Why don't they start right up? - ZR-1 Net Registry Forums

Schrade · 07-21-2014

Does any one know with certainty why LT5 doesn't start right up immediately?

Was it the same way on the showroom floor?

This is the first electronically FI car I've owned that didn't do so instantly. Even the first one I owned, an L-98 that was in a poor state of tune when I got it, would start immediately. Foreign, domestic, 4's, 6's, etc.

On RARE occasions, it WILL fire almost instantly. But most of the time, it's 2 - 3 seconds. And I'll let off the starter then, and re-try.

I thought I read once on the boards here that ECM had to see some crankshaft position first, before issuing fire @ the plugs; this would mean, if correct, that it WOULD have exhibited the same behavior at the dealer, when new.

Does anyone know DEFINITIVELY the answer here?

Kevin · 07-21-2014

Quote:

I thought I read once on the boards here that ECM had to see some crankshaft position first, before issuing fire @ the plugs; this would mean, if correct, that it WOULD have exhibited the same behavior at the dealer, when new.

this is what I've always heard to be the case also.

BigJohn · 07-21-2014

Never noticed!
Mine starts right up with a good battery.

QB93Z · 07-21-2014

It could be because the Crankshaft has to rotate until the Ignition Module gets a signal from the Crankshaft Position Sensor so it can determine the correct ignition timing.

Jim

RyanChappel · 07-21-2014

with new Accel injectors and a good (batt-tender maintained)charge, has to crank a couple seconds to fire...and I'm always thrilled it did...

We Gone · 07-21-2014

Quote:

Originally Posted by QB93Z

It could be because the Crankshaft has to rotate until the Ignition Module gets a signal from the Crankshaft Position Sensor so it can determine the correct ignition timing.

Jim

This is what I have read also crank needs to make one complete revolution, but it may also have something to do with were the sensor is at shut down.

Fully Vetted · 07-21-2014

It could just be in my head but I've noticed it seems to fire quicker when I turn on the ignition and wait a couple of secs before engaging the starter.

USAZR1 · 07-21-2014

Quote:

Originally Posted by Fully Vetted

It could just be in my head but I've noticed it seems to fire quicker when I turn on the ignition and wait a couple of secs before engaging the starter.

I've noticed this,too.

BigJohn · 07-21-2014

Try starting my 32!

Fully Vetted · 07-21-2014

My Dad's '31 Model A starts so fast we had a standing challenge: If you can engage the starter at all and it not start he would buy dinner.

He never bought dinner....

07-21-2014	#1
Schrade Join Date: Dec 2012 Location: NC Posts: 1,786	Why don't they start right up? Does any one know with certainty why LT5 doesn't start right up immediately? Was it the same way on the showroom floor? This is the first electronically FI car I've owned that didn't do so instantly. Even the first one I owned, an L-98 that was in a poor state of tune when I got it, would start immediately. Foreign, domestic, 4's, 6's, etc. On RARE occasions, it WILL fire almost instantly. But most of the time, it's 2 - 3 seconds. And I'll let off the starter then, and re-try. I thought I read once on the boards here that ECM had to see some crankshaft position first, before issuing fire @ the plugs; this would mean, if correct, that it WOULD have exhibited the same behavior at the dealer, when new. Does anyone know DEFINITIVELY the answer here? __________________ I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG]

07-21-2014	#3
BigJohn Join Date: Feb 2012 Location: Ledyard,CT Posts: 8,251	Re: Why don't they start right up? Never noticed! Mine starts right up with a good battery.

07-21-2014	#4
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,689	Re: Why don't they start right up? It could be because the Crankshaft has to rotate until the Ignition Module gets a signal from the Crankshaft Position Sensor so it can determine the correct ignition timing. Jim __________________ If it isn't fun, you aren't doing it right! 1990 Black ZR-1 - sold 1993 Quasar Blue ZR-1 1994 Competition Yellow ZR-1 1995 Dark Purple ZR-1 Maryland State Coordinator WAZOO Member

07-21-2014	#5
RyanChappel Join Date: Aug 2012 Location: Boone County, Indiana Posts: 132	My lo-mile '91 with new Accel injectors and a good (batt-tender maintained)charge, has to crank a couple seconds to fire...and I'm always thrilled it did...

07-21-2014	#7
Fully Vetted Join Date: Sep 2012 Location: Rockwall, Tx Posts: 1,510	Re: Why don't they start right up? It could just be in my head but I've noticed it seems to fire quicker when I turn on the ignition and wait a couple of secs before engaging the starter. __________________ _________________ 1994 AB/Grey #141 430 RWHP/392 RWTQ FBI Lyposuction / Secondaries relieved of duty / SW Long Tube Headers / Corsa Exhaust / FIC SS Injectors / MSD Coils / Lightweight Pulleys / Corey tuned B & M Shifter / Aluminum Flywheel / Samco Hoses / Shelby Series One's / C4 No Flex Frame Stiffener BBC - Bling By Carter: Custom ZR-1 Center Caps / Custom Plenum Plate / Air Box Knobs / TB Cover / Oil Filter Cover