My engine is hard starting

Good morning

From your description and the key is putting the fuel pedal to the floor, it sounds like it is flooded. by putting the pedal to the floor, it goes into clear flood mode.

This indicates an injector may not be sealing when the engine is turned off. that will allow fuel into the intake system.

if you can check the fuel pressure with a gauge, there is a port on the fuel rail, you can monitor the pressure. let the truck get hot and then turn it off. watch the pressure and see if it drops off.

These guides can help us fix it.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

and

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator


Roy

2000 Chevy Silverado 5.3 Vortec Starts very hard when it's cold(it loads up, once it starts and gets the excess fuel out it runs fine)

has the check engine light come on? It sounds like a temp sensor, but I can't be sure without the code.

Let me know.

Air temp sensor?

The engine temp sensor. It tells the computer what the ambient temp is as well as the coolant temp sensor. With that information, the computer determines how rich to make the fuel mixture to start the engine and keep it running. If the temp sensor tells the computer it is -40°F outside, it will dump fuel to start and maintain the engine.

Let me know if you have other questions.
Joe

It has a 5.3 liter. if engine ran for a while and shut off for 20 min or more it doesnt want to start untill i press the gas pedal. if left over night it fires right up. I ran full diagnosis and no codes and nothing wrong. I have replaced the IAC valve, plugs and wires, didnt help. truck runs good and drives fine good idle @ 600 RPMs. I am at a loss as what to do please help

check for fuel leaking into the vacuum hose to the fuel pressure regulator.

i checked the vacume line from the regulator and there was gas in the line. I replaced it and seems to be working good now. thanks a million!

Engine Mechanical problem
2000 Chevy Silverado 6 cyl Two Wheel Drive Automatic 241000 kilometers

first start of the day is a hard start warm or cold shop crank and crank and finally fires up .
after first start it runs fine no missing at all .
i shoot some carb cleaner in the throttle body and it fires up right away. no check engine lights come on or anything .

It sounds like low fuel pressure. What I need you to do is check fuel pump pressure. Here is a how to:

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Pay special attention to fuel pressure drop off. THat is when you shut the key. Does the system hold pressure or does it drop quickly?

Let me know.

Joe

thanks for the advice that,s exactly what it was

This truck has been hard to start since I got it over a year ago. Now I am trying to fix it. 75% of the time it takes a few couple second cranks before it turns over and when it does it takes a second to get up to idle rpm's where it will run okay. I do not notice any other problems besides the starting. I have cleaned MAF and throttle body and it may have helped a little but still does it. It has thrown a code for running rich in both banks and random misfire a while back. I am not sure where to start but would like to know your opinions.

Hi and thanks for using 2CarPros.com.

Since you are getting a rich code, the first thing I would check is the coolant temperature sensor. This sensor tells the computer how rich or lean to make the fuel mixture. What you need to do is this. Get a live scanner. With the engine cold, scan through until you come to the coolant temperature sensor (CTS). The CTS should be telling the computer the coolant is about the same temperature and ambient temperatures. If it tells the computer it is -40 degrees F (that is an extreme) the computer will react by providing a rich fuel mixture for the vehicle. Thus, it will be hard to start, run poorly. I attached a picture of the sensor location if you find that is the problem.

Next, if that is fine, you need to check fuel pump pressure. If there is a faulty fuel pressure regulator, it will cause the same issues. Here are directions for checking pressure and the regulator:

Fuel pressure should be: Key On Engine Off 60 - 66 psi

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Okay, one last thing. If the fuel pressure is good, then I question if there is a leaky fuel injector.

If the check engine light is on and this information does not help, let me know all the codes which are found.

Take care,
Joe

Thank you I will try this and get back to you.

Sounds like a plan. Let me know what you find.

Take care,
Joe

My truck will not start when warm. I replaced the fuel pump, fuel pump relay, plugs and plug wires. The dealer replaced the fuel pressure regulator, fuel filter, and cleaned the throttle body. The truck starts normally when cold and runs fine at all times. However, when the engine is not cold, it won't start on the first crank. It always starts on the second crank. I know the injectors will run much leaner when the engine is warm, its seems as though they're running too lean. Any suggestions you could offer would be appreciated.

HAs it ever given any codes? (check engine light) What brand fuel pump was used? I have installed customers aftermarket pumps just to take them right back out for low pressure/flow

no, check engine light has not come on at all. fuel pump was bought from Chevrolet dealer. It looked identical to the one that came out of it. If I wait less than 5 minutes to restart it when warm, it usually starts the first time.

i would look at the fuel pressure regulator again. its simple to check. just remove the vacuum line and see if gas is present. if it is or the hose is soft. replace the regulator again.

pressure regulator is fine - hose is firm and dry, no gasoline is present. Today I let it crank for about 10-12 seconds, still didn't start. Still started second time no problem but there was a distinct odor I noticed from inside. Not sure what it was but i think it may be related.

