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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Sat Sep 08, 2012 5:55 am Post subject: Bockscar's EFI Ultra-Conversion (Lots-o-pics) |
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I've decided to make an epic ultra-mega thread to document my 2nd attempt at an EFI conversion. I tried once before and for various reason, it was a semi-failure. I used MSExtra with MS1 hardware and opted not to control the spark and let the late-style Bosch ignition handle everything. This was a huge mistake. The ignition timing went nuts and I couldn't keep a steady idle and I certainly couldn't drive it (never mind the problems with the clutch). Also, I was not at all impressed with MegaSquirt. Nevertheless, I've decided to try it again, this time from a different angle. Lots of lessons were learned and I'd like to share them with everyone and start on my 2nd attempt. Here was my engine bay after I got MegaSquirt running the first time:
The CIS to EFI conversion itself was.. interesting. When I bought the car, it was a mess. It had been sitting in a field under a tree for about 9 years. The good thing was that the engine was brand new; the PO had just had it installed. The bad news was that he stopped working on it in the middle of reinstalling everything so I had no idea what was needed to be finished. Many parts were still missing/disconnected/lost, etc. I decided to take the head off and start over. The engine bay itself was a disaster. The hood wasn't firmly covering the motor so there was tree crap and dirt everywhere. The holes for the spark plugs were completely plugged with gunk, there were rat nests in pretty much every nook and cranny.. It was nasty. When I removed the head, I found this:
Anyway, fast forward to the EFI conversion. I decided to scrap CIS because I was missing many parts and I know nothing about it so, into the garbage it went. I picked up a very nice fuel rail made by forum member Endwrench from someone here on the forum. It fit perfectly. Next, I bought 4 Bosch 'Green Top' (skinny style) fuel injectors on Ebay for about $45 each. I bought injector bungs from 034 motorsports
http://www.034motorsport.com/fuel-injection-solutions-injector-bung-cis-to-efi-billet-aluminum-24mm-p-424.html.
Not only were these injector bungs expensive, they did not fit right out of the box. They threaded in just fine but the inside of the cups have a lip that prevents the injector from sliding down all the way. I needed to drill the lip out. After that though, it worked perfectly.
The injectors and rails were the easy parts. Simply take the old fuel lines, get some fuel grade hosing that will run from the existing hard fuel lines to the fuel rail, and attach em all together. Don't forget about the fuel pressure regulator. I'll talk more about that later. I need to replace mine anyways. The sensors were pretty simple. I placed my air temp sensor in the charge tube where the old boost pressure sensor went. You can plumb the map sensor anywhere after the throttle body, really. The coolant temperature sensor was a little more difficult. I'm sure there are better ways of doing this but, we used brass plumbing fittings and placed it onto the coolant flange.
But regardless, it worked. We bought the "pre-built" wiring harness from DIY autotune, however that harness was built for the latest version of MS and we were using the oldest of MS, so there were some complications. The ancillary sensors were all really easy to wire up, though the injectors were a little more difficult. When powered, the injectors would emit an audible click sound which made us this we had them wired wrong. Apparently this single click sound was the 'Purge' stage which was not well documented in the MegaManual.
Needless to say we got everything wired up and working (kinda) but discovered another problem. Something was wrong with the clutch. Actuating the shifter level did nothing. When the engine was running (in neutral) and the shifter was pressed in, the engine would make this awful squealing sound. It was around this time when we ascertained that the stock ignition system did not play nicely with an aftermarket ignition system. We decided to scrap the whole project. But I am insane and I've decided to resurrect the ol'931 project. We have some theories about the clutch but really these theories mean nothing unless we can see what's going on inside the bell housing. I rolled the car into the garage, acquired an engine hoist, and out the engine came
The next step in the process is to take the bell housing off. It's not hard with the engine removed, is it? _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped
Last edited by Bockscar on Mon Sep 24, 2012 2:10 am; edited 1 time in total |
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kcoyle
Joined: 15 Jan 2011 Posts: 712 Location: Long Island, NY
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Posted: Sat Sep 08, 2012 9:04 am Post subject: |
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Very cool, thanks for this.
Mind if I ask what parts you wound up using for TPS , MAP and coolant temp sensors?
