Hard to Start...

[Rumblin70SS396]

My 90 Z always take a little bit to start.......I crank it for about 5 seconds, let off the key then crank it again and it fires up. Is that something common with these cars or an issue I should look into?

Thank you,

Tony


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[TX '90 ZR1]

Seems to me that is a bit too long before it fires off. Might check fuel pressure with key on and bleed down rate after turning key off.
Be careful letting off the key before it starts. They are prone to backfire and blow off vacuum lines. More times than not this will result in a plenum removal to correct.
:cheers:

[Paul Workman]

I turn the ignition to ON a few seconds (like 3-4ish) before rolling the starter. My '90 ZR-1 usually take a 2-4 seconds after the fuel rail is pressurized, depending on how long it was idle, before it fires up. My wife's 91 ZR-1 fires much quicker - only one or two seconds in most cases.

[lfalzarano]

Never turn the key off until it fires up. I’ve had backfires that have blown out injectors twice. Other bad things can happen.

When I installed Marc H’s chip, if fires immediately. Also old gas can also contribute to the delay in firing up.


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[Rumblin70SS396]

Thanks guys......what are you all using for fuel pressure gauges? The old gas is almost out as well...


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[DRM500RUBYZR-1]

Never turn the key off until it fires up. I’ve had backfires that have blown out injectors twice. Other bad things can happen.

When I installed Marc H’s chip, if fires immediately. Also old gas can also contribute to the delay in firing up.


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Simplest way to avoid trouble is to do exactly as he said!
Experience teaches you this!
Great advice!
Marty

[Paul Workman]

Thanks guys......what are you all using for fuel pressure gauges? The old gas is almost out as well...


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Got mine AND an extension hose so I can tape the gauge to the windshield to do dynamic tests at Harbor Freight.

[Rumblin70SS396]

Paul,

I hate HF but I will head there this weekend! Thank you!


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[Rumblin70SS396]

Thanks again guys, I will time joe long it takes to start as well. Last thing I want to do is pull this plenum again as it was almost impossible to seal


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[32valvZ]

I turn the ignition to ON a few seconds (like 3-4ish) before rolling the starter. My '90 ZR-1 usually take a 2-4 seconds after the fuel rail is pressurized, depending on how long it was idle, before it fires up. My wife's 91 ZR-1 fires much quicker - only one or two seconds in most cases.

Thats how I do it also... I just wait for the vac pump to shut off, then start it.

[32valvesftw]

Not a fan of HF either, most decent local autoparts stores will also have a fuel pressure gauge.

Paul,

I hate HF but I will head there this weekend! Thank you!


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[jss06c6]

Agree with Paul.. I turn on the key for about 5 seconds before I crank, and never let go until it starts. Some days are shorter crank times, some days a bit longer..

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[Paul Workman]

Thats how I do it also... I just wait for the vac pump to shut off, then start it.

Vacuum pump? VACUUM PUMP!? WEE DOAN NEED NO STEENKING VACUUM PUMP!

[-X;)

[Rumblin70SS396]

After reading the posts I think I understand the car a bit better and what I have seems normal. I now let it sit 5 seconds with key on then crank till it starts. When I actually timed it, it took about 3 seconds to fire. I guess I am used to my newer cars and even my high compression Chevelle which fires right up. Either way, it is not cranking excessively.

Thanks again all!!


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[Paul Workman]

IIRC, it seems I was reading the FSM where I read that it takes the ECM to receive enough signal blips from the reluctor to determine crank position before the spark is authorized. (Someone pls correct me if I'm wrong on this.)