LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Fuel problem maybe?

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Old 03-15-2011, 08:46 PM
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Default Fuel problem maybe?

Ok so yesterday i was driving around for a little while. I pulled up to stop sign and as i go to drive off my car just all of a sudden starts to sputter like it was running out of gas. I pull off the road and try to crank it and it wouldnt crank so then i put the car in ignition on engine off and let it sit a second and if fired up and i drove home(2 min drive from where i live) and it did fine. I come back a little later and drive it around to see if it does it again and nothing. Today i was leaving to go work and it drove fine. I park, go in and 15 min later come back to move my car because someone was complaining about where i was parked and when i crank it and back it up it starts to sputter again and dies and with engine off and key on after it dies i can hear my fuel pump running and my tach is jumping. I take a second and let it sit for about 5 seconds and takes a few seconds of cranking and it starts. I drive back home and it does fine until i get in my drive way and it does the same thing. Can anyone point me in the right direction in what this could be?
Old 03-15-2011, 08:50 PM
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Originally Posted by lethal bird
Ok so yesterday i was driving around for a little while. I pulled up to stop sign and as i go to drive off my car just all of a sudden starts to sputter like it was running out of gas. I pull off the road and try to crank it and it wouldnt crank so then i put the car in ignition on engine off and let it sit a second and if fired up and i drove home(2 min drive from where i live) and it did fine. I come back a little later and drive it around to see if it does it again and nothing. Today i was leaving to go work and it drove fine. I park, go in and 15 min later come back to move my car because someone was complaining about where i was parked and when i crank it and back it up it starts to sputter again and dies and with engine off and key on after it dies i can hear my fuel pump running and my tach is jumping. I take a second and let it sit for about 5 seconds and takes a few seconds of cranking and it starts. I drive back home and it does fine until i get in my drive way and it does the same thing. Can anyone point me in the right direction in what this could be?
Never dealt with automatic LT1's but i would start with the fuel. We need some info though, what parts have been replaced already, what brand, etc etc. Also, just because the pump whines doesnt mean its pumping correctly. When mine went out it was still making noise but didnt pump anything. Run a fuel pressure test.
Old 03-15-2011, 08:57 PM
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Its a m6 car, 124xxx miles stock pump and mod in sig.
Old 03-15-2011, 08:59 PM
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Originally Posted by lethal bird
Its a m6 car, 124xxx miles stock pump and mod in sig.
Any replaced ignition parts?
Old 03-15-2011, 09:05 PM
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New ac opti, new wires, new plugs about 1500 ago.
Old 03-15-2011, 09:09 PM
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Originally Posted by lethal bird
New ac opti, new wires, new plugs about 1500 ago.
Deffinetly start at the fuel system first, run a fuel pressure test, might also be worth a try to replace the filter if that hasnt been done before.
Old 03-16-2011, 07:09 PM
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Maybe a loose wire or terminal.
Old 04-13-2011, 04:24 PM
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Bump i finally got back home to work on the car and hooked up the fp guage and held at arould 38 psi at idle and key on engine off. And wouldnt stay running for more that 10 seconds. I could keep it running for about 30 seconds if i give it gas and hold it to 3k rpm. A friend which is a machanic said to check the maf and clean it and see if it helps. It wont crank unless i let it sit for about 2 or 3 min. I had just put on lca relocation brackets and a shif light (whuch didnt work) and i took if off i had it tapped to radio ground and power and spliced into the white tach wire in the passenger kick panel if that helps. I had the icm tested and the said it was good. Still havent tested the coil.
Old 04-13-2011, 09:05 PM
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Any help ready to get out of the dd for a while
Old 04-13-2011, 11:15 PM
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I have the exact same symptoms with my car. I'm having it looked at over the weekend so I'll let you know what happens with mine. Could be a similar problem.
Old 04-13-2011, 11:38 PM
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Cool it would be nice to get some help because im pretty stumped. If i cant get it soon im just going to have someone look at it too. Im a college student and dont have a lot of time or money for trial and error. Im good with most things but when it comes to wiring and electronic i would prefer on having someone who knows what there doing.
Old 04-14-2011, 06:01 AM
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Just on an "off the wall" shot...You mentioned putting the DD back on the road. Is your 'Bird stored during the winter or driven infrequently? have you just put gas in it, or has it been sitting for a long time with the same gas in it? Maybe you have gotten some water in the gas. Hit it with some "dry gas" or Techron, and a few gallons of fresh fuel.

