No Spark?

[travisn]

Ls1 from a 98 firebird, re pinned with an 0411 ecu. Removed VATS and turned off a few codes, switched the trans to manual.

Can connect with VCM editor and scanner, see attached log/tune. Is there anything I can be looking for there that would point me in the right direction? I can smell fuel after cranking so the injectors are firing, I can see RPM during crank so the crank sensor is working. No codes as far as I can tell.

I've stripped the harness and only have the essentials and to ensure everything is powered that needs to be. Separate switches for 12v, ign, and starter so everything keeps power during crank. Battery is charged.

I did get a few times where it turned over faster as if it was getting one cylinder to fire like it was almost maybe going to start but nothing.

Thanks in advance.

[Jay@HAP]

Are you using the wiring harness from the 98? The 98's are a little different than the 99+ F bodies.

I know that the coil packs are side specific on the 98's but I can't remember if they are swapped if it just runs poorly or won't run at all. I am "assuming" the wiring is different that year.

If you are getting an injector pulse the PCM is seeing the CKP.

I would get a wiring diagram for a 98 and a 99+ and start looking for differences.

Do you have 12v at the coils? Do you have 12v at the coils when cranking?

Do you have the grounds installed on the rear of the cylinder heads?

[travisn]

Ok, some updates fro last nights debug:

only the drivers side has spark/fuel.
Crank/cam sensor is working properly via scope
I have 12v and gnd at the coil bank plug.
Engine thinks it's spinning at 900 rpm during crank (per vcm scanner).
the signal to the#1 spark plug is firing at about 50/sec during crank.

[travisn]

Are you using the wiring harness from the 98? The 98's are a little different than the 99+ F bodies.

I know that the coil packs are side specific on the 98's but I can't remember if they are swapped if it just runs poorly or won't run at all. I am "assuming" the wiring is different that year.

If you are getting an injector pulse the PCM is seeing the CKP.

I would get a wiring diagram for a 98 and a 99+ and start looking for differences.

Do you have 12v at the coils? Do you have 12v at the coils when cranking?

Do you have the grounds installed on the rear of the cylinder heads?

Thanks for replying.

I've repinned and triple checked the wiring. per the second post on this thread: http://www.ls1truck.com/forums/lsx-t...-diagrams.html along with http://www.mrk-motorsports.com/wp-co...o-1999-PCM.pdf and http://www.lt1swap.com/98-02_ls1.htm

I'm fairly confident I haven't switched coil banks side to side, but the part number on each coil is the same so that wouldn't cause anything.

The grounds are installed on the head and double checked.

Those replies with my previous post should have a lot of clues for someone with more experience

[Jay@HAP]

Ok, some updates fro last nights debug:

only the drivers side has spark/fuel.
Crank/cam sensor is working properly via scope
I have 12v and gnd at the coil bank plug.
Engine thinks it's spinning at 900 rpm during crank (per vcm scanner).
the signal to the#1 spark plug is firing at about 50/sec during crank.

So you have 12v to the coils and a signal but it's not firing?

[travisn]

I think it's sending spark so often that it doesn't have any chance for compression to build. I've had puffs/backfires from the drivers side.

[miker2]

58x crank and 24x tune ?

[Jay@HAP]

58x crank and 24x tune ?

I was wondering if the crank sensor is bad or if it's the wrong one. He said he scoped the CKP, it's pretty on obvious on a scope the difference between the two. Another thing he mentioned is that the scanner is showing 900rpms cranking. Either the CKP is reporting wrong or the engine is out of time and doesn't have any compression.

[travisn]

I don't know the difference between 24 and 58 on the scope but my buddy who was helping me does. I think it has compression because of come of the backfires, but I will specifically check tomorrow night. We also thought the tune could be but it's for an 01 express 5.7L.

Anything else I could check? I have a stock truck harness and another 0411 ecu. I've tried the second with the same results, so it's either the wiring or a sensor. So strange and just my luck.

[Jay@HAP]

Do a relative compression test with the scope and see if it looks right.

[travisn]

Double checked some things tonight:

-power and ground to the coil connector and ecu
-#2 coil fires on #1 connector but not the other way around
-#2 coil wire put into the #1 coil ECU pin fires the #2 coil
-all 4 ecu grounds are good

Possibly worth noting but probably common: when I unplugged the crank sensor the #1 coil fires the plug

I've also unplugged all sensors besides the oil level and crank position with no change in spark.

Is there any chance the pinout for an 01 express 2500 is different than the links I posted?

Summary: wires are good, coils are good, ecu is maybe, engine sensors (crank?) is maybe. I'm trying to find someone with a local LS that I could try my ecu on.

[travisn]

SOLVED!

The express van only has one coil signal wire, which lines up with the 99-02 0411 coil #1 pinout. Put in a tune from the repository and it fired right up. Hopefully this endeavor can be of use to someone in the future