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When Well Enough Can't Be Left Alone; Backdate, EFI/ITB, AC, and more!

That’s pretty cool.

You’re just a few steps away from divorcing everything engine related from the original wiring which would be very cool given the state of most 911 wiring.

All you need is a PDM and ignition system and the original wiring will be for lights and whatnot.

My ECU has PWM outputs which can create an “analog” signal, or one that looks like an analog signal to an analog receiver like a gauge, and a few other low voltage outputs for driving relays, etc… I have one reserved for triggering the oil cooler fan or something in the future that I haven’t thought of yet.

Mine is a stripped down version of the MS3 pro evo which has more features than I needed or wanted (along with more than double the cost).

For this car it’s more than sufficient. For a more high strung engine or twin plug it wouldn’t cut it.


Sent from my iPhone using Tapatalk

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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html

Last edited by Showdown; 05-20-2025 at 12:54 PM..
Old 05-20-2025, 12:50 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #541 (permalink)
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I'm fairly far into getting rid of the old wiring. I'm running Denso COP's in sequential mode. Not much left now, it's basically just lights, oil level sender, and the alternator field wire at this point.

Hopefully, you'll be able to drive the gauges with the PWM outputs. Here's a shot of how I setup the temperature gauge. The oil pressure gauge still needs some dialing in. The values for the oil pressure gauge are inverted.
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1980 911SC Targa
1990 S2 Cabrio (sold)
2004 C4S (sold)
2006 Boxster (sold)

Last edited by montauk; 05-20-2025 at 05:00 PM..
Old 05-20-2025, 01:16 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #542 (permalink)
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Quote:
Originally Posted by TastyReuben View Post
been thinking about doing the same, was this straight forward switch wiring to swap? didn't want to upset the blinking/clicking function. would like to add a flashing LED indicator above as well.
I can't recall exactly as it was a while ago that it was converted, but from my loose memory and looking at the flow chart I recall it wasn't too complicated.

I had to use a more robust toggle switch with 8 poles and some of the poles housed two wires... Again, not terribly complicated but reference your flow chart and diagram it out...

Here's the back of the switch (the wires are mine and don't necessarily reference the Porsche wires.)

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1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 05-21-2025, 07:21 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #543 (permalink)
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Quote:
Originally Posted by Showdown View Post
Ok, so years ago I hacked together a remote version of TunerStudio to run on a little screen via a raspberry pi a slew of relays and general hackery. ... it worked but was glitchy. It was a good proof of concept and convinced me that having data on the dash would be a nice feature.

Fast forward and I've spent the past 2 years on and off working on this: it took about 9 months of starts and stops to make the display and the chip even talk to each other. I taught myself C++ Arduino and PCB design.

It's running approximately 3000 lines of custom C++ code that I wrote on custom hardware that I built and lives in a custom 3D printed housing.


*It receives a CAN BUS signal from the MS3ProMini (or any Megasquirt product) and can display any metric that the ECU has. So any base data point from the ECU or any data from additional sensors are available to display.

*There's a GPS module and antenna so that real-time speed, distance, MPG, trip data, altitude, heading, etc.. can be calculated and displayed.

*There's a built in TPMS system that uses off the shelf sensors that screw onto the tire nipples.

*There's a real time clock with a 10-year battery for accurate time display.

*It all lives in a custom 3D-printed housing with matching Porsche bezel. There's a hidden button that allows rotating of the screens. The bezel has a magnetic phone holder (or not, I printed both versions.)

*It has an anti-glare screen so that you can actually see it...

I've been playing around with what works and looks good and I've had versions with one screen, 5 screens 10 screens, etc...

Some of the screens I've made are:
*The above master display with 18 data points
*A VDO clock
*A trip screen with distance, mpg and the like
*A text screen with 20+ data points in text only
*A TPMS screen with a graphic of the car
*A shift light that goes form clear to yellow, orange and red based on the RPM
*A blank screen for night driving

I can make just about any screen with any graphic and any available data.

The gauge has active bluetooth for TPMS monitoring and can become a WiFi access point so that the user can interact with it and select from the available screens, set the time, set the injector rating, set the redline shift limit, and reset the current trip metrics.

