CIS to ITB EFI conversion

[dannichols1474]

I started cleaning the fan and fan housing using soapy water, Scotchbrite maroon pads and Formula 409. My fan and fan housing have pitting and a really tough coat of dried oil/grease so I really had to scrub. The Formula 409 helped cut through the oil/grease. The leading edges of the fan blades were especially tough. I spent 3 hours on the fan and 1 1/2 hours on the fan housing. Getting better, but not done yet. I have a can of Eastwood Diamond Satin Clear on the way so when I decide I'm done cleaning, I can shoot a couple coats of clear as was recommended in a PP forum thread from 2021.

Cleaning set up:


Before cleaning:


After first cleaning session:

[NickW21]

Originally Posted by dannichols1474

Hi Nick,

I was working on my daily drive (05 MB C55 AMG, I am the original owner) that has 212k miles and I am changing the driveline carrier bearing and changing the differential gear oil since both have not been replaced yet (front and rear wheel bearings and front and rear flex joints on the driveline have all been replaced within the last 50k miles).

Anyway, back to your question. Yes, the hose connected the fan shroud on my car does connect to the evaporation charcoal canister. I think it serves as the canister purge source - fast air / lower pressure. Here are a couple of photos:

Thanks Dan!! Nice work on the fan, btw. It's amazing how much better things look with just a little elbow grease Couple other items I wanted to run by you. The yellow wire from the starter solenoid running back into the engine bay seems no longer required, as it served to supply juice to items no longer needed in EFI setup. Am I correct in this thinking? Also, I only have the large defogger relay and the small circular blower relay in the engine bay. You seemed to have another one in your setup. Did you add this or this was already there? Trying to figure out which wire to get the switched 12v from and it's a bit confusing back there

Oh the joys of being a newb to all this DIY stuff. It is quite fun, though. I have a hard time doing my actual job sometimes since I have so much work to do on the car!!

[dannichols1474]

Hi Nick,

1. There are 2 yellow wires connected to the starter solenoid, 1 wire is coming from ignition switch and the other wire goes to the CIS throttle valve switch then to the thermo switch and the cold start valve so that yellow wire is no longer needed.

2. My car has 2 small round and 1 large rectangular relays on the electrical panel at the left rear corner of the engine bay. The large rectangular relay is for the rear window defogger. The small round relays were for the rear heater blower motor and the warm up regulator. I used the black wire from pin 87 (yellow / black wire at the relay then becomes black wire at the 14 pin connector) of the heater blower relay.

NOTE: The heater blower relay (on my car) as wired from the factory is set up as starter cranking interrupt (pin 85 is connected via yellow wire to starter solenoid). While I had the electrical panel disconnected to install the MSD ignition box, I clipped the yellow wire at the relay and connected pin 85 to ground with a brown 16 awg wire. With that modification I had switched 12V.

[NickW21]

Thanks again, Dan. I meant to say the yellow/black wire, because as you correctly pointed out there are two yellow wires coming from the starter. Glad to know I wasn't missing anything by thinking that yellow/black was no longer needed. The engine wiring harness is greatly simplified with EFI in one aspect, but is also complicated in another due to the many ECU connections and power distribution required. I'm also likely over-engineering the whole thing, wanting to keep things tidy and looking "new"

I'll have to confirm if I'll need to do the same pin 85 grounding that you did. I might not need to do, though, based on my initial overview of the wiring diagrams I have. The things that give me pause are always that the official diagrams and what has transpired over the years of the prior owners don't always line up... hehe... Good thing I'm an engineer at heart and like to solve problems. There's a never a shortage of them with these old cars!

[dannichols1474]

Hi Nick,

Just to be clear. On my 75 Carrera, BOTH wires connected at the starter solenoid are yellow.

On the blower motor relay pin 87 (output power out, normally open) is yellow/black to the 14 pin connector (male, bullet) at the back of the rear left corner electrical panel. From the corresponding female 14 pin connector pin 87 is black. That black wire is now the switched 12V supply to my EFI electrical panel.

