CPI 4.3 V6 intermittent starting problem

[dgumoe]

need help bad. my wife has a 1996 s-10blazer 4wd with the CPI 4.3 V6 in it. it has an intermittent starting problem. it will just crank and crank and crank and wont fire. i checked for fuel pressure, i have 50 psi. it has spark cause eventually it will fire and stay running. once its running there are no problems at all. i checked the ignition control module and its fine. the coil is ok cause it fires. there are no trouble codes and the SES light isnt on. im perplexed. got any ideas? im ready to sell this thing but i cant even do that cause the bitch isnt dependable.

[Madspeed]

Does the security light come on?
I had a 2001 S10 that did that once and since it was under warrenty I sent it off to the dealler instead of fixing it myself
they said it was a common problem and it was the ignition switch
after I got it back it never did it again in the three years I owned it
Onley problem I had was my oakly sunglasses missing from the glove and a dent in the drivers door. Needless to say I DO not take my cars to ANYONE for ANYTHING anymore =)

do you have fuel pressure before you crank it? It should hold pressure after you turn it off
Do you have injector pulse when cranking?
Does it have spark while cranking? Pull a plug wire off and attatch an old plug and see
Is it possible an injector is sticking open? that is another common problem
can you get ahold of snapon scanner? if so you can run an injector balance test
Unfortunatly the cars of today are not so easy for the do it yourselfer to diagnose.

[68nate]

You should have 62 PSI fuel pressure key on. These things will not start unless there is at least 60 psi. Try giving it a shot of carb cleaner while cranking and it will probably start and run fine until you shut it off. If you have spark and only 50 psi, 99.9% sure this is your problem. I've been a GM tech for 13 years and seen this many times before.

[ahowudoin]

You should have 62 PSI fuel pressure key on. These things will not start unless there is at least 60 psi. Try giving it a shot of carb cleaner while cranking and it will probably start and run fine until you shut it off. If you have spark and only 50 psi, 99.9% sure this is your problem. I've been a GM tech for 13 years and seen this many times before.


Yes, It sounds like a fuel pump. I think the magic number is 58 psi .

68nate You have any tech tips on doing a set of head gaskets and timing cover gasket on a 02 aztec? Thats what i have to look forward to at work tomm.

[rolltide]

Please don't be offended...but the cars of today need the same things to run as the cars of yesteryear. The do-it-yourselfer has to have a different set of skills today, but the engine hasn't changed that much in reference to what it takes to make it run.

Hope the fuel pump solves your problem. Sounds likely to me.

[David Pozzi]

Make sure your fuel filter is not plugged.

[dgumoe]

still lost. the fuel pump is working fine. my fuel pressure gage was leaking and i didnt realize it. i fixed the leak, now when you turn the key on the pressure holds steady at 58 psi. i drove it all day yesterday and had no problems except for when i first went out and the engine was cold. same thing this evening. it sat since last nite. we went to take it out and it was a bitch to start. stopped at the grocery store and my mother in laws. both times it started no problem. seems to be a cold start issue. for the life of me i cant figure out why.

[EFI69Cam]

Check the fp after it sits. I had a similar problem on a Tahoe, and the pump ran, but took longer than the prime pulse to build the pressure.

[David Pozzi]

Aren't you still below specs on fuel pressure? 58 isn't 62.
I had a v8 pickup that would not start but had a 50 something fuel pressure. It would start with fuel added and then run.

I found a leak in a press on pulse damper chamber just above the fuel pump. I substituted a short piece of hose and it started fine after that.

68nate said it here:
"You should have 62 PSI fuel pressure key on. These things will not start unless there is at least 60 psi. Try giving it a shot of carb cleaner while cranking and it will probably start and run fine until you shut it off. If you have spark and only 50 psi, 99.9% sure this is your problem. I've been a GM tech for 13 years and seen this many times before."

[Madspeed]

[quote=rolltide]Please don't be offended...but the cars of today need the same things to run as the cars of yesteryear. The do-it-yourselfer has to have a different set of skills today, but the engine hasn't changed that much in reference to what it takes to make it run.

You are somwhat right
But Id like to see the do it yourselfer diagnose troubble code at home
without my snap on scanner and my vantage Id be lost
A Labscope is a must for some of these suckas

[Damn True]

Totally non-helpfull, but when I saw the word "dynomite" the only thing I could think of was:

https://static1.pt-content.com/images/noimg.gif

[PRO TC]

drive it with the pressure gauge on it and so you can see it. leave it on untill it doesnt start. this way you can rule out fuel pump and relay.
barry