Sometimes it's the simple stuff.....
Old 04-14-2011, 11:33 AM
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Originally Posted by leadfoot4
Just on an "off the wall" shot...You mentioned putting the DD back on the road. Is your 'Bird stored during the winter or driven infrequently? have you just put gas in it, or has it been sitting for a long time with the same gas in it? Maybe you have gotten some water in the gas. Hit it with some "dry gas" or Techron, and a few gallons of fresh fuel.

Sometimes it's the simple stuff.....
No it wasnt stored i just only really drive it on the weekends and i had driven it before i put gas in it.

Last edited by lethal bird; 04-14-2011 at 11:58 AM.
Old 04-14-2011, 11:48 AM
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Shot in the dark kind of but take a look at your ignition, Drop the steering shaft and see if it looks burnt in any way. When mine was going out it would do something similar. When I would wait a few Min's for it to cool down it would start back up until it went completely out
Old 04-14-2011, 11:51 AM
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Originally Posted by djjab57
Shot in the dark kind of but take a look at your ignition, Drop the steering shaft and see if it looks burnt in any way. When mine was going out it would do something similar. When I would wait a few Min's for it to cool down it would start back up until it went completely out
Ill go check that. Question if it was my maf sensor, if i unpluged the maf wouldnt it quit?
Old 04-14-2011, 11:56 AM
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Originally Posted by lethal bird
Bump i finally got back home to work on the car and hooked up the fp guage and held at arould 38 psi at idle and key on engine off.
You need to check the pressure with the vacuum off the fuel pressure regulator. Regardless of engine speed the pressure should be between 43 and 45psi (43.5psi to be exact) while the engine is running. When it's acting up like this is a perfect opportunity to check the pressure.
Old 04-14-2011, 12:02 PM
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Originally Posted by SS RRR
You need to check the pressure with the vacuum off the fuel pressure regulator. Regardless of engine speed the pressure should be between 43 and 45psi (43.5psi to be exact) while the engine is running. When it's acting up like this is a perfect opportunity to check the pressure.
Please explain alittle further if you dont mine. Im still a little new to all this.
Old 04-14-2011, 12:27 PM
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pull the vacuum hose off the regulator is what he means. While the engine is running at idle and see if the pressure jumps up. It should. But 38 running seems OK (a little low, but now enough to cause the symptoms your seeing), so I don't think that's your problem.

If you unplug the MAF and it runs normal, then yes that is probably it, but I doubt that's the case. Anyone suggested O2 sensors?
Old 04-14-2011, 12:32 PM
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Originally Posted by mguidry629
pull the vacuum hose off the regulator is what he means. While the engine is running at idle and see if the pressure jumps up. It should. But 38 running seems OK (a little low, but now enough to cause the symptoms your seeing), so I don't think that's your problem.

If you unplug the MAF and it runs normal, then yes that is probably it, but I doubt that's the case. Anyone suggested O2 sensors?
Thanks the o2s are used i bought from a guy here that said they had low miles on them but i havnt checked them. The mechanic friend said that it could be the pcm.
Old 04-14-2011, 12:32 PM
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Take the vacuum line off the fuel pressure regulator. If you don't know where that is, this page is a great reference:
www.shbox.com

Start the engine and see where the pressure is. It should never fluctuate with the vacuum line off. It should always read constant. Taking the vacuum line off will eliminate any idle speed variables.

If it were O2's it would would most likely run fine until going into closed loop.


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