makes for the cold driveability.

[This message has been edited by pmbrunelle (edited 05-02-2021).]

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ericjon262
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Report this Post05-02-2021 01:43 AM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
how long is your fuel pump prime? do you let the pump run prior to starting? the metal in the rail would still hold heat, but I wouldn't think the new fuel would be able to absorb that much heat that quickly. it would be quite interesting to put a temp sensor on the supply and return as close to the rail as possible and see what the difference is. that said, the fuel rail on your engine is completely encapsulated by the intake, and much larger/heavier than later 3x00 style rails, so the rail itself is probably hotter, and holds more heat. can you hit the rail with an IR thermometer and see how hot it is under these conditions? do you have a fuel pressure sensor?

the joys of having your project become a DD, what's up with the truck?

I'm very much looking forward to having full sequential available on my engine, it should be available in the next round of beta testing, I'd rather not run beta code, but it will need someone to test it, hopefully I'll have my garbage fixed by then.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

cognita semper

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pmbrunelle
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Report this Post05-02-2021 01:06 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Maybe the fuel heating is a bad hypothesis with the return-style system; probably the prime flushes out the hot fuel quickly, though the rail itself would stay hot. Returnless would be different. Even though I have a line of sight, I wouldn't trust an IR thermometer on the fuel rail; it's too shiny.

I should pick up a set of temperature-indicating wax crayons; they would be more handy for situations like this, measuring the surface temperature without having to worry about reflections.

I haven't been measuring the fuel pressure, but I don't think that Fiero regulators have a known problem.

There's also the theory of fuel injector heatsoak. As the injector gets heatsoaked, the electrical resistance of its copper winding increases. With greater resistance, it takes longer for the injector to open; less fuel is injected for a given electrical pulse width. I think I like this theory now.

********************************************************************************

My Fiero is a pretty nice DD (well, except for the clutch), so as long as I'm not driving it in the corrosive winter salt, I'm happy DD-ing it.

The truck had a leaking exhaust manifold, and one bolt was broken off in a cylinder head. I removed the head, drilled out the bolt, and heli-coiled the hole. I did that in a day. So it's just putting it back together that's long.

I'm not good at slapping things quickly back together, things need to be cleaned/wirebrushed/painted.

[This message has been edited by pmbrunelle (edited 05-02-2021).]

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ericjon262
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Report this Post05-02-2021 05:36 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

Maybe the fuel heating is a bad hypothesis with the return-style system; probably the prime flushes out the hot fuel quickly, though the rail itself would stay hot. Returnless would be different. Even though I have a line of sight, I wouldn't trust an IR thermometer on the fuel rail; it's too shiny.

I should pick up a set of temperature-indicating wax crayons; they would be more handy for situations like this, measuring the surface temperature without having to worry about reflections.

I haven't been measuring the fuel pressure, but I don't think that Fiero regulators have a known problem.

There's also the theory of fuel injector heatsoak. As the injector gets heatsoaked, the electrical resistance of its copper winding increases. With greater resistance, it takes longer for the injector to open; less fuel is injected for a given electrical pulse width. I think I like this theory now.

********************************************************************************

My Fiero is a pretty nice DD (well, except for the clutch), so as long as I'm not driving it in the corrosive winter salt, I'm happy DD-ing it.

The truck had a leaking exhaust manifold, and one bolt was broken off in a cylinder head. I removed the head, drilled out the bolt, and heli-coiled the hole. I did that in a day. So it's just putting it back together that's long.

I'm not good at slapping things quickly back together, things need to be cleaned/wirebrushed/painted.



I think electrical heat soak makes more sense, the fuel would be refreshed quite quickly through the rail, the injector windings would need some about of time to cool.

I worry less about non critical surfaces when I'm crunched for time, but otherwise, I try to also clean things up as best as I can. it makes later work easier, and makes finding new problems easier.
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