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Shannon Martin
Shannon Martin, ASE Certified Master Technician
Category: Chevy
Satisfied Customers: 587
Experience:  over 20 years as a line technician both asian and domestic.
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Chevrolet Silverado 1500 HD LT: my truck will not start the

Customer Question

my truck will not start the first time you turn the key. it may take up to three times of turning the key before it starts. i have replaced the fuel pump, fuel filter, spark plugs, spark plug wires, and the fuel pressure regulator. what may be causing this?
Submitted: 2 years ago.
Category: Chevy
Expert:  Dave Nova replied 2 years ago.
Hello and thank you for trusting me with your question. My name is XXXXX XXXXX I will do my best to help you with your Chevy problem.
Does the starter engage and turn the engine over, just no starting?
Customer: replied 2 years ago.

yes it turns the engine over butt it may take alott of cranking before it actually turns on


 

Customer: replied 2 years ago.

the very first time you turn the key it will crank but not start. when you let off of the key and turn it again is usually when the motor will start. butt if you just hold onto the in the on position it will just crank and crank butt wont start

Expert:  Dave Nova replied 2 years ago.
With a new fuel pump and regulator, we will assume fuel pressure is okay. This would normally be the cause of a hard starting problem such as the one you have. Testing fuel pressure would still be a good idea. When turning the key on, the pump should run for 2 seconds to prime the system. You should get 55-62 psi fuel pressure with the key on, engine off.

If fuel pressure is okay then there are a few more things that could cause a hard start.

A possible problem is a vacuum leak at the intake manifold gaskets, this would cause a lean condition and hard start.

Another possibility is a weak crankshaft position sensor. If the crank sensor signal is weak, the PCM may not signal spark and injector pulse. The fix would be to replace the crankshaft position sensor. It is located on the passenger side of the block, the starter must be removed to access this sensor.

If you would like any additional information or have more questions please don’t hesitate to ask!

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Thank you,
David
Customer: replied 2 years ago.
the crank shaft sensor has also been replaced
Expert:  Dave Nova replied 2 years ago.
Has the intake been checked for vacuum leaks? Has fuel pressure been tested since the fuel pump replacement?
Customer: replied 2 years ago.
The fuel pressure was checked the same day the fuel pump was installed and a local michanic has checked the intake for leaks butt no one knows why it is doing this
Expert:  Dave Nova replied 2 years ago.
I am at a loss on this one as well. I will opt out and allow other experts to help you. Best of luck with your repairs!!
Customer: replied 2 years ago.

but i spent my money sir


 

Expert:  Walt-mod replied 2 years ago.
Hi,
I’m a moderator for this topic. Your Professional has opted out and I wonder whether you’re still waiting for an answer. If you are, please let me know and I will do my best to find another Professional to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!
Customer: replied 2 years ago.
i still need an answer
Expert:  Shannon Martin replied 2 years ago.
hi i am shannon i will help on this issue .i have read both your post .i would like you to try a test for me .when you believe the engine will not start. get a spray can of Berrymans carb cleaner. spray two seconds in to the intake just in front of the throttle body.open the throttle and spray into the intake. if it starts right up. you will most likely have a fuel problem. if it dose not then you will need to test for spark. that is harder so please post back your results .thanks Shannon.
Customer: replied 2 years ago.
Okay it starter when i sprayer the carb cleaner into intake
Expert:  Shannon Martin replied 2 years ago.
now you will need a fuel pressure gauge .it should be installed and left over night to see if the fuel system is losing pressure.and will not build up enough to start. the system should not drop below 25 psi. if it dose lose pressure fast enough to see on the gauge then you will want to pinch off the fuel and return line to see if you can stop the pressure loss. 1. if it stops from the fuel line pinch then its the fuel pump. 2. if it stops from the return line pinch then it the pressure regulator. 3.if you can pinch both and still lose pressure then its a fuel injector. this all assumes there is no external fuel leaks.
Customer: replied 2 years ago.
Its has great fuel pressure. It has a brand new fuel pump that is maybe 2 months old. I purchased a fuel regulator and it didnt solve the problem soo i took it back. And every so often you can smell gas when the truck starts
Expert:  Shannon Martin replied 2 years ago.
new parts fall that's is why there are warranties . try the testing you may have a leaking injector
Customer: replied 2 years ago.
Okay.. and you also said to leave it over night.. well the truck starts just fine in the mornings after it has been sitting it seems to have ita little spells if you rin the truck for a little while and then let it sit for thirty minutes or so
Expert:  Shannon Martin replied 2 years ago.
testing is the way . if you can get the engine to start by adding fuel or carb cleaner .the engine must not be getting fuel. first you need to know that the pressure is not dropping the only way i know to do that is with a fuel gauge.
Customer: replied 2 years ago.
The truck didnt start right off. It studderrd died and then it turned on.. would you say this would have anything to electronically since it happens to act when the truck is hot?
Expert:  Shannon Martin replied 2 years ago.
it is possible but you are jumping to a very technical issue to diagnose. must start with the basic first. if you prove there is no pressure loss over the time it takes for the no start. then you should test the electronics.to start that you will need a noid light and a spark tester.
Expert:  Shannon Martin replied 2 years ago.

i like this spark tester

graphic

Expert:  Shannon Martin replied 2 years ago.

graphic

Expert:  Shannon Martin replied 2 years ago.
graphic
Customer: replied 2 years ago.
I will try all the simple things butt im just trying to get all the info i can. Do you think it could possible be the maf sensor?
Expert:  Shannon Martin replied 2 years ago.
yes it can.try unpluging it when you think it will not start.it will not drive but it should start.
Customer: replied 2 years ago.
Okay and then would you consider checking the injectors. And when i do what will i be looking for to determine what is wring with them
Expert:  Shannon Martin replied 2 years ago.
not until i did the pressure test .but if it runs ruff on start up try removing the spark plugs and look to see if any are fuel fouled . just after a failed start attempt the one or ones that look rich. may have a leaking injector
Customer: replied 2 years ago.
Okay and one more thing. When it eventially starts it shakes and sputters and builds up power its not a smooth start
Expert:  Shannon Martin replied 2 years ago.
sound like you may have fouled out a spark plug or two. if you can determine which plugs are fouled . i would check those injectors.
Customer: replied 2 years ago.
Okay and where exactly are all the injectors?
Expert:  Shannon Martin replied 2 years ago.
graphic
Customer: replied 2 years ago.
Okay i used a fuel pressure tester and with key in engine off it shoots to 60 then drops to zero
Expert:  Shannon Martin replied 2 years ago.
thats bad it must mantain some pressure. now you need to do the fuel line pinch test. at the rear of the engine you will see two fuel lines one goes to the rail the other is the return line it comes out of the fuel pressure regulator. find where the plastic pipe is with a pair of big needle noise pliers clamp down on each line as you watch the gauge . you may need to cycle the key to get the pressure up.if the pressure still goes down after pinching off both lines you have an injector leak.
Shannon Martin, ASE Certified Master Technician
Category: Chevy
Satisfied Customers: 587
Experience: over 20 years as a line technician both asian and domestic.
Shannon Martin and other Chevy Specialists are ready to help you
Expert:  Shannon Martin replied 2 years ago.
i see you have given me a negative rating so i have opt out so your question will go back to all techs. can only give advice on the info you give me . with out testing and posting the results its hard to know what you see.please if you need more post what you have found .

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