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so far i've replaced the crank sensor, cam sensor and the icm and still nothing. i have also tried the re learn process incase of a security issue and still no luck. It's getting fuel and turning over normal but no spark, any ideas of what else it can be?
 

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Any codes stored in the PCM?
 

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The ignition pulses for spark originate in the PCM. You may have to trace the signals from the PCM to the ICM. Be very certain that you have good grounds and power connections to all components. Clean and tighten them, including the Positive Post nad Ground to Chassis...a tough one...Good Luck..KEV
 

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From my perspective you should probably have a "known good" shop (not a dealership for your pocket book's sake) do a diagnostic on your ride. They will have a good scanner.....snap on, otc, tech 2/3, etc. Also, it would be most helpful to know if any work was done before this started happening or if there were any strange or different things going on before this started.

Good luck, Jake L.
 

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I believe the fuel pump relay has to be initiated to get the command for firing the pulses to the ICM from the PCM. If you are certain your fuel pump runs with ignition ON, the PCM may be suspect. It is unlikely that you may have replaced the crank or cam sensor or ICM , and had a new DOA part. However, I worked on expensive blood analyzers for about 8 years in my past and had my share of DOA parts.
Please let us know what resolved your problem. I know how frustrating it is to troubleshoot difficult problems. Good advice from Jakesq. Best of luck to you..KEV
 

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I am in the same boat with my sons 97 Pontiac GPT....it just shut down one day on his way to work. No spark at all and no codes. I replaced Crack sensor, he wanted a better PCM so he went ahead and replaced that as well. His Ignition module was fairly new but we went ahead and swapped it on warranty since it was free.
I am not sure what the heck is going on now and I am done throwing parts at it. Where are the grounds located that I should be checking? I will have a look at those to see if that may be the problem.
 

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Hi Todmac!

In response to your sons GTP, look at my previous post on fuel pressure. You must make certain that the fuel pump relay is working or you may not get commanded spark. I cannot say for certain, but I think that is the case.

Start at the battery ground to the subframe. Remove and clean it wery well and sand the sub frame around the bolt. I do not know the easy locations of others, but I have seen a lot of weird problems get resolved, including my car , with starting with the basics. Really, best of luck with you both on this difficult problem...cheers KEV
 

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The ICM grounds to the bracket it is bolted to.
There is a ground in the ckp/cmp/icm harness that goes to a stud on the ICM/supercharger bracket.
I added a 14g jumper from the ICM stud/bolt to that location as well during rebuild.
 

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Thanks for the info, I will take a look this evening at grounds. On the fuel pressure idea, I have switched out the relay with a matching one that worked. I can smell fuel when we crank so she is getting fuel but absolutely zero spark. I will let ya know what we find. Thanks Again!
 

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Well to throw another iron in the fire, my son just informed me that the car doesnt display any of the warnining-idiot lights when he first turns on the key. I checked the battery ground and its good at the frame, not loose at all. I did not see any ground from the harness between icm and pcm that ran to the supercharger anywhere so Im not sure if that is specific to some years maybe?

I talked to another guy today and he said there is a body control module that can fail out...anyone got any experience with those? Could it cause loss of fire at all?

Mark- didnt mean to threadjack ya! I was hoping we would come across some shared info that helped us..LOL I am guessing you are not having any luck with yours either?

Todd
 

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There may be the possibility of the security system not allowing spark. I do not know if it controls spark or fuel. I am not certain if the vats security system is on the body control module, but I think that is a strong possibility.
NO warning lights?...if not the BCM, again look at the grounds and possibly power distribution....when I get a problem that bad, I say a prayer to St. Anthony!!! ...especially since i always need my car running!!! again good luck KEV
 

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Just a thought, could it be the Ignition switch??????
It is what is common between the idiot lights and the ignition system.
I have had bad ignition switches burn the points up in my old SBC's.
Good Luck!
Bryan
 

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The ground isn't on the supercharger,it is on the tensioner bracket kinda to the left/firewall side of the SC tensioner.
There are 3 studs/bolts holding on the bracket iirc and it is the far left one pretty sure,i'll take a pic for you.

With the new info though,I would lean towards montana's suggestion of verifying ignition switch.
The PCM will shut off injectors or starter generally,not spark.

I would test the switch,but cluster issues are common enough on these and will cause wacky readings and dead lights also.
My wife's is wacked out like that now and need to yank for friend to rebuild,common on GM clusters.
 

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Mark, 1st question is what is the year, make and model? The L67 was used from 1996-2005 in many different vehicles.

To clear some misleading information up. The fuel pump and fuel pressure have nothing to do with the vehicle having spark or not. During cranking the PCM does not control spark, unless of course you have a security issue that can disable spark. During cranking the Ignition Control Module controls all spark from the signals received from the Crank sensor.

You need to check your Ignition Control module power and grounds, as well as the circuits to the crank shaft position sensor.

Todd, In response to your 1997 GP-- The BCM has no say in whether the car runs or not! There is active theft system on the 1997, and even with the BCM disconnected the car will still start in run.

From the sound of things you may have a power or ground issue. Be sure to check all of the fuses in the under hood fuse block and inside. Pay close attention to the large maxi fuses underhood. The ignition switches on these vehicles is a common failure. If all of the fuses are good, test your power and ground at the ICM as well.

Good Luck guys! Hope this information helps. If you need wiring diagrams let me know.
 

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Howdy gang, Didn't have a lot of time today to mess with the GTP but I did run thru the full security system reset since his alarm light was flashing all the time....it corrected the alarm issue LOL However still no spark.

I will check the grounds tomorrow off of the tensioner bracket location. I also wondered if this car 97 GTP has a 2nd cps on the back of the engine? I saw that somewhere on another forum but it wasnt the same year and Im not sure if that one could keep it from getting spark since.

Ignition switch does sound like a possible issue based on some of the comments and the fact the warning lights are not showing when the key first comes on. I have got to get this dang thing fixed, the boy is driving my truck during the downtime and I hate that LOL.

On the wiring diagram offer....I have a chiltons manual ...do you have better digrams than it has? It pretty much sucks so if you have something better, I would be interested! Also are there any grounds within the car interior I need to hunt down? I got to be honest here and say I can't with 100% certainty that the dash warning lights thing is new....the boy just mentioned it yesterday however this has been ongoing for a week now and I would think he might of noticed that soon since we have cranked the dang car no less than 50 times...LOL There might be a chance I have two issues here..
 

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Glad to have someone respond that has dug into the schematics. and is familiar with different years 3800's.

This link would be helpful for a quick overview of your ignition system.

3800 GM Ignition System Description and Operation



Hoepfully, you may find out that you lost an important ground or not a solid voltage to your ignition system.
 

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Sorry for the misinformation. I got it crossed with the fuel injector pulses. They originate in the PCM and are buffered(amplified) by the ICM and sent to the injectors. Been awhile since I had had ignition control issues...cheers KEV
 
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