650rwhp help on ignition...

Reply Subscribe

Thread Tools

Search this Thread

Apr 7, 2007 | 05:16 PM

#21

CALL911

TECH Addict

iTrader: (17)

Joined: Feb 2006

Posts: 2,940

Likes: 2

From: IN

I'm by no means a pro for the FI on LS1's, but I know a bit on the LT1's. I would guess you need to upgrade to an aftermarket ignition like the MSD coil packs. This should strengthen your ignition system. Regaurdless though, you should be able to at least crank it over with the stock setup. I also would check your gapping in the spark plugs, as to wide of a gap can be blown out on a decent powered FI setup. Best way to start chasing the proplem would be to try and diagnos the computer with a tuning program on a laptop, and try and see what is going on by reading all the sensors from the car as it is attempting to start.

Good luck.

Apr 7, 2007 | 09:44 PM

#22

Pro Stock John

LS1Tech Co-Founder

iTrader: (34)

Joined: Nov 2001

Posts: 45,348

Likes: 1,779

From: Chicago, IL

No you don't need MSD coils. Check fuses and relays. Make sure the valves are opening and closing.

Apr 8, 2007 | 07:00 AM

#23

Blownramair

Thread Starter

TECH Apprentice

Joined: Sep 2005

Posts: 333

Likes: 0

From: Detroit

im pretty sure the factory ls1 ignition is capable of handling up to 1000hp @ the crank... I'm def. not over that level, maybe close to it by time i've figured this thing out...

i talked to someone this weekend and something similar to this happend person... they said when this happend to them it was the ecu - they fried it because it got too hott... after the last dyno pull he let the car cool off for a good hour - tried starting it and fired right back up... ran it on the dyno and did the same thing... he replaced the the ecu and no problems since... now i dont know if this is my case but that would def. relieve alot of stress from me knowing it was...

how big of a pain in the *** is it to replace the timing chain/ reluctor wheel?

Apr 8, 2007 | 09:17 AM

#24

ddnspider

10 Second Club

iTrader: (26)

Joined: Aug 2004

Posts: 14,628

Likes: 1,778

From: FL

timing chain....take off front cover and crank pully and a few bolts and u can swap it.
crank reluctor wheel.....PITA,gotta pull the motor and take it apart i believe.

Apr 9, 2007 | 11:50 AM

#25

Blownramair

Thread Starter

TECH Apprentice

Joined: Sep 2005

Posts: 333

Likes: 0

From: Detroit

it better as hell not be the reluctor wheel which im presuming it is... were gonna throw a new crank sensor on and see if the engine will fire... the engine would not fire when she cooled down... so i believe were leaning towards a ecu fried or timing chain/ reluctor wheel...

either way i probably will not be at milan friday... ****!

thanks guys for your help... once i figure the problem out for certain... i'll post what happens... along with some rwhp numbers itching at 700...

Apr 13, 2007 | 07:04 PM

#26

Blownramair

Thread Starter

TECH Apprentice

Joined: Sep 2005

Posts: 333

Likes: 0

From: Detroit

Okay... Running out of ideas and still can not diagnose the problem...

The reluctor wheel is tack welded - could it move even tho its welded?

Crank sensor was reading 69rpms when engine ignition is on acc... We replaced the sensor and the thing will still not start... No other codes were showing up and no check engine lights... All fuses are good... Relay's okay...

I removed the two step and that wasnt the problem...

After trying these things, which everyone recommended the car still WONT START... Now, what was odd to me is the engine cranks over and it seems like she wants to fire, but doesn't... At one time the engine almost fired but herd a big "boom" outta the exhaust... I called it quits after that...

I dont know what else to do? I'm getting a new pcm on monday to see if the pcm is fried... Could the timing chain be shot? Does anyone have any other ideas I can check...?

Apr 13, 2007 | 09:52 PM

#27

ss1

TECH Fanatic

iTrader: (32)

Joined: Jul 2005

Posts: 1,264

Likes: 1

From: Scarborough, Maine

Even if the reluctor wheel is tacked, the tack welds could still break free. Anything from changing RPM's, harmonics, vibration, or balance could be a cause.

If the timing chain is broken, it shouldn't sound like it wants to start because the cam wouldn't be turning and there wouldn't be any valve events. More than likely it wouldn't turn over as anyway. I think if that were the case it would cause more problems than you're having.

I'd guess a backfire out the exhaust is better than back out the intake, but if there is no spark why did it backfire to begin with?

Apr 13, 2007 | 10:27 PM

#28

black98ws6ta

TECH Addict

iTrader: (77)

Joined: May 2002

Posts: 2,107

Likes: 2

From: louisville,ky

If you remove the crank sensor you can see if anything weird is going on with the reluctor, other then if it spun. Pull all of the plugs out and do a compression and leakdown to verify the motor still being in good shape. Does the fuel pump prime? Are the injectors firing?