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Chevrolet S-10 Truck Starting Problems Answered

1994 Chevrolet S-10 4.3 tbi. I never get the signal to turn on the fuel pump or fire the injectors but if i poor gas in the intake once the truck starts it runs fine. Any ideas ? I have replaced the fuel pump relay oil pressure switch and computer.

ProTech:
If you’re not getting a signal for fuel, then you either have a faulty crank sensor, or bad ignition module.

But the truck runs great until you cut it off. If you poor a little gas in the intake to get it started would that only effect the starting ?

Ok. If it will start by adding fuel to the throttle body and stay running afterward, then you have a bad fuel pump.

Don’t understand ???? Pump runs and can drive the truck at highway speeds. Pump nor injectors work while in crank mode.

User 551, let’s start from scratch. Are you checking for power at the fuel pump when you’re cranking the truck? And how do you know they don’t work? Do you have a noid light on the injectors?

Yes and have nothing.

Well getting to start by adding fuel to the throttle body is not going to turn on some special switch that will send a signal to the pump and injectors. I’m sure you probably just have a bad fuel pump that doesn’t have enough pressure or volume to start the truck, but at running speed can keep up.

Ok but I straight wired the pump and can ground the blue and green signal wire on the two injectors at will spray fuel then you can turn the switch over and the truck will run on its own . Trust me I know it makes no sense. Been turning wrenches a long time and I don’t understand it. Just can’t afford to throw money at it.

That’s a new one on me. There’s no way you have no signal, but then starting the truck by adding fuel will then turn on the injectors and pump. That’s just crazy. Good luck with that one.Chevy truck fuel Pump Assembly picture

Once the truck starts and is running you can remove the jumper to the fuel pump and it will continue to run.

I’m at a loss, you’re on your own on that one. Good Luck.


Chevy S-10 Won’t Restart

It turns over fine. Sometimes starter fluid seems to help, sometimes not?

Hard to say exactly why that is happening. It could be a fuel pump that is going bad, or an ignition problem, or even a computer issue. I would recommend a fuel pressure check just to make sure it is within specs.

I also asked you if the check engine light comes on at all?

Sorry I missed it? No the check engine light doesn’t come on.

OK it’s a good thing then that the check engine light doesn’t come on, as that would rule out a probable sensor issue. I would get the fuel pressure checked to start with, because that’s where the problem is most likely to originate from.

Thank you sir.


Throttle Body

Hey fellas I’ve got a 1998 Chevy s-10 that suddenly died on us, thinking it was the battery like AAA guy said we replaced it but the truck still wont start- might turn once then goes absolutely dead. have checked fuses, not getting any juice to the fuel pump- even tried to direct wire from battery to fuel pump and nothing. now if you pour gas into carburetor it’ll run fine till gas is gone ( i know not real smart ) but we’re not having any luck finding the ground wire either thinking maybe it was just losing ground..ive had four men look at this –any advice would be greatly appreciated.

Do you mean throttle body? Your truck would not have a carburetor on it.

Yes, throttle body.

OK that’s better. But I’m still a bit confused. You say it will go completely dead, but if you pour gas in the throttle body it will run? So it is going dead, like a dead battery, or do you mean it just won’t start, but it will crank?

Cranks fine like its not getting fuel

OK so then it’s NOT going complete dead. Have you done a fuel pressure check?

Yes but there’s no pressure. Fuel pump will not kick on.

So you could have a faulty fuel pump, a bad fuel pump relay, or even a bad computer.

Relay tested good.

OK then that leaves fuel pump or computer.


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23 comments to Chevrolet S-10 Truck Starting Problems Answered

  • chance

    I have a 2002 Chevy S-10 4.3L and it is losing fuel pressure as soon as the pump shuts off and I replaced the pump and the pressure regulator and it still loses pressure. Any ideas what could be wrong?

    • Mechanic JK

      Hmm. That is a good one. About the only thing that can cause a leak down of pressure IS the pump or regulator. Make sure you do not have a leak anywhere. When it starts, see if there is a puff of smoke from the tailpipe and see if it it runs rough. You may have an injector stuck wide open. If that all checks out good, then you may have fixed it with the fuel pump, but got a bad new one doing the same thing. Using fuel line shut off tools to determine which way it is leaking back will tell you if it is in the tank or engine side.

  • Dee

    my s10 is hard starting when cold,and when it starts it has a continues miss.

