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The 931EFR Goes EFI (the first time) with VEMS!

 
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lildude4life  



Joined: 27 Apr 2015
Posts: 24
Location: Milwaukee WI

PostPosted: Tue Jan 12, 2021 1:23 pm    Post subject: The 931EFR Goes EFI (the first time) with VEMS! Reply with quote

Quote:
TLA is a three letter acronym for three letter acronym
-lildude4life

Before we start I want to give some shoutouts to Dan (Ideola), RaceBoy and Mike9311 for helping to make this come to life. Dozens of emails, facebook messages and 3D printed parts were exchanged over the last few years and I could not have done this alone.



So as some of you know I bought a 931 and immediately rebuilt the entire engine. See here:
http://www.924board.org/viewtopic.php?t=43003

I knew as I was doing the rebuild and working with Dan, (always dangerous to the checkbook) that the plan was always on going to EFI eventually, but it made more sense to first get it running with the stock CIS system. This was all way back in 2017 when Ideola’s was still a thing, Corona was only a beer, and people were actually excited for Star Wars movies…. So Dan and I as well as others teamed up in an attempt to bring you the fabled “924 plug and play EFI kit”.. Heh…..


Original plan/kit:
VEMS ECU from RaceBoy running EDIS with wasted spark/ semi-sequential injection
VR sensor + 36-1 crank trigger wheel
Bosch Injectors
Custom fab’ed fuel rail
AEM fuel pressure regulator
Ford style EDIS coil pack
Custom Coil offset mount to plug the distributor hole
In line fuel filter
All required AN hoses and fittings

Ya the whole kit thing never happened. RIP Ideolas Garage

Disassembly:
So first up was to pull everything in the engine bay that has to go.
(make sure to disconnect the battery!)
-For the 931 the intake/Cylinder head removable wiring harness
-Primary Coil+coil wire
-Distributor
-Plug wires
-Airbox
-Fuel dizzy
-Dizzy to turbo pipes
-primary fuel line and return line from below brake booster all the way to the dizzy
---this includes the fuel filter and under the windshield pipes (note, you may have to remove the cabin air intake cover to get the lines out)
---they are kind of a pain to get disconnected from below the brake booster due to tight fitment. Take off only the male hose ends and leave the female hex pieces there
-all fuel lines coming off the fuel distributor
-Injectors+all adaptors down to the intake
-WUR
-All the intake/CIS pipes and hoses
Pretty much EVERYTHING on the intake other than the air hose coming off the rear near the CSV and the Throttle body
-HALL sensor that is mounted to rear of bell housing
-O2 sensor
---NOTE: you can take the O2 sensor wire and the hall sensor completely out of the car if you carefully trace the wires back through the fire wall, to the computer that is under the center counsel on the drivers side. In fact, that computer can come out as well. Not an easy undertaking due how the stock wiring harness is.


First up Replacing the Coolant temp and Intake Air temp sensors:
Bosch 0280130026 EV1 Coolant temp sensor
Bosch 0280130039 EV1 Air Temp sensor
Optional: M14x1.5 plug https://www.amazon.com/gp/product/B00OZ6TB1E
Coolant switch simply replaces the sensor on the rear of the intake (gray plug in the removable CIS harness) and intake air replaces the sensor just after the throttle body.
Note: I put the intake air temp sensor in my top mount intercooler post cooling nearest to the throttle body. MAT should be installed in your charge tube or Intercooler, not in the manifold if you can help it as it will get more heat soaked there.
Note2: I thought it was easiest to get to the coolant sensor from under the car with the turbo downpipe removed. I did get wet doing it this way...

New IAT in the cold side of the TMIC as well as the brake booster line:


M14x1.5 plug in the intake where stock IAT went:



Jumper harness for stock oil pressure and water temp gauges:
On the removed intake wiring harness there are 3 wires that you will need to make a new jumper harness for to keep the stock oil pressure sensor and water temp sensor that link up to the dash gauges.


If you have the harness loose and look INTO the 9 pin plug with male pins, have the 3 humps on the top, the three wires are located Top Center (Oil ring terminal), Left middle (Oil spade) and Right middle (water temp spade). They should be obvious based upon the connectors on the ends of the wires:
Blue with white: Oil pressure with O-ring connector
Blue with black: Oil pressure spade connector
Blue with yellow: Water Temp spade connector

What you will need:
2x female spade crimp connectors or similar
1x Ring crimp connector or similar
~1.5ft (40cm) each of 3 different color of wires (~20awg)
1x: A25472-ND from Digi Key
3x: A25454-ND from Digi Key
Shrink wrap

If you do it like I did you will end up with this. It will plug into the plug near the firewall that the old harness plugged into.



