My PMO ITB Project

[brads911sc]

Final Coil/Wiring/MSD Pic



Close up of Fuel Filter setup...

[brads911sc]

Ok... Here is what I am thinking... Rear Shelf. There is enough room for speaker clearance to sit the ECU in. Have all the sound/heat pad...

Will I have any issues?

Here is placement.. in between two speakers...

[Halm]

I am no electronics expert, but I would be worried about two things in that location. First is the lack of air flow. Since it is electronic, it will heat up. Second is that the rear window will allow a lot of direct sunlight to hit the parcel shelf and again more heat build up.

[brads911sc]

I was abit concerned as well. I had planned on installing speaker grills (without the speakers) to allow heat to escape since I dont use the radio...

I will look at other options. Issue with under the pass seat is that the cable from the relay board to the ECU isnt long enough and i really didnt want to reinvent the wheel...

Originally Posted by Halm

I am no electronics expert, but I would be worried about two things in that location. First is the lack of air flow. Since it is electronic, it will heat up. Second is that the rear window will allow a lot of direct sunlight to hit the parcel shelf and again more heat build up.

[Halm]

Brad. I am watching this thread with great interest. I think an EFI conversion may be in my future as well and you seem to be doing this right!

Again, I am no expert on this but even with just speaker grills to allow air flow I would be worried. I lived in Ft. Worth for 10 years and I know 1.) how hot the Texas sun is and 2.) heat is the enemy of all things electronic. Intuitively, I would think that the parcel shelf would be hotter than even the engine compartment.

Is there a cable extension you can get from the ECU vendor?

Good luck!

[brads911sc]

Agree. I have a call into them. They sell 12 foot cables with the DB37 connector on one end. Would just need to add a DB37 connector to the other end and I would have a 12 foot Relay Cable instead of a 6 foot cable. Probably the best option...

Originally Posted by Halm

Brad. I am watching this thread with great interest. I think an EFI conversion may be in my future as well and you seem to be doing this right!

Again, I am no expert on this but even with just speaker grills to allow air flow I would be worried. I lived in Ft. Worth for 10 years and I know 1.) how hot the Texas sun is and 2.) heat is the enemy of all things electronic. Intuitively, I would think that the parcel shelf would be hotter than even the engine compartment.

Is there a cable extension you can get from the ECU vendor?

Good luck!

[jpnovak]

The MS unit does not generate much heat unless you are driving ignition coils directly. I would probably not install on the rear deck due to the heat from the sunlight. Another consideration is the access to the serial outport. You will need easy access to the port for tuning and adjustments. Also, The LED visual indicators are useful for trouble shooting and power verification.

A longer cable is your best option. The hard part is the installation. The DB37 is large and will not fit through a hole. You will need to solder and shrink-wrap the connector in place after running wires from your ECU location.

It is pretty simple to run through the tunnel and exit under the seat for ECU location.

I don't have rear seats and mounted mine on the vertical segment of the rear deck on top of RS style carpet. A hidden installation would mount under the seat, passenger floorboard or under the dash by the glove-box.

[gsmith660]

Why not relocate the relay kit to under the seat also and run a longer harness to the motor from the relay kit?

[brads911sc]

That is not a bad option and wouldnt require too much extra work... I have ordered a 12 foot cable, so I think that placement of relay board is ok for now. I have heard that the relay board is the weak link... so if it is I can always remove the D37 end and use it to wire the components directly...

Originally Posted by gsmith660

Why not relocate the relay kit to under the seat also and run a longer harness to the motor from the relay kit?

[brads911sc]

Cable has been ordered. Thanks for the insight Jaime.

Originally Posted by jpnovak

The MS unit does not generate much heat unless you are driving ignition coils directly. I would probably not install on the rear deck due to the heat from the sunlight. Another consideration is the access to the serial outport. You will need easy access to the port for tuning and adjustments. Also, The LED visual indicators are useful for trouble shooting and power verification.

A longer cable is your best option. The hard part is the installation. The DB37 is large and will not fit through a hole. You will need to solder and shrink-wrap the connector in place after running wires from your ECU location.

It is pretty simple to run through the tunnel and exit under the seat for ECU location.

I don't have rear seats and mounted mine on the vertical segment of the rear deck on top of RS style carpet. A hidden installation would mount under the seat, passenger floorboard or under the dash by the glove-box.

[gsmith660]

Originally Posted by brads911sc

That is not a bad option and wouldnt require too much extra work... I have ordered a 12 foot cable, so I think that placement of relay board is ok for now. I have heard that the relay board is the weak link... so if it is I can always remove the D37 end and use it to wire the components directly...

If the relay board is the weak link then it would make sense to get it out of the heat of the engine comp. and into a more friendly environment like under the seat I mean I dont leave my car out in the direct sun very often and there must of been a reason that the factory put all the engine electronics in that spot.