Here's a video of it on the bench in a previous iteration where I had several 4-gauge silver dot displays that I've since consolidated into the above



Here's a video of the phone/computer interface.




All that's needed is a CAN BUS H&L, 12v power and ground.

And here it is from a drive to the dyno. Cool to see real time MPG. The delta MPG for the current trip (since gauge power on) is incorrect as it's factoring in idle and non-moving time. I've corrected the code and just need to push it to the gauge.



I plan on running it for a while to iron out any bugs and then making some more. I have the fixings for 10 additional gauges right now. Currently I'm only working with Megasquirt. While it's certainly possible to adapt the CAN BUS code to any ECU that outputs non-proprietary CAN BUS, I would need an ECU to test against and eventually a car running said ECU to finalize the code.

I've looked at some of the other ECU CAN BUS protocols and they're strange looking and not standard. That means it's a lot more work to adapt code. So for right now it's Megasquirt-only.

I anticipate starting to take "orders" in late summer/fall. Each gauge will be completely bespoke- every screen and feature, all the graphics, fonts and colors will be unique to each gauge I make. It's possible that I can make a very stripped down basic stock Megasquirt gauge but we'll see...

Count me in for +1. Currently running a round AFR screen but this is just awesome!
Old 05-24-2025, 04:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #544 (permalink)
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PART 1

It's 4am in Chicago right now and I should be en route to Indianapolis to rendezvous with Chris, Nate and a few others and pointed to the mountains of West Virginia for Ruchlos 5.

Instead, I'm on my couch because Tuesday, this happened:



-----------------------------------------------------------------------

A long long time ago in a galaxy... Wait, wrong story...

This is a story all about how my life got twisted, turned upside down... No, that's not right

Here's the story, of a lovely lady... yup, that's not it...

Sit right back and I'll tell you a tale, a tale of a fateful trip... Sure, close enough.

-----------------------------------------------------------------------

This is a story of grit, tenacity and ultimately, failure.

Let's back up for a minute. After the dyno fiasco I spent a few days re-tuning the car and found that in fact there was noting wrong with it. I tuned it on the road to a very respectable place and spent many days ripping the one nice curvy road we have here in Chicago. I have found that the M1 cam is really quite mild below 4000 RPM but once you hit that, it's heaps more power and that's just lovely.

Last weekend in anticipation of Ruchlos, I cleared my calendar and devoted two full days to driving. Refining the highway fueling to give me nearly 30mpg, dialing in a wnadering idle and just shaking the car out. IT was wonderful- me and the girlfriend took senic drives, I made her giggle with a 40-120mph rip and life was feelign good.

I decided to commute to work this week becasue why not- it's a 4 mile trip through a forest preserve and spring has sprung so it's quite lovely. Monday was flawless. Tuesday was flawless... until it wasn't.

Midway through the drive the car died while going 20mpg. I got it restarted instantly but then it promptly shut down again. No noises, no smoke, no nothing. I pushed on to a side street and began diagnosing it.

I found a blown fuse on spark bank 2 (456) and changed that. Success! THe car fired up and I was on my way... or so I thought. It was idling rough and the AFRs were spiking to 20 but I could smell the fuel... Fals lean... Ok. In gear and under acceleration, it stumbled and nearly shut down. More RPM and it seemed fine... Until again, it shut down.

Tow called. Morning shot.

Back at my work where the car lives, I pulled out my laptop and started triaging the situation. I used TunerStudio to confirm the injectors were working and then moved to spark. I was able to get cyl 1 to test positively but none others. Moving back to cyl 1 and it too was now not responding. I confirmed all the wiring and continuity just in case something had become loose or melted and then called AMP/EFI the makers of the ECU to troubleshoot. The tech was great and we worked through a bunch of tests. Having no success with spark, he suggested sending the ECU in for evaluation just in case as he started to worry about a transistor or something…

So, I pulled and packed the ECU and relayed the news to the boys who had been texting all day trying to brainstorm: no Ruchlos for me.

I cleaned up my work, threw away a bunch of crap and went home gutted.

Sigh.

