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Will not stay running

Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 1999 CHEVROLET S-10
  • 4.3L
  • V6
  • 4WD
  • MANUAL
  • 170,000 MILES
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.
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Wednesday, March 31st, 2021 AT 9:59 AM

27 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
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.
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Thursday, April 1st, 2021 AT 12:14 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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
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Friday, April 2nd, 2021 AT 7:51 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
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.
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Saturday, April 3rd, 2021 AT 11:18 AM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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
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Monday, April 12th, 2021 AT 10:20 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
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?
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Monday, April 12th, 2021 AT 6:03 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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.
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Wednesday, April 14th, 2021 AT 12:25 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
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?
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Wednesday, April 14th, 2021 AT 2:29 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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.
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Wednesday, April 14th, 2021 AT 4:52 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
Wondering if there's an electric problem.
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Wednesday, April 14th, 2021 AT 4:53 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
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.
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Wednesday, April 14th, 2021 AT 5:29 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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.
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Wednesday, April 14th, 2021 AT 5:37 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
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.
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Wednesday, April 14th, 2021 AT 5:44 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
I've already had 2 pumps in it. I will let you know. Thanks
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Wednesday, April 14th, 2021 AT 6:09 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
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
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Friday, April 16th, 2021 AT 11:28 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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.
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Saturday, April 17th, 2021 AT 6:24 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
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
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Saturday, April 17th, 2021 AT 6:22 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
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.
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Sunday, April 18th, 2021 AT 3:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
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
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Sunday, April 18th, 2021 AT 5:33 PM
Tiny
WILLIAM SCHROEDER2
  • MEMBER
  • 19 POSTS
Right on. Thanks I will let you know.
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Sunday, April 18th, 2021 AT 6:02 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
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.
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Sunday, April 18th, 2021 AT 7:05 PM

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