Problems starting when cold ?
Thread Starter
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From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Problems starting when cold ?
My LS1 is a real BI*&^ to get started when cold, (as in sitting overnight for 8 hours or more) but once it's running it's smooth and run great and doesn't have a problem starting for the rest of the day, and it doesn't leave any codes. I have a code reader and it doesn't register zip ?
Thread Starter
Race Director
Joined: Aug 1999
Posts: 11,115
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From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Le Mans Master
Joined: Nov 2005
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I'm betting on a leaky injector-bet the fuel fail has no fuel in it when it sits for a while. Get a fuel pressure guage and see if the fuel rail holds pressure after you shut it off-the pressure should hold for quite some time.
Last edited by dougbfresh; Sep 19, 2011 at 10:08 AM.
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You need to check cold start fuel pressure and the fuel system pressure leak down. How fast does the system come up to operating pressure when the key is cycled ON??
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
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From: Van Buren Arkansas
Wounded Warrior Escort '11
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From: Dyer, IN
You need to check cold start fuel pressure and the fuel system pressure leak down. How fast does the system come up to operating pressure when the key is cycled ON??
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
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Thread Starter
Race Director
Joined: Aug 1999
Posts: 11,115
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From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Fuel bleed down taet.
You need to check cold start fuel pressure and the fuel system pressure leak down. How fast does the system come up to operating pressure when the key is cycled ON??
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
Sounds like you are having a fuel pressure issue (no codes for that one ) or a leakey injector allowing the system to bleed down into the manifold/cylinder.
BC
Tech Contributor
Joined: Jan 2007
Posts: 19,360
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From: Dyer, IN
So what are you waiting for ? ! 
It's not an "overnight" bleed down test. Install a gauge at the rail, turn the key to on (do not start). The fuel pump will prime for 2 seconds. Observe the reading on the gauge, and note how long it takes the pressure to drop.
It's not an "overnight" bleed down test. Install a gauge at the rail, turn the key to on (do not start). The fuel pump will prime for 2 seconds. Observe the reading on the gauge, and note how long it takes the pressure to drop.
Melting Slicks
Joined: Dec 2003
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From: Near Jacksonville Fl.
The first question I will ask is do you have an aftermarket tune?
A quick check for bleed down is to key on the ingition for a few seconds before you engage the starter.
If it starts normal then bleed down is your issue, BTW it may be your check valve in your fuel system and not an injector at all.
Usually if you have a leaky injector you engine will run like a** for a couple of seconds after it fires because of excessive fuel in 1 cylinder.
A quick check for bleed down is to key on the ingition for a few seconds before you engage the starter.
If it starts normal then bleed down is your issue, BTW it may be your check valve in your fuel system and not an injector at all.
Usually if you have a leaky injector you engine will run like a** for a couple of seconds after it fires because of excessive fuel in 1 cylinder.
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If all the fuel bleeds down and returns to the tank after sitting over night, your going to have hard starting the engine.
I AGREE,, put a gage on the fuel rail shredder port and see how long it takes to come to full fuel pressure and how long it takes to bleed down.
There are NO DTCs for long starting, low fuel pressure or lean cold start. The PCM uses the Coolant Temp Sensor to sense when the PCM needs to enrich for cold start. If theres no fuel to enrich, the PCM cant do anything about it but let the engine crank till it starts.
BC
BC
I AGREE,, put a gage on the fuel rail shredder port and see how long it takes to come to full fuel pressure and how long it takes to bleed down.
There are NO DTCs for long starting, low fuel pressure or lean cold start. The PCM uses the Coolant Temp Sensor to sense when the PCM needs to enrich for cold start. If theres no fuel to enrich, the PCM cant do anything about it but let the engine crank till it starts.
BC
BC
Last edited by Bill Curlee; Sep 20, 2011 at 05:18 PM.