Kevin _________________ 1982 931- Stock with MBC at 8psi
Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it. |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Sun Sep 09, 2012 4:31 pm Post subject: |
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The TPS ended up being a bit of a bear. First, I thought I [img]might[/img] be able to use a late generation Bosch TPS from a Saab 900. This turned out to be false because switches of that era were just that; switches. Really what is required for MS is a potentiometer. The good thing about these is that pretty much all cars after '94-ish used potentiometer-style TPS's, and they cost pennies if you get one from a junk yard. I stopped by my local pick-n-pull and snatched one out of a '01 Hyundai Accent. It was some Korean parts brand, but it was exactly what I needed. The only problem was mounting it. I took 2 small strips of metal and drilled a hole at each end of both of them. This allowed me to screw one end of the strip into the throttle body, and the other end into the TPS. Voila, done. Wiring it up was easy. Please do a better wiring job than I did
The coolant temperature sensor was a little more complicated. The standard '90s GM Coolant Sensor (as prescribed in the MegaManual) was not only much too large to fit into anything on the rear coolant flange, but it of course used SAE threads. I didn't want to drill and tap anything onto the coolant flange because the metal on the flange wasn't that thick to begin with. This is where things got interesting. I made a few trips to Lowes with the sensor and the coolant flange. Over in the brass plumbing fitting section, we found a female and made adapter that ended up working perfectly. At first glance, it may look like it would stick out too far from the flange, but it just barely cleared it. We used plumbing tape on the threads and screwed it right in. It worked perfectly. Where is the part I used. $18 is rather spendy, I'm sure you can find a better price elsewhere. do not forget to buy the pigtail. http://www.summitracing.com/parts/SMP-TX3/
The air temperature sensor was probably the easiest part. I drilled and tapped a new hole where the old boost-pressure switch (I think that's what it was) used to be. Make sure when you buy the air temperature sensor, it is the open element type. You can buy the sensor online here, but $42 is stupidly expensive. Just go to a junkyard and find one there. http://www.autopartswarehouse.com/sku/Standard/IAT_Sensor/SIAX1.html
The fuel rail and injectors were rather difficult, but not impossible. Sourcing a fuel rail can be difficult. I bought a used rail from a member here on the forum, but I understand there are other cars that happen to have a similar injector spacing as our cars. As I said in the first post, I bought injector bungs from 034 motorsports. From what I understand, you must have some kind of injector bungs or inserts to do the conversion. The bungs from 034 motorsports are pretty spendy so if you find alternatives, please let everyone know. I bought my injectors on eBay for pretty cheap. I suggest you buy the shorter stuby style injectors because they will fit between the injector cup and the rail better. The tall skiny ones that I have barely fit. Also be very careful when you slide the injector tip into the bung because the lips of the injector bungs are rather sharp and they can tear up the o-rings on the injectors if you are too rough.
Also I wanted to point out, I didn't outline it here but, I did use a narrow-band O2 sensor, the stock sensor the car came with when I bought it from the PO. I cleaned it up a bit and spliced it right into the wiring harness. Keep in mind that tuning using a narrow band O2 sensors that you can only reliably tune for stoich. I've read in a couple threads that it is not possible to tune the engine without a wide band O2 sensor. This is false. I would say you can't tune for performance with a narrow band, but a narrow band O2 sensor is still very tuneable.
I'm in the process of replacing my clutch but I have some pipe dreams on how I am going to go about the EFI conversion this time. It won't be MegaSquirt this time around, that's for sure. _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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Horizonblue
Joined: 13 Oct 2011 Posts: 307 Location: Sorring city, Denmark, Europe
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Posted: Mon Sep 10, 2012 7:49 pm Post subject: |
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Regarding injector bungs, the original plastic bushings can be machined to fit electric injectors. But you need a lathe to do that job. I have machined 4 old original bushings for my EFI project. I have a very, very old and noisy lathe(worn bearings) but it did the job. _________________ Euro 924, 1976
"If you can't fix it, don't break it"
/P.G. Andersen |
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PORSHCE 924
Joined: 27 Jun 2012 Posts: 3 Location: warren , rHODE ISLAND
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Posted: Sat Sep 15, 2012 12:38 am Post subject: |
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So is this your first attempt with the efi conversion , or most recent ? also the diy tune , do you have to assemble the board on those? |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Sat Sep 15, 2012 12:56 am Post subject: |
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PORSHCE 924 wrote: | So is this your first attempt with the efi conversion , or most recent ? also the diy tune , do you have to assemble the board on those? |
This attempt is my second attempt. The my first attempt failed for 2 reasons: First, the stock S2 ignition system does not play well with EFI and the timing was constantly screwed up. Second, there was a major problem with my clutch that required me to tear it down
DIY autotune is, imo, the best MS vendor out there. I emailed the guy for support, a lot. The MegaSquirt community and documentation is a joke so I ended up emailing the DIY autotune guy and the behind TunerStudio a lot. Both of them were great. As far as the PCB, I actually did both. I bought the package to build my first MS and screwed it up during assembly and toasted the board. Lesson learned, just pony up the extra dollars to buy the pre-assembled (with firmware pre-installed) one. _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Mon Sep 24, 2012 2:16 am Post subject: |
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I finally got around to poking at the Porsche today and removed the spark plugs just to see how they were doing. I have a feeling that maybe the engine was running a little too rich.