Wednesday morning comes and I’m pissed. I had been anticipating Ruchlos for a full year, the car had new cams, a new ECU, a brand new trans with a taller 5th and LSD. I was ready to rip! I started thinking about the system and what could have gone wrong. Gabe suggested that I go buy another coil and test it with the ECU just in case. Well it turns out that I had three VW/Audi coils… or I thought I did… where were they… IN THE TRASH and I COULD HEAR THE TRUCK COMING!

Like a raccoon in the early hours I was in my dumpster digging around for a bag of coils whine the truck waited. In what would be the first of many triumphs I shot up and exclaimed “not today motherfu…” with coils in hand.

ECU unboxed, and installed, coil rigged up as the connectors on my Denso coils don’t fit the Audi coils (dear reader, note this moment of foreshadowing) and into TunerStudio test mode and WE HAVE SPARK!!!

Ok, it’s 9:00 am and I have a plan: order more coils and connectors, build new harnesses and reap the rewards! Unfortunately, none of those parts are in stock locally at any stores. But NAPA will have then delivered for same-day pickup. Order placed. Now to wait.

And wait.

And wait.

I suppose the wait was good as in the ensuing 6 hours I completed the rest of the week’s work, cleaned my studio, and caught up on emails.

2:30pm rolls around and I receive a text that my order is ready. I hightail it to the NAPA store, giving my A6 Allroad a workout that undoubtedly left the turbo glowing red. 20 mis later I was back at work with PARTS IN HAND!!!

Success!!
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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-05-2025, 02:31 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #545 (permalink)
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PART 2

Except not.

The connectors did not fit the coils. NAPA website confirmed the fit. NAPA customer support confirmed the fit. It ain’t fitting. Back online and scouring for new connectors or coils; I was ready to throw money at the problem, but alas, nothing would arrive in time.

Game over. Back to gutted.

I picked up my kids and we went out to dinner. I had a big beer and settled into the reality that once again, I wasn’t going to Ruchlos. In explaining to my girlfriend what the problem was she asked me if I could just make a connector; after all I’m pretty handy and I do have a studio full of tools and machines. I tried to explain the subtle intricoes of automotive connectors to her when these exact words came out of my mouth:

“I just wish I had a way to make a plastic housing…like a mold or a… 3D printer”

Holy cow, batman I do have a 3D printer, a brand new Bambu Labs H2D, probably one of the nicest ones on the market. Holy cow, there’s a chance...

After dispensing with the kids I raced back to work, again putting the Allroad through its paces and whipped up a 3D model of a connector that I whiped would fit. 20 mins later and I had a PLA test piece and….

IT FIT!

But PLA isn’t suitable for an engine bay. Luckily for me I have a roll of PA6-GF: glass reinforced nylon; the stuff that half of my Audi is made of! YES!

Print time for 3 connectors: 1.5 hours: just enough time to cut the harness open and begin wiring. And wire I did. As the printer finished up so too did I and sitting in front of me was a new harness awaiting connectors which were cooling in the printer.

I peeled off the supports, cleaned them up and went to put the pins. But they didn’t click into place. I tried again to no avail. It turns out that in an attempt to speed up the print time from 3 hours to 1.5 I had changed some of the settings and while that made the print faster, it resulted in less fidelity. Detail and resolution that I desperately needed to ensure the pins would snap into place.

Ok, no problem. Except time was running out. It was now near midnight and I had to he on the road in 4, maybe 5 hours.

Screw sleep; if I got tired, Nate would trailer my car and I could sleep in his Cayenne.

So, I fired up the printer again and set it to fine as hell, we’re talking Jennifer Lawrence, Amber Heard levels of tight. I figured that I’d sleep on my couch for a few hours- the harnesses were ready and all they needed were plastic housings. It would take 20 mins max and then I’d be on the road, literally.

I settled into the couch ready for some rest as I had been burning through adrenaline, cortisol, serotonin and whatever else pulses though your brain when you hit the FULL SEND button when I heard a beep beep beep from the printer.

This printer is sensational and I highly recommend Bambu Labs. I’ve thrown everything at it and its never blinked.

Today, my friends, at nearly midnight, it blinked. A beep, a flashing red light and an error. The print head something or another. A quick search on Bambu’s wiki told a story I didn’t want to hear: the print head was either clogged or had failed and would need to be disassembled.

