I hate wiring, Help me 4x4 my IX! No Spark, FML

[delphini]

YES , the obc if its the 13 button variety will cause a no start condition ..... remember that the security device with the security code prevents the car from being started if it is enabled. Get a new black box and your problem is solved .

[JakeP]

Would the OBC cause the car to not start? or honk once when the key turns on and off?

Nope, don't have that exact connector. I have this one:

[JakeP]

The car is an 88. I'll be by the shop tomorrow afternoon, I'll look for that connector then. I have 2 unplugged connectors near the black box that I can't ID either.

[DaveSmed]

Also, what year is the car?

Specifically, Do you have this connector?

[DaveSmed]

The little clock mileage computer thing next to the radio. Also happens to be the thing that controls the black box by the clutch pedal.

[JakeP]

No power at pin 27?

What is your OBC up to?

Huh?

[DaveSmed]

No power at pin 27?

What is your OBC up to?

[JakeP]

Put a new ignition switch in. Still no power at pin 27 of the DME connector.

[JakeP]

In the following posts, you're talking about the round connector on the firewall? On the round connector, (C101?) What pin is #18?

I traced the pin 27 all the way through that connector to the plug near the brake pedal using the ohm-meter on my multimeter, so that wire is continuous. Hopefully we can get this hammered out tomorrow so I can take it out for a test drive.

I think this is a connector for an e21, but I'll just use the diagram. I believe I traced the pin from the ECU to #8 on this diagram...

the switch could be bad, yes. the ignition switch also powers the coil and FP relay.

you can check pin 18 on the C101 connector, it should be hot with the key turned on.

well you can just check for voltage at pin 18 of the C101 with the key on. I think you can uplug the engine harness side of the C101 for that.

the C101 is a round 20 pin connector on the firewall above the brake booster. the top portion of the plug goes to the engine harness, the bottom portion to the body harness.

then the switch isn't the issue.

How about the pin itself, is it clean? can you check continuity/resistance from the engine harness side of pin 18 to pin 27 of the motronic connector?

heres another one - are you sure the main relay works? since the ECU turns on the FP relay, without a working main relay the FP will not work.

[nando]

but pin 18 at the C101 is working and that is hot from the switch.

I think you are missing that part, I'm not talking about pin 18 at the motronic connector.

pin 7 of the C101 is also switched 12v from the ignition switch (and connects to pin 27 at motronic).

although I realized he should be testing pin 7 and not 18, as 18 is only hot when you are trying to crank the motor. I just glanced at my C101 chart and saw that 18 went to the switch.

[dark89e30]

but pin 18 at the C101 is working and that is hot from the switch.

The Alldata wiring diagram shows pin 18 hot at all times, not through switch. Do you have one that says different? Maybe a factory book?


Here's what I'm going off of.

[nando]

Just because you have continuity to ground does not mean you have good ground. You'd have to measure voltage drop under load to determine that. If your coil is not getting batt positive, its prob a 90% chance the ignition switch is the problem, just based on that. Pin 18 is hot at all times, pin 27 is the dme turn on lead and splits to the coil AFTER the ignition switch. Go buy a NEW ignition switch.

but pin 18 at the C101 is working and that is hot from the switch.

[accident]

i have a spare ignition switch.

[JakeP]

Thanks Matt. If I get one before then, I'll let you know.

[E30Nova]

Hey Jake, I'll try and pull my ignition switch so when you come by Friday you can grab that too. Unless you have a spare on hand already.