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My truck has trouble starting in the morning.


Guest nwilliamson1022
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Guest nwilliamson1022

After sitting over night my truck(2000 chevy blazer) turns over but doesn't want to start. My husband has been having to spray starting fluid into the engine for it to finally start. My neighbor keeps saying it's the fuel pump but im not having any trouble with fuel pump signs of it failing. My father n law said it could be the crank shaft sensor because the check engine light us on and it's getting bad gas mileage. I need help before my husband replaces the fuel pump and that's not the problem

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Is there some reason you have not Attended to the check engine light to ascertain the problem ? Wayne

X2, too bad for the owner the car is OBD2, at least a OBD1 car's ECM can talk to you direct without a scanner.

Edited by helfen (see edit history)
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you need to have the fuel pressure checked --the pump may be working but if pressure is on the low side of the specs. the injectors will not fire properly---I have seen this on may Blazers---they will not start cold but will start hot most of the time.

the other problem we have with them are bad cap and rotor ---but it sounds like a fuel pump with low pressure --need to check this on a cold start to get the proper reading --Allan

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Turn the key on for 2-3 seconds, then of for 2-3 seconds, then on again for 2-3 seconds..

Do this key cycling 3 times ...then try to start the truck....if it starts right up fuel pressure is bleeding off.

Possibly fuel pump check valve or leaky pressure regulator or injector (s).

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After sitting over night my truck(2000 chevy blazer) turns over but doesn't want to start. My husband has been having to spray starting fluid into the engine for it to finally start. My neighbor keeps saying it's the fuel pump but im not having any trouble with fuel pump signs of it failing. My father n law said it could be the crank shaft sensor because the check engine light us on and it's getting bad gas mileage. I need help before my husband replaces the fuel pump and that's not the problem

How about a little common sense?  If the truck runs AT ALL, the fuel pump is working.  Replacing it is a complete waste of time and money.

 

As noted, the most important troubleshooting step is to turn the key to RUN and listen for the pump to run for it's two second priming.  These trucks activate the pump when you first turn the key to build fuel pressure to ease starting.  You might need to have someone listen at the open filler neck to hear the pump run.  If you don't hear it, that is likely your problem.  The priming function typically operates separately from the normal pump operation.  The computer sends a signal to the fuel pump relay to activate the pump for a few seconds.  Failure to prime could be something as simple as a bad fuel pump relay.  Hard starting COULD also be the result of a crank sensor, sticking injector, or a whole host of problems, but again, if the truck runs at all, it is NOT the pump itself.

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How about a little common sense?  If the truck runs AT ALL, the fuel pump is working.  Replacing it is a complete waste of time and money.

 

As noted, the most important troubleshooting step is to turn the key to RUN and listen for the pump to run for it's two second priming.  These trucks activate the pump when you first turn the key to build fuel pressure to ease starting.  You might need to have someone listen at the open filler neck to hear the pump run.  If you don't hear it, that is likely your problem.  The priming function typically operates separately from the normal pump operation.  The computer sends a signal to the fuel pump relay to activate the pump for a few seconds.  Failure to prime could be something as simple as a bad fuel pump relay.  Hard starting COULD also be the result of a crank sensor, sticking injector, or a whole host of problems, but again, if the truck runs at all, it is NOT the pump itself.

Then there was my 1992 Chevrolet Cavalier that over the course of about a year started running worse and worse at times. Became more and more a problem. Tried everything I could think of. I took it to a local shop that I use occasionally when I am at wits end. They measured the fuel pressure. So low they couldn't believe it ran. I changed the pump. All problems solved.  It still ran with the bad pump, just not very good.

Edited by plymouthcranbrook (see edit history)
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The injectors on that engine have a 50 psi spring loaded valve that has to be overcome before the fuel reaches the electronic valve that is opened by the PCM.

A weak pump may not be able to make 50 on just the 2 second prime.

But will once the engine is started and the pump runs constantly.