I’ve been here before and the process to remove and disassemble the print head, while not terribly difficult is time consuming. Last time it took over an hour. An hour I just didn’t have to spare; it was 1am, I was wrecked exhausted and even if by some miracle the prints worked and I was able to get the car running, I’d still have to cannonball to Indy solo with no backup and no room for error, then drive another 8 hours to West Virginia and recover to be sharp enough to rip super technical roads with the homies.

And though my girlfriend who was with me at the studio, cheering me on, feeding me water and encouragement pushed me to keep going; clean the printer, use the other print head (the H2D has 2 print heads) hardwire the injectors, use hot glue to hold the pins, do something DAMNIT, you’re on the precipice of the greatest comeback in automotive history (she doesn’t know much about cars or well, comebacks) I knew this was the end of the road.

-----------------------------------------------------------------------

The drive home at 1:30 was serene and calming. The cold air in the windows felt good on my sweat stained and greasy face. The lack of traffic in the forest preserve felt a lot like the twisties in West Virginia and for a moment I was there, awaiting the next rest break where I’d trade stories with the boys.

-----------------------------------------------------------------------

This car has put me through the wringer this winter- I didn’t post about it for a lot of reasons but at many point I was dejected and thought about tarping it. I felt/feel that way now. But I’m also angry as hell. I had the thing that I was looking forward to snatched away from me. And it wasn’t just about fun driving with friends. These past few years have been brutal for me and this last one in particular has tested me to the core of who I believe myself to be. Everywhere I turn are fires, arrows, and firey arrows.

The one refuge that has allowed me to escape myself, to be free of all that ails me and to be comprehensively present was ripping the car around, smashing the accelerator and engulfing myself with the deafening roar of the engine.

Ruchlos was a heavy, potent dose of mainline self care that I desperately needed. Still do.

Lst night I decided to trailer the car to storage and leave it for a week, month, year.. who knows. I just couldn’t take that pain anymore. I was up at 3am this morning because see above. I decided that this story wasn’t over and that if I’m to be beat, it’ll take more than a failed coil.

Parts ordered, weekend cleared, and as Tony often says when it’s go time. LFG
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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-05-2025, 02:33 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #546 (permalink)
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Holy crap Julian, I had to read every word of the last couple posts. A riveting story with a (currently) unhappy ending. We've all been there in one way or another, and when you stick your neck out sometimes it doesn't go your way. But these things DO get solved. You're tenacious and talented, you'll get it sorted. Sending good vibes your way
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2004 Boxster S
2021 Cayman GTS 4.0 manual "Olive"
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The slope is not slippery; in fact it is entirely frictionless.
Old 06-05-2025, 06:08 AM
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Quote:
Originally Posted by Wizoftk View Post
Count me in for +1. Currently running a round AFR screen but this is just awesome!
Me too! What an amazing piece of kit!
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1981 911SC restomod "Minerva"
2004 Boxster S
2021 Cayman GTS 4.0 manual "Olive"
2014 Cayenne GTS V8 (wife's lover)
The slope is not slippery; in fact it is entirely frictionless.
Old 06-05-2025, 06:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #548 (permalink)
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Unusual to have multiple coils fail. Are these dumb coils that perhaps your hitting with too long a dwell period?
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Old 06-05-2025, 04:32 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #549 (permalink)
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Denso smart coils.

Bench tested a bunch of them for resistance and they were shot. I didn’t test all of them because at that point who cares.

Dwell was 3ms, cranking dwell 6ms.

My guess is that they were either crap coils or the heat caused them to fail. Dunno. Theories welcome


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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-05-2025, 05:01 PM
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What a story. Old cars giveth and old cars taketh away.

Hope you get yours back on the road soon and are able to enjoy the smells, vibrations, and sweet sounds these cars make.
Old 06-05-2025, 08:10 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #551 (permalink)
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Quote:
Originally Posted by Showdown View Post
Denso smart coils.

Bench tested a bunch of them for resistance and they were shot. I didn’t test all of them because at that point who cares.

Dwell was 3ms, cranking dwell 6ms.

