Has spark in start, no spark in run

Tiny
MRUSDCAR
  • MEMBER
  • 2002 FORD TAURUS
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 126,000 MILES
OHV

I got this car as payment for some work I performed on an auto shop's building, figured I could flip it and make a little extra money.
When I got the car the only issue was it was blowing the cap off the power steering pump and up chucking power steering fluid and it had a miss on cylinder number two. Tackled the rough running first and determined it was a coil pack found one in a junkyard that looked brand new and installed it and the car ran fine.
Fast forward a couple months, I decided to try to tackle the power steering issue I drove the car to a local car wash no problems (other than the power steering. (We actually have driven the car here and there several times), got out to get change etc, got back in the car, started it up, put it in reverse and when I went to put it in drive so I can pull in and rinse the engine off it quit running. Never got engine wet etc.
The car will run if you hold the key in "start" position (trying to find the sweet spot so the starter doesn't run on is virtually impossible).
I was limited on tools etc, but here is what I have done/learned:

1. Checked spark with a spare plug and wire there is spark when engine cranks but as soon as key is released, no spark (update now only throws one spark on crank then nothing)
2. Replaced ignition switch with new one, same symptoms.
3. Grabbed a junkyard coil pack that looks virtually new, same situation
4. Checked fuel by depressing Schrader valve, enough pressure to darn near blow through the hood also, scantool reports frp in hi 30's.
5. Scantool reports ECT=37° (this is the ambient temperature outside), RPM 0 then starts at about 60 when cranking up to 170 or so, MAF 0 and went up to 1.7 or so while cranking, TPS responds to peddle movement (can't remember exact numbers).

No fault codes set.

I know older ignition circuits would start on 12 volts then cut back to approximately 5 volts or so in run is that still true on these "modern" cars?

Haven't really found a good wiring diagram but is there a resistor on the coil pack?

Any help would be greatly appreciated!

*UPDATE- I was going through and rechecking everything and when I got to the coil pack, I just happened to notice that center ground wire is grounded all the time even with the key off. So when I get a little more time, I'm going to check the wiring to the PCM but it's looking more and more like a bad PCM and unfortunately I think that's a little too much to spend on this turd.
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Saturday, January 5th, 2019 AT 10:09 AM

42 Replies

Tiny
KEN
  • ADMIN
Hello,

It sounds like the PCM relay is not working right. here is a guide to help you test it with the location of the relay and the engine wiring diagrams so you can do some testing:

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

and

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what happens.
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Monday, January 7th, 2019 AT 11:57 AM
Tiny
MRUSDCAR
  • MEMBER
Thanks for the diagrams.

I don't see how a power relay would affect the ground circuit of the coil - but I went ahead and retested them and here is what I found:
The center ground circuit (one of the yellow wires at the coil) is grounded all the time Key on or off and the PCM relays removed. The harness is good (unhooking it from the PCM opens the circuit).
I used a test light and went from the battery + to each of the yellow wires (unplugged from the coil) and only the center one showed continuity.
When cranking, the other two wires will flash but the center one is illuminated brightly while, in my opinion the other two flashes are very dim. This leads me to believe that it is a faulty PCM.

