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Why are the injectors cycling

Tiny
COLUMBUSA
  • MEMBER
  • 2005 SCION TC
  • 135,000 MILES
My son's 2005 Scion TC has injector issues. They are not spraying. I have replaced the fuel pump (It was not putting sufficent pressure out) and insured that the line was clear. I had the injectors bench tested and rebuilt. There is fuel to the bar. What would prevent the computer from cycling the injectors at the proper time.
FWIW- he noted that the problem has been getting worse with time (harder to start each morning over about a 1 week period) and now it completely will not start. Also- when I pulled the bar/injector assembly some fuel leak around the ports---it actually tried to start for a moment.
Thanks
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Saturday, June 16th, 2012 AT 12:42 PM

12 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
A faulty cam sensor circuit or PCM would result in no pulsing of the injectors.

Did you check for trouble codes?
Is the MIL indicating?
Did you test the fuel pressure at fuel rail?
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Saturday, June 16th, 2012 AT 12:54 PM
Tiny
COLUMBUSA
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There were no 'check engine' lights on- so I didn't go there. I'm not sure what a 'MIL' is-
Fuel pressure at the rail is excellent- now. The cam sensor was kinda what I was thinking after some research.
I'm old school (points- condensor, plugs and carbs) just never made the transition over to computer based stuff.
Will a standard OBD reader do the job or is there a special model I'll need?
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Saturday, June 16th, 2012 AT 1:42 PM
Tiny
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The other thing was that the problem was slow in onset- I would have thought that something electrical (ie a sensor) going out would have been sudden and complete.
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Saturday, June 16th, 2012 AT 1:45 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
It could just be a dirty sensor, contaminations to the wire connectors or the pickup of the sensor has a fault. Try checking the connectors and note if there are any contaminations.

MIL = Malfunction Indicator Light = Check Engine Light.

Not all code readers works and if it does, it would only tell you if trouble codes are there.

A proper scan tool would be able to show you more.

Btw I am old school too but had to keep up with the times in order to survive, not an option to stay old school. Lol.
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Saturday, June 16th, 2012 AT 1:58 PM
Tiny
COLUMBUSA
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  • 6 POSTS
Okie-Dokie, went and rented a scanner from O'riely's---
"P0453
Evaporative Emission
System Pressure
Sensor/Switch High
input"
Is what the scanner reported. Ive checked all the connections at what I think is the device. Nothing seems to be out of place. Is there a way to test this thing or is it replace only?
Thanks-
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Saturday, June 16th, 2012 AT 2:34 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
I thought most parts stores provides free scanning services?

Anyway I never believed in replacing components without confirming if they are faulty.

The file for this is rather large and not convenient for me to post here. Let me have an email address that I can send to in PDF format.
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Saturday, June 16th, 2012 AT 3:16 PM
Tiny
COLUMBUSA
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EF1Nobles@gmail. Com

FWIW---I bought a Noid light set. They ain't flashing! LOL
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Saturday, June 16th, 2012 AT 5:42 PM
Tiny
KHLOW2008
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That can mean a bad PCM or it is not getting the signal to fire the injectors.

I just sent the filers, hope it can get through correctly. I sometimes cannot send files that are too large.
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Saturday, June 16th, 2012 AT 6:01 PM
Tiny
COLUMBUSA
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What is PCM? Pollution control module?
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Saturday, June 16th, 2012 AT 6:07 PM
Tiny
RASMATAZ
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Its the computer ( Powertrain Control Module ) lol> Pollution
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Saturday, June 16th, 2012 AT 6:15 PM
Tiny
KHLOW2008
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Hey Jess, Check this out, lol.

https://www.2carpros.com/questions/1997-ford-mustang-does-car-start-stall-unless-giving-gas-after-changed-manifold
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Saturday, June 16th, 2012 AT 6:26 PM
Tiny
RASMATAZ
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Lol-I dunno anymore-they don't listen, they don't learn-you're beginning to pick-up on my bad habits-lol BTW thanks for all the back-ups-You take care and God Bless-
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Saturday, June 16th, 2012 AT 7:03 PM

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