14 pin connector for engine wiring harness:



EFI eletrical panel:



The big red wire is the switched 12V supply and is connected the black wire from pin 87 of the blower motor relay:



Good luck with your project!

[dannichols1474]

Hi Nick,

Another thought came to mind. When I was planning the CIS to ITB EFI conversion on my car, I initially thought about combining the existing wiring with the EFI wiring into a single engine harness. I later decided against a single harness and decided to keep 2 separate harnesses. I did so because I didn't want to disturb / replace the 14 pin connector for the stock engine wiring harness - if I truly made 1 engine wiring harness then I would need all of the wires EFI and stock to connect/disconnect through preferably through 1 connector (I could use 2 connectors but that in my opinion would not look good/professional).

The key point for me was how could I best wire the EFI so the whole system (engine / transmission) would remain serviceable without having to disturb my EFI wiring connections to either the EFI power panel or the EFI connector blocks. So I decided against combining stock with EFI wiring. That serviceablity issue also drove me to install weather tight connectors on the TPS and the O2 sensor interface unit (14Point7) cable.

My modified stock engine/transmission wiring harness:




EFI wiring 1 (EFI 12V switched power, ECT sensor, O2 sensor interface cable, distributor Pertronix signal, distributor Pertronix 12V power, MSD ignition coil + & -):




EFI wiring 2 (Injector connectors bank1, TPS, Injector connectors bank2):




Hope this is clear / helpful.

[NickW21]

Definitely helpful, Dan. We are on the same page.. mostly. You and I were both referring to those two yellow wires attached to the starter. In my case, one was solid Yellow the other was Yellow/Blue... or Yellow/Black, it was hard to tell given the condition of the wire

When I was taking out the CIS and fuel lines, etc., the harness had cracked in a few places and the wires were compromised. So, I do plan on replacing the entire harness with new wires, as I'm also upgrading the alternator, which necessitated replacing the old power/ground wires with higher gauge anyway. Since I'll be doing all that, I figured I'd create a whole new harness. That said, I'm still debating whether to just purchase a new stock connector for the harness or replace with a modern connector that would be much more waterproof than the open, plastic one that is on there now.

I was hoping to keep the new fuse box tucked away with the existing relays/fuses, but that might just be too hard to do. Still noodling that one. Where did you route the B+/B- wires from the MSD? They say they need to route to the battery directly. I've assumed there's an existing B+ in the engine bay that I can tap in to and I can just ground to the chassis, but haven't gotten that far to confirm yet. Will post pics once I leave my planning phase and get into the doing phase

Love this DIY community!!

[dannichols1474]

Hi Nick,

I connected the MSD B+ to battery terminal on the starter (thank you Al for the idea) and I connected MSD B- to the chassis ground connection that the thick copper webbed cable from the transmission uses (near / beneath the starter).

[dannichols1474]

The single large red wire (6 awg I think) from the starter runs up to the alternator where there is a 12 awg red wire connected that runs through the harness and 14 pin connector and is the source for unswitched 12V to the left rear electrical panel and is connected to pin 30 (output power in) for the relays.

[dannichols1474]

My fan and especially the fan housing were very dull and pitted. After 14 hours of sanding and polishing, I am done - just need to spray several coats of clear, then ready for re-install.

[NickW21]

Looks great, Dan!! I was hoping to do the same. Actually had it lined up for a cerakote finish, but then I noticed the housing was cracked in a few spots and thought it better to just bite the bullet and buy a new housing/fan.

Also, thanks for the additional details for the MSD power lines. That makes perfect sense.

[Jeff Alton]

Originally Posted by dannichols1474

My fan and especially the fan housing were very dull and pitted. After 14 hours of sanding and polishing, I am done - just need to spray several coats of clear, then ready for re-install.