Now, as stated earlier, I recently got this car and when I unhooked the PCM, the bolt that retains it was loose so I'm thinking someone else had been in it and determined it needs a PCM and decided to send it on down the road for someone else (me) to get stuck with it.
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Monday, January 14th, 2019 AT 3:17 PM
Tiny
KEN
  • ADMIN
Yep that is my thoughts as well, bad PCM. I would try to find a used or rebuilt unit to see what happens. Here is the location. Check out the diagrams (below). Please let us know what you find.
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Tuesday, January 15th, 2019 AT 10:45 AM
Tiny
MRUSDCAR
  • MEMBER
Well it took me awhile but I finally found another PCM on eBay it came with two uncut keys.
The weather has been rather crappy here so this project kind of got put on the back burner so to speak.
Got the PCM installed and tried to sync the keys up. Then I ended up with a no crank situation and I was certain that I had screwed up something when I was trying to sync those keys.
The guy I got the PCM from was pretty adamant that it was pretty tough to screw the key syncing up (I thought maybe I had inserted the same key twice and he assured me that the system wouldn't recognize it that I needed to definitely have two different keys for the sync to take place).
I reinstalled the old PCM and still no crank, back when the engine was cranking fine it would actually run if you held it in the start position (with the old PCM).
This is where "expertise diagnosis" comes in - I was certain that the PCM sent the 12 volt signal to the start relay. After pouring over many many electrical diagrams trying to figure out which pin on the PCM set the 12 volts to the starter relay, I discovered that the PCM only provides a ground for the starter relay. I turned the key to run and then jumped the starter relay and the car fired up and purred like a kitten.
So after tracing wires back to the new ignition switch and probing it with a test light it showed it was sending the 12 volts to the starter relay however I discovered a if you work the starter switch just a hair further into the start position or all the way to the end there was no signal so I grabbed the used switch (hoarding pays off again) and tested it and it would provide 12 volts all the way through the start position.
I installed the original switch and the car starts and now fires on all six cylinders.
So to summarize, the original PCM was bad and the new ignition switch went bad just sitting there.
Now I just need to figure out why the power steering cap blows off and it upchucks all the power steering fluid.

Thanks
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Wednesday, February 27th, 2019 AT 5:55 AM
Tiny
KEN
  • ADMIN
Great find! Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Wednesday, February 27th, 2019 AT 10:49 AM
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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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
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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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
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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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
BOB1959BOB
  • MEMBER
  • 2000 FORD TAURUS
  • 195,000 MILES
Car just had continuios clcking sound changed neg battery cable it was bad. Now cranks but will not start, no spark to spark plug. Car always started before replacing neg battery cable.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
SPORTZFAN38
  • MEMBER
  • 1998 FORD TAURUS
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 190,000 MILES
What would cause a no spark issue?
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Check for codes 1st

possible cause
crank sensor,
fuse,
wiring,
coil,
PCM.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
SPORTZFAN38
  • MEMBER
Could a aftermarket remote start possibly cause no spark. The coil is pack is testing good and all fuses are good.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Some do some dont
if has an alarm system with it
and wired to disable the spark,
but if no alarm just a remote starter it shouldn't effect the spark
in both cases checking wiring would tell
if coil tested OK and no codes my next step would be crank sensor
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
WISTED
  • MEMBER
  • 1996 FORD TAURUS
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 168,000 MILES
The motor just died after pulling out of my garage.I do not get any spark. I have coil checks out ok. How can I check the CKPS? Or the PCM?
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
BLACKOP555
  • EXPERT
Check to see if you have +12v to one side of the coil with the vehicle key on. Then when cranking check for a -12v pulsing on the opposite side of th ecoil.

Do you have a tachometer reading when cranking the engine?

Get back to me with what you find.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
WISTED
  • MEMBER
Thanks for the response. I did check -12vdc and found it was not pulsing so I started to trace this back to the crankshaft trigger sensor. I found somebody had broken the latch that held the connection together. After reseating the connector, I then tie wrapped it together, I now have spark and it runs.
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
BLACKOP555
  • EXPERT
Glad to hear you got it fixed! I would suggest getting a new connector
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Wednesday, February 27th, 2019 AT 10:50 AM (Merged)
Tiny
RICK892
  • MEMBER
  • 1997 FORD TAURUS
Electrical problem
1997 Ford Taurus 6 cyl Front Wheel Drive Automatic

Good Afternoon Gentlamen: I just bought 1997 Taurus 3.0 L. The car was running rough so replaced spark plugs and wires. The car still running rough; I check the compression on all cylinders I have good compression. But I don't have fire from #3 and 4. I have replaced PCM because someone told me that would take care of the problem. But I still have the same problem; Can someone HELP ME PLEASE !
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Wednesday, February 27th, 2019 AT 10:51 AM (Merged)
Tiny
MHPAUTOS
  • EXPERT
I would be more inclined to be looking at a faulty coil pack or faulty leads.

Mark (mhpautos)
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Wednesday, February 27th, 2019 AT 10:51 AM (Merged)

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