No Spark

[atl.cut]

I have a 1995 Oldsmobile Cutlass Supreme V6-204 3.4L DOHC VIN X SFI. I put a 1993 Lumina 3.4 DOHC crate engine in it. I have fuel pressure. I can not use the scan tool. When I plug it in I dont get the usual blinking 12 code. The light just stays on. New coil and ignition module. No spark to the plugs. The motor just turns over. Any thoughts?

[RedZMonte]

crank possition sensor... IIRC when it fails you get no spark... if it doesnt know where the crank position is it doesnt know when to fire each cylinder... I would start there.... seems to be a issue that has been comming up recently.

Hope this helps.
Shane

[OldSkoolGP]

If you just have Code 12 blinking over and over, you have no codes. Code 12 is just there to let you know that the ECM is working and when it has shown you all the codes. I agree with Red, it's probably the crank position sensor, or it could be the ignition control module, but the crank sensor is about $25 so start with that.

[55trucker]

Do you know for certain that the scan tool you have is functioning properly?...(try it on another vehicle?)...If you plug it into the ALDL connector and the led light just comes on solid without flashing anything at all I'm suspecting an ECM related problem. The scan tool is seeing voltage but it's not receiving the diagnostic input from the ECM. I'm not certain if the *paper clip* method of bringing on the diagnostic mode works with OBD1.5 cars as I've never had the opportunity to try. Anyone else with a 1.5 car know if you can?

[atl.cut]

I checked the scan tool in my truck and it works. When I put it in the car, nothing happens.

[bszopi]

Paperclip method does not work with OBD1.5 cars (94-95). Is your scan tool for OBD-1 or OBD-2 vehicles? That may be issue right there...

[atl.cut]

I have been using an OBD I, I do have an OBD II also.

[Dave96z34]

Test your scanner unplug something like tps and see if throws a code.

[jmgtp]

Do you get the smell of raw fuel after a lot of cranking?

If you do not, then you can assume there is no crank signal and suspect the CPS/wiring.

If you do get a fuel smell that means the ecm is getting a signal from the CPS that the engine is turning over so you can then assume you have a problem with the ignition module/coils.

[atl.cut]

Theres no smell of gas while cranking. Thank you everyone for your input. So Im going to look into the crankshaft pos sensor and why Im not getting any diagnostics from the ecm.

[55trucker]

I might consider focusing on the loss of diagnostics to the ALDL. If there is no transmission there, something has to be faulty upstream. I'm wondering if the ECM has shorted? If it has failed that would explain why you have no other systems active.

[atl.cut]

What is the best way to diagnose up stream

[55trucker]

Now keep in mind that my car is a 91 so this diagram is 91 related, but the basics for the wiring are the same with regards to the loss of the scan tools ability to read anything.

[RedZMonte]

just a thought.... did you fix your no start issue? the 1995 DOHC has a "Cam Possition Sensor" on the front cam tower and the 1993 engine does not... if that is not hooked up would the car start?

here is the sensor im talking about on the corner of the valve cover.


Here is the '91-93 engine, notice the valve cover is not notched for the sensor.

[atl.cut]

Everything is plugged in and accounted for.