hard starting 1990 k-1500

[57 3100]

guys,
i have a 1990 k-1500 4x4 with 5.7, 350 v-8 with 140k mileage.
lately on some days, when hot, a turn of the key will crank it over as normal, but wort start, like there is no spark or fuel.
3 years ago when i first purchased it at about 115k miles, i put a new ignition module and coil on it, and just recently tuned it up completely with rotor, cap and plugs. wires were replaced 3 years ago. about 1 year ago i had a new fuel pump and relay installed.
wonder if i should start by installing a new ignition module and coil, since those are easy to access ?
hope it aint a fuel problem again.... i really dont care much for these injected motors... i like old school manual fuel pumps and such.
when it wont start, i turn the key off, try cranking again, and most times will start the second time. a few times i had to do this 3 times before it would start. once started, it runs fine and smooth and never cuts off once started.
leonard
any thoughts guys ?
thanks

[speedygonzales]

Ever have the problem the next day when parked over night and its cool in the morning?

[57 3100]

not yet, only when the engine is at running temperature, like when i go inside a store and come back out....... only when hot.
thanks

[speedygonzales]

I had that problem with my 84 TransAM which was TB fuel system. Later after I got rid of the car I found out the fuel in the bowl was boiling away. What this created was a problem just after start up when I would lets say pull out of a parking lot, the engine would fall flat on it's face. Then pick up and be fine for the rest of the trip.

Never had a problem on the next morning restart.

Here's an explanation of 2 things that I think will help you. I think somewhere along your fuel system you are developing an air bubble. Sort of like vapor lock.

Right now I have a problem with the check ball in my fuel tank. After sitting for extended periods of time, the fuel is draining back into the tank. So what happens is extended crank times until the fuel line is filled up again. What I do in this case is turn KOEO for 3 seconds. Then key off. Then KOEO again and repeat this 4 or 5 times. Then finally crank the engine over just like times of old. Fires right up on first try. BUT if I forget and just turn the key to the crank position, takes many rotations before it fires up since the fuel line has to refill first.

Yours is not like that since the mornings are fine. If your check ball in the fuel sending unit were bad like mine, the longer it sits, the worse the cranking time gets.

I'm sorry but I'm not familiar with your fuel system. If it has a schrader valve, get you a fuel pressure gauge with a long hose and run it up to the windshield and tape it so you can see it while driving.

Watch it while running normal and see where it is. Now watch what it does when you have the problem. Now watch what it does when you try cycling KOEO a few times like I described before finally cranking it over.

The only thing that fits into your problem is an air bubble developing in the fuel system.

If you think about the injectors, the fuel filter(I would still change it), fuel pump. All of these things would effect a cold start as well.

Hopefully you will vindicate me by monitoring fuel pressure during good and problem times and report back what you found.

[ChevyTech]

Do the injectors drip after you shut off the engine?

See if it has spark, or if the injectors spray fuel, when the problem is occurring.

[57 3100]

wow, thanks guys. when i get a chance i will look into each of these suggestions. i did replace the fuel filter a while ago, but never touched the injectors. i never have messed with anything fuel injected related, so dont know much about them. i think the tbi injectors are just held in there with one screw, and easily accessible ?
i got a 57 chevy 3100 truck with a 1980 sbc and can work on that motor all day long.

thanks again guys

[ChevyTech]

You're welcome!

Originally Posted by 57 3100

i never have messed with anything fuel injected related, so dont know much about them. i think the tbi injectors are just held in there with one screw, and easily accessible ?

The regulator and cover come off the TBI unit together after removing about 7 screws.

The injectors need to be gently pried out. I would not just tear into to it without doing more diagnostics first.

It is not a common failure for the injectors to drip but it does happen.

A much more common failure is the coolant temperature sensor that the computer uses to determine how much fuel to inject gets poor connections or fails. The is a sticky in the FAQs post at the top of the board about this.

It is very common for the distributor module to fail. Even more so when hot. Make sure when you install or reinstall the distributor module that you use heat sink compound/grease under it. The compound helps dissipate heat from the module. Without it, the module will fail.

Note:
The computer needs to receive a distributor reference pulse from the distributor module to trigger the injectors.

[57 3100]

thanks so much ChevyTech for the detailed info, and others who have chimed in.
i hope to mess with it next weekend.

leonard