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z24 dead cylinders


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garycoleman
Novice

Mar 28, 2014, 10:16 AM

Post #1 of 13 (1449 views)
  post locked   z24 dead cylinders  

I have a 98 z24 2.4 twin cam the car sat for maybe 2 weeks and I go to drive it one day and its not getting fire from coil to 1 and 4 cylinders p0300 multiple misfire rebuilt motor @ +/- 80xxx I replaced pcm ckp cmp icm plugs coil housing getting 12v to coils I'm sure its electrical unfortunately I'm not to familiar with ignition or electrical systems I checked the timing everything seems to line up but the car is heavly modified shops wont touch it


kev2
Veteran
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Mar 28, 2014, 10:27 AM

Post #2 of 13 (1441 views)
  post locked   Re: z24 dead cylinders  

  the answer STOCK is best is a little late,,,


swap coils see if issue moves to other cylinders... the issue is likely in the coil mounting to the cover OR a loose wire at the 1-4 connector....


garycoleman
Novice

Mar 28, 2014, 10:33 AM

Post #3 of 13 (1440 views)
  post locked   Re: z24 dead cylinders  

I tried that and a new coil housing


kev2
Veteran
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Mar 28, 2014, 10:53 AM

Post #4 of 13 (1434 views)
  post locked   Re: z24 dead cylinders  

then we need to confirm 12v at coil connector, and check the other wire for the switching signal - noid light- are often used to do this - it should flash when cranking...

Do you need wire colors? - really it just 2 one will have the 12v the other is the switching, the switching should NOT be grounded- it will pulse to ground when the PCM fires 1-4


garycoleman
Novice

Mar 28, 2014, 1:35 PM

Post #5 of 13 (1422 views)
  post locked   Re: z24 dead cylinders  

I don't know what a noid light is or how to use it and exactly what wires and how to test each wire


kev2
Veteran
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Mar 28, 2014, 1:42 PM

Post #6 of 13 (1415 views)
  post locked   Re: z24 dead cylinders  

  I do not know how to advise other than seek the services of a technician. This is basic technician skills- circuit testing and diagnosing


garycoleman
Novice

Mar 28, 2014, 1:44 PM

Post #7 of 13 (1413 views)
  post locked   Re: z24 dead cylinders  

Could I just use a regular power tester and I believe its a orange and white wire that runs from pcm to icm correct?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 28, 2014, 1:52 PM

Post #8 of 13 (1409 views)
  post locked   Re: z24 dead cylinders  

You're not checking power. You're checking pulsing ground on a very low impedance circuit. Just using an incandecent bulb can take out your computer or ICM.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



garycoleman
Novice

Mar 28, 2014, 4:39 PM

Post #9 of 13 (1398 views)
  post locked   Re: z24 dead cylinders  

So this noid light will just confirm I'm not geting signal.


garycoleman
Novice

Mar 28, 2014, 5:32 PM

Post #10 of 13 (1393 views)
  post locked   Re: z24 dead cylinders  

Where can I get a noid light and where would I perform the test on the wiring


Discretesignals
Ultimate Carjunky / Moderator
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Mar 28, 2014, 5:34 PM

Post #11 of 13 (1393 views)
  post locked   Re: z24 dead cylinders  

Don't think you should use a NOID light on IC control circuits that goes between the ICM and the PCM.


The PCM signals the ICM to fire the coils. There are two circuits one is 1-4 IC and the other is 2-3. It is going to be digital signals of either 5 or 12 V. Either the PCM will pull up or pull down those circuits.

You can actually do a bypass test using a 12 volt test lamp on the IC circuits to see if the ICM fires the coils. That tests everything underneath the coil cartridge. If you can get the 1-4 coil to fire doing the bypass test, that leaves input, PCM, or wiring from the PCM to the ICM.

The only way your going to test inputs, such as cam and crank sensor signals, is with a lab scope or graphing meter.

Here is a video on bypass testing and ignition control testing (very good information if you can understand it):

http://www.youtube.com/watch?v=jJmqdhhduVc

http://www.youtube.com/watch?v=VG3EZJlyjl8





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 28, 2014, 5:42 PM)


garycoleman
Novice

Mar 30, 2014, 7:37 AM

Post #12 of 13 (1359 views)
  post locked   Re: z24 dead cylinders  

That info was very informative for future reference but turns out coil negative white wire on harness pcm/icm ( for coil 1&4 cyl.) been spliced prior to me owning the car and came apart somehow, but the car is firing proper and running as it did before. Thanks again for the help Tec.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 30, 2014, 8:27 AM

Post #13 of 13 (1355 views)
  post locked   Re: z24 dead cylinders  

Good find. Trust you did a quality splice so that isn't a routine issue. I'll close this thread as solved to keep spammers out and you can ask any moderator to open it upon request,


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