Cranks but no start.....Have a ?

[ram360]

I have no spark at my coil wire. I had my coil tested. They said it was bad so I bought another....but It still wouldn't start (I had the new coil tested and it was fine)

Replaced the TFI even though the one on the car tested fine.

Replaced the pick-coil.

The computer is brand new (not sure if I can have this tested to make sure it's not faulty?) .

If all the above is good (which it should be since it's all new) I guess that leaves me with the following.........BTW I'm using Jrichker's helpful tutorial but just want to make sure I check the rest of the stuff out the right way.

ECC relay next to computer - look for 12 volts at the fuel injector red wires

Fuse links in wiring harness - look for 12 volts at the fuel injector red wires

Ignition switch - look for 12 volts at the fuel injector red wires

I'm somewhat confused? If I have 12 volts at the red FI wires then that means the eec relay, ignition switch, and fuse links in the harness are all ok?

 

[jrichker]

Yes, provided your car is a 87-93 model.

Following diagram courtsey Tmoss (diagram designer) & Stang&2Birds (website host)

 

[ram360]

I have 12v at the red fuel injector wire (I only checked the #5 injector) w/ the key in the run position.... Should I have the key there or should I be cranking the car and checking the the volts then? Thanks!

 

[ironmedic]

have you taken your distributor apart to see if anything fell apart in there?

 

[jrichker]

Use a noid tester to test & see if the PIP is sending signals to the computer to tell it to turn on the injectors. If the nold lamp flashes, the Distributor is working OK. The computer pulls the tan/yellow wire to ground to fire the coil. Look for 12 volts at the red/lt green wire. Look for the tan/yellow wire to pulse between 12 volts & ground.
see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif for a diagram

 

[ram360]

Use a noid tester to test & see if the PIP is sending signals to the computer to tell it to turn on the injectors. If the nold lamp flashes, the Distributor is working OK. The computer pulls the tan/yellow wire to ground to fire the coil. Look for 12 volts at the red/lt green wire. Look for the tan/yellow wire to pulse between 12 volts & ground.
see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif for a diagram

Ok, here's a few dumb questions.... What is a noid tester? Is it just another name for a test light? Is the PIP the distributor pick-up ? Should I be cranking the car to make the noid light flash? Sorry for all the questions....I've never been very good w/ troubleshooting electrical. So far this car has me . Thanks!

 

[ram360]

The red/lt. green running to the coil had 12v. (w/ key in run position)

I think the Autozone diagram is wrong. They are showing that tan/yel wiring running to the other side of the coil but I think it's suposed to be grn/yel (both my 88 and 89 wiring have the grn/yel wire there instead) I tried this wire w/ the key also in the run position and I got a constant 1.7v???

 

[jrichker]

Ok, here's a few dumb questions.... What is a noid tester? Is it just another name for a test light? Is the PIP the distributor pick-up ? Should I be cranking the car to make the noid light flash? Sorry for all the questions....I've never been very good w/ troubleshooting electrical. So far this car has me . Thanks!

Noid light is a test lamp that plugs into the injector harness. Its most common use is to test to see if the injector lead it is plugged into is firing.

The pip or hall effect sensor is located inside the distributor. It has a magnet, a shutter wheel and a sensor that detects when the magnet is uncovered by the rotation of the shutter wheel.

Cranking the car with the ignition on makes the pip send pulses to the computer, which in turn pulses the noid light if the pip & wiring is good. You can use a test light with on lead on the battery and the other on the tan/lt green wire attached to the coil to see if the computer is telling the coil to fire.

Since you aren't geeting any spark, it is pretty obvious that it isn't making a ground to fire the coil. That leaves only five possiblites:

1.) the computer is not receiving a signal to tell it to provide a ground to fire the coil.

2.) there is no power to the coil or computer. Look for 12 volts on both of them, as they are fed by different power paths.

3.) the wiring to the coil or from the TFI module is bad

4.) no pip signal or the TFI is bad.