Also, I was reading around the forums about the piping and plumbing for the turbo and I read about some late model "upgrade" for the turbo. From my understanding, Porsche added a outlet on the head to help the turbo breathe, or to help prevent the oil from becoming foamy. Interesting idea. From what I understand, this is the outlet:
_________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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Grenadiers
Joined: 20 Feb 2007 Posts: 3222 Location: Nelson, WI & Prescott, AZ
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Posted: Mon Sep 24, 2012 3:17 am Post subject: |
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yeah, but if you have EFI, it interferes with your fuel rail. I blocked mine off, and, I have a turbo oil return line minus that drain piping, and potmetal box to use. _________________ '83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Mon Sep 24, 2012 9:51 am Post subject: |
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Grenadiers wrote: | yeah, but if you have EFI, it interferes with your fuel rail. I blocked mine off, and, I have a turbo oil return line minus that drain piping, and potmetal box to use. |
Ah, that is super interesting. I noticed that it caused issues the last time I put a fuel rail on there. I took a trip to the junk yard and found a fuel rail that fit perfect, I'll just need to rig something up for the brackets.
Does the turbo unit itself take a durability hit by blocking that off? _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Mon Sep 24, 2012 1:14 pm Post subject: |
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Took a trip to the good'ol junk yard today. Left with two things, a fuel rail from an early 90s Dodge Neon, and a throttle body from a mid 80s BMW 3 series. The throttle body was the same shape, but it didn't exactly fit. Despite being the same general shape, it was quite a bit larger. Using an S1 intake manifold, you could actually make it fit pretty easily by drilling new holes on the throttle body itself, though you would need to bore out the intake manifold opening itself quite alot and that's not really something I want to do right now. The fuel rail on the other hand was a near perfect fit. The positioning of the fuel injectors to the ports on the head were perfect-o -
The primary issue is either fabbing new brackets, or modifying the current brackets to work. Also, Dodge Neons use a return-less fuel system, which means when fuel enters the rail, it only has one place to go.. through the injectors! I don't understand why that wouldn't work on our cars.. Perhaps someone could enlighten me. However, the particular rail (the early 90s style) has a nifty pressure-tester hole right on the center of the rail. While this could come in handy for an NA engine, on a turbo engine the charge tube hits it. I could either remove and weld over where the pressure hole is, or I could get a late 90s model fuel rail which appears to have the pressure hole on the opposite end.
Oh one last thing. Since our fuel systems have to have a return line (right?), I'll need to drill and possibly tap a hole on the opposite end of the rail for the return line. Not a huge deal. Considering this rail costed me $20 at the local wrecking yard and it is in great shape, if you are going EFI, use this fuel rail! _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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fiat22turbo
Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR
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Posted: Mon Sep 24, 2012 1:23 pm Post subject: |
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Get a regulator with a return line built in and you'll solve that problem. _________________ Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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kmd924
Joined: 17 Dec 2010 Posts: 30 Location: New York
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Posted: Sat Sep 29, 2012 1:59 pm Post subject: |
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I just took an old saab FPR I got from a junk yard and used a T to route back my return line. So the send line goes to the one end of the T, the middle goes to the FPR and the "out" end of the T goes to the rail. I'm also using a neon rail. Looking back, since I have the newer style neon rail that has a shrader valve bleeder on it I might just gut the shrader valve and pipe a return off the end of the rail. _________________ '74 Plymouth Valiant
'77 924
'98 Ford Ranger
"Life's what happens while you're busy making other plans" -John Lennon |
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Grenadiers
Joined: 20 Feb 2007 Posts: 3222 Location: Nelson, WI & Prescott, AZ
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Posted: Sat Sep 29, 2012 11:12 pm Post subject: |
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Brian, I'm using that exact same fuel rail. I have a return line on my FPR though. Also, the brackets were cut off the rail when I got it. I used, in the mean time, plumbers metal pipe hanger 'tape' to hold it down. Looks boogery, but it does the job. I'll take a pic and PM the ugliness to you! _________________ '83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Tue Oct 02, 2012 8:37 am Post subject: |
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Grenadiers wrote: | Brian, I'm using that exact same fuel rail. I have a return line on my FPR though. Also, the brackets were cut off the rail when I got it. I used, in the mean time, plumbers metal pipe hanger 'tape' to hold it down. Looks boogery, but it does the job. I'll take a pic and PM the ugliness to you! |
I'd be curious to see how you did that. I actually took a trip back to the junk yard and picked up a new(er) one. The fuel rails with the pressure valve in the middle appear to be the early Neons. The later Neons have a thinner chrome fuel rail with the pressure valve on the end instead of the middle.
Its pretty nasty looking now, with all that rust on it. After I drill the end out so I can put a hose on it, I'll probably sand it out and paint it. The rust aside, I think the chrome looks tacky. _________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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Bockscar
Joined: 16 Nov 2010 Posts: 392 Location: Sandy, Oregon
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Posted: Tue Oct 02, 2012 1:07 pm Post subject: |
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I drilled out the other end of the fuel rail. Because of the threads, I'm sure it will accommodate a fuel hose quite nicely. Drilling the hole out was quite a bit more difficult than I had expected. Make sure you use cobalt drill bits with oil, the fuel rail heats up quick. Drilling this hole should effectively make this a fuel rail with a return line.
_________________ Brian
'79 924 - Restoration In Progress
'81 924 Turbo w/EFI - Scrapped |
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