Black_924_S

I am trying to find out what might be wrong with my car. It is cranking but not starting, as far as i can tell it's not sparking either. I was told to check the coil first. Can anyone tell me what the ohm measurements are suppose to be on it? (87' 924S) or if there are any good aftermarket coils like MSD that will work? Any other suggestions on what to test would be appreciated. Thank you so much.

Matt O.

I really don't know if it's the coil just because it won't start, but the MSD coil is a good upgrade for the buck anyhow, so you might try it regardless. What are some other symptoms?

-Matt

Skip

Not knowing any other history than you listed here, but have you tried the DME relay yet - most likely cure to "cranks but no start".

Coils rarely fail.

Good Luck!

Carl Carlson

I believe that the two most likely causes of no spark are the DME relay as mentioned above, and the flywheel sensors. Try rapping the tops of the Reference Mark Sensor and the RPM Sensor with the HANDLE of a hammer. They are located above the flywheel on the driver's side. They look like two bolts with wires held in place with a third bolt.

It works for me.

Carl Carlson

Danno

Porsche in their service-oriented design, managed to make BOTH the connectors for those sensors the SAME!!! It's actually possible to reverse the sensors and not have the car start up either. And those connectors can get corroded over time; so unplugging, cleaning them up and wiggling them when connected can help rule that out as a factor.

ribs

I think I finally cured my no start problem for good! I went through a lot of stuff, and I think I had more than one contributing factor to my problem because after I would replace one part it would get better for a while then get worse. Here is everything I have done and now my car appears to have been excercised of the no-starting demons (I'm not 100% on it since I just re-soldered the entire DME today, but it seems to have cured everything)...

I did the following:
-cleaned the battery terminals (try this first as this can cause the no start problem and is a free fix)
-added new main engine to chassis ground (cured my dancing gauges and other weird electrical problems too)
-new coil/cap/rotor/wires/plugs
-new DME relay
-cleaned connectors for crank angle and speed sensors
used di-electric grease on all ignition wire connections
-replaced fuel pressure regulator (put in a 3 bar unit for future upgrades) and fuel damper
-had injectors cleaned, balanced, and sealed
-replaced fuel lines with braided stainless steel variety (not really related, but good idea anyways)
-replaced fuel pump
-re-soldered the entire DME today

So, after doing all of that work, my car finally seems to start on command. The only things out of that list I did to specifically cure this problem were coil/cap/rotor/wires/plugs, DME relay, crank/speed connectors, FPR and damper, and resoldering the DME. The easy way to tell if its your DME is next time you have the problem with no starting, use a pole or sit shotgun while starting or have a passenger do this for you...tap on the pass. floor board where the DME is while cranking and see if it starts then...if this is the case, pull your DME and re-solder all of the connections...it took me around 2 hours overall to do it (well...actually 5 hours, but I was watching TV, eating, doing homework, drinking a bit, hanging out, etc. while doing it) and wasn't as hard as I thought it would be. If you want to know if its your crank angle/speed sensors or their connections, watch the tach, and if it isn't bouncing up and down when you are cranking it when the car isn't going to start, but does bounce up and down when the car is going to start, it is most likely these. Good luck, and let us know what you find.

Skip

[quote]Originally posted by Danno:
<strong>It's actually possible to reverse the sensors and not have the car start up either...</strong><hr></blockquote>

In theory, right Danno