My guess is that they were either crap coils or the heat caused them to fail. Dunno. Theories welcome


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What was the "shot" resistance? Typically with a later COP system (5-12V input signals), you can't really measure the primary coil resistance.
So your coils are most likely conventional coils requiring an ECU output coil driver capable of 5-8 amps for the 3ms or longer dwell time.
If ECU provides a too short of a dwell time, an inadequate spark will result. Hopefully the coil supplier provided the proper coil for your ECU setup.

But when you note, "Denso Smart coils", this implies the ECU is providing a low level switching voltage (5-12V).

So what type of COP system do you have? For proper troubleshooting, you need to use a scope to check the coils' primary signals.

Post 545: "Well it turns out that I had three VW/Audi coils"

So with just three coils, it's a wasted-spark system, conventional coils (primary ~ 2-3 ohms)?
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Last edited by mysocal911; 06-05-2025 at 11:23 PM..
Old 06-05-2025, 10:05 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #552 (permalink)
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Dave,

These are Denso smart coils requiring 5v logic signal from the ECU to fire them. No output coil driver necessary as with "dumb" coils.

You most certainly can measure resistance on a smart coil and I followed multiple procedures for these coils and of the several I tested, they were out of spec.

I had initially purchased the Audi pencil coils for the car but went with Denso as they were smaller and fit the engine better and have been used by many folks on 911s, including TurboKraft which sells them as part of a kit. As a Toyota product it also seemed logical to think that they were reliable, ubiquitous and economical. I couldn't return three of the the Audi coils (I did return the other three) so I tossed them into a box.

The dwell time I had for these coils was 3.5ms, but I saw that the cranking dwell was 6- I checked my notes and it should have been 4 and I can't recall why it was set to 6, so that may have contributed to fatigue on the coils...

The system is wasted-COP. I considered going full sequential with spark but the cost for an ECU that was capable (and had the other features I wanted) was more than double the cost of the ECU I went with and for a single spark low compression engine I felt the benefits to sequential spark weren't necessarily worth the cost.

Now, perhaps with COP sequential really is necessary as it reduces the frequency of firing and load on the coils. and if I find that to be the case (all research and documentation conducted thus far runs contrary to that) then I'll pull the eCU and wiring harnesses and switch to one that is capable of sequential spark...

New connectors are arriving today and I've already remade the harnesses- I have this weekend cleared to work on the car and hopefully solve this supremely inconvenient problem.
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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-06-2025, 08:04 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #553 (permalink)
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Julian,
I'm using a copy of the Denso coils.
https://www.amazon.com/dp/B091YJ9B3T?ref_=ppx_hzod_title_dt_b_fed_asin_title _2_0

For cranking and dwell, I'm using these values. The coolant temperature is actually cylinder head temperature. I'm using a cheap circuit board to convert a spark plug thermocouple to an output that the Haltech ECU can interpret.


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1980 911SC Targa
1990 S2 Cabrio (sold)
2004 C4S (sold)
2006 Boxster (sold)
Old 06-06-2025, 12:46 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #554 (permalink)
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I'm surprised you didn't just stick the pins on the coil without the connector - it's just a holder after all. It would be fine temporarily.
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Old 06-06-2025, 01:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #555 (permalink)
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Trust me, I consider doing that. I also considered soldering the pins to the connectors, using plasticine clay, my girlfriend even suggested filling the void with hot glue. And while all of those seemed like perfectly reasonable solutions in a pinch, starting off a 2000 mile road trip with that as the basis seemed a bit reckless.

It turns out not going was for the best. Even after going home and getting four or so hours of sleep on Thursday, I was a wreck. I ended up having to take three naps at work and going to bed at 8 PM; certainly not the state one desires to be in while piloting a 50 year-old car in the mountains and inclement weather.


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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-06-2025, 01:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #556 (permalink)
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Quote:
Originally Posted by Showdown View Post
Dave,

These are Denso smart coils requiring 5v logic signal from the ECU to fire them. No output coil driver necessary as with "dumb" coils.

You most certainly can measure resistance on a smart coil and I followed multiple procedures for these coils and of the several I tested, they were out of spec.
Yes, but not actually measuring the primary of the coil itself, you're measuring the input circuitry for the 3-5 amp power device that drives the coil primary (<5 ohms).

