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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24725
Experience:  14 years GM dealer Technician.
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I have a 01 gmc jimmy 4.3 crank no start. mil indicator is

Customer Question

hello i have a 01 gmc jimmy 4.3 crank no start. mil indicator is erratic on/off. auxillary pcm grounds ran to neg. all power to pcm stays constant during cranking. has spark no fuel . 60 psi koeo & cranking. starting fluid fire up and die. injector pulse is there. and spider injectors have been replaced.
Submitted: 1 year ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 1 year ago.

Hi, My name is ***** ***** for the delay.

I will do my best to assist you

it has an injector pulse at all times?

the fuel pressure does stay at 60psi and above
?

Expert:  Tim's Auto Repair replied 1 year ago.

sense the engine ight has came on,can you give me the trouble codes?

Expert:  Tim's Auto Repair replied 1 year ago.

.

Customer: replied 1 year ago.
hello there same here passed out, there is unfortunately no dtcs set, koeo 55-60 psi and cranking 55. what i mean about the mil is right after crank & sputter acting like it wants to start up to about 400 ish rpm(not every crank cycle), the mil light disappears and doesn't return even when key is cycled many times. (pcm not grounding that circuit). ive never seen that before even after a key cycle.
Expert:  Tim's Auto Repair replied 1 year ago.

ok,,wil it fire everytime with a prime?starting fluid or a ittle fuel in the throttle body?

Customer: replied 1 year ago.
it will everytime
Expert:  Tim's Auto Repair replied 1 year ago.

are you sure it has an injector pulse?

if so there is no reason for it not to run..are you sure?

Customer: replied 1 year ago.
exactly im stumped. i used an incandescent test light as a noid light it was a little dim but its a higher wattage bulb if im not mistaken. im just worried about the check engine light not turning back on after it fires up on its own ( very sporadic at best.)
Expert:  Tim's Auto Repair replied 1 year ago.

to the best of my tinking,,it can not have injector pulse,,if the metering body was operating,it would send fuel to the cylenders with over 55psi of pressure,,so,i dont think it is getting fuel..

perhaps a bad crank sensor or ignition module..

Customer: replied 1 year ago.
what is your primal thinking on the check engine light deal? not to worry im assuming..
Expert:  Tim's Auto Repair replied 1 year ago.

the light does come on when you firsturn on the key,,right?

Customer: replied 1 year ago.
yep fresh ignition on in the morning crank it over until stumbles them bam lights GONE. i could do 100 key cycles and it still wont come back on. I've never seen this behavior in any make/model that why im so concerned/ confused about it.
Expert:  Tim's Auto Repair replied 1 year ago.

that doesnt make sense i,it is powered by the pcm[main computer]..

it is possible that the ignition switch or even computer is bad

Customer: replied 1 year ago.
exactly "grounded" by the pcm... igntion 1 feed is always there when the keys on so that rules out igntion switch. 3 pcms later still doing same thing. cluster is good as i can always ground out that circuit when the light isn't on and make the light come on..
Expert:  Tim's Auto Repair replied 1 year ago.

please stand by.one of the other guys may have an idea of what is going on.

someone will be right with you

thanks

Customer: replied 1 year ago.
thank you sir.
Expert:  Pete replied 1 year ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

If you cycle the key off for about 3 seconds then turn the key back on when the light isnt coming on does the light come on then at all?

Customer: replied 1 year ago.
Not at all, if i let it sit overnight and come back to it however it will come back on and crank no start until it decides to sputter over like its going to start them bam lights gone for id say at least an hour with the key off. Cycle the key all you want. Also brand new battery w/ help of a diesel sized jump starter to keep battery drain to a minimum.
Expert:  Pete replied 1 year ago.

If you havent yet,check the wiring leading to and running from the PCM and see if there are any wiring issues like corrosion in the connection or bent open terminals causing poor contact or corrosion or damage to the wiring.If a fault is found it will need repaired to correct this here.If this is checked and all found to be o.k. let me know.

Thanks Pete