silverado won't start....sometimes

[wesson123970]

hey guys,

sorry it's taken me so long to get back to y'all...i replaced the pressure regulator and it didn't do any good(even though it was messed up....the spring was in 3pieces!!)...i can hear a little difference on startup(little crisper maybe?), but it still fails just as often.i don't have a pressure tester...and I'm out of ideas...AND money right now....anyone have any ideas??HELP!!

wes

[wesson123970]

well guys....the pressure regulator didn't work!....even though mine was definitely damaged(spring broken in 3pieces!)...still sometimes won't start...i'm out of ideas...and money!..i don't have a pressure tester either...any ideas anyone?..i've replaced ever fuel component i know of

thanks,
wes

[MT-2500]

Originally Posted by wesson123970

well guys....the pressure regulator didn't work!....even though mine was definitely damaged(spring broken in 3pieces!)...still sometimes won't start...i'm out of ideas...and money!..i don't have a pressure tester either...any ideas anyone?..i've replaced ever fuel component i know of

thanks,
wes

Proper testing is the key.
Some parts places will loan or rent a fuel pressure tester. Lot cheape thaan throwing parts at it.
Good luck and let us know how it goes.
MT

[wesson123970]

thanks mt-2500.....i'll have to look into that

on another note....you said in another post that blinking A/C on control panel prob wasn't bad display, but low freon???you sure on that?

wes

[MT-2500]

Originally Posted by wesson123970

thanks mt-2500.....i'll have to look into that

on another note....you said in another post that blinking A/C on control panel prob wasn't bad display, but low freon???you sure on that?

wes

If I remember right I said low freon will trip the air cond controls and shut off compresser and make it blink.
Low freon is the first thing to check.
Depending on year and set up some you can get the codes and see why the light is blinking.
Post back in that post and I will refresh my memory or can tell you more about it.
MT

[wesson123970]

it happened again today....had the chance to let someone else turn the engine over while i looked at the 2 injectors....neither of them were spraying anything!!...of course it cranked fine once i sprayed the starter fluid in it....apparently the injectors kick right in once the engine fires(or is rotating fast enough from firing---enough suction??)good.

[MT-2500]

Originally Posted by wesson123970

it happened again today....had the chance to let someone else turn the engine over while i looked at the 2 injectors....neither of them were spraying anything!!...of course it cranked fine once i sprayed the starter fluid in it....apparently the injectors kick right in once the engine fires(or is rotating fast enough from firing---enough suction??)good.

First things first.
The first thing to check is to check for good hot blue spark to all plugs.
If you have spark then move on to fuel pressure.
If you have spark and fuel then go for injector pulse.
You have to have all 3 before injectore will squirt fuel.

[wesson123970]

does anyone know what causes the injectors to deliver gas on startup?...w/out pressing the accelerator???...it seems that is what's wrong....sometimes the injectors deliver...sometimes not...but always runs fine after it starts?..i know this may be due to clogged line..and i'm gonna check...but does anyone know what sends the signal to the injectors to fire when you crank the engine?

thanks,
wes

[MT-2500]

Originally Posted by wesson123970

does anyone know what causes the injectors to deliver gas on startup?...w/out pressing the accelerator???...it seems that is what's wrong....sometimes the injectors deliver...sometimes not...but always runs fine after it starts?..i know this may be due to clogged line..and i'm gonna check...but does anyone know what sends the signal to the injectors to fire when you crank the engine?

thanks,
wes

When the PCM/VCM sees ign spark it triggers the injectors.
But the key is fuel pressure in the right amount.
Even a couple of lbs low and the injector will not squirt.
Check my post on testing fuel pressure.
MT

[wesson123970]

hey guys...still haven't figured out the intermittent starting...i've replaced everying fuel related i know of..fuel pump,strainer,fuel pump relay,regulator...i did confirm that it's not getting any fuel when it fails(nothing coming out of injectors while cranking engine)...a couple of you mentioned the fuel pressure...if it's fuel pressure,what could be causing it??

on a better note!..MT-2500...you were right about the a/c light blinking on display and not working...just needed freon!!my dad an old can of R-12, so i used that....i reset everything first, by disconnecting, then reconnecting battery so the a/c would work for a min or so(not even sure i needed to do that?) i had the can of freon on and open as i cranked truck and turned engine on...went smooth...didn't take long to empty the can..that was about a week ago now..still doing great!!thanks MT-2500...i've been going w/out a/c for 2 years now, thinking my display was bad!!
Please help w/ the intermittent starting?!!!

Wes

[MT-2500]

Originally Posted by wesson123970

hey guys...still haven't figured out the intermittent starting...i've replaced everying fuel related i know of..fuel pump,strainer,fuel pump relay,regulator...i did confirm that it's not getting any fuel when it fails(nothing coming out of injectors while cranking engine)...a couple of you mentioned the fuel pressure...if it's fuel pressure,what could be causing it??

on a better note!..MT-2500...you were right about the a/c light blinking on display and not working...just needed freon!!my dad an old can of R-12, so i used that....i reset everything first, by disconnecting, then reconnecting battery so the a/c would work for a min or so(not even sure i needed to do that?) i had the can of freon on and open as i cranked truck and turned engine on...went smooth...didn't take long to empty the can..that was about a week ago now..still doing great!!thanks MT-2500...i've been going w/out a/c for 2 years now, thinking my display was bad!!
Please help w/ the intermittent starting?!!!

Wes

Get a fuel pressure gauge and check for fuel pressue up to specs.
Do not leave home with out it.
MT

[wesson123970]

well...a mechanic has my truck...had it all day yesterday....he said it cranked fine for him every time...so doesn't know what's wrong w/ it yet....i prob ought to ask him if he's checked the fuel pressure?...what do u think MT?
i'll let you guys know how it went


wes

[MT-2500]

Originally Posted by MT-2500

First things first.
The first thing to check is to check for good hot blue spark to all plugs.
If you have spark then move on to fuel pressure.
If you have spark and fuel then go for injector pulse.
You have to have all 3 before injectore will squirt fuel.

Do you have all 3?

[wesson123970]

hey guys,

my mechanic finally fixed my truck(i hope)...he had it for 5 days and it never messed up on him....he tested the distributor module though, and it was reading wrong....replaced that....and my oil pressure sensor was bad....the oil pressure sensor sends signal to shut fuel pump off, if oil pressure gets too low....i haven't picked truck up yet, but he feels confident my problem is solved (i do too)...and he said it cranked a lot faster than before...just fires right up....

thanks for all your help guys

wes

[MT-2500]

Originally Posted by wesson123970

hey guys,

my mechanic finally fixed my truck(i hope)...he had it for 5 days and it never messed up on him....he tested the distributor module though, and it was reading wrong....replaced that....and my oil pressure sensor was bad....the oil pressure sensor sends signal to shut fuel pump off, if oil pressure gets too low....i haven't picked truck up yet, but he feels confident my problem is solved (i do too)...and he said it cranked a lot faster than before...just fires right up....

thanks for all your help guys

wes

Was the fuel pressure test ever done?
What was the readings?
Oil pressure switch will not turn off or shut off the fuel pump.
It only keeps the fuel pump running if the fuel pump relay quits.
MT