Engine will crank but won’t start unless you spray starter fluid or fuel in it

Maintenance/Repairs
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1

I have a 1993 Chevrolet S10 blazer, i am facing a problem every morning or whenever i leave it more than 7 8 hours or so, the truck won’t start without putting some starter fluid or fuel in the intake manifold then it will run normally until its left for another set of hours. any idea?

2

Cycle the key on and off the energize the fuel pump to get pressure up to the injectors and see if that works.

If it does, you have leaking injectors or it is draining back into the tank.

2 Likes
3

I was thinking weak or dying fuel pump myself.

That’s where I would start.

4

i tried cycling the key dozen of times no response and i hear the fuel pump relay clicking every time i put in a new Central Port Fuel Injector Assembly with the new pressure regulater same issue

5

i thought as much but it the worst part to change have to dismantle the entire fuel tank to get to that or cut a hatch in the boot

6

If you can hear the fuel pump relay click, the fuel pump should run. Can you detect its whining sound for a few seconds each time you turn the key the Run (not all the way to Start)? It may be more audible if someone takes off the gas cap and listens at the filler neck.

A new fuel pump can be bad, but a wiring problem seems more likely if two different fuel pumps have made no diff. Good luck and please let us know what you find.

7

i haven’t changed the fuel pump yet but i think changing it is the best choice for now thanks will keep you posted

8

Sorry, I misunderstood the part you changed. Can you test the wiring to the FP (downstream of the FP relay) to see if there’s 12V there for those moments when the key is turned to Run? The relay may be bad, or some connection between it and the pump.

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yes i will in the morning while its cold as during the day as it ran the first time it works all day

11

If you give all of the information when you first post, you will get better answers.

There must be a test port some place on your fuel rail where you can test fuel pressure when it won’t start. I would check with Advance or Autozone to see if they have a p.ressure gauge in their tool loaner program.

1 Like
12

Thank you richard till now all indicate its the pump and will change it for sure

13

i think changing fuel pump won’t hurt after i got all the feedback saying i should so and as long as i remember since i got it in 95 i haven’t changed it

14

If you would rather change your fuel pump rather than test to see if that is the problem, it is fine with me.

15

i will surely test everything i can on the way making sure all is well but i think its time to change the pump

16

There is a small cable in the engine compartment that connects directly to the fuel pump i think intended for testing when i connect it directly to 12v battery the car starts as if nothing is wrong what does that mean?

17

If you have a fuel pressure master test kit . . . the one with countless adapters . . . deadhead the fuel pump and report back to us

In any case, you have several symptoms of a bad fuel pump

18

If that always makes the fuel pump run, the pump is working and the problem is upstream of the pump: its wiring, connections, relay, or ignition switch. Look at a wiring diagram and see what’s between the battery and the fuel pump.

1 Like
19

sure, the pump runs . . .

I’m concerned if the pump is strong enough

That is why I’m asking op to deadhead the pump and report the results

I’ve worked on enough vehicles where the pump always energized, but didn’t put out enough pressure to reliably start the vehicle

20

That info isn’t needed if the pump runs and the car starts and runs OK even under high fuel demand.

21

I think the problem is the fuel pump.

The CPFI system requires high fuel pressure to blow open the poppet valves at the fuel injectors. The fuel pressure required is 63 PSI.

The couple of seconds the fuel pump runs when the ignition turned to run before starting the engine might not be developing enough fuel pressure to blow open the poppet valves. So the engine doesn’t start.

But if you prime the engine with starting fluid so the engine starts/runs, or apply a constant voltage to the fuel pump so in runs long enough to develop the proper fuel pressure, this allows the poppet valves to be blown open, and the engine starts/runs.

Tester