1977 Fuel Injection Wiring Question

[Newfie911s]

So I installed a New Re-Built 78 3.0 motor made to fit my 1977 Fuel Injection. Using the 3.0 wiring harness. The car is running but terrible, cold start is non-existent and once warmed up it bucks badly.

Obviously there are air leaks and I'm working on those. My question is when I turn on the ignition should I have power going to the thermotime switch, warm up regulator and the cold start injector?

With the ignition in the on position and not cranking I have no power to any of these sensors.

Any help would be greatly appreciated.

[timmy2]

The TTS and CSI only see power when the solenoid switch is activated when starting the car, and the CSV will only get power when the TTS is closed due to low temperature at that moment in time. Yellow/blue wire to solenoid goes to CSV then through the TTS and back on red/black wire to CSV.

Your WUR should have power to the connector when the switch is in the run position. The red and white wire in the 14 pin connector is the power supply to the WUR and should be switched power. Brown wire is ground,

Have you tested your system, cold, and warm running fuel pressures with a gauge yet?

Hope that helps you begin to troubleshoot your cold start issues. Post your fuel pressure results and we can go from there.

[Newfie911s]

No pressure test yet due to lack of gauge and CIS Boot has cracks.

Porsche = Money Pit with no chance of filling.

[Newfie911s]

So my understanding is that the TTS and CSV only get power while cranking?

The WUR has constant power when ignition is in the ON/RUN Position?

[timmy2]

Correct.

[Newfie911s]

Thanks,

I'll check that tomorrow.

So I did a reverse pressure test of the system with a shop vac blowing through the exhaust and found three major sources of air leaks after spraying with soapy water.
Injector #1


Air box around the seam


Injector #3


Oh the joys of an old Porsche!!!

[boyt911sc]

Originally Posted by timmy2

The TTS and CSI only see power when the solenoid switch is activated when starting the car, and the CSV will only get power when the TTS is closed due to low temperature at that moment in time. Yellow/blue wire to solenoid goes to CSV then through the TTS and back on red/black wire to CSV.

Your WUR should have power to the connector when the switch is in the run position. The red and white wire in the 14 pin connector is the power supply to the WUR and should be switched power. Brown wire is ground,

Have you tested your system, cold, and warm running fuel pressures with a gauge yet?

Hope that helps you begin to troubleshoot your cold start issues. Post your fuel pressure results and we can go from there.

Edit: Thermotime switch below should be 'thermotime valve' my mistake.

Dennis,

I beg to disagree. The FP, WUR, AAR, and Thermotime switch (optional) all get power from terminal #30 (FP relay). With the ignition switch @ ON/RUN position (not start), there is no power to terminal #30 unless:
1). You have a bad FP relay.
2). The AFS switch has be detached or disconnected or defective.

With the above two (2) conditions, there would be power to terminal #30 which should not be the case in a normal operating condition. My two cents.

Tony

[timmy2]

TTV or TTS Tony?
TTV is the thermo time vacuum valve on the pre 1980 cars.

TTS is the temperature controlled resistor switch on the chain case that powers the cold start valve CSV.
Yes, the power to the WUR and other daisy chained devices is on when the ignition is in run.
The cold start valve and thermal switch only see power when the ignition is in the start position.

[timmy2]

Tony,
The OP doesn't seem to have power to the WUR when the key is in the on position, and also asked about when power goes to the cold start valve.
His fuel pump runs. He has a rough running condition and has discovered the air leaks appropriately using the pressurized air method.

He has installed a freshly rebuilt '79 3.0 engine with small port heads installed, using the original '77 CIS intake and controls with a '79 engine harness that I helped him to re-wire to enable it to work properly in the '77 chassis.

I was directing him to troubleshoot the wiring in the 14 pin connector to ensure he had power to the WUR routed correctly in the connector as the body connector in the car had been rewired by the PO.

I have asked what WUR he has installed and what his fuel pressures are.
We are also corresponding through email so not everything gets posted here as he troubleshoots.
Once the false air leaks are corrected and he begins setting up the fuel system again I'm sure he will be asking for more CIS help with his hybrid engine.
I know you will be better able to help with the fuel system than I can and look forward to your contributions.

[Newfie911s]

Thanks again guys,

#1 - What's an AFS Switch?
#2 - There was NO previous body connector or engine wiring harness connector, all wires were just joined up.
#3 - Even with the bad 2.7l there was a cold start issue, I just figured it was the fact that 4 of 6 cylinders had very little compression and bad head gaskets.