Coil:
1x Ideola coil bracket (NLA but i have one for sale!)
1x ford EDIS style coil (I don’t know the part number as I got rid of mine and never wrote it down)

Coil simply mounts to the standoff, and then slips into the distributor hole on the rear of the cylinder head. Depending on what hose ends you use on the rear of the fuel rail, you may have to play around with what order to install things in to get the bracket to fit around the hose. You should be able to reuse your stock plug wires. In terms of what side of the coil goes to what cylinders, you will have to check once you have the ECU on by cranking the car and checking with a timing light.



Fuel Pressure Regulator
I put the AEM pressure regulator where the primary coil went. I put a plug in the left side port and a double male 8AN to NPT fitting on the right hand side. Out of the bottom the 45 degree 8AN swivel fitting. The distance from the rear of the fuel rail to the left side port on the regulator was too close to fit 2x hose ends so I ended up using a 180 degree swivel on the right hand side. If you were to use different hose ends you might be able to get it to fit and can ignore the 180 degree swivel.
Note: mounting bracket that comes with the regulator will need at least one of the mounting holes enlarged/elongated to line up with the bolt holes if you are putting it in this location.
Note 2: if you are running a turbo/boost the Vac line port on the regulator should go to the post TB nipple on the intake. Another option is to go off the rear of the intake next to the CSV as there is a vac line that ran into the cabin for the CIS computer that will no longer be used.



Injectors & Rail:
You will need:
4x:VW 058133555 injector inserts
4x 60mm height, 14mm top and bottom O-ring high impedance injectors. (You should do your own fuel calculation to make sure you are buying the right sized injectors. Injector Dynamics has an awesome calculator on their website.)
Fuel Rail+mounts. Not sure if Dan has any of his custom ones lying around the shop or not…

IF you have ideola’s rail you can use the following:
1x of Mike9311’s custom fabbed “931 breather fitting” (PM him here on the board)
1x new gasket for turbo breather port on the cylinder head (or gasket maker)
Rail Front: VP- 24905 (the only 90 degree fitting we could find to clear the thermostat housing)
Rail Rear:
-¾-16 to 8AN double male adaptor
-90-degree 8AN swivel Hose end (or another VP-24905 and you can also skip the adaptor)
You will also need a NPT plug to go to the top of the fuel rail. Not sure what size it is. I plugged this port as it didn’t fit with the TMIC but if you are using the stock charge tube you can put a gauge here.

First replace the turbo breather port in the cylinder head as the fuel rail will not fit with the stock one there.


The injector inserts have a lip on the top that will have to be filed off. The specific version of insert I have has a 17mm hex pattern inside and I would highly recommend getting a 17mm hex socket if you don’t have one to tighten them down. Also I would recommend using a non locking thread sealer on the threads. Snug them into place with the wrench.

Rail again is Ideola’s design so I don’t think there are any more of them. Before you install with the injectors install the hose ends on the front and rear and install onto the intake for measuring hose lengths.

VP-24905 on the front of the rail and how little clearance there is:


Rear of fuel rail showing the adapter and a 90 degree swivel. I’d honestly recommend just getting two of the VP-24905’s and using them on the front and back of the rail.



Fuel Filter
1x SUM-230116-B 10micron 8AN replaceable fuel filter
2x 8AN 90 degree swivel hose ends

I deleted my overflow tank and have a 951 style tank that mounts atop the wheel well, so I mounted the filter where the bracket used to be for the 924 tank with an aluminum bracket and a hose clamp.





Cold Start Valve:
Simply remove from the rear of the intake and cover the hole with a piece of aluminum with two holes drilled for the bolts. I just used a liquid gasket maker to seal it.
Cad file link:
https://grabcad.com/library/931-csv-cover-plate-1



Crank Sensor:
36-1 tooth trigger wheel (NLA from Ideola)
-VR sensor (any 2 wire Stick style VR sensor should work)
-VR sensor bracket (NLA from Ideola)
First remove both auxiliary belts from the front of the engine but leave the timing belt. Then remove the harmonic balancer. Next install the sensor bracket onto the front of the oil pump, install the VR sensor onto the bracket. Finally sandwich the trigger wheel between the ballancer and the timing belt pulley.

NOTE: Depending on what ECU you use, the angle between when the VR sensor sees the missing tooth and when the car is at TDC may or may not be critical. Carefully read any literature that comes with your ECU on what this angle should be. In general, the VR sensor should see the missing tooth ~60 degrees BEFORE the car gets to TDC. I’d recommend installing the trigger wheel without the balancer first and just use the 6 bolts to hold it in place, and then crank the car over with a wrench on the main crank bolt. Watch for when the missing tooth travels across the sensor, and then check where TDC is. Adjust the position of the trigger wheel as necessary so that the missing tooth is seen by the sensor, and then you have to rotate the crank 60degrees to get to TDC.

