Starting Time...

[PhillipsLT5]

I usually turn key to on but not start for a couple of seconds prior to turning key all the way/starting to let fuel pumps pressurize

[XfireZ51]

Originally Posted by Dynomite

It usually takes 3 seconds and never over 4 seconds to start (very little chain slap)......it then takes about 2 seconds for oil pressure to reach 75 lbs.....after warmed up oil pressure 50 lbs at idle.

On idling down to 750/800 another 3 seconds with Haibeck Chips in ALL.
Thermostat in 95' starts to open at 195 deg and replaced that with 180 deg thermostat that starts to open at 175 deg (180 deg Thermostat in ALL).


And......I use the Battery Disconnect Switch on ALL
With the Battery Disconnect you can Disconnect your Battery as often as you like without wearing out the Original Battery Negative Terminal on either the Battery or on the Negative Cable Connector.

Not a fan of those. They get loose and a bit worn. I was stranded once by one of those.

[Dynomite]

Originally Posted by BlackSheepz

Dynomite, where did you get the battery quick disconnect? Thanks!

The Battery Disconnect Switch TIPS



Side Mount Battery Disconnect Switch

Originally Posted by XfireZ51

Not a fan of those. They get loose and a bit worn. I was stranded once by one of those.

Too bad for you

I use the Side Mount Battery Disconnect Switch on ALL Corvettes with no issues. Batteries are always full charge as I disconnect battery with this Disconnect Switch if Corvette sits for more than a couple days

[Hib Halverson]

There is no four-second delay in the starting sequence of the LT5.

That said, unlike some other EFI engines, the LT5 has to crank long enough for the cam sensor to signal the ECM where the engine is in the firing order. Once the ECM "knows" where TDC #1 is, it enables the injectors and ignition.

LT5 was the first GM engine with SEFI. The next one didn't come along until 1994 when increasingly stringent exhaust emissions standards had GM making the LT1 an SEFI engine. In four years, technology advanced such that SEFI LT1s didn't need the long crank time.

But...if your engine is needing to crank for longer than a couple of seconds before it lights, the first thing I'd do is run the fuel pressure tests listed in the Factory Service Manual because, sometimes, excessive time cranking is indicative of either failing ball check valve or valves in one or both fuel pumps or leaking injectors.

As for turning the key to on to let the fuel pumps prime, know that the ECM shuts the pumps off after a couple of seconds if it does not get a signal that oil pressure is building. If you really want to "prime" the fuel rail after a long period of non-op, you have to turn the key on, then off several times, with a break in between key ups, to get the pumps to run enough two-second "bursts" to prime the system.

It was said that 92 LT1s start-up quick. Well...yeah, they do because they are not SEFI engines. Like the L98s before them, 92 and 93 LT1s are "batch-fire" EFI engines.

Lastly, if you think your battery is "tired", have it tested. If it's weak, replace it with the best battery in the aftermarket, an Odyssey Battery. I had an Odyssey 75-PC1230 in my '95 when I sold it and it had been there for six years before that. You put an Odyssey in your ZR-1 and, while there still be a crank time longer than newer SEFI engines, the crank speed will be higher because the Odyssey has a much higher "pulse-cranking" rating than any Delco or even the well-marketed (but over-rated) Optimas.

[Hog]

Originally Posted by Dynomite

The Battery Disconnect Switch TIPS



Side Mount Battery Disconnect Switch


Too bad for you

I use the Side Mount Battery Disconnect Switch on ALL Corvettes with no issues. Batteries are always full charge as I disconnect battery with this Disconnect Switch if Corvette sits for more than a couple days

I think you lose your fuel trims every time you power down the ECM?

[Hog]

Originally Posted by PhillipsLT5

I usually turn key to on but not start for a couple of seconds prior to turning key all the way/starting to let fuel pumps pressurize

Does priming the fuel system decrease your crank times?

[Hib Halverson]

Originally Posted by Hog

I think you lose your fuel trims every time you power down the ECM?

Depends on what you mean by "power down".

If you mean, turn off the ignition, the answer is "Yes." for short term trim (ie: integrator) and "No." for long term trim (ie: block learn).

If you mean, turn off the ignition and disconnect the battery for at least 15 seconds, then yes, you loose all fuel trim information and you start from zero for both STFT and LTFT.

Also, just so we're all on the "same page", the above is true for all ZR-1s and any GM vehicle from 81-95.

[Hib Halverson]

Originally Posted by Hog

Does priming the fuel system decrease your crank times?

If you have leakage somewhere in the fuel system or the period of non-operation has been long enough for the fuel pressure to slowly bleed off, the answer would be "Yes".

[BlackSheepz]

Lot of good info in this thread, really appreciate it.

As an update, I started the car last night and it took 7 seconds to turn over and start. Today I got out the battery tester and the battery lit up as Fair. The battery was stickered 6/2013 and while it should have still been good I decided to just replace it anyway. (The battery in my 92 is stickered the same and lit up like a Christmas tree when I tested it.)

Ended up putting a Duralast Gold in there. Hib I greatly appreciate the Odyssey suggestion but I'm not going to lie $300 for a battery seems a bit much to me.

Started up in just under 3 seconds. I feel much better about the whole thing now.

Injectors are still high on the To Do list. Just got to find a free weekend to do them now.

Thanks again!

[RussMcB]

Originally Posted by BlackSheepz

<snip>... but I'm not going to lie $300 for a battery seems a bit much to me.

I was able to get one last month for $234, which seemed reasonable considering the specs and reputation. I shopped around (maybe via Amazon?), and ordered one from 4wheelparts.com. My car is starting a little faster now (but still 1-2s longer than my other cars).

A side note: I have a FP gauge and my fuel pressure stays pretty high while shut down. Maybe I'm lucky to not have much bleed off.