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Diagnosing the pcm

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Old Jan 13, 2010 | 12:22 AM
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canuck94z28's Avatar
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Question Diagnosing the pcm

My 94 cranks but doesn,t start.I can hear pump when i turn key & there is fuel reaching the scrader valve connection.I also sprayed starting fluid into the throttle bores& it still didn,t start!.My ? is how to determine that the pcm is bad?What about plugging in another computer?Btw i do have spark.Any ideas are appreciated.
Old Jan 13, 2010 | 05:24 AM
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Have you scanned the PCM for codes?
Old Jan 13, 2010 | 08:20 AM
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Maybe its the opti or coil? Maybe u have a broken rotor inside of the opti or a bad ICM, Did the car just stop running or was there any stumble or missfire prior to the no start condition? How is the spark? Is it random or is it steady while cranking? Need more info.

Last edited by mightymouse383; Jan 13, 2010 at 08:23 AM.
Old Jan 15, 2010 | 08:15 AM
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Originally Posted by mightymouse383
Need more info.
What he said.
Old Jan 15, 2010 | 11:19 AM
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Originally Posted by Injuneer
Have you scanned the PCM for codes?
On my scanmaster no codes are shown.
Old Jan 15, 2010 | 11:50 AM
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Originally Posted by mightymouse383
Maybe its the opti or coil? Maybe u have a broken rotor inside of the opti or a bad ICM, Did the car just stop running or was there any stumble or missfire prior to the no start condition? How is the spark? Is it random or is it steady while cranking? Need more info.
I put in a opti/coil in summer 08.I ran car @local track in Sep 09&trap speed was 101.15(8 passes)&everything seemed good.I drove car from work to the storage yard Oct.12 which inc. some high speed driving&again car ran great.I went to store car a week later &that when problem started.I hooked up some spark leads&spark was steady,i even tried w/o my MSD 6a;everything good.Btw how to do you test the ICM?I also have a 94 camaro shop manual(x2)that someone said has a step/step diagnostic way to test pcm,does anyone know what page it,s on?I will keep you guys updated&thanks again.
Old Jan 15, 2010 | 05:04 PM
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You can go to shoebox's web page it has a large amount of troubleshooting proceedures and tech info. http://shbox.com/page/index.html

I think you can take the ICM of off the engine and take it to your local auto parts store and they should be able to test it, If u have i multimeter u might be able to test it.....I think shoebox has some instructions on how to test the opti curcuit.

Last edited by mightymouse383; Jan 15, 2010 at 05:08 PM.
Old Jan 21, 2010 | 01:14 PM
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Thnx. for the replies.I, m going to hook a fuel pressure gauge to that schrader valve &chk. that pressure.There seemed to be very little fuel that squirted from that port when checked.
Old Mar 29, 2010 | 01:45 AM
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The icm chk,d out ok a local auto parts store.I bought another coil& car started up right away like it hasn,t for yrs.So yes, that Msd coil i installed was garbage& might have been causing drivability issues b/f& then completely died last Oct causing a no-start cond.This was completely different from car starting then stalling for no reason.
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