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No fiire from coil

  • Thread starter Thread starter stang22
  • Start date Start date May 7, 2005
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stang22

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Jan 29, 2003
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May 7, 2005
#1
  • May 7, 2005
  • #1
No fire from coil

The coil is good, I have a spare that I tried as well. Fuse #18 has power and the red/green wire going to the coil is pulling 12v's. Is there another fuse or fusible link that I can check? The TFI, plug wires, cap and rotor are new. Thanks!

Tim
 
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Daggar

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#2
  • May 7, 2005
  • #2
Start swapping in the old stuff piece by piece. I've got a dollar that says the new TFI is the culprit!
 

stang22

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#3
  • May 7, 2005
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I put my spare on and no spark or fire from the coil. I hate electrical gremlins...
 
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Daggar

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#4
  • May 7, 2005
  • #4
Damn... that a buck out the window.

Have you already checked the harness going to the dizzy? Maybe one of the pins was pushed back.
 

stang22

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#5
  • May 7, 2005
  • #5
Yeah, I just pulled it off and double checked everything. There's gotta be a fusable link that I missing or something. Very frustrating!

With the key on, should the red/green wire going to the TFI have 12v's as well?
 
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Daggar

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  • May 7, 2005
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I will check and get right back to you.
 

stang22

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If the PIP in the dizzy is bad, would the coil stop firing?
 
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Daggar

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Here's what I got with the plug disconnected and the Key on:

Blue: 4.26v
Yellow: 12
Red/wht: 0
Red/Grn: 12
Grn/wht: 12
Blk/red: 4.75
 
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Daggar

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#9
  • May 7, 2005
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stang22 said:
If the PIP in the dizzy is bad, would the coil stop firing?
Click to expand...

Yes... I believe that it would. How else would it know "when" to fire?
 

stang22

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#10
  • May 7, 2005
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My wires are different colors, but my/your green-white (mine looks like a tan wire) wire is only pulling 1.5 something volts and yours was pulling 12volts. If you are looking at the TFI connected, it is the 5th wire towards the bottom. Am I on to something yet?
 

stang22

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#11
  • May 7, 2005
  • #11
I found the wire in the diagram, but not sure what eng supres is? What does it look like?

Tim

View attachment 515289
 
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Daggar

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#12
  • May 7, 2005
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As I listed them... it's top down.
 

5.0Droptop

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#13
  • May 7, 2005
  • #13
swap the dizzy out.
 

stang22

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#14
  • May 7, 2005
  • #14
No spare dizzy my friend...

Tim
 

jrichker

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May 7, 2005
#15
  • May 7, 2005
  • #15
Crank then engine up to TDC so that the timing pointer & timing marks line up. Mark the distributor & engine block with a scribe or chisel so that you know exactly where they line up.

Loosen the distributor hold down bolt & turn the ignition switch to Run. Pull the high voltage coil wire out and hold it near the block. Twist the distributor back and forth. You should be able to make a god, fat blue spark if everything is working correctly. This saves the aggravation of having to crank the engine to do the test. When you are done testing, line the marks back up & tighten down the hold down bolt.

here's some troubleshooting help...

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

1.) Remove push on connector from starter solenoid and turn ignition switch on. Place car in neutral or Park. Remove coil wire from distributor & and hold 3/8” away from engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.
No spark, possible failed items in order of their probability:
A.) MSD or Crane ignition box if so equipped
B.) Coil
C.) TFI module
D.) PIP sensor in distributor
E.) ECC relay next to computer - look for 12 volts at the fuel injector red wires
F.) Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire.
H.) Computer

See the following links for wiring diagrams...

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model cars


2.) Spark at coil wire, pull #1 plug wire off at the spark plug and check to see spark. No spark, possible failed items in order of their probability:
A.) Moisture inside distributor – remove cap, dry off & spray with WD40
B.) Distributor cap
C.) Rotor
D.) Spark Plug wires
E.) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil

3.) Spark at spark plug, but no start.
Next, get a can of starting fluid (ether) from your local auto parts store: costs a $1.30 or so. Then pull the air duct off at the throttle body elbow, open the throttle, and spray the ether in it. Reconnect the air duct and try to start the car. Do not try to start the car without reconnecting the air duct.
Two reasons:
1.) If it backfires, the chance for a serious fire is increased.
2.) On Mass Air cars, the computer needs to measure the MAF flow once the engine starts.
If it starts then, you have a fuel management issue. Continue the checklist with emphasis of fuel related items that follow. If it doesn’t, then it is a computer or timing issue: see Step 4.

Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 5-20 seconds and shut off. To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground. See http://www.mustangworks.com/article...c-iv_codes.html for a description of the test connector. If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. Beware of fire hazard when you do this. In pinch you can use a tire pressure gauge to measure the fuel pressure. It may not be completely accurate, but you will have some clue as to how much pressure you have.

No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – Coupe & hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay. The fuse links live in the wiring harness near the starter solenoid.
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

Fuel pressure OK, the injectors are not firing.

A.) A Noid light available from Autozone, is one way to test the injector wiring.
B.) I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.

a.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
b.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
c.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the ECC relay and the red wire for the 10 pin connectors.


4.) Spark & fuel pressure OK.

A.) Failed IAB (no airflow to start engine). Press the throttle ¼ way down and try to start the car.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off: only likely if the engine has been worked on recently).
D.) Firing order off: HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8
E.) No start when hot - Press the throttle to the floor & try starting it if you get this far. If it starts, replace the ECT.
 
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Daggar

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#16
  • May 7, 2005
  • #16
Thanks Jr... I was hoping you'd come along. The search wasn't helping much. hehe
 

stang22

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May 7, 2005
#17
  • May 7, 2005
  • #17
Where does the ground wire on the coil get its ground from? With the key off, it was pulling .037 ohms at the 2k setting on my multi-meter if I said/did it right.

JR, is the tan-yellow wire that goes to the coil the same one that goes to the TFI? If they are, the one going to the coil is pulling 12 volts and the one to the TFI is only pulling 1.5 volts. Thanks guys!

Tim
 

stang22

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Jan 29, 2003
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Washington, D.C.
May 7, 2005
#18
  • May 7, 2005
  • #18
I guess now the mystery is why the tan-yellow wire going to the TFI is not pulling 12 volts.
 

HISSIN50

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Nov 29, 1999
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May 7, 2005
#19
  • May 7, 2005
  • #19
stang22 said:
Where does the ground wire on the coil get its ground from? With the key off, it was pulling .037 ohms at the 2k setting on my multi-meter if I said/did it right.
Click to expand...
Tim, I think that the neg side of the coil connector gets ground from the TFI (the ground pulse lights off the coil). I would check with JR first (to be sure).

good luck.
 

stang22

Active Member
Jan 29, 2003
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May 7, 2005
#20
  • May 7, 2005
  • #20
Ok, I just went and re-checked the power to the coil and it is pulling 1.55 volts, which is the same amount as the wire going to the TFI. Hmmmm... It should be getting 12 volts, but what could be wrong?

Tim
 
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