3.6 Engine - What should I do to it before plugging it in - Page 7

JeremyD · JeremyD's Garage

Quote:

Originally Posted by DW SD

Remember, like the 3.2, the computer turns on stage 2 of the DME relay which energizes the fuel pump. It has to see crank movement, first. Lots of times the crank position sensor isn't adjusted properly.

Are you getting spark? If you are getting spark, the DME is seeing the crank move.

Buy, if you don't have one, the fuel injector test light. I think they are called noids.

Hopefully, is something simple. I'm sure it is.

Good luck!

Doug

Thanks Doug - so I have stage one with the DME relay clicking - I'm guessing that the flywheel needs to be seen for the 2nd stage to kick in and the fuel pump to be energized. Obviously don't have that yet.

at least it has gas and oil in it - that's a big step...

PcarPhil · 09-12-2011, 05:30 AM

Quote:

Originally Posted by JeremyD

OK - Thanks Scott - I was trying to get into my head how the starter was energized without connecting to the wiring harness of the chassis. from the key side - how does the system know to start the starter? I also need to check that I have 12 volts on the coils too.

I'll PM you my phone number thanks for the offer. But the more I'm thinking about it - there's probably some bridges that I need to make with the chassis harness.

On my '77 I had to move a few pins around on the chassis 14 pin connector when I installed my 3.2. When I installed the 3.6 (again from memory) I don't believe I had to make any additional wiring changes with the chassis connector. The 964 engine was similar to the 3.2 in that regard.

So yes I believe you'll have to move a few pins in your 14 pin '74 chassis connector. Alternately you could make a jumper conversion cable between the chassis connector and "extra" engine 14 pin connector.

I suggest getting the pin out diagram for your '74 connector and the pin out diagram for your 964 engine. Adjust pins as necessary. Once your wires are straight your starter should start crankin'!

When you turn the key - with the PMS harness and the 964 DME harness installed - once the DME sees the engine spinning at a certain RPM from the starter it'll send signals for fuel and spark.

DW SD · 05:52 AM

I think the starter relay is a yellow lead on the 14 pin connector.
Use a test light and a friend to find which lead at the 14 pin connector (chassis side) lights up with the starter position on the key. From there find the lead on the engine side which you've attached to the starter relay.

Another common problem is to wire the DME computer off from a terminal at the fuse box which turns off under start. IE the radio turns off under start, probably headlights, too. The DME will have power, except under cranking. Make sure you don't do that. This problem has been highlighted in many threads.

When I think back to my install, I bought a new 14 pin connector, dissassembled the chassis side and moved many of the pins, checking each one with its partner on the engine side. I think several ended up in different positions.

Engine sensors like temp, alternator energizer, of course, starter relay are all on that 14 pin connector. Others, disabled are also on there (I think), are the heater blower motor.

Doug

PcarPhil · 09-12-2011, 05:57 AM

My '77 chassis 14 pin connector currently only uses the following pins with my '91 3.6 engine:

1, 5, 9, 11, 4, 6

Here's a pinout pic of an '81 connector to be attached to a '91 engine:

My 14 pin connectors. One goes to the DME harness the other goes to the chassis harness:

DW SD · 09-12-2011, 06:20 AM

Notice, I had some trouble getting the pins correct.

I think the photo shows the engine connector. Like Scott, I only used 5 (or six) of the pins.

Printout:

Testing process:

Tom '74 911 · 09-12-2011, 06:21 AM

Quote:

Originally Posted by DW SD

Another common problem is to wire the DME computer off from a terminal at the fuse box which turns off under start. IE the radio turns off under start, probably headlights, too. The DME will have power, except under cranking. Make sure you don't do that. This problem has been highlighted in many threads.

When I think back to my install, I bought a new 14 pin connector, dissassembled the chassis side and moved many of the pins, checking each one with its partner on the engine side. I think several ended up in different positions.

Engine sensors like temp, alternator energizer, of course, starter relay are all on that 14 pin connector. Others, disabled are also on there (I think), are the heater blower motor.

Doug

Jeremy -
I made the mistake Doug mentions in the first quoted paragraph. It took me a few frustrating days of troubleshooting to find it. I posted a thread on it too.

I also bought a new 14 Pin connector and rewired the chassis side to mate w/the engine side cleanly. I spent some time w/wiring diagrams from '74 & '90 and a multi meter to make sure everything was where it should be. I'm assuming you have the wiring diagram for the Patrick conversion harness too which is pretty easy to follow (except one wire - see first paragraph!)

You're getting good advice from Doug & Scott here - they covered everything I was going to suggest.

Tom

JeremyD · JeremyD's Garage

Quote:

Originally Posted by Tom '74 911

Jeremy -
I made the mistake Doug mentions in the first quoted paragraph. It took me a few frustrating days of troubleshooting to find it. I posted a thread on it too.

