Will not stay running

1999 CHEVROLET S-10
170,000 MILES • 4.3L • V6 • 4WD • MANUAL
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WILLIAM SCHROEDER2
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The vehicle listed above will run on starting fluid. Replaced the fuel pump and filter. Spider injection, Crankshaft Position Sensor, MAP Sensor, Idle Control Valve. Injectors are getting the ground pulse to fire. 60 PSI fuel and will hold for days. The only time it ran on its own, we covered the throttle body as to choke it. It started and ran for 2 ten mile runs. Shut it off and it restarted a couple hours later. The next morning back to the same trouble. I'm stumped. The fuel out of the pressure gauge looks like foam. If I hold the release and crank the engine all of the fuel is like foam. If you let it sit it clears up. Stumped, never came across this before. Help. I have even got a re-flashed ECM.
Mar 31, 2021 at 9:59 AM
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STRAILER
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Could you have bad fuel? I would drain the tank and add new fuel. Also lets run the codes to see what comes up. these guides can help us fix it:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/car-cranks-but-wont-start

Let us know what happens and please upload pictures or videos of the problem.
Apr 1, 2021 at 12:14 PM
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WILLIAM SCHROEDER2
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I've already drained the tank, and the only code that came up was for the MAF sensor. I can't see that not letting it run. Can you explain how it ran for a half hour or so just by actually choking it on the throttle body? I've never seen anything like this before. Thanks
Apr 2, 2021 at 7:51 AM
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STRAILER
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the MAF sensor can cause this issue. If the sensor stops working the computer sees the engine not running and cuts the fuel delivery. Here is a guide to help you step by step with instructions in the diagrams below to show you how on your car:

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf


Check out the diagrams (below). Please let us know what happens.
Apr 3, 2021 at 11:18 AM
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WILLIAM SCHROEDER2
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Well, I appreciate the input Ken.I replaced the MAF sensor and still no good. So far I've replaced the fuel pump and filter. Replaced the spider injection, ECM, Crank position sensor, IAC sensor, MAP sensor. The guy I bought it from did a hack job on a radio install. I redid the wiring back to stock, no radio yet, but no matter what I've done it will only run on starting fluid. I don't know where to go next. It's only got just under 170,000 miles on it. Where next? Help
Apr 12, 2021 at 10:20 AM
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STEVE W.
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Okay, it will start on spray but not run on tank fuel, you replaced the pump and it shows good pressure. However you say that when you try testing the fuel you get foamy fuel and not a solid stream? That sounds like a bad fuel line inside the tank, between the pump and the housing outlet is letting air into the line or one of the lines is sucking air. Try this: open the fuel cap and have someone turn the key on to run the pump to prime, listen to the sound, does it just make the normal hum of the motor or does it sound like a waterfall or spray can? If it sounds like either it's likely the pump module has a problem on the lines in it.
What was replaced with the pump? just the motor or a complete module?
Apr 12, 2021 at 6:03 PM
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WILLIAM SCHROEDER2
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The whole pump module was replaced. I noticed yesterday that it doesn't seem to be making vacuum. Pulled the hose from the brake booster and no vacuum was there. Is it possible to have an intake gasket be bad enough to keep it from starting, and not build vacuum? Or does it need to be running to actually have vacuum? I appreciate you taking the time to help. I'm 60 years old and been working on my own stuff since I was 16. I've never seen anything like this before. Thanks again.
Apr 14, 2021 at 12:25 PM
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STEVE W.
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Engine has to be running to have vacuum. You said that it did start and run for 20 miles then once it sat it hasn't driven again, that all points to a fuel issue. The foam from the fuel system sounds like it is sucking in air somewhere. Try this, turn the key on for 2 seconds, now repeat that about 3 more times with about a 5 second pause between turns. Now try to start it. What does it do when you do this?
Apr 14, 2021 at 2:29 PM
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WILLIAM SCHROEDER2
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Tried that tons of times. Does not make any difference how much you try it. She just won't start. The first time I turn the key the pump sounds like it should, on for 5 seconds or so. Then every time after that the pump makes more noise when you turn the key off. It sounds like it is running another 5 seconds with more noise.
Apr 14, 2021 at 4:52 PM
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WILLIAM SCHROEDER2
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Wondering if there's an electric problem.
Apr 14, 2021 at 4:53 PM
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STEVE W.
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It doesn't sound electrical it sounds like there is a fuel leak inside the tank that is not allowing the fuel to get up to the engine. Try this: you have the fitting to test pressure, connect to that with the testing hose but don't connect the gauge, just put the end into something to catch the fuel. Cycle the key, you should get a large volume of gas in a steady stream with no bubbles.
Apr 14, 2021 at 5:29 PM
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WILLIAM SCHROEDER2
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I will give it a try tomorrow. When I replaced the spider injection I noticed that the pressure side of the fuel line was full of the foamy gas. But the return side was empty. I will give your test tomorrow. I will let you know one way or another. Again, I appreciate your help.
Apr 14, 2021 at 5:37 PM
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STEVE W.
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Not a good sign, it wouldn't be the first time to get a bad pump straight out of the box. Especially for that platform. I had a 99 here years ago and it took 3 pumps before one that actually worked as it should showed up. Keep us informed.
Apr 14, 2021 at 5:44 PM
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WILLIAM SCHROEDER2
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I've already had 2 pumps in it. I will let you know. Thanks
Apr 14, 2021 at 6:09 PM
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JACOBANDNICKOLAS
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Hi,