NOTE: You will need a set of shim gauges to check the spacing between the trigger wheel and the sensor. Aim for ~0.8mm or whatever distance is recommended for your sensor. What ECU you use will also change how close the sensor should be.


Fuel Lines:
Best pathway I came up with is as follows. This will likely not work if you have the stock 931 coolant tank.
Starting from the firewall and fuel coming from the fuel tank:
-Fuel line from under booster to Filter
-Filter to Front of Fuel Rail at Cyl 1 over alternator
-Rear of Fuel Rail to AEM Pressure Regulator
-Regulator to return line under brake booster

What you will need if you do it like I did:
1x 16mm Crush Washer
1x 14mm Crush washer
1x 16mm to 8AN double male adaptor
1x 14mm to 8AN double male adaptor
1x 8AN straight hose end
2x or 3x 8 AN 90 degree hose ends (2x fuel filter, one for rear of cylinder head as mentioned previously)
1 or 2x VP- 24905 (mentioned previously for fuel rail)
1x 8AN 45 degree hose end
1x 8AN 120 degree hose end
~6ft of 8AN hose line

Fuel from tank under booster:
16mm crush washer
16mm to 8AN double male
8AN swivel straight hose end

Fuel return line under booster:
14mm crush washer
8AN to 14mm double male adaptor
8AN 120 degree swivel hose end

NOTE: Getting the two adaptors seated under the brake booster is quite difficult. You will likely need a second set of hands, a 5 sided crows foot wrench, lots of patience and extra crush washers. Took me 3 tries to get them seated without fuel leaks.


Fuel filter top and bottom:
8AN 90 degree swivel hose end


Front of Fuel Rail
As mentioned previously Vibrant 90 degree swivel

Rear of Fuel Rail
As mentioned previously Vibrant 90 degree swivel

Fuel Pressure Regulator In:
8AN 180 degree hose end swivel
-other port(s) on regulator will need a plug

Bottom of Regulator:
8AN 45 degree hose end



Intake:
2.5” aluminum pipe (roughly 3ft)
1x 2.5” 90 degree elbow
1x K&N KNN-RU-4950 air filter
1x VPE-11182 ½” aluminum weldable hose barb bung
1x VPE-11184 ¾” aluminum weldable hose barb bing

So I chose to delete the entire intake setup from the air box all the way to the turbo inlet. I copied the general design of the stock setup with a vertical pipe out of the turbo, 90 degree elbow, then a horizontal pipe running towards the drivers side with a K&N Cone filter. Welded in bungs in the vertical pipe for the carbon canister/fuel tank vac line, and one in the horizontal pipe at an angle for the crankcase breather.
I also made a steel piece that then fit around the aluminum intake and the thermostat return pipe and used two hose clamps and some extra silicone hose to hold the intake in place.






ECU install:
So Raceboy provided the ECU and pre-terminated wiring harness. Only issue was that the harness was meant for a euro spec car and for the ECU to mount in the cabin, passenger side under the glove box. Well in the US spec cars with AC that’s not exactly an option. Ended up putting it next to the battery as a temporary solution. I would NOT put it there if you drive in the rain. I didn’t want to buy a new harness, or make my own so I just dealt with it being next to the battery. I'd suggest figuring out where you want to mount it first and make sure to either ask for a longer harness, make your own, or put it under the glove box as recommended.
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ECU install:
So Raceboy provided the ECU and pre-terminated wiring harness. Only issue was that the harness was meant for a euro spec car and for the ECU to mount in the cabin, passenger side under the glove box. Well in the US spec cars with AC that’s not exactly an option. Ended up putting it next to the battery as a temporary solution. I would NOT put it there if you drive in the rain. I didn’t want to buy a new harness, or make my own so I just dealt with it being next to the battery. I'd suggest figuring out where you want to mount it first and make sure to either ask for a longer harness, make your own, or put it under the glove box as recommended.


Wiring:
ECU Signal:
For ECU signal wire, under the dash trace the black wire coming from the key module and splice into it as it's the 12v on+crank. Verify with a multimeter. This will run to the ECU 12+ signal wire.

