No fire - where to start ?

[mysocal911]

Check with the Stable in San Luis Obispo (805-545-9323). They may have a car you can test your DME ECM in, or provide a loaner DME ECM.

[Tori]

Originally Posted by wazzz

To make it clear, the DME is actually the ECU. When you say you swapped the DME, I guess you mean the DME relay. If you have no spark, you don't need to try and swap the DME relay, since it has no relation with the ignition.
You need to check the basics. First make sure the ECU is powered on when the ignition is switched on. You can check this by listening in the engine compartment. You should hear the idle control valve (ICV) humming. If not that means the ECU has no power or is completely dead.

Next, if the ECU is indeed alive, you need to check if you have fuel.
If you have no spark, maybe you have no fuel either. In this case it would point to a failing sensor (maybe). The ECU won't allow any spark or fuel if it doesn't get proper signals from both flywheel sensors at startup. No spark no fuel is typical of a failing sensor or a failure of the IC inside the ECU that is used to format these sensor signals for the processor.

Okay.... here's where we are currently in this process.
-I have verified ICV is getting power. I can hear and feel it humming.
-I've verified i have power at DME relay on both pins, 86 and 30 (86 when ign. on)
-I've swapped coils with another Bosch coil (not 100% positive it's a good coil, but it's what i had. I do have 12v at coil.
-Checked ohm readings of speed and ref. signal sensors. 971k and 973k respectively.
-Pulled dist. cap to inspect, rotor looks fine, cap has normal buildup and does show wear on a few of the terminals - looks like rotor contacted a terminal at some point, but nothing looks excessive or beyond it being able to function. (at least to some degree). - I'll order new cap and rotor for later this week.

I'll pull the DME apart next and look for failed solder joints next.

Open to any other suggestions.

[mysocal911]

Originally Posted by Tori

Okay.... here's where we are currently in this process.
-I have verified ICV is getting power. I can hear and feel it humming.
-I've verified i have power at DME relay on both pins, 86 and 30 (30 when ign. on)
-I've swapped coils with another Bosch coil (not 100% positive it's a good coil, but it's what i had. I do have 12v at coil.
-Checked ohm readings of speed and ref. signal sensors. 971k and 973k respectively.
-Pulled dist. cap to inspect, rotor looks fine, cap has normal buildup and does show wear on a few of the terminals - looks like rotor contacted a terminal at some point, but nothing looks excessive or beyond it being able to function. (at least to some degree). - I'll order new cap and rotor for later this week.

I'll pull the DME apart next and look for failed solder joints next.

Open to any other suggestions.

Read here again step B, i.e. voltage measurements;
http://forums.pelicanparts.com/porsche-911-technical-forum/621262-911-3-2-no-start-troubleshooting.html

[Schulisco]

Originally Posted by Tori

-I've verified i have power at DME relay on both pins, 86 and 30 (30 when ign. on)
-I've swapped coils with another Bosch coil (not 100% positive it's a good coil, but it's what i had. I do have 12v at coil.
-Checked ohm readings of speed and ref. signal sensors. 971k and 973k respectively.
-Pulled dist. cap to inspect, rotor looks fine, cap has normal buildup and does show wear on a few of the terminals - looks like rotor contacted a terminal at some point, but nothing looks excessive or beyond it being able to function. (at least to some degree). - I'll order new cap and rotor for later this week.

I'll pull the DME apart next and look for failed solder joints next.

Open to any other suggestions.

Sorry to say, but your tests are not appropriate. You cannot rely on simple voltage measurements of the DME relay. It's contacts corrode, and they fail more likely when heat (after driving some time) or vibrations rather than being cold with a sitting engine...

Tinker a three wire cable by yourself as I linked earlier, as this creates a solid and permanent connection between the contacts instead of errorprone switched contacts.

Your Ohm readings on both speed and reference sensors are not correct, the numbers you want to read is approx. 0.6 - 1.6 kOhms each. Not 970kOhms!! If the sensors really got these numbers, ther're crapped and have to be replaced! Place the test probes at the plug of each sensor directly! Otherwise you probably measure everything else but the sensors.

Visual inspection on ignition parts is senseless without electrical check. You want to read 4-6kOhms on each wire from plug to rotor cap. The rotor itself for the 3.2 Carrera has 1kOhms resistance. Wiggle the cables too while measuring to rule out broken cables.

Thomas

[wazzz]

I'm pretty sure he meant ohms and not k-ohms. Actually, 971 and 973 ohms are very good values for these sensors and they are very close to each other. At 970 kohms no way the engine would ever run.
As for the three-wire trick, totally agree. That's an easy way to eliminate bad contacts that are only intermittent.

[Tori]

Originally Posted by wazzz

I'm pretty sure he meant ohms and not k-ohms. Actually, 971 and 973 ohms are very good values for these sensors and they are very close to each other. At 970 kohms no way the engine would ever run.
As for the three-wire trick, totally agree. That's an easy way to eliminate bad contacts that are only intermittent.

Yes, thank you for clarifying that for me. I'm not super versed in electrical... i'm okay at DC current and simple tests, but not clearly versed in terminology.

