No spark during crank cycle

Tiny
JB41073
  • MEMBER
  • 1999 FORD TAURUS
Electrical problem V6 Front Wheel Drive Automatic 100000 miles

I have a 99 Taurus, w/3.0l overhaed valve (U code).
The engine turns over fine yet I have no spark wile the engine is cranking over, there is a quick spark after letting the key ruturn to the run position. I have replaced the coil pack (old one showed low resistance for all 3 secondary windings), ignition switch, CKP, CMP and MAF sensors, as well as the PCM pre-calibrated (AA). The car Does not have a PATS or RAP module. I have been checking for bad wires at this point, I started with the main power and grounds to the PCM, in hopes that during the crank cycle I would loose power or ground, I'm not all main, memory power and grounds are strong. The car was sent to a local garage (for 3 weeks) they couldn't figure it out, I have had it for 4 weeks.
ANY HELP?
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Monday, December 3rd, 2007 AT 5:14 PM

2 Replies

Tiny
JACK42
  • MEMBER
Hello,

The clue is when you get one spark and then nothing. This is telling us the ECM is spending its capacitor energy and not getting recharge. This is due to a power issue like a relay or fuse. Here is the engine wiring diagrams so you can test the fuse power feed and PCM relay.

Here are some guides and diagrams (Below)

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please let us know what happens.

Cheers
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Thursday, December 6th, 2007 AT 9:51 AM
Tiny
JB41073
  • MEMBER
The injectors pulse, I've also checked the EEC relay along with the EEC diode and they both check fine, just to humor myself I swap both with the A/C relay and diode. Still no spark during the crank cycle, only time I'm getting spark is when I'm letting the key go back to the run position, then it is only a single plug at random (I take it from the exciter ring making another or partial rotation). I've also checked the AC voltage for the CKP at the PCM during the crank and it is within specs. The3n I changed out the PCM relay and bam! The car started, Nice work 2Carpros you really know your stuff.
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Monday, December 10th, 2007 AT 8:39 AM

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