What would cause my injectors not to fire all of a sudden?

[SinisterX]

I assume it's the injectors. Just did the tune Wed, drove it Thurs and yesterday.
Drove the car, parked it. Went to start it an hour later and it cranks, has spark, fuel to the rails but the injectors wont squirt at least from what I can hear.
All fuses under dash and in box under hood are good.

I have a return fuel set up

 

[wjurls]

Perhaps a bad TPS is sending a WOT signal to the PCM?

 

[SinisterX]

good ? how can I tell. I just took a test light and there is power going to the injectors. Something is keeping them from firing

 

[04fivefour]

got a noid light you can plug into the one of the injector connector's?

 

[SinisterX]

I can get a injector light

 

[cobracide]

Check the ecu for error codes.

 

[wjurls]

Doubt the problem is your injectors dude. They may not be firing but if they aren't the problem lies elsewhere. An injector light is a noid light. It plugs into the injectors harness and will flash to indicate the pulsed signal to the injector. The injectors are always supplied 12V on the red wire and the white or tan (depends on which side) will get a pulsed signal from the PCM. If a noid shows an injector signal and you have fuel pressure you can move onto a spark problem. If no noid activity test your TPS for a wide open throttle signal. With the key on back probe pin 2 on the TPS harness. (the middle wire thats gray with white stripe) and clip the ground probe to ground you should read around .98 volts with the throttle closed and about 4.5V with the throttle wide open. Do NOT!!! use a regular test light on any engine circuit on a modern car. Many outputs from the PCM cannot handle the current draw of an incandescent light and you could burn up the cars computer. Use a DMM or a LED style test light only.

Good luck

 

[KILRSVT]

+1with ^^^^ if the noid light does not pulse...it can be a bad pcm....the transitors could have fail (worse case scenario). how do you know the injectors arent firing....other than by sound. perhaps it could have to do with the tune. i have heard of cars dying and stalling after getting tuned..if there are no codes i would talk to the tuner.

 

[SinisterX]

I only assume the injectors arn't firing b/c I smell no gas after long engine cranks, and I do have spark.
wjurls ill try the TPS tests this week.
When I was letting the car idol to cool the turbos, I did notice my idol was high, about 400 rpms higher than usual. I fiddled w/ the TB and peddle with no change. Then I shut it off and an hour later I had this problem

 

[SnakeBit]

Put a fuel pressure guage on the schrader valve and verify that you have adequate fuel pressure.

 

[hotcobra03]

no start

didnt know that about a test lite:shrug:

your fuel pump should come on to prime systems,,do you hear it?

what was used to tune your car,,even though it did run for a short time,,your pats system could be causing the no start,,it shuts down spark fuel and cranking,,,,at different times,,,maybe you need to put back the factory tune to than start over,,

see if this works for you download it and it opens with windows word pad.its from the ford service manual

https://share.acrobat.com/adc/document.do?docid=5981648c-0067-4f1a-961e-b9475154f136

 

[hotcobra03]

pintest A1

https://share.acrobat.com/adc/document.do?docid=09e5d19d-c40f-407c-815e-432a6b78b24f

 

[SinisterX]

Fuel piump is a A1000, I can sure hear it alright. YOu can hear the fuel pushing thru the Y block under the hood. So I know that's not the problem.
hotcobra03 thanks for the links anything helps at this point.

 

[SinisterX]

I have a switch chip, I have the newest tune on when it crapped the bed and I have the old tune saved on slot two before the changes where made. Do I need to disconect the battery and reset the PCM in order to try the previous tune?

 

[SinisterX]

hotcobra03, those links only tell me the section to look up[ the problem. It don't take to the section to show mw what to do

 

[hotcobra03]

test

hotcobra03, those links only tell me the section to look up[ the problem. It don't take to the section to show mw what to do

the second link does,but its only acouple of them,first one is charts...

fuel/ignition is chart 3...it says go to pin test a1.

second link has pin test a..

 

[SinisterX]

Noid light showed the injectors are not firing, tested the TPS and unplugged the voltage was a ok, plugged in the voltage was really outta whack. So I'm hopping a new TPS does the trick.
Anyone else think so?

 

[hotcobra03]

no start

does it start with the tps unplugged? i just tryed it on my 03 cobra and it started

 

[hotcobra03]

no start

if it doesnt start go to pin test a1,,

those test need to be done in order or you will spend alot of money for nothing,,also thier is a test for the pats,,that little red lite on the dash blinks,,,,keep us posted

 

[hotcobra03]

pats system diagnostic

[ame="http://www.scribd.com/doc/11145204/PATS-Troubleshooting-DIAGNOSTIC-Service-Tips"]PATS Troubleshooting: DIAGNOSTIC Service Tips@@AMEPARAM@@/docinfo/11145204?access_key=key-2f0d8ldmyoh4ruubtqbe@@AMEPARAM@@11145204@@AMEPARAM@@key-2f0d8ldmyoh4ruubtqbe[/ame]