Fuel Pump:
This one was a bit tricky. The VEMS ecu has a fuel pump signal wire that will need to be routed to and replace the stock fuel pump relay signal wire under the dash. The stock fuel pump relay has an extra pin for the overboost cutoff. I simply replaced the stock relay with an off the shelf 4 pin 20amp relay as I am not using the stock cutoff as you can program overboost settings into the ECU. Using a off the shelf 4pin will simply bypass the cutoff. You have a few options then on how to run the ECU fuel pump signal wire to the relay. The cleanest way would be to remove the signal pin from the rear of the relay mount, and try to either carefully bend open the crimp connector so you can replace the wire, or if you have relay socket pins (can buy them online) you can just make your own new signal wire. Then shrink wrap or tape up the stock signal wire you just removed. Another option is to cut the signal wire going to the rear of the relay, and use some sort of butt-connector. Third option, simply ignore the stock fuel pump relay all together and get your own relay and wire it appropriately. The primary fuel pump wire is easy to find under the dash and you would then wire the new relay output to the fuel pump wire.

Tach:
ECU also comes with a tach wire. If you are under the dash and can see the rear of the tach gauge, there should be a thin green wire with a female spade connector plugged into the tach. That is the signal. Simply run a new wire from the ECU with a female spade and plug it in to the tach.

Fuses:
You will likely also need to install fuses into the fuse holders as I don’t think they came with any. 20amp for ignition, 15amp for injection, 5 or 10amp for ECU.

For routing the harness into the engine bay, I carefully cut a notch directly in the center of the firewall and then used a grommet to prevent any damage to the wiring harness. Harness came labeled so it’s just a matter of carefully routing each plug to its correct sensor/injector. If you are mounting your ECU in the cabin or somewhere else you will not need to do this.



Talking to the ECU via Bluetooth:
Install the VEMS software and use the following pins to try and connect to it via Bluetooth. I do not recall the exact sub menus in VEMS tune you may need to play with to get it to connect properly..
PIN: 0000, 9111, 1234. (its one of those)



And there you have it, how I installed my VEMS ECU! With probably lots of things I’m forgetting to write in here as I did this all 2-3 years ago… I’m not going to go into the pros and cons of it vs a Haltech Elite 1500 that I am currently running until I get that write up done nor specifics on how to tune with VEMS as I am not an expert and don’t want to lead anyone wrong. If you have questions on anything here let me know!

Video:


Dyno:
http://www.924board.org/viewtopic.php?t=44826





3 weeks after the dyno and what led to me going to a haltech:





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"931 EFR" 81 931 S2 w/ EFR 6258 turbo
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Mike9311  



Joined: 14 Dec 2004
Posts: 983
Location: Chicago-ish

PostPosted: Wed Jan 13, 2021 1:38 am    Post subject: Reply with quote

Wow, I actually did not know that's what led to the Haltech...That is an awesome write up though and nice that you took the time even with the switch to Haltech

Don't look at the breather fitting Tyler has too closely. He took the gouged prototype.





I am currently working on a aluminum tube with beading to replace the steel breather tube so the stock tube doesn't need to be shortened. I did entertain a longer necked fitting but it looks strange, is harder to make, and uses a lot of aluminum.
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924RACR  



Joined: 29 Jul 2001
Posts: 8373
Location: Royal Oak, MI, USA

PostPosted: Wed Jan 13, 2021 6:01 am    Post subject: Reply with quote

+1, very nice writeup.

Makes me glad I skipped the EDIS and went to the VW 4-tower coil; I chose the latter simply because I could run it directly from the Microsquirt I chose (instead of VEMS).

I also have one of Mike's Al breathers; shortened my steel breather just by cutting out a chunk and rewelding.
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chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Wed Jan 13, 2021 7:44 am    Post subject: Re: The 931EFR Goes EFI (the first time) with VEMS! Reply with quote

lildude4life wrote:
Quote:
Note: I put the intake air temp sensor in my top mount intercooler post cooling nearest to the throttle body. MAT should be installed in your charge tube or Intercooler, not in the manifold if you can help it as it will get more heat soaked there.

New IAT in the cold side of the TMIC as well as the brake booster line:



Very interesting. Thanks for that particular note and picture.
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lildude4life  



Joined: 27 Apr 2015
Posts: 24
Location: Milwaukee WI

PostPosted: Wed Jan 13, 2021 7:52 am    Post subject: Re: The 931EFR Goes EFI (the first time) with VEMS! Reply with quote

chuck21401 wrote:
lildude4life wrote:
Quote:
Note: I put the intake air temp sensor in my top mount intercooler post cooling nearest to the throttle body. MAT should be installed in your charge tube or Intercooler, not in the manifold if you can help it as it will get more heat soaked there.



Very interesting. Thanks for that particular note and picture.


No problem! That was a suggestion from RaceBoy actually to keep temps accurate. I saw your post on your Inter cooler thread and was going to comment what I did, but I'm glad you found it here!

I actually now have an air temp sensor on both the hot and cold sides of the TMCC, and a water temp sensor for the coolant. Should make for some fun data logs once I can drive again. Dam snow.....
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