[damien98gt]

I hope that someone can help me on this one. My Mustang isn't allowing spark on initial crank. If Crank it over then let it set with the key on for 20 to 30 seconds it will start. When it is cold the problem worsens some days I can't get it to start at all. It cranks fine and I know that I am getting fuel. I have changed the crank position sensor and still not any better. Please any other guidance would be greatly appreciated

 

[mustang87will]

do you have any check engine codes?

 

[damien98gt]

o2

I am getting a trouble code for the B1S1 O2 sensor. But from what I have read and understand that should not be part of a start permissive for the coils

 

[damien98gt]

New O2 sensor

I picked up a new o2 sensor today and will get it in this weekend. I did check for fuel at the valve at the end of the rail and had good pressure. Still thrown that it is worse when it is cold. If there is a cam sensor also where is it on the engine?

 

[damien98gt]

Replaced O2 Still not getting fire

Well I replaced the O2 Sensor. Cleared my trouble code but the car still will not get spark initially. It STILL has a long delay before i am getting any fire. I guess the next thing to throw money at is a new key, maybe it's a PATS issue

 

[wmburns]

FWIIW, a bad O2 sensor will not cause a no-start.

Confirm that all fuses in the engine bay and passenger compartment are good.

It is NOT a PATS issue. For the 1996-1998 Model year, PATS disables the starter. This gives a no-crank. For the 1999-2004 Model Year, PATS disables fuel and spark. This causes a crank with no-start.

To confirm, what is the Theft light doing? Turn the key to the run possition (do not start). Does the theft light go out after a 3 second "prove out"? Does the theft light blink during cranking?

Try this. Hold the throttle half way open during cranking. Does this improve starting? If yes, suspect a bad IAC.

Next, disconnect the MAF. Does this improve starting? If yes, suspect a bad MAF. Note, this trick works becuase the PCM uses default values to replace the missing sensor data.

The cam sensor is not normally associated with a no-start condition. But it couldn't hurt to try. The cam sensor is right behind the power steering res.

Not a bad idea to get a "noid" style testing light. HarborFreight has in inexpensive set. Test the fuel injectors for a pulse during cranking.

A spark tester can be used to verify spark. The noid tester can also confirm if the coil packs are getting a spark signal from the PCM.

The crank shaft position sensor (CKP) can cause a no-start. Two quick tests of the CKP. Does the RPM (tach) bounce during cranking? Does the check engine light blink during cranking? Better yet, monitor RPM's with an ODB2 scanner. If the RPM's change during cranking, the PCM is seeing a good CKP signal.

Post up the test results and let's go where the tests point.

 

[damien98gt]

I came up with a mac tools obdII scanner and was not showing rpm while cranking. I replaced the crank and cam sensors and still am not showing rpm initially. I also unplugged the maf sensor and still no change. As the weather is getting colder it is taking alot longer before i get the engine to fire. i am taking it to a local mech to see if they show anything my palm scanner isn't.
Let me know if you have any other ideas. I plan on replacing the coil packs, plugs and wires next

 

[wmburns]

You are wasting your time/$$ replacing coil packs and wires as the clue to your problem is in your post.

If the ODB2 tool is not showing RPM's, that means the PCM is not receiving a signal from the crank shaft position sensor (CKP). The mising CKP signal is a NO-START sensor.

No CKP means No spark, No fuel, No start.

Since the CKP is new, look for a problem with the wiring to the CKP sensor. Check the connector itself for loose/bent/pushed pins. Check for corrosion in the connector itself. Remember, the CKP signal is very small. It doesn't take much to upset it.

It may be necessary to pull the PCM and test out the wiring harness from the connector back to the PCM.

Test the Red (RD) wire on the injectors for +12 volts. If no voltage, STOP. There is an electrical problem in the VPWR engine buss. The 98 MY cars have a different method to distribute power to the engine. The power is routed through the PCM. This means that an electrical problem is more likely to fry the PCM. However, in your case, the PCM is obviously talking to the ODB2 scanner. So the PCM is functional at some level.

Test the R/LG wire on the low voltage side the the coil packs. An easy place to access the R/LG wire is at the radio interference capacitors. There must be +12 volts with the key on. If no voltage, STOP and find out why.

Double check your fuses. All of them. Then go back and throughly inspect the wiring harness from the CKP back.

Put an AC Volt-Ohm meter on the CKP set on the AC scale. You should be able to measure a small AC voltage from the CKP while cranking.

 

[damien98gt]

Thanks for all the help I will let you know how it goes