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Old Fart
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Discussion Starter · #1 ·
I have looked and haven't had any luck finding any answers so I'm hoping one of you 4.3 experts can point me in the right direction.

I was going to pick up a piece of furniture that I had bought and my truck acted like I had turned off the ignition, tach went to zero immediately so I pulled over looking for a loose connection somewhere but found nothing. after sitting for a few minutes it started again and I made it 3 or 4 miles and it did it again. It happened 3 times before I got home. To me, the symptoms said coil going bad so I ordered one from Rock Auto. Before it arrived I needed to use my truck again and I decided to take a chance and I made it about 5 or 6 miles and it shut off again but this time it would not restart. I had it towed home to wait for the new coil to arrive.

I installed the new coil as soon as it arrived and it still will not start so I ran a scan and got no codes. I don't want to waste more money throwing parts at it so I'm asking for help diagnosing my problem.
 

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B4U Task Force Admin
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I was having that trouble with the SS. Turned out to be bad cables. I made my own and it's been trouble free. I'm glad it didn't happen on the freeway.
 
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I had this same symptom a couple of years back...I would wait a few mins, start, go about 3-5 miles, die....turned out, was a failing fuel pump...try rent'n a fuel press gage set from AutoZone to verify..also, change the fuel filter while yer at it
 

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Old Fart
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Discussion Starter · #5 ·
I was having that trouble with the SS. Turned out to be bad cables. I made my own and it's been trouble free. I'm glad it didn't happen on the freeway.
The first time was on the freeway. Which cables? My plug wires distributor cap and rotor were all replaced 10,000 miles ago with premium parts. The plug wires are the spiral wound type that should last at least 50,000 miles.
 

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Two tones of terror
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First check for spark at one of the plugs, if theres no spark check the crank position sensor plug and maybe try changing that sensor. That thing gets blasted with oil, mud and road grime and if it's not getting a good connection the ignition won't fire. Try at least replacing ignition coil wire too as that's the only one that could cause a no start issue.

If you do have fire I would be looking more at a fuel related problem. Spider or fuel pump usually.
 

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Old Fart
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Discussion Starter · #7 ·
I had this same symptom a couple of years back...I would wait a few mins, start, go about 3-5 miles, die....turned out, was a failing fuel pump...try rent'n a fuel press gage set from AutoZone to verify..also, change the fuel filter while yer at it
The fuel pump and filter were replaced about 750 miles ago and since the last one only lasted 2 years that was the first thing I checked. It is definitely an ignition problem. Like I said before when it happened the tach drops to zero like you turned the key off when this happens even though the engine is still spinning.
 

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Old Fart
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Discussion Starter · #8 ·
I don't need guesses at which parts to replace next, I need to know how to test the parts to see if they are bad. Please read thoroughly as I have eliminated the fuel system already, and checked all fuses so I'm pretty sure it is an electrical component I just need to know how to test to find the culprit.

Sorry if I seem impatient with you well-meaning people but at this point, I'm frustrated as I'm used to working on old-school noncomputerized vehicles and have never had this much trouble finding a problem before.
 

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The fuel pump and filter were replaced about 750 miles ago and since the last one only lasted 2 years that was the first thing I checked. It is definitely an ignition problem. Like I said before when it happened the tach drops to zero like you turned the key off when this happens even though the engine is still spinning.
k...I threw that out there 'cuz no mention was made about the pump n yer symptom mimic'd my issue from a few years ago..and what I suggested wouldnt have cost no $$ to check-ya get yer rental fee back..yep, def sounds elec-related, which is wayy above my pay grade. Good luck
 

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Old Fart
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Discussion Starter · #10 ·
k...I threw that out there 'cuz no mention was made about the pump n yer symptom mimic'd my issue from a few years ago..and what I suggested wouldnt have cost no $$ to check-ya get yer rental fee back..yep, def sounds elec-related, which is wayy above my pay grade. Good luck
Yes, too many things that could cause this from sensors, ignition module, or even the ECU.
 