Did you consider having it media blasted (glass bead)? Takes less than an hour.

[dannichols1474]

Hi Jeff,

Before I started reconditioning my fan and fan housing, I searched the internet and happened upon a PP forum thread from 2021 in which you made the recommendation for glass bead blasting. That forum thread also discussed with recommendations of use of the various grades of Scotchbrite pads and recommended Eastwood Diamond Satin Clear.

So being a DIY'er, I started cleaning / sanding /polishing and I ordered a can of Eastwood Diamond Satin Clear. I spent a number hours over 3 days and was able to clean up the fan and fan housing quite a bit, but I still couldn't get the oxide / grime out of all the nooks and crannies. I thought maybe enough is enough.

Then you added your reply above and I thought "what the heck, give it a try". So after another internet search, I headed over to Spray Technology in Santa Clara, CA (spraytechnologysv.com) and talked with Fidel who said he could clean out the areas I had not been able to with Vapor Honing (their name for glass bead blasting with water).

The price was right ($125) and he said they would have the job completed and ready for pickup tomorrow, so I left my fan and fan housing with Spray Tech and I'll find out tomorrow how they did. Photos of their work will be forthcoming...

[Jeff Alton]

That is great, let us know how it turns out what you get it back!

[montauk]

Originally Posted by dannichols1474

Hi Jeff,

Before I started reconditioning my fan and fan housing, I searched the internet and happened upon a PP forum thread from 2021 in which you made the recommendation for glass bead blasting. That forum thread also discussed with recommendations of use of the various grades of Scotchbrite pads and recommended Eastwood Diamond Satin Clear.

So being a DIY'er, I started cleaning / sanding /polishing and I ordered a can of Eastwood Diamond Satin Clear. I spent a number hours over 3 days and was able to clean up the fan and fan housing quite a bit, but I still couldn't get the oxide / grime out of all the nooks and crannies. I thought maybe enough is enough.

Then you added your reply above and I thought "what the heck, give it a try". So after another internet search, I headed over to Spray Technology in Santa Clara, CA (spraytechnologysv.com) and talked with Fidel who said he could clean out the areas I had not been able to with Vapor Honing (their name for glass bead blasting with water).

The price was right ($125) and he said they would have the job completed and ready for pickup tomorrow, so I left my fan and fan housing with Spray Tech and I'll find out tomorrow how they did. Photos of their work will be forthcoming...

I'm having the fan and bunch of other parts vapor blasted by Mark E. at the Ninestore. I've gotten a few pieces back already. The results are amazing.

My fan housing was cracked beyond saving so I bought the Rennline two piece replacement. It looks great but it's $$$.

[dannichols1474]

I got my fan and fan housing from Spray Tech, all of the oxide / grime are gone:




Now I can buff with Scotchbrite pads and bring out the shine.

I knew I would like the result, so I dropped off the cam chain boxes and covers and the exhaust valve covers to have them glass bead blasted as well. So much easier than scrubbing by hand!

[dannichols1474]

I worked on polishing the fan housing after returning from Spray Tech this afternoon. I started with maroon scotchbrite, then grey scotchbrite, then white scotchbrite. I rinsed off and dried the fan housing, then I made multiple passes rubbing in metal polishing cream followed by dry towel buffing and I finally got the result I was looking for:




Next step is to repeat the above process with the fan.

Thank you Jeff for the glass bead blasting suggestion. I wouldn't have gotten this result without it.

[dannichols1474]

Fan cleaned up pretty well....




I'll shoot a couple coats of clear on the fan and fan housing next week.

[dannichols1474]

Refreshing the engine tin....



Dry overnight then flip over and do the other side.

[dannichols1474]

Paint is drying faster than expected. Batch 1 is complete and now resting on cardboard under the front end of the car. Batch 2, side 1 is done, maybe I can do side 2 before I turn in.

Hint: I just mopped the entire garage floor to get up the black overspray dust to keep the wife on-board with the project.