Order going into Pelican today for Fuel Injector Guides, guide seals, airbox seal (hoping its not cracked) and a CIS Boot. The Boot has many cracks where it connects to the fuel distributor.

I'm going to start to remove the fuel injection and then test the electrical while waiting on the order.

[digdug]

If you airbox turns out to be blown I have a spare off my 74.

[boyt911sc]

Originally Posted by Newfie911s

Thanks again guys,

#1 - What's an AFS Switch?
#2 - There was NO previous body connector or engine wiring harness connector, all wires were just joined up.
#3 - Even with the bad 2.7l there was a cold start issue, I just figured it was the fact that 4 of 6 cylinders had very little compression and bad head gaskets.

Order going into Pelican today for Fuel Injector Guides, guide seals, airbox seal (hoping its not cracked) and a CIS Boot. The Boot has many cracks where it connects to the fuel distributor.

I'm going to start to remove the fuel injection and then test the electrical while waiting on the order.

Newfie911S,

With Dennis behind you, you are indeed in good hands. Let me answer some of your questions.
1). AFS (air flow sensor) switch..........the round disc sitting in the throttle body is the AFS (AF sensor or plate) and mounted to an arm or lever. The switch (contact) is located/mounted on the arm/lever and makes ground contact at rest position. Once the engine starts to run (sucking intake air), the AFS is lifted upward causing the ground contact to open. This ground contact is connected to terminal #85 (FP relay socket) where the FP relay coil is connected.
2). Not sure what you meant. The engine wire harness has the 14-pin connector and goes to the 14-pin connecter from the chassis. The main difference (electrical) between '76-'77 and SC's is the CDI wire connectors. They use different CDI with different wire numbers.
3). I don't agree with this statement. You should be able to start the engine anytime of the year regardless if the engine is cold or warm. Only if you don't have a problem in your system like fuel pressures, air leak, etc.

Let's start with the basic condition:
a). There will be no power to WUR, AAR, and FP with the ignition @ ON/Run position. If you do, there is an obvious anomaly in your wiring set-up.
b). The CSV (cold start valve) is controlled by the ignition switch and TTS (thermotime switch) not by the starter solenoid. You could activate or test the CSV and TTS without a starter installed in the car.
c). You need to test and confirm to differentiate between a good working part/component and a bad one. Without a fuel pressure gauge kit, there are too many variables. Eliminating these variables to the minimum, makes the problem solving a lot easier.
d). Since you are doing all the work and investigation, feedback is very important. We have no idea what's going on without you telling us the results, observation, actions, etc. you have done. So communication is critical between you and the readers.

Keep us posted.

Tony

Edit: Deleted the last section. It was intended for a different post.

[Newfie911s]

Parts ordered to resolve air leaks, once done will report back

[timmy2]

Tony, the ignition switch does control the CSV power electrically on a schematic, but the yellow wire from the 14 pin connector runs to the starter solenoid terminal first in the harness and branches back to the CSV from there.
Some harnesses have a separate yellow and yellow/blue wire run to 2 seperate terminals at the solenoid, others have them crimped in one terminal.
Physically, the power to the CSV is run in the harness from the starter solenoid terminal back to the CSV.
One could lift the yellow terminal(s) at the starter and insulate them from grounding out on the car, then turn the ignition switch to start to see if the CSV circuit functions correctly.

[timmy2]

And my screw up on power to the WUR etc with ignition in run, I was assuming the fuel pump relay was jumpered for testing. They are powered when the jumper is in place.
DOH!

[Newfie911s]

If the fuel pump relay is jumpered will the fuel pump still run?

[timmy2]

Part of testing the fuel pressures involves jumpering the fuel pump relay socket to enable it to run with the ignition in the run position. It shouldn't run otherwise due to the air flow switch being closed.
The current CIS for dummies thread is a good read.

[Newfie911s]

All the CIS System is now removed. Appears that someone plastic welded the air box together as it will not come apart at all. Small crack near the seam too. Will post pictures later.

[boyt911sc]

Originally Posted by Newfie911s

All the CIS System is now removed. Appears that someone plastic welded the air box together as it will not come apart at all. Small crack near the seam too. Will post pictures later.

Newfie911S,

Now that you have the air box out, pressure test it before installation. This is the best time to determine the condition of this piece of equipment. Even if it looks good, you could never tell or see the presence of hairline cracks around the perimeter. Use the water immersion test technique. Pictures posted in this forum.

Tony

[Newfie911s]

Pic of the welded air box