I saw that last night - where did you end up putting that wire? I went with my sunroof fuse - because I don't have a sunroof - but now I'm worried that it also may switch off during cranking.

Alright I have some ammo now... Silly of me to assume that buying a 3.6 conversion harness meant that it was all I needed...

DW SD · 09-12-2011, 06:44 AM

Quote:

Originally Posted by JeremyD

I saw that last night - where did you end up putting that wire? I went with my sunroof fuse - because I don't have a sunroof - but now I'm worried that it also may switch off during cranking.

Alright I have some ammo now... Silly of me to assume that buying a 3.6 conversion harness meant that it was all I needed...

whip out a friend and your test light. I want to say fuse #6, but that's a wild ass guess from five years ago.

Crank at the key and make sure you still have power to the DME at the fuse panel under crank. If not, move to an open one that does.

If you see the above photos of my 14 pin connector, I'm almost certain yellow is the starter relay. You'll notice it is of larger gauge than those feeding sensors like temp and oil pressure.

Doug

Tom '74 911 · 09-12-2011, 06:46 AM

Quote:

Originally Posted by JeremyD

where did you end up putting that wire? I went with my sunroof fuse

I went to the next fuse past the sunroof fuse (#6 I think). I had my wife crank the motor while I used my voltmeter at the fuse box to verify that the fuse had 12V while cranking.

Tom

Tom '74 911 · 09-12-2011, 06:47 AM

Doug is quicker than me! At least we're telling you the same thing!!!

JeremyD · JeremyD's Garage

Thanks - I'm feeling a little better about this.

KTL · 09-12-2011, 08:51 AM

I'll just reinforce the pin switching for fun. When I worked on a 3.2 going back into a '78 (because we had a 3.6 coming out of a '78 going into an '88 3.2), we had to move pins on the 14 pin harness. I remember vividly that Timmon's instructions saying the red #2 needed to be moved or disconnected or something, otherwise it would "backfeed" the system. Well the eager goofball named einreb who can't read directons just hooked up the 14 pin and turned the key to see what would happen. A ground wire behind the instrument panel decided to release it's magic smoke.....

Definitely make sure you've got all the wires going where they should be, before hooking up the battery and keying her on!

JeremyD · JeremyD's Garage

helpful post here

Quote:

Originally Posted by tholyoak

Joe

Here are some pictures that will hopefully help you

You should have a total of 3 wiring harnesses for the 964 engine as stated above

1) The engine should have a harness on it for the various sensors, as well as a long pigtail with connections for the starter and reverse light switch, it terminates near the fuse panel in the engine bay with these two connectors

The large 12 pin connector will mate with the DME harness coming from under the drivers seat which we will see in a minute.

The small 14 pin connector will mate with the 14 pin connector on your relay panel on the chassis

This it the connection you will have to check for compatibility as some of the pin outs are not compatible between the chassis and the motor, you will need to check what the pin out on your chasiss is on a site like marcesq has above

The pinout for the engine side of the 14 pin connector is
1 yellow;starter
2 not used, disconnect
3 not used
4 gn/red; oil pressure gauge
5 gn/ye; reverse light switch
6 gn/br; reverse light switch
7 bl/gn; heater fan, not needed
8 br/bl; heater fan, control signal
9 gn/wht; oil pressure warning light
10 re; relay blower motor, not needed
11 bl; alarm, not needed
12 re; a/c compressor
13 ye/gn; relay blower motor
14 re; relay fuse panel heater blower motor

The other harness is the DME harness as shown below

At the center of the picture is the large 12 pin connector that connects to the mate coming off the engine shown above
The rest of the connectors mate to the motor sensors.

At the top of the picture is the large DME connector which connects to the brain, and 2 smaller connectors a 6 pin and a 14 pin, these will interface with a homemade wiring harness shown below

This is the one I made

At the center is three connectors
A 14 pin and 6 pin to mate to the connectors above by the large DME connector, and another 6 pin connector that holds the DME relay. Several wires extend from this harness to the battery, the fuel pump, fuse panel, switched ignition, oil temp gauge, check engine light, fan belt breakage light etc, Ingo has a nice shematic on his site.

Hope this helps you and others. The interface harness is really quite simple to make, but then I have also done 2 of these swaps now.

Let me know if you need more help
Todd
holyoak@brandeis.edu

JeremyD · JeremyD's Garage

success - I used the fuse for the air blower - heated rear window - that doesn't go "dead" on crank.

woo woo - I'm a happy camper now.

DW SD · 09-12-2011, 04:52 PM

that was simple

when do you fire it up for the first time?

You can double check your gauge connections by either grounding the gauge wire at the engine or using a rheostat and checking gauge sweep (at least for oil pressure and temp).

Doug