[alausch]

This one is a little weird. My cabrio is experiencing an intermittent starting issue. The battery is good and fully charged, and the engine cranks over just fine. Don't think it's a starter problem. It wouldn't start cold, for about 10 or so tries. Then, it fired right off. I cycled the anti-theft a couple of times before that. I don't know, I saw this issue on Pelican forums with no real clear answer. My spark plug wires are only a year or so old, and are all intact. I see no loose connections or issues that are obvious. Anyone have similar issue? It distinctly feels like an ignition problem.

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[J.Elenbaas]

Hi Alausch,

 

You could try to change the starter relay, their not expensive as well.

I have had a problem years ago but only after driving the car, so when the engine was still warm.

When i wanted to start lets say 30 to 60 minutes after shutting down the engine it just wouldn't.

Everything else worked just fine, but no ignition.

Appeared to be a faulty starter relay, after a long search to close out possible problems.

 

Hope this will solve your problem.

 

Regards,

Jack

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[94SilverCab]

Likely a DME Relay...this is a known failure point.

 

Part #: 993-615-227-00

 

Regards,

 

Jay

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[az968]

If you don't have a spare DME in your car you should have one. OP, you could try a new DME and see if that solves the problem. If not, you now have a spare that could save you grief on the road.

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[J.Elenbaas]

Yep, that's the one i had to replace, but still no spare one in the car  :whine:

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[alausch]

Ok, thanks guys. Really appreciate it. DME Relay huh? I'll take a look and see if I have a spare. If not, we'll get one on order. I really appreciate the advice. I'll let you know if that solves the issue.

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[baz]

If the DME does not prove to be the cause might I suggest the problem could be the fuel pump check valve (part# 944 608 951 01). I had a similar problem to the one you described and after much trouble shooting finally replaced the fuel pump  and the problem was fixed.  Only after this did i realise i only had to replace the check valve. Live and learn.   you might also like to consider when was your fuel filter renewed?

Problems with dirty fuel are not unheard of and should not be discounted.

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[unknown4u]

Ok, thanks guys. Really appreciate it. DME Relay huh? I'll take a look and see if I have a spare. If not, we'll get one on order. I really appreciate the advice. I'll let you know if that solves the issue.

Yes indeed the dme. Because the dme delivers the power to the idle stablizer mounted under the manifold. If it has no 12 volts. The cars has symptoms like this.

Bad starting. Perhaps if you crank it for .5 of a second the second time is fires right up. This because of the extra fuel the injectors deliver at that time. After it fires up. The rpm rumble and stumble before it stabilize.

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[pdxmike]

Like others said - DME relay. DME relay powers the DME itself and the fuel pump. It has nothing to do with the idle stabilizer unit. Search for the jumper bypass to rule in/out. You can do the troubleshooting (and, at least short term, solve your problem) before ordering although as others have said it is good to have a backup in any event.


Could be DME temp sensor or even just a loose connection. Located at the right of #1 cylinder under the intake manifold. Super easy to check.


Diagnostics for fuel pressure and check valve are on the clarks garage site and worth doing if the first two arent the issue.


Good luck!

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[unknown4u]

Check the electrical diagram for the dme and you will see that it powers more than the fuelpump....

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[pdxmike]

DME relay schematic via Clarks Garage:


   


The DME control unit must be turned on by the DME relay, and the control unit powers many items including the idle stabilizer unit so in that sense, you would be correct. But it does not directly power the idle stabilizer, unless I am really misunderstanding something, in which case I do apologize.


IF the DME relay is faulty, you can jumper 30 to 87 and 30 to 87b and the car will be driveable, as long as you take care to remove the jumpers each time you turn the car off - otherwise the fuel pump will run until the battery is depleted.


Ruling out the idle stabilizer should be pretty simple: accelerator to the floor on start. If it fires up, could be the idle stabilizer (not necessarily though). If it still fails to start, it is pretty definitively not idle stabilizer.

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[pdxmike]

Two other points:


1) I had this problem a few weeks ago and it was just that the connector for the DME temp sensor wasnt seated. I removed it, sprayed some CRC contact cleaner on the harness, and it fixed the problem.


2) Jumpering the DME relay doesnt rule out the check valve as the fuel system will come up to pressure when jumpered. But it will at least point you in the right direction.

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[unknown4u]

The dme schematic is not equal to the wiring diagram. The wiring diagram will show you more where it is al connected. Read the diagram and it will show you a lot more than only a picture of a relay.

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[alausch]

My people,

 

I just installed the new DME relay and it started right up! I'll continue to monitor the issue, but I stopped and started the car x4 and it was instant every time. Again, really appreciate the advice and help. $18 on Amazon for a Uro brand (we'll see).

 

I'll be moving back to the east coast next summer. I'm so excited. Going to the Naval War College in Newport. I've really missed the Porsche Swap in Hershey. I was last there in 2015. I'm originally from Ephrata/Lititz/Lancaster PA. Can't wait to bring one of the cars and meet some of you in person. Hope we can do something in say...2021.

 

Adam

Likely a DME Relay...this is a known failure point.

 

Part #: 993-615-227-00

 

Regards,

 

Jay

You and PDXMIKE nailed it....thank you guys

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[MCL968]

I hope you bought a spare! Now that you know that they fail at the most inconvenient times you will likely want to keep a spare around. Some folks on here claim they notice a difference in performance between the cheap ones and the original ones, but nothing succeeds like success and it sounds like the problem is solved.

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[pdxmike]

Awesome! I love easy fixes.

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[jsheiry]

I like the Ftech9 Solid state relay with fuel pump prime.  I like to hear the fuel pump run before the motor turns over like on most modern cars.  I would buy one of these and throw the URO in the glove box as a spare.  Not the cheapest but so far has been a great choice for me.

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