Quote:
Originally Posted by Showdown View Post
I had initially purchased the Audi pencil coils for the car but went with Denso as they were smaller and fit the engine better and have been used by many folks on 911s, including TurboKraft which sells them as part of a kit. As a Toyota product it also seemed logical to think that they were reliable, ubiquitous and economical. I couldn't return three of the the Audi coils (I did return the other three) so I tossed them into a box.

The dwell time I had for these coils was 3.5ms, but I saw that the cranking dwell was 6- I checked my notes and it should have been 4 and I can't recall why it was set to 6, so that may have contributed to fatigue on the coils...
Keeping the dwell time too long causes the voltage of the primary winding of the coil to go to zero volts, over-stressing the internal power transistor resulting in a failure. Assume a coil primary resistance of 2 ohms @12V equals 72 watts @ COP transistor switch once the primary of the coil saturates.

Quote:
Originally Posted by Showdown View Post
The system is wasted-COP. I considered going full sequential with spark but the cost for an ECU that was capable (and had the other features I wanted) was more than double the cost of the ECU I went with and for a single spark low compression engine I felt the benefits to sequential spark weren't necessarily worth the cost.

Now, perhaps with COP sequential really is necessary as it reduces the frequency of firing and load on the coils. and if I find that to be the case (all research and documentation conducted thus far runs contrary to that) then I'll pull the eCU and wiring harnesses and switch to one that is capable of sequential spark...

New connectors are arriving today and I've already remade the harnesses- I have this weekend cleared to work on the car and hopefully solve this supremely inconvenient problem.
Your existing wasted-spark system should be more than adequate, as long as you don't over-drive the ECU output pulse width to the COPs. You should use a scope to verify the actual signal pulse width the ECU supplies to each COP,
and determine what the minimum is to avoid a misfire. Most importantly, the COP datasheet should reviewed! Each COP only sparks once per engine revolution, so @ 6K RPM that's every 10ms.
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Dave

Last edited by mysocal911; 06-06-2025 at 03:45 PM..
Old 06-06-2025, 02:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #557 (permalink)
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Well, the new connectors arrived and fit…phew. So first thing tomorrow I’ll be wrenching on the car to get this hopefully sorted. I have an exhaust leak to chase and a stripped head that needs a timesert so tomorrow will be a project for sure.
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-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-06-2025, 02:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #558 (permalink)
 
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It’s amazing how quickly things can go from good to bad to good to bad to good, etc…

This morning, after sleeping for nearly 10 hours on Friday night I woke at 5am thanks to the newly hatched birds in the nest outside my bedroom window. The miracle of life is something to behold… anytime other than 5am. It was almost the miracle of death but I refrained.

Instead, I took the opportunity to hightail it to my work studio to begin either wresting the car into working order or planning its demise.

The tasks at hand were not terribly complicated, yet we all know hoe that goes:

Finish the wiring harnesses for the VW/Audi 1.8 coils,

Get the coils and harnesses installed and button up the engine bay

Remove the SSIs

Drill, tap, timesert and install a new exhaust stud on cylinder 1.

Start the car.

The harnesses came together quickly and I’m satisfied with them. I made them removable from the main harness with Deutsch connectors (something I didn’t previously do… d’oh) There’s a real zen in making harnesses and doing a nice job- it’s one of those detail that I think communicated the care that went into the build. Sometimes it’s the little things that speak volumes.



In any event, with the harnesses built and the coils installed the work inside the engine bay was complete and it was on to the real labor of the day: removing the SSIs.

These were installed by the shop I first took the car to and among a litany of things they did wrong, sloppy, or just didn’t do even though they charged me, was ordering thin flange SSIs. This car is a 1977 and the exhaust studs are long… like 58mm long so ordering the thin flange will of course work but it leaves a LOT of exposed stud. This means that it’s damn near impossible to get a wrench on the stud due to the limited space between the end of the stud and the SSIs.

Even with the SSI wrench that Al loaned me (lifesaver) it was painful and arduous. I cut up a few other wrenches and made some custom ones; what works on cylinder 1 doesn’t work on cylinder 3…

Eventually, after much cursing the SSIs were off. Clearly there were some exhaust leaks. I knew about them- I could hear them after all but this was absurd. Brand new gaskets were used and the car has maybe 500 miles on it since the motor went back in…



Al also sent me the Stomski tool which is designed for drilling out broken studs. For that, it does an admirable job but for what I needed it to do, some modifications were to be made.

