LT1-LT4 Modifications 1993-97 Gen II Small Block V8

No Spark about to Burn this Car

Thread Tools
 
Search this Thread
 
Old 01-31-2018, 12:11 PM
  #1  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default No Spark about to Burn this Car

Gents,
I've owned an LT! for 13 years and never had an opti problem.

History of my recent problem.

Currently building a camaro mustang challenge car. I reworked the engine harness to make it a stand alone harness. The motor is completely stock fresh rebuild. Went to fire it has no spark. So I started testing everything I could think of. Engine grounds. Then checked every wire individually. for continuity and for short to ground.

Swapped to a known working PCM. Still same result.

So now to replacing parts. So I took the coil and ICM off of another LT1 camaro (same year). Still not spark.

So I started testing the individual connectors to the ICM and the OPTI Per shoebox how to's:

At the ICM harness
Pin A = 12.07VDC (10 to 12V needed)
Pin B = 0VAC (needs 1VAC to 4VAC While cranking)
Pin C = 0 OHMs of resistance with key off
Pin D = 12.05 VDC

At the opti harness where it plugs into the opti
Pin A = 5.03VDC (needs 5VDC)
Pin B = 5.03VDC (needs 5VDC)
Pin C =12.03VDC (Needs 12VDC)
Pin D = .3 ohms with key off

So I took this as it needs a new opti. Researched optis seems like a crap shoot now with ACdelco being a reman.

Started with just replacing the opti sensor with one off amazon. Still same result above.

Got pissed ran to Jegs and picked up the only OPTI they had in stock. it what their JEGS opti. Heard bad things but wanted to get the car running that day. Same result.

Am I missing something? I do not have an oscilloscope to test the actual wave lengths. I could buy one but figured I would ask what you gents thought before I through any more money at it.
Old 01-31-2018, 12:52 PM
  #2  
TECH Senior Member
iTrader: (36)
 
ss.slp.ls1's Avatar
 
Join Date: Jan 2008
Location: Orange County, CA
Posts: 8,188
Received 26 Likes on 24 Posts

Default

Through troubleshooting you seem to have eliminated the PCM, ICM, coil, and opti as the culprit. This leads me to believe that you have a wiring issue, possibly corresponding to your reworked harness?
Old 01-31-2018, 12:59 PM
  #3  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

That’s what I was thinking but everything seems to check out on that end. I even took a new wire from the pcm to pin b on the icm. What’s the chances I have 2 out of box failures on the opti?
Old 01-31-2018, 02:14 PM
  #4  
TECH Veteran
 
BALLSS's Avatar
 
Join Date: Apr 2008
Posts: 4,904
Received 87 Likes on 78 Posts

Default

Originally Posted by Claytor
. I reworked the engine harness to make it a stand alone harness. .
By "reworked the harness"...what exactly did you do to it and why?

what year/car is this LT1 in?
Old 01-31-2018, 02:23 PM
  #5  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

Year 1995
I made the harness stand alone. I used LT1swap.com as a guide. Ultimately I took 31 pounds of wire out of the car. Hence why I deleted the AC and accessories out of the harness.

The car is going to be a track only car.
Old 01-31-2018, 03:07 PM
  #6  
TECH Veteran
 
BALLSS's Avatar
 
Join Date: Apr 2008
Posts: 4,904
Received 87 Likes on 78 Posts

Default

Might want to re-visit the wire loom

I think 2 bad out of box opti is way less likely than a potential "oops" in the wire harness diet

maybe a shared signal .5 vdc wire or ground wire that was omitted needs to be restored

has VATS been programmed out?
Old 02-01-2018, 06:30 AM
  #7  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

I did have the VATS programmed out.

As much as I don't want to I'm going to split the loom and make sure I do not have any shorts. All the tests I have done shows there isn't any shorts but I didn't think of maybe the wires sharing the same source.

I'll do that on Saturday morning and post an update.
Old 02-01-2018, 10:47 AM
  #8  
FormerVendor
iTrader: (1)
 
pantera_efi's Avatar
 
Join Date: Nov 2008
Location: Santa Ana, CA. USA
Posts: 2,157
Likes: 0
Received 16 Likes on 16 Posts

Default OPTI Pin Out

Hi Clay, I manufacture both early/late Opti Spark Distributors.

I have sold this item to LS-1 Tech members.

Your use of a Voltmeter has been good.

This is the Pin Out/Signal specification.

A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground

This test should be done when the engine is cranked.

Report your observarion.

Lance
Old 02-01-2018, 11:09 PM
  #9  
Staging Lane
 
Ghostinthemachine's Avatar
 
Join Date: Jan 2018
Posts: 75
Received 1 Like on 1 Post
Default

Originally Posted by Pantera EFI
Hi Clay, I manufacture both early/late Opti Spark Distributors.