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B4U Task Force Admin
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Battery cables?
Yes...battery cables. I should have been more specific. As old as these cables are, they tend to corrode inside of the insulation. You may or may not see a bulge. I started flexing the cables as a last ditch effort to find the problem...it was like someone turned the key off. I made a set out of welding cable and it hasn't missed a beat.
 

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Old Fart
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Discussion Starter · #13 ·
Try flexing the battery cables...
I'll try that but I don't think that is the problem as a voltage check shows 12.6 V when not running.
 

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i know its not what you want to hear, but I too think you may have an intermittent issue with your fuel pump... albeit from the electrical side of things. i am sort of curious to know how you totally ruled out your fuel pump and fuel pump's power/ground?
fuel pressure tests alone may not be sufficient since it is an electric pump which may have an intermittent electrical issue. did you check the pump's electrical? if so, how did you do it?

because on many s10's you practically need to get to the top of the pump to test it electrically... ie. my 2000 doesnt have the fuel pump electrical test port under the hood... but i have a fuel pump hole/hatch in the bed now...
 

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You mentioned you want to know how to diagnose your problem. I'm happy to walk you through step by step diagnostics, however when I have you check something you have to be specific. For instance, if I have you check fuel pressure I want to know how much fuel pressure you have, not "it's good". To start you need to check 3 things. Check fuel pressure, spark at one of the spark plugs wires, and injector pulse. You can wait on injector pulse for the time being because it's a little difficult on these engines. If you check these while it's not starting you will be missing at least one of them. Once I know what you're missing we can move onto the next step
 

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Been there Done it
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What you are describing in your initial post is the classic symptoms of a failing CKP sensor. The tach going to zero even before it shut off completely is the dead give away. And dying after a few miles repeatedly is also a classic symptom.
My GXP did exactly that last summer. Be glad you don't have an LS engine. They're a real pain to get at being behind the starter. On yours is hanging out in plain site at the bottom of the timing cover. 5 minute job, but you'll need to get the relearn done.
 
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What you are describing in your initial post is the classic symptoms of a failing CKP sensor. The tach going to zero even before it shut off completely is the dead give away. And dying after a few miles repeatedly is also a classic symptom.
My GXP did exactly that last summer. Be glad you don't have an LS engine. They're a real pain to get at being behind the starter. On yours it's hanging out in plain site at the bottom of the timing cover. 5 minute job, but you'll need to get the relearn done.
ive had a crank position sensor problem on a gm 3.9l... it threw a code luckily...
 

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Old Fart
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Discussion Starter · #19 ·
What you are describing in your initial post is the classic symptoms of a failing CKP sensor. The tach going to zero even before it shut off completely is the dead give away. And dying after a few miles repeatedly is also a classic symptom.
My GXP did exactly that last summer. Be glad you don't have an LS engine. They're a real pain to get at being behind the starter. On yours is hanging out in plain site at the bottom of the timing cover. 5 minute job, but you'll need to get the relearn done.
Thanks, Slayer, After watching a lot of videos and doing some reading I was thinking it had to be that or the cam sensor.

How do I do the relearn?
 

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Old Fart
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Discussion Starter · #20 ·
You mentioned you want to know how to diagnose your problem. I'm happy to walk you through step by step diagnostics, however when I have you check something you have to be specific. For instance, if I have you check fuel pressure I want to know how much fuel pressure you have, not "it's good". To start you need to check 3 things. Check fuel pressure, spark at one of the spark plugs wires, and injector pulse. You can wait on injector pulse for the time being because it's a little difficult on these engines. If you check these while it's not starting you will be missing at least one of them. Once I know what you're missing we can move onto the next step
Why would a fuel pump problem shut the ignition off? I have had the fuel pump go out on this truck twice and a wiring problem with the fuel pump once so I am quite familiar with those symptoms. This is definitely a no spark ignition problem so what I am looking for is how to test the components that control the ignition system like the crank sensor, cam sensor, and ignition module.

For the life of me, I don't understand why so many people think it is the fuel pump causing my no spark problem. :rolleyes:
 
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