I first milled a drilling busing out of some spare aluminum I had lying around. This allows the 10.2mm drill for the Timesert to be held perfectly perpendicular to the surface of the exhaust flange.



With the bushing in the Stomski tool, drilling could commence. I measured the depth of the hole and made sure to not extend past it with the bit. That’s what the very scientific piece of tape on the bit was for.


With the hole complete it was then time to tap it for the timesert. For this I 3D printed a PAHT-CF sleeve that was the same diameter as the tap, ensuring that it too would be perfectly perpendicular to the exhaust flange.



Tapping the magnesium wasn’t hard at all save for the limited space in which I had to work. Keep in mind I was doing all this on my back under the car; I figured it would be faster than pulling the motor.





Some high-temp red locktite (272 IIRC) and the timesert was in. Easier than I thought it would be but of course having the right tools makes hard work deceptively easy. You can see the delta in the length of the studs. I ordered 12 studs and was very, VERY tempted to try and extract the others and replace them with shorter studs until I hear in the distance the words of John Walker: “Don’t” and that was enough, so I left them…





It was then time to put the SSIs back on and I will say this; if they ever have to come off again, they’re staying off for good. Yes, I like heat and want to be able to drive up until the first salt, but these SSIs are a nightmare. Well, now they’re a bit less of a nightmare thanks to one shorter stud that went on rather easily. I was going to mill some spacers to slide onto the studs but I was out of steel and I didn’t want to use aluminum, nor did I want to wait to buy or receive steel so the studs will be a problem for future Julian, F that guy.

I decided to sand the surfaces of all the flanges- on the heads, on the SSIs and on the muffler, just to ensure good contact with the new gaskets.

This is a photo of the AchtungKraft flange that mates up with the SSIs. Notice how buttery smooth and free of imperfections it is… this yields a phenomenal seal to the gasket.



This is a photo of the same mating surface of the SSIs. Notice all the deep vertical gouges. Well, that's what's left of the deep, deep gouges in the surface, like .25-.5mm deep- deep enough that I had to spend a good 40 mins sanding them down. And while an exhaust leak right before the muffler isn’t the end of the world, these gorges were on all of the flanges that mated to the heads. No wonder there were leaks. In addition, the MFI bung weld was open and not complete around the nipple and worst of all, the holes that allow you to feed a socket through the body of the SSIs to tighten the nuts don’t line up with the nuts, making it impossible to tighten them without some very custom offset wrenches. And even then it takes a helluva lot of twisting, bending a contortion the SSIs so that they line up and fit.



Perhaps this is just the norm with SSIs but for the price, these are trash. I can’t wait to get rid of them and go with headers. I’ll run an electric heater or make my own head exchangers.



Anyhow. That work took from 7-about 1pm. Way longer than it should have but also infinitely shorter than it could have.



And then I sat in the seat, heart pounding, hand trembling and turned the key.



And she fired right up.



I took the car out for a 40 min drive to log some data and my initial impressions are that the car is a totally different animal. It’s way smoother, the acceleration under load is much more aggressive and it just feels way tighter and more powerful. The exhaust leaks are gone (oh the joy!) and everything was doing what it should.

I’m convinced that some if not all of the child I bought were duds or fakes. That, combined with a too-high cranking dwell just put too much stress on them and they failed. These VW/Audi could were 2x the price and came from NAPA with a warranty and if first impressions are any indication, they were worth every penny.

It’s too bad this couldn’t have happened 1 day sooner as I would have made RR5 and well, who knows. But, I’ll take the win today and live to fight another…
__________________
-Julian

1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
Old 06-07-2025, 02:40 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #559 (permalink)
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Man I’m just glad you got to drive the car after all that! My car has been similarly testing and I folded and handed it over to a professional. I commend your persistence on this. Hopefully you get to enjoy a bunch of easy miles on it now

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Mike
1980 911 SC 3.1 Coupe // 1986 VW Vanagon Syncro EJ22 // 2015 Macan Turbo // 2017 i3 REX
Old 06-07-2025, 04:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #560 (permalink)
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