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Too much Fuel or Air at crank???

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Old Nov 8, 2004 | 04:20 PM
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Too much Fuel or Air at crank???

Sometimes when my car is warm and it's only shut off for a little bit, I have to push the gas pedal a little more for it to start sooner otherwise it will turn over more than it should to start.

Is this a sign of too much fuel or not enough fuel when cranking?
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Old Nov 8, 2004 | 06:56 PM
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From: Mims, Florida
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
I believe that this is a sign of not enough fuel. Since I got a 395 stroker, I needed more fuel at startup.

So I added fuel via the "crank fuel PW vs coolant temp" table.

I'll check my Eprom files and repost if the above is wrong.
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Old Nov 8, 2004 | 07:05 PM
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From: Mims, Florida
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
I got it wrong, I needed more fuel at cold start-up.

If you need to push the pedal to the floor (and hold it there) and the engine then starts after a bit of cranking, then you have too much fuel to begin with. Holding the pedal to the floor, puts the ECM into clear flood mode.

Try that experiment, next time you start a warm to hot engine.
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Old Nov 8, 2004 | 08:13 PM
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I'll try that. Normally I only have to push the pedal a tiny bit. Also I noticed that if I put in my key and go straight to cranking it fires better than if I put the key in "on" position and wait there a couple seconds for the pump and the IAC to prime/adjust...

You know come to think of it I have my IAC startup steps set to 70, maybe I should increase that? Would having that too high cause my idle to start too high when I fired up though? I lowered it trying to get rid of an idle surge I had at startup where when it started it jumped to like 1500RPM then starting going normal.

Last edited by 92GTA; Nov 8, 2004 at 08:16 PM.
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Old Nov 9, 2004 | 11:11 AM
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From: Mims, Florida
Car: '87 IROCZ
Engine: 395 ZZ4
Transmission: ProBuilt 700R4
Axle/Gears: 9 bolt 3.70s
If it starts better just turning the key to start, then I figure that the fuel pressure has not come up completely and at start-up you have less fuel going into the cylinders. Therefore, You might want to think about taking fuel away (reduce the PW) in the "Cranking PW vs Coolant Temp" table, only in the higher temp cells, like above 60*C. Try multipling these upper temp cells by 0.90...

Program a new Eprom, and try it out.
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Old Nov 9, 2004 | 01:28 PM
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Re: Too much Fuel or Air at crank???

Originally posted by 92GTA
Sometimes when my car is warm and it's only shut off for a little bit, I have to push the gas pedal a little more for it to start sooner otherwise it will turn over more than it should to start.

Is this a sign of too much fuel or not enough fuel when cranking?
Let's see:
Could be a just marginal battery.
Min idle set too low.
Too much initial timing.
Too rich.
IAC (park) counts too low.
Too much crank fuel.

And it can be a combination.
Might try adding a 10% to what ever your IAC park count is at the temp., and try it.
If that doesn't cure it, then reset the IAC counts to what they were, and lean down the crank fuel.

Some times you gotta just try things to see what your engine likes.
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