[Tori]

Originally Posted by Schulisco

Sorry to say, but your tests are not appropriate. You cannot rely on simple voltage measurements of the DME relay. It's contacts corrode, and they fail more likely when heat (after driving some time) or vibrations rather than being cold with a sitting engine...

Tinker a three wire cable by yourself as I linked earlier, as this creates a solid and permanent connection between the contacts instead of errorprone switched contacts.

Your Ohm readings on both speed and reference sensors are not correct, the numbers you want to read is approx. 0.6 - 1.6 kOhms each. Not 970kOhms!! If the sensors really got these numbers, ther're crapped and have to be replaced! Place the test probes at the plug of each sensor directly! Otherwise you probably measure everything else but the sensors.

Visual inspection on ignition parts is senseless without electrical check. You want to read 4-6kOhms on each wire from plug to rotor cap. The rotor itself for the 3.2 Carrera has 1kOhms resistance. Wiggle the cables too while measuring to rule out broken cables.

Thomas

I have 3 different DME relay's, one original, one replacement, and one solid state version. Can't see 3 of these failing at the same time. Pretty poor odds of that one.

I also doubt highly that all my plug wires have failed at once.

Thanks for the help though.

[Tori]

Originally Posted by mysocal911

Check with the Stable in San Luis Obispo (805-545-9323). They may have a car you can test your DME ECM in, or provide a loaner DME ECM.

Visited them last week. No help.

[Tori]

I've run out of things to check...

Today i verified the wires from Speed and Ref. sensor connectors to the DME - all good.

Also made the 3 wire jumper for the DME relay connector, no change to my issue.

At this point, i have to suspect the one thing i cannot test, the DME. Is there anyone that tests them ?

[pmax]

Originally Posted by Tori

..
So far i've swapped 3 different DME's, and swapped the computer chip. Wiggled all connectors and inspected those of the DME and Computer.
...

To clear the confusion, you mean DME relays, not DME's.

Why don't you send the DME to a pro for testing ?

[mysocal911]

Originally Posted by Tori

I've run out of things to check...

Today i verified the wires from Speed and Ref. sensor connectors to the DME - all good.

Also made the 3 wire jumper for the DME relay connector, no change to my issue.

At this point, i have to suspect the one thing i cannot test, the DME. Is there anyone that tests them ?

Read post #4. There's a link for a SoCal company who's been testing/repairing DME ECMs for 30+ years for Porsche dealers, independent shops, & 911 owners.

[ischmitz]

I can provide a loaner DME and/or test and repair yours as required. Reach out via PM if interested.

[scarceller]

You already confirmed the ICV hums and vibrates with key in RUN.

Your next step is:
- Remove the center ignition cable from the distributor, the cable that connects the coil to the distributor.
- Put a test spark plug on the end of that cable and ground the plug
- Have someone crank the engine.
- Do you have spark?

Please do this test next.

You have not yet done all the possible in car tests, you have missed a few items that could be causing your no start.
Lets go slow with test by test.
Start with above test to verify spark or no spark at the coil.

[pmax]

Originally Posted by mysocal911

Read post #4. There's a link for a SoCal company who's been testing/repairing DME ECMs for 30+ years for Porsche dealers, independent shops, & 911 owners.

Appreciate your active participation in this forum, this thread being no exception.

[Tori]

Originally Posted by pmax

To clear the confusion, you mean DME relays, not DME's.

Why don't you send the DME to a pro for testing ?

Did you read my last sentence looking for recommendations on who/where to send it ? Thanks for your help.

[Tori]

Originally Posted by mysocal911

Read post #4. There's a link for a SoCal company who's been testing/repairing DME ECMs for 30+ years for Porsche dealers, independent shops, & 911 owners.

Yep, planned to call them but also open to other suggestions. Thanks.

[Tori]

Originally Posted by scarceller

You already confirmed the ICV hums and vibrates with key in RUN.

Your next step is:
- Remove the center ignition cable from the distributor, the cable that connects the coil to the distributor.
- Put a test spark plug on the end of that cable and ground the plug
- Have someone crank the engine.
- Do you have spark?

Please do this test next.

You have not yet done all the possible in car tests, you have missed a few items that could be causing your no start.
Lets go slow with test by test.
Start with above test to verify spark or no spark at the coil.

I appreciate the help, but there is no spark coming thru the new rotor and cap and thru any of the wires. I already know there is nothing coming out of the coil.

[Tori]

Originally Posted by ischmitz

I can provide a loaner DME and/or test and repair yours as required. Reach out via PM if interested.

Gotta give a big shout out to Ingo, we connected today and he brought me a known good DME to try in my car !

Clipped it in, and VROOOOOOM !!! The car came to life like normal !!

He's letting me borrow this one while he repairs mine. Great guy, and this saved me a few weeks of shipping mine off and waiting for someone to test it and ship it back to me.

Thank you to all that offered help and advise to get me to this point.

[ant7]

That's good to hear, well done Ingo.
Ant.

Originally Posted by Tori

Gotta give a big shout out to Ingo, we connected today and he brought me a known good DME to try in my car !

Clipped it in, and VROOOOOOM !!! The car came to life like normal !!

He's letting me borrow this one while he repairs mine. Great guy, and this saved me a few weeks of shipping mine off and waiting for someone to test it and ship it back to me.

Thank you to all that offered help and advise to get me to this point.