I have sold this item to LS-1 Tech members.

Your use of a Voltmeter has been good.

This is the Pin Out/Signal specification.

A = Low Resolution Signal with FOUR high/low for each crankshaft turn (+5/0) a Hall with my Opti.
B = High Resolution Signal with 180 counts for each crankshaft turn. (+5/0) a Hall with my Opti.
C = 12 Volt Power
D = Power Ground

This test should be done when the engine is cranked.

Report your observarion.

Lance
.
Hi lance i have a 95 Z28 LT1 and interested in the omnispark do you have a link
.
OP sorry i subscribe not ment to jack your thread a lot of good advice to follow after modifie LT1ECM stock wiring...
Old 02-02-2018, 03:35 PM
  #10  
FormerVendor
iTrader: (1)
 
pantera_efi's Avatar
 
Join Date: Nov 2008
Location: Santa Ana, CA. USA
Posts: 2,157
Likes: 0
Received 16 Likes on 16 Posts

Default PanteraEFI.COM web site = New Porducts

Hi Ghostin, NOT a Hyjack, A "Freejack" = OK

I Believe Clay's Report OR YOUR report will help ALL members.

My site is Panteraefi.com, look under NEW products.

Lance
Old 02-02-2018, 05:16 PM
  #11  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Pantera EFI
Hi Ghostin, NOT a Hyjack, A "Freejack" = OK

I Believe Clay's Report OR YOUR report will help ALL members.

My site is Panteraefi.com, look under NEW products.

Lance

I’m scoping it tomorrow. I’ll let you guys know what I find out.
Old 02-21-2018, 07:23 AM
  #12  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

Gents,
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.

Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.

Thanks again for your reply's.
Old 02-21-2018, 11:01 AM
  #13  
TECH Senior Member
iTrader: (36)
 
ss.slp.ls1's Avatar
 
Join Date: Jan 2008
Location: Orange County, CA
Posts: 8,188
Received 26 Likes on 24 Posts

Default

Originally Posted by Claytor
Gents,
Wanted to thank everyone for chiming in on this. So the problem was not with the harness nor the opti. Since I rewired the entire car using an aftermarket Fuse/Relay block. I had the PCM (pink wires) connected to a circuit that was powered when key was switched on. But shuts power down during cranking. Just like your typical accessories circuit from GM. I was unaware this block had that function. It was difficult to test with just one person.

Moral of the story While cranking the PCM was getting shut down. As soon as I fixed that car fired right up with no problems.

Thanks again for your reply's.
That happens often actually with custom wiring. Glad you found the problem.
Old 02-24-2018, 08:21 AM
  #14  
FormerVendor
iTrader: (1)
 
pantera_efi's Avatar
 
Join Date: Nov 2008
Location: Santa Ana, CA. USA
Posts: 2,157
Likes: 0
Received 16 Likes on 16 Posts

Default Clay = Quality Tech

Hi Clay, your work is great, good "tech", BEST reports, not common here at LS-1 Tech.

I offer "best price", help to you, to suite your needs.

YOU have EARNED this on your own, best wishes.

Lance
Old 02-26-2018, 07:13 AM
  #15  
Teching In
Thread Starter
 
Claytor's Avatar
 
Join Date: Jun 2015
Posts: 14
Likes: 0
Received 0 Likes on 0 Posts
Default

Lance,
I won't forget you chipping in on this!! Thanks.
Old 03-04-2018, 12:24 PM
  #16  
FormerVendor
iTrader: (1)
 
pantera_efi's Avatar
 
Join Date: Nov 2008
Location: Santa Ana, CA. USA
Posts: 2,157
Likes: 0
Received 16 Likes on 16 Posts

Default Opti Help + Clay

Hi Clay, I "brought-up" YOUR quality tech.

This may be of help with the Thread below.

Lance
Old 08-04-2018, 04:53 PM
  #17  
Registered User
 
Shane Schminkey's Avatar
 
Join Date: Aug 2018
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default No spark fix

I had to reset my computer after changing out a camshaft sensor do to lost spark on my 2002 firebird. on the GM cars you can reset the computer by disconnecting the negative post on your battery , wait at least 30 min before hooking your battery back up (I waited overnight), turn your key to auxiliary position for two full minutes, next take the key out of the ignition for ten seconds then try starting, This allows your computer to relearn your car, (My car started right up). If your car starts do not rev your car and drive normal the first few drives while the computer is relearning your car. You could also have corrosion at your computer harness that can be cleaned with spray Electrical cleaner from the parts store, Oder test on the computer wouldn’t be a bad idea to see if anything burnt out. If still no spark and you have a security or anti theft light on you might want to YouTube how to bypass the anti theft with a wire. Hope this helps



Quick Reply: No Spark about to Burn this Car



All times are GMT -5. The time now is 11:30 AM.