[brads911sc]

My understanding is that the board is great and designed for the engine bay... however the connections tend to self losen, and for that reason while it adds ease of setup it also can be the weak link. ive experienced some wires losening on their own. basically any wire that is larger than 16 guage... so we will see... i do like having the fuses and relays on a board...

Originally Posted by gsmith660

If the relay board is the weak link then it would make sense to get it out of the heat of the engine comp. and into a more friendly environment like under the seat I mean I dont leave my car out in the direct sun very often and there must of been a reason that the factory put all the engine electronics in that spot.

[brads911sc]

I made some additional progress.

1. I powered up the fuel pump... fixed one leak and set the pressure to 42 psi.
2. I had my helper assist and i have the fuel linkage set up to floored in the car = Butterflies wide open on all 6 cyl.
3. Put the seat/shelf/speakers back together. I will not put the ECU there for a few reasons.
4. Removed the pass seat, removed the K-Jet computer and the entire CIS / O2 wiring harness.
5. Installed the new ECU use two of the three existing mounting points. Keeps it 1 inch off the floor. Still no higher than seat.
6. Ran the vacuum line, drilled hole, installed a grommet. Used 5/32 goodyear vacuum hose.
7. Installed the Wideback O2. Getting a gromet that fit was the hard part. Bought 4, 1 worked.
8. Drilled 2 small holes in each air cover base and installed return throttle springs.

To Do:

1. Install the ECU to Relay Board Cable.
2. Install manual hand throttle from 72 911 i purchased from Jim WIlliams.
3. Load MSQ file from Jaime set up for stock 3.0/SSI's as a starting point.
4. Install new Distributor pick-up wire made by Barry Hershon.

Then we'll be ready to turn the key and see if she runs! Very Close. Probably next weekend since they have to make the cable.

Cheers!

[brads911sc]

One other note... If you completely remove the CIS/K Jet wiring harness there is a hole with a grommet already there for you right above the tunnel and below the middle of the rear seat.. No need to reinvent the wheel and drill holes in the tunnel area. Wires just go where the current K Jet harness went. I have found NO reason to keep that harness and have removed it. I am hoping there was nothing in there that i needed.. but I couldn't find any...

[gsmith660]

Glad to see a project come together. Looks like you are making great progress and a clean intall. Looking forward to the final setup pics.

[brads911sc]

Update....

Wiring is complete.
Adjust Fuel pressure to 43.5.
Initial Configuration files installed on the ECU.. and it started and idled smooth... was able to adjust the ITB's for an initial baseline with a Sychrometer.

Some issues to work out...

1. It idle's rich. VERY rich. I will be making some adjustments this coming week.
2. The main / switched power is incorrect. Once the car is running, the key does not shut off the engine. I think my power at the rear fuse box needs to be tested and adjusted. It may be the two pole breaker for switched power that is my problem.
3. Some fine tuning with the Synchometer on the ITB Balance.
4. still need to get the hand throttle installed. Its 70 degrees here in Houston this weekend, so no really issues with cold start.
5. Once I get idle taken care of, I will move to driving tuning.

Special to Jaime Novak. He has given me the confidence to get to the next step. Thanks!

Ill take some final pics and get them posted and provide a tuning update next week!

Thanks

[kiwiokie]

There were two guys in the UK doing ITB on the impactbumpers forum several months back. I think one was Mr Perkles. I recall one of them had exactly the same issue with the key not turning off the engine once started. It may be worth looking at that thread or perhaps Mr Perkles will chime in? I would love to do ITB's on my SC but the amount of work and $'s is daunting. In the meantime I am living vicariously through your thread. Keep up the good work!

[brads911sc]

I verified this AM that I have full time 12V when needed and 12V only when in Run/Crank Position when needed. Both at fuse area and on relay board.
So my EFI is overriding the ignition switch? Any thoughts?
After I start the vehicle, I get power at both "on" all the time and "switched" as expected.
When I turn off the ignition, I get 11 volts at switched power. Enough to run the ECU. For some reason the act of turning on the car wrecks havoc on the switched power.
Merely turning the key into the Run position, does NOT do this.
Thoughts?

Originally Posted by kiwiokie

There were two guys in the UK doing ITB on the impactbumpers forum several months back. I think one was Mr Perkles. I recall one of them had exactly the same issue with the key not turning off the engine once started. It may be worth looking at that thread or perhaps Mr Perkles will chime in? I would love to do ITB's on my SC but the amount of work and $'s is daunting. In the meantime I am living vicariously through your thread. Keep up the good work!

[78SCRSMAN]

I'm not sure about your ECU setup but you should have power (don't worry about voltage readings) to the coil when the key is on and none when it is turned off. If your ignition (coil) gets power from the ECU via a relay then check the relay and wiring to the relay. I'm sure it is something very simple.

[MrPerkles]

Brad I wired direct from the battery to relays for the ecu and fuel pump,my ignition key only turns the starter motor now,the ecu primes the pump for 10secs on start up via the ecu,wasnt realy a problem just didnt expect it to work this way.