I have a 1999 chevy 2500 with U motor. I just replaced the in tank fuel pump and also the fuel filter after I started to have starting problems and then it seemed to run sluggishly under load and just now 1200 miles from home, I just barely got it to my brother's house with lots of popping and no power. I have gotten two incidences of low oil level requiring adding 2 quarts of oil. I do get a smell of oil when it does start (usually 3 to 4 cranks). I don't want to get stranded and I don't want the expense of a dealership if I can help it. I am stranded and need a response quickly. I am standing by at the computer now.

Do this find the fuel pump relay start the truck and then remove the fuel pump relay tell me what happened.

Starter engine (two cranks) removed fp relay and enginer stallled. Swapped out a/c relay,isolated O2 sensors. I am getting a little ticking sound that appears to come from the front of the engine and is engine speed dependent.

Also, can the fuel pressure regulator when failing or failed produce the same hard starting symptoms due to not holding fuel in the fuel rails and if failed would operation of the engine become sluggish w/o power (liken to fuel starvation).

When you turn key to run do you hear the fuel pump? If so check the fuel pressure and comeback with the readings.

I do hear the pump running and also I get spray of fuel from fuel port (need to get a pressure gage ??) to get exact number.

A local chevy tech suggested that the fuel pressure regulator may be suspect. There is vacumn supply to it, but he suggested that it may be responsible for allowing fuel in the fuel racks to drain back to the fuel tank and have to be recharged before starting. Comments, please

when i turn over the engine on my 99 silverado, it usally takes a few seconds to start, and when it does, it slowly chuggs up to the idle speed, almost as if it wasnt getting any gas. i have recently replaced the fuel pump and filter, done a fuel intake cleaning service, changed the air filter, cleaned the intake manifold at the butterfly valve, changed the spark plugs. and yet it still has this problem. im not sure if its a problem with the fuel injectors, or mabey the computor. but once its started and at idle speed, it drives just fine, every once in a while when i come to a stop, the idle drops down but then chuggs its way back up. any idea of what the problem might be?

Check the idle air control valve, throttle position and coolant temperature sensors by using the repair manual

also check the mass air flow sensor, if it is going bad it won't read the correct air intake and you won't be getting enough fuel into the motor.

If the truck sits for a few hours it takes longer than normal to start. If I drive the truck for a while shut it off and then start it again it will fire right up. Any suggestions?

What it sounds like you are describing is an extended crank. Most often the cause of this is a failed check valve in the fuel system(pump), which is allowing fuel pressure to bleed down over time. The extended crank is a result of the pump having to build pressure from zero, to a range where the engine will fire. You can test this theory by cycling the key on a few times, 15-30 seconds apart. This will provide a few 2 second cycles of the pump to build rail pressure. It most likely will not have the extended crank after this. To correct it, replace the fuel pump, and also the filter if it has been some time.

If I cycle the key 3 times as described the truck will fire right up. We replaced the fuel filter the other day and after sitting all night the truck fired right up in the morning. After the truck sat again for 4 hours it had the extended crank again. Just making sure there arent any more possibilities before I replace the fuel pump

To be more accurate on the diagnosis, you would need to install a fuel pressure gauge. This would certainly confirm what is suspect at this point.

Need to crank engine six to eight times before will start. Also, sometimes come out and battery is drained. Once I was told horn was going off constantly for hours until stopped. Because battery was drained.Disconnected horn and relay.

Good morning.

When it does not start, you need to check a couple of things.

See if it has spark.
Can you hear the fuel pump run?

It could be a bad fuel pump where the check valve is bleeding back and not allowing fuel pressure to build.
It could also be a bad crank sensor as well.

Roy

Fuel pump runs.Not sure about spark. But always seems to start after six to eight cranks.

okay, I would still check the actual fuel pressure. there is an access port in the fuel rail back by the distributor. if you do not have a tester, you can rent one at a parts store. need to verify if correct pressure is being produced by the pump.

on the dash, you have a tachometer that measures engine speed. when you crank the engine, does the needle move up a little while cranking?

Roy

I have checked that port by pushing down on relief valve and fuel shot out immediately. But I probably still need to check pressure. Also, I just went out to see if tachometer moved while cranking and of course it started first crank.

yep, you need to do the testing when it will not start.

Roy

Where and what does the crank sensor do?

The crank sensor is in the oil pan.

it sends a signal to the PCM that the engine is turning and commands the ignition system and fuel system to turn on.

Roy