2002 Silverado 5.3 Slow start, starter or wires?

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Aug 30, 2009
Own a 2002 Chevy Silverado with 340k miles. Been noticing a slow crank before the truck starts. At first I thought it was the battery but it was tested and its good. Then I thought it might be the starter but since the truck has been starting fine each time and hasn't missed I thought I better look elsewhere. Again, its a weak crank (weak start) but starts each time. Have not checked the alternator. I figure the battery would have been dead by now if the alternator was the culprit (need to check that) Wires? starter? battery? alternator? Any advice is greatly appreciated
Have you load tested the battery? I've seen some batteries that seem to be putting out adequate voltage until load testing them. Check all wire connections and make sure they are shiny clean and tight. If all of the above tests fine your starter might be going out. The starter in my Jeep just died a month ago. It was cranking slower and slower until one day it barely turned over. At one point my oil filter housing adapter gasket was leaking all over the starter, which I'm sure is what led to it's death.
Check the battery terminals for corrosion, or just clean them up anyway. A small amount of resistance can drop the voltage.
Either put a multimeter on your current battery or jump it with jumper cables or a jump box to rule out the battery.. My guess is that its a warning sign of your starter.
Originally Posted By: pcoxe
Check the battery terminals for corrosion, or just clean them up anyway. A small amount of resistance can drop the voltage.
you need to diagnose the problem,,check all the listed parts you mentioned then if they are fine check some more. It sounds like new vehicle time.
Father in law also drives a Silverado. Swapped out batteries a few minutes ago and my truck has same symptoms. Battery not the issue.
If battery passes a load test and battery terminals are clean and tight, the problem is elsewhere. Test the wiring between battery, starter, and block. You will need a helper and a digital multimeter for this. Pull the fuel pump fuse while engine is idling to bleed off the fuel rail pressure. Now the engine will crank without starting but without dumping in raw fuel. Put a multimeter on the 2 volt range. Attach one meter lead to the battery positive terminal. Attach the other meter lead to the starter positive terminal post. Use the points of the probes to dig in through any dirt or corrosion to get a solid connection. Now have your helper crank the engine for 5 seconds and watch the multimeter reading. You should see under 1 volt, preferably under 0.5 volt. Next connect one meter lead to the starter housing, and the other to the engine block. Again dig in the points of the probes to get a good connection. Have your helper crank again for 5 seconds. There should be very little voltage drop here, under 0.1 volt. Now check between engine block and battery negative terminal. Dig in probe points, crank for 5 sec, watch the meter. Should be less than 0.5 volts here. If any of those tests returns a high voltage drop, there is a bad connection that is starving your starter of voltage. Solutions could be as simple as cleaning terminals at starter, at battery, and at the engine block negative connection. Could be as invasive as cleaning between starter and block or replacing internally corroded starter positive cable or engine block negative cable. But if those tests come back okay, and the engine still cranks sluggish, maybe there is a problem with the starter motor itself.
Originally Posted By: pcoxe
Check the battery terminals for corrosion, or just clean them up anyway. A small amount of resistance can drop the voltage.
Time for new cables. The crimp ends now have crevice corrosion and I'll bet the ground point on the engine has never been touched ... New ground cable (mostly needed) with the crimps soldered too while the wire is fresh. I'd go up a size. But that's up to you... I'd also add a >#8 fine stranded wire from Bat (-) clamp bolt to radiator support and one to alternator mount. Crimped and soldered terminals. Remember that all the current going though a circuit has to return via ground path, but with no available voltage to drive it. So ground is mostly overlooked and is more in need of attention. Should spin right up smile
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What everybody said so far, once you have battery, cables, starter, connections all verified, with that many miles on the engine it might be time for a rebuild. Over the years I've noticed the ones that are ready for a rebuild will start to turn over slowly. Hope that's not your case...
After cleaning up all the electrical connections and vehicle grounds, the next step is to check fuel pressure at the fuel rail. You can get a gauge to use from Auto Zone. Mine didn't want to start and it turned out my fuel pump was going and the fuel pressure was low, 45psi and it is supposed to be 50spi. What was happening is it wouldn't start on the first crank of the key but the second bump it fired right up. Now if fires right up every time.
I had a Taurus that had similar symptoms. The starter was going out, I took it to OReilly's and had them hook up their electrical test equipment. The starter was drawing way more current than it should have been. I replaced the started and all was good again.
FWIW I've had a couple different SBC starters turn over really slowly but test out fine on the bench at the auto parts store. The first time, I chased it around everywhere - battery, terminals, cables, etc. Finally put a new starter in (even though it tested fine on the bench) and problem solved. The second time it happened, I purchased the new starter right away after the battery and cables checked out. Problem solved. My theory is that the starter tests fine on a bench with no real load. Something to consider, anyway.
these years are known for having deterioration of grounds - all connections from battery (-) to the body/engine. Suggest inspecting them. There's a smaller one down low, left behind the bumper that seems to be a weak link. Starter current doesn't go through that particular one (or shouldn't) but it's an easy one to start with. -m
Slow cranking over = electrical Rolling over fast as usual but not catching = fuel pump Fuel regulator or filter. GM s of that ilk are famous for lousy fuel pressure refs and worse for pumps. Psi at the shader valve 60 needed to start. Press reg is on side of valve cover or top. Down dirty test is pull the far end of the vacuum line at reg. If gas in there get a new one., cheap. Pumps are just cheap trash, they can fail most any time from what I’ve seen . Some do last forever though. Change that filter unless it’s known by you to be new. Check those fuel lines,and returns particularly the places you can’t see right on the frame rails where dirt collects. They do rot out in one small place and the rest can be pristine. Look for those wet spots. They can leak and not be noticeable as drips puddles or problem for a while. If you do need lines, ROCK AUTO. Chevy will bring tears to your eyes Rocks are nice cheapest around. I just put some on a 2003 a couple months back . Grounds. These trucks have at least 3 maybe 4 off hand around that engine bay. With age they literally turn to green powder. The ends fall off end the rest just crumbles when you tug on them . You can make your own more easily than buying braided replacements.. My buddies 2003 got funky starting a couple years back . It lasted that long even here in the arctic swamp of rust belt. Took 3 hours to change that beast because the wires were fused to the terminals with corrosion. The solenoid literally crumbled when I twisted one of the nuts loose. The case was rusting through solenoid cracked and just fell apart yet it was still starting, go figure. If you go down there and the terminals are nasty clean everything . If ithe starter is looking funky just pull it and get a rebuilt or have starter shop rebuild then you aren’t back down there on your back with mud , rust in your eyes ever again. With those miles you just might have worn out the one replaced years earlier in normal usage. Those old trucks do demand getting filthy but your time and a few repairs is cheap compared to a fat payment.
I should clarify that I when I had my starter tested at the parts store they did a load test while is was still installed in the car. They had me crank over the engine with their equipment attached. I never had it bench tested.
Take the Battery Cable ends apart, Side post cable ends will corrode on the inside where you can't see it. Use a heat Gun if the rubbers ends give you trouble. Don't just cut them off! If the starter is original.....It's about time. '07-'13 Truck/SUV & '10-'15 Camaro starters fit (The '09 & up requires a Solenoid wire pigtail) You can find a low mileage OEM starters at wreaking yards. I bought a 2015 ZL1 Camaro starter for my car for $100 & it came with the pigtail. For fuel pumps.....Run a Racetronix pump for better reliability, They are cheaper than buying the entire module..... http://www.racetronix.biz/itemdesc.asp?ic=FPA-021A&eq=&Tp=
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