I noticed it has been a couple of days since we heard from you. Have you been able to make any progress? We are interested in knowing.

Take care,

Joe
Apr 16, 2021 at 11:28 PM
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WILLIAM SCHROEDER2
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I ordered a new pump. Was supposed to be here today. But, was told this morning it won't be here until Tuesday. So, I will be sure to let you know. But so far I'm still getting foamy gas. Thanks again for all your help. Talk to you as soon as I get the pump.
Apr 17, 2021 at 6:24 AM
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JACOBANDNICKOLAS
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Hi,

Thanks for the update. As far as the "foamy gas" I have a feeling Steve is correct. It sounds like air is getting into it. However, I would think it would start.

I read through all the different conversations you have had. If I'm correct, it will not start at all at this time. Tell me. Will it start on starting fluid?

Let me know.

Joe
Apr 17, 2021 at 6:22 PM
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WILLIAM SCHROEDER2
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It does, but it seems like it is not as willing to as it was. This thing has got me and a few other people stumped. And it won't even set a code.
Apr 18, 2021 at 3:56 PM
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JACOBANDNICKOLAS
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Hi,

If it does start with starting fluid, then for sure it is a fuel-related issue. When you remove the pump, make sure to inspect all hoses on the sending unit and on the pump.

Let us know what you find.


Take care,

Joe
Apr 18, 2021 at 5:33 PM
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WILLIAM SCHROEDER2
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Right on. Thanks I will let you know.
Apr 18, 2021 at 6:02 PM
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STEVE W.
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I usually find the line between the pump and the housing has a small split, or it is loose. I have seen one where the problem was the fuel lines being reversed at the nut connection on the intake, but that was not a common thing and it showed low pressure when tested.
Apr 18, 2021 at 7:05 PM
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WILLIAM SCHROEDER2
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Hey guys, thanks for all the help. I finally got it. It was the O-rings on the pressure side of the pump. It was drawing air in, but wasn't leaking gas. Strange but that's vehicle for ya.
Apr 23, 2021 at 7:41 AM
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STEVE W.
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Well that's a bit different, but glad you found it. Thanks for using 2CarPros. Please return anytime.
Apr 23, 2021 at 8:32 AM
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WILLIAM SCHROEDER2
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Well, I've never seen it before either. But, she starts and runs. Only thing now is that when you start it, wants to hesitate. But if you don't touch the gas she comes to life. And when you hit the gas before it's warm, takes a minute for it to level off.
Apr 23, 2021 at 4:04 PM
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JACOBANDNICKOLAS
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Hi,

Glad to hear you got it running. The o-ring makes sense based on what you were getting at the engine, foam.

As far as the new issues, confirm fuel pressure is within spec. If you need us, please start a new thread specific to the issues. We try to keep the threads specific to one topic so they are more likely to help others. I hope you understand.

IF you decide to post the new questions, click on the link below. It will take you right to the new post page.

https://www.2carpros.com/questions/new

Again, please feel free to come back anytime in the future. You are always welcome here.

Take care,

Joe
Apr 23, 2021 at 6:17 PM
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WILLIAM SCHROEDER2
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I thank you for your help. I'm pretty sure I got it from here. But I won't hesitate to holler again. Thanks.
Apr 23, 2021 at 6:51 PM
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STEVE W.
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My guess would be that the o-ring had a small amount of damage and with the way those lines attach the fuel flowing in the line through the connector was acting like a venturi when the pump was on and that pulled in the air. Then when the pump shut off the air acted to limit the fuel pressure and the ring pushed back enough to seal so there were no leaks. Not a common failure but it happens.
Apr 23, 2021 at 7:04 PM