Have fuel pressure tested. With just the key cycled to run, if it hovers around 50 or a little less you need a pump.

A good pump will have 60-66

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By the way I was a tech at a chevy dealer 23 years

If I had to throw one part at it with no more information , it would be a fuel pump.

Make that 2 parts ,put a fuel filter on it too, that old pump may have filled it with debris

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all I will add to this is start with fuel pressure test ---it needs to be in factory specs. --- not saying I am correct just start there--if it is low the injectors will not spray --- I do run a repair shop and we find many with low pressure. do the test cold. this motor should have a test port on the fuel rail. -- low pressure can be due to pump and or plugged up filter but we have found most of the blazers will be a pump that runs but the pressure is to low..this is where we would start if brought in to my shop.--Allan

Edited by 32plywood (see edit history)
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I need to add you do need to scan the engine lamp -- most of the time it will be something different with the emission system but the motor will start and run. the engine lamp on will put motor in open loop and fuel mileage will be bad. ----DO the testing first then the repairs--Allan

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Guest AlCapone

Is the fuel filter clogged ? After fixing the engine light this would be my first step. Even if it is not the problem it likely needs replacing. Wayne

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Guest AlCapone

If the fuel filter was CLOGGED, NO fuel would pass through such, dirty filter is a possibilty.

Dale in Indy

The filter does not have to be totally clogged to cause a problem, it can indeed be partially clogged!

Wayne

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How about a little common sense?  If the truck runs AT ALL, the fuel pump is working.  Replacing it is a complete waste of time and money.

 

As noted, the most important troubleshooting step is to turn the key to RUN and listen for the pump to run for it's two second priming.  These trucks activate the pump when you first turn the key to build fuel pressure to ease starting.  You might need to have someone listen at the open filler neck to hear the pump run.  If you don't hear it, that is likely your problem.  The priming function typically operates separately from the normal pump operation.  The computer sends a signal to the fuel pump relay to activate the pump for a few seconds.  Failure to prime could be something as simple as a bad fuel pump relay.  Hard starting COULD also be the result of a crank sensor, sticking injector, or a whole host of problems, but again, if the truck runs at all, it is NOT the pump itself.

 

Not true.  If the truck will run any time at all it could be the fuel pump is on the final stages of its life.

 

Let me take a guess that the truck has maybe 135,000 miles +- 10,000 miles.

 

If you put a pressure gauge on the fuel rail which I think the port is at the back of the fuel rail that attaches to the fuel injectors.  It is a Schrader valve and takes a gauge that has a Schrader valve attachment.

 

The fuel pressure on the truck should be about 55 psi +- maybe 5 psi if my memory is good.

 

The truck will run sometimes at the low 40's psi but not consistently. 

 

If it does not have at least 50 psi, change the pump so you will not be in tennis shoe mode in the near future.

 

Just my experience changing a lot of those pumps.

 

A scanner will not find low fuel pressure.

 

PS: just be sure to change the fuel filter at the time you change the pump.

 

32plywood

you need to have the fuel pressure checked --the pump may be working but if pressure is on the low side of the specs. the injectors will not fire properly---I have seen this on may Blazers---they will not start cold but will start hot most of the time. the other problem we have with them are bad cap and rotor ---but it sounds like a fuel pump with low pressure --need to check this on a cold start to get the proper reading --Allan      

 

Allan is correct    

Edited by Larry Schramm (see edit history)
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I'm with Larry and Allen. Had a problem with my 96 Buick Century Running like Crap a number years ago. It only had like 50 something thousand on it to boot but time and the age of the parts can work against you. First problem was a bad wire that went from the starter to the Fuel pump relay that made it not run at all. After I had that solved, it had very low power and did a lot of skipping. Got a pressure gage and took a reading. It was way low and everyone said it should not even run at that amount. As memory serves me this was actually a pump that I replaced already when it did not run from the faulty wire problem. Just my bad luck, A lemon. Picked up a new pump and put it in. No problems since and the car now has around 85,000 miles on it. Dandy Dave! 

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