    Protech: A couple different things can cause a situation like this, and are mostly fuel related. Usually, a tell-tale sign of a fuel pump that is going bad is a hard starting condition when cold. You might want to start with a fuel pressure check just to see if it’s within specs. You should have at least 50psi with the key on and it should hold steady. Any lower than that and you’re looking at a bad fuel pump. Also, low fuel pressure or volume can lead to misfires. Faulty fuel injectors can also lead to a misfire condition as well but depending on the year of your S10 Pickup there is really no quick way to test them. A scanner would come in handy to see which cylinders are indeed misfiring so you could concentrate on those only. You may also want to check ignition components, as things like a distributor cap that has corrosion inside, or a corroded rotor can cause these same conditions. As you can see, there is lots to check. Good Luck.

  • joe cobb

    1999 S10 4.3 eng some times want start in driving and some times after drivig. Did pressure ck. ok but bleeds off after eng. is turned off. ive found the lower intake gasket is leaking and may be getting in to the oil the oil pressure is higher than normal looks like 3 qt”s over after fixing these will that efect the fuel pump problem

  • joe cobb

    1999 S10 4.3 eng. will not start sometimes after driving pressure bleeds off after the eng is turned off is the fuel pump bad?

    • Stan

      The oil is overfull? Make sure it is not from gas. If it is that would explain the pressure bleeding off too. That would be caused by a bad fuel pressure regulator under the intake.

      If that is not leaking, the you need pinch off the return fuel line and the then the fuel feed line to stop the bleed back. This will tell you if the problem is the fuel pump or after the pump- like the regulator or an injector.

  • stevel

    My 01 chevy s10 wont start tested fuel pressure its good I checked cam shaft position sensor it reads at 11v I replaced fuel filter spark plug wires cleaned plugs and distubter cap and roter I have spark and good fuel presdure but don’t know if fuel is reachin the throttle body injectors please help.

    • Admin

      You would have to have a fuel pressure gauge and a scanner to turn on the injectors one at a time and watch for a pressure drop to confirm if the fuel injectors are firing or not. Make sure your pressure is at least 55 PSI. Even 1 lb. less, it will not start.

  • troy

    1999 s10 2.2 engine will not crank unless throttle is wide open

  • troy

    What is the problem is it in the fuel

    • Techjk

      I thnk you mean the engine cranks but will not start unless the throtle is wide open. Check fuel pressure. Check for a leaking fuel pressure reguator causing a rich condition. The oil would smell like gas.

  • DannyBoy

    Lifter noise finally at 174k miles, lol. Heres my beef; TWO WEEKS OF LIFTER NOISE AT START UP AND TEN MINUTES OF DRIVING TIL IT QUIETS. BATTERY IS TWO YEARS OLD, WHATEVER, CHANGED THE FUEL PUMP 3 OR 4 YEARS AGO. ANYWAYS, IT SHUT OFF WHILE DRIVING STILL HAD ELECTRICAL NO ENGINE. I HAVE A CHECK ENGINE LIGHT ON FOREVER AND CODES READ CRANK SENSOR, HOWEVER, IT STILL RAN. NOW IT JUST CRANKS, WONT START
    IF YA HAD TO GUESS??????????

  • russ

    1999 s10 2.2 New pump no power to the relay and no fuel pressure

  • cesar

    I have the same problem not getting any signal to the injectors on a 94 2.2lt checked fuel pressure and different sensors basically it will run for a couple of mins then its like the injectors just cut off no signal at all anybody have a clue to this don’t what else to do to it

  • Stan

    94 s10 new full pump has good presure new plugs wires rotor button dis cap don’t think it’s getting fuel to injectors how can I check no check lights on

  • david

    I also have 95 s10 2.2 not getting ground pulse from computer to injectors truck shut off and changed fuel pump ,pressure regulator ,computer,crank sensor checked all grounds on truck has spark has great fuel pressure just injectors not firing on.

  • jerry

    I have a gmc sonoma 4.3 v6 , i had a faulty fuel pump and replaced it and now it will only start if i pour gas into the throttle body and then it will run until i turn it off and then it will not crank? what do you think is the problem?

  • jerry

    i mean that it will not start again until i pour some more gas in this 98 sonoma/

  • Anonymous

    Is there a sensor that works with the injectors? Because my works with the fuel in the throttle body but when you turnoff injector are not spraying. I changed fuel pump and filter and injectors too.

  • walter

    i have a 2000 chevy 1500 4.3 v6 im not getting a ground to the injectors i am getting positive to the plug on top of the spider injector any ideas

  • walter

    where does the ground come from

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