5.) the computer is defective

Some of these things you have already eliminated as possiblities.

The computer is getting power since there is 12 volts on the read wire: that elminates no power to the computer as being a problem.

 

[ram360]

Computer is getting power-----yes, 12v at red fuel injector wire

Coil Getting power-----yes, red/lt green wire has 12v w/ key in run, and start

I hooked up the test light w/ one lead on the + battery terminal and the other lead connected to the tan/ lt green wire connected to the coil. I had nothing w/ the key in the run postition but when I started cranking the car it lit up. It appeared to be blinking really fast. So does this mean my computer, wiring, TFI and pip are good?

I'm totally lost now. Everything seems to test out fine and it still doesn't have spark. I think that eliminates everything on the list I'm going to re-test everything again just to make sure. Thanks for the help so far.

 

[jrichker]

Computer is getting power-----yes, 12v at red fuel injector wire

Coil Getting power-----yes, red/lt green wire has 12v w/ key in run, and start

I hooked up the test light w/ one lead on the + battery terminal and the other lead connected to the tan/ lt green wire connected to the coil. I had nothing w/ the key in the run postition but when I started cranking the car it lit up. It appeared to be blinking really fast. So does this mean my computer, wiring, TFI and pip are good?

I'm totally lost now. Everything seems to test out fine and it still doesn't have spark. I think that eliminates everything on the list I'm going to re-test everything again just to make sure. Thanks for the help so far.

Pip, computer & TFI are switching on and off like they should. I would power up the coil and ground the other side and look for a spark from the high volt output (wire that goes to the distributor). Look for a big fat blue spark at least 3/8"-1/2" long.

The only time I have had a similar experience, the coil was bad.

 

[ar1424]

I have no spark at my coil wire. I had my coil tested. They said it was bad so I bought another....but It still wouldn't start (I had the new coil tested and it was fine)

Replaced the TFI even though the one on the car tested fine.

Replaced the pick-coil.

The computer is brand new (not sure if I can have this tested to make sure it's not faulty?) .

If all the above is good (which it should be since it's all new) I guess that leaves me with the following.........BTW I'm using Jrichker's helpful tutorial but just want to make sure I check the rest of the stuff out the right way.

ECC relay next to computer - look for 12 volts at the fuel injector red wires

Fuse links in wiring harness - look for 12 volts at the fuel injector red wires

Ignition switch - look for 12 volts at the fuel injector red wires

I'm somewhat confused? If I have 12 volts at the red FI wires then that means the eec relay, ignition switch, and fuse links in the harness are all ok?

I just completed my 5.0 EFI swap. I have the same problem, but when I pulled out the timing spout connector it start and idle pretty good and with a base timing of 10* BTDC.

You may want to disconnect your spout and see if it start.

And if you solve your problem can you please post it in this forum? I stiil want to fix my problem. I heard some people do not have their spout pluged with out problem. If I can't fixed my problem I just leave the spout off.

 

[ram360]

Pip, computer & TFI are switching on and off like they should. I would power up the coil and ground the other side and look for a spark from the high volt output (wire that goes to the distributor). Look for a big fat blue spark at least 3/8"-1/2" long.

The only time I have had a similar experience, the coil was bad.

Ok, I'll give that a try. I might just take the coil out of the other stang and drop it in this car. I know everything is fine because that one starts right up. Thanks for all the help!

 

[ram360]

I just completed my 5.0 EFI swap. I have the same problem, but when I pulled out the timing spout connector it start and idle pretty good and with a base timing of 10* BTDC.

You may want to disconnect your spout and see if it start.

And if you solve your problem can you please post it in this forum? I stiil want to fix my problem. I heard some people do not have their spout pluged with out problem. If I can't fixed my problem I just leave the spout off.

I'll definetly let you know when I get this fixed. I haven't tried it w/ the spout disconnected but it's worth a shot.