My truck is hard to start?

Either not enough fuel pressure or a clogged catalytic converter. You can borrow a fuel pressure tester from the local parts shop and hook it up to the test port. Turn the key on, and you should get a reading of 55-62 psi. With the engine idling, you will see a drop, which is not laid out by GM. But I would think it should still stay above 45 psi. If it drops as the engine warms up, then you have found your problem.

this guide can help us fix it

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

The test for the catalytic converter is a little simpler. The problem with a clogged converter is that the exhaust cannot get through fast enough, so it creates back pressure on the engine, keeping it from breathing and causing it to bog down and generally runs bad. The test is to simply take the upstream oxygen sensors out and go for a ride. Yes, it will be "make the neighbors mad" loud, so do it in the middle of the day. If the truck runs noticeably better, then your problem is the catalytic converter.

Does that make sense to you? Let us know what you find.

When my truck starts hard, it runs ok until you let off the throttle. It will hesitate for a split second. When it starts ok, it runs fine. Lately I've been getting dtc P0131, P0137, P0151, and P0157. I have replace the fuel filter and cleaned the EGR valve. Please, any Ideas?

Hello,

It sounds like the fuel pump is going bad but to be sure this guide can help us fix the problem.

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

Please run down this guide and report back.

Replaced the fuel pump. Now it starts fine.

i have a chevy 1500 hd 6.0 sometimes you have to spin it over 3 or 4 times before it starts once warm does fine!!!! please help chris

Try checking the fuel regulator or fuel pump.Sounds like the regulator is leaking fuel into the system .Then when you try to start it ,it cranks over several times to expell the excess fuel..Test with a fuel press gauge.

Trying to fix a problem where my Silverado will not start the first couple times. Starter seems to be working fine, but engine won't start to run until after 2 or 3 times of cranking it. Seems pretty certain to be a fuel pressure problem from what I have read so far. Added fuel injector cleaner, no help. Replaced fuel filter, no help. Ready to replace fuel pressure regulator, but can't find the dern thing. I assume it is leading up to potentially the fuel pump, but trying the cheaper stuff first. If anyone can point me to where the FP regulator is and how to get to it, I would appreciate it.

Chances are the fuel pump is pumping fine, but loosing its prime when the key is off. The schrader valve is on the fuel rail to check pressure. Here is a how to for checking pressure. WHen you check it, pay special attention to fuel pressure drop off. THat is when you shut the key and the pump is off. Does the system maintain pressure???

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

Let me know what you find.
Joe

Joe-

Thanks for the input. I ended up taking it to a shop just to diagnose. For 40 bucks they told me it's the fuel pump. Are there more questions I need to be asking them about what they found?

Jeff

Really there are no other questions. If the pressure is low, that will cause the problem. Unless, there is a leak in the system. Did they tell you that it was loosing its prime (fuel pressure drop off)?

I dont know if this is a computer issue or not but it takes 2 or 3 trys to start my truck. I had the fuel filter changed and it still not starting right. what else should I look at ?

Thanks

You need to check fuel pump pressure, the regulator, and fuel pressure drop off. Drop off is when the key is turned off. The system should maintain pressure. If it doesn't, you lose the prime and it will take a few tries to start it. Here is a how to for checking all that I mentioned. You will need a fuel pressure gauge. Most parts stores will lend them to you.

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

Let me know what you find or if you have other questions.

Joe

I have a 2001 chevy silverodo 2500hd with a6.0 v8after the first start no matter what time of day it is the only way this truck will start is if I step on the gas peddle then everything is fine.Ive changed idle steep motor,plugs,air and fuel filters,cleaned the throttle body,check fuel pressure key on engine off 60 psi,check for vacume leaks and found none.this truck has 180,000 miles on it but once it starts it has pleanty of power.bought this truck and the only thing that was done assording to the prev.owner was cold air kit and headders.Ant suggustions? Also truck onlys gets 10 miles to gallion

Using a fuel pressure gage, how fast does the pressure bleed off, everything turned off? Maybe the fuel pressure is bleeding into the engine?

I haven't checked that yet but if I start the engine and then shut it off and then try to re start it right away the same thing.I know it holds pressure for 10 min with out droping off at all.How long should the fuel system stay pressured and what is the dropoff rate

If pressure holds that long, sounds good. Did you take the throttle-body off and clean it?

yes

just got a code po300 engine misfire detected

could I possibly have a bad map sencer,not bad enought to through a code but in the begining stage of going bad

Something common to all your cylinders, fuel or air, egr? You may need to use a scanner that will show live engine data. You can use a dmm to look at some sensor signals, engine running. If you suspect a sensor. At idle the map and tps usually show close to the same signal voltage, may not exact to the tenth of a volt, but close.

r placed spark wires they were oem truck runs great!

Nice work, we are here to help, please use 2CarPros anytime.

I have a chevorlet 2000 silverado 4x4 5.3 here lately its been hard to start before it would start on the first try and now it take about 2, 3, 4, cranks before it starts any ideas where to begin

Start by checking fuel pump pressure. I am most interested in drop off pressure. That is when the key is turned off. How quickly does the pressure drop.

Here is a how to for checking. Let me know what you find.

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

about 50% of the time the truck will crank over but will not start. When I hit the starter 2nd time it fires right up. It had a new fuel pump put in about 30,000 miles ago and I never let the truck go below 1/4 tank, so I don't think it the fuel pump. It has had this problem for about 750 miles, and I'm afraid that it will not start someday. Thanks for your help Brad

Brad, try this. Turn the key from off to the run position and wait a few seconds each time. Do it 3 times and on the 4th, see if it starts quickly. Even though you have a newer fuel pump, that doesn't mean it is building pressure quickly enough. There could be a leak bleeding pressure from the system, the pump may be getting what I call, lazy, there could be a fuel pump relay issue...

Vehicle only has 32,000 miles. Battery is good, air filter clean. When starting cold (as low as 20 degrees F) the truck starts fine. When hot it starts fine. Problem is that if I shut the truck off for more than 10 - 60 minutes, it cranks many seconds before starting. My solution (as the manual states) is to push the accelerator to the floor and then, the truck starts right up. I've tried the three time ignition trick (holding the key on for three seconds each time) and this seems to have no effect. Problem seems to be heat related or vacuum loss. Does this problem sound familiar? Thank you

Hello,

This sounds like one of two things either the fuel pump is weak or you have a fuel pressure regulator leaking into the vacuum line which these trucks had problem with. Here is a guide to help you test it.

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

Can I ask if the truck is a z71?

Please let us know what you find. We are interested to see what it is.

Cheers, Ken