Having a little engine trouble...

[Skunksmash]

Hi all. I seem to be having a little engine trouble with my 1987 Silverado 5.7L automatic, 2WD. It has to do with a starting issue. When I go to crank 'er up, the engine turns over, and makes a typical sound like the truck is going to start. I think the engine may even run for 1/2 of a second. But then there is some... sound, and the engine doesn't start. It's sounds like the starter just stays spinning for a second. But you can't just keep cranking on it, because the starter will grind. So you crank it, the engine starts to start, but then it doesn't, and the last thing you hear is the "ZZZZZZZZZzzzzzzzz....." of the starter winding down. Or something. I am not real sure what it's doing, to be honest. It could be making the dead starter sound, for all I know.

I have already replaced the fuel pump/s trying to fix this issue. I have two tanks, and one pump was dead, so it gave me an excuse to go ahead and fix the dead pump. Plus I kinda wanted to replace the one I was using, since I had no idea how old it was or when it was going to die on me. Of course I kept the one that may still be good, just in case it is still good. Anyway, has anyone here had this happen? Or possibly have an idea on what it could be?

[Da67goatman]

Check to see if the starter bolts are loose and while your down there check the flexplate for broken and missing teeth.

[Skunksmash]

Ok, I will try that. But how will I be able to see all the teeth on the flexplate? Just crank the engine, then check, crank, check, etc? Sorry I am a noob when it comes to flex plates.

[Da67goatman]

There should be an inspection pan that covers the torque converter and flexplate that you can remove from the bottom for inspection, hence the name.  It turns over by hand if you take the spark plugs out that way you can spin the flexplate and see exactly whats going on.  Id  start with the starter bolts cause if the starter is loose it will move when you crank it causing it to skip teeth and miss the flexplate all together.

[74chev4x4]

yea mine did this too, ended up being the starter, it could be the teeth on the flex plate though.

[Irish_Alley]

sounds like the flex plate might be missing some teeth but you will have to check like they said above

[78silver]

The starter solenoid may be bad.  If you have 12 volts going to solenoid on the circuit from the ignition switch with key turned to start, the neutral safety switch is ok.  Check voltage at the solenoid at the end of the battery cable. Less than 12 volts point to a bd battery cable.  Check voltage going from solenoid to starter. Less than 12 volts points to a bad solenoid.  A new solenoid is less than $20.  You can also test this by jumpin from the battery terminal on the solenoid to the terminal which goes to the starter with insulated pliers or a jumper cable.  Jumper cable can also be used to test the battery cable. If you jump the solenoid and the starter is ok the engine will turn over normally.

[Skunksmash]

Ok. I finally got time to check it all out, and nothing seems to be missing any teeth. On either end. I went ahead and replaced the switchkey, which needed to be done anyway cause it was getting to that stage where you can tell, that it was about to start falling apart.

And it seems I was wrong about one of the key descriptions, the starter will not grind if you keep cranking on it. I think maybe I just tried to start it again (too soon) after I had just tried to start it. So basically the thing just turns over and never starts. And it's not a fuel problem, cause I sprayed starting fluid in there and it still won't start. So now we are looking at a spark problem. I replaced the plug wires, the distributor cap, the distributor rotor, and the spark plugs, right after I bought the truck.

And I have put maybe 2000 miles on the truck since I bought it a year and a half ago. Could be more like 1500 miles. Since I have a car that get's far better mileage, and this is just an old project I am fixing up for fun. So it's my guess that the tune up is still good. So what should I try next? Replace the coil?

[Irish_Alley]

could be the control mod. Pick up Coil, coil do u have another dis laying around to switch or switch parts with

[jaredts]

Have you checked for spark?  Ground an old spark plug with one of your plug wires on it and turn the engine over to watch for spark.  Check for voltage to the distributor to make sure its getting its 12v (or hasn't come unplugged).  Is it turning over faster than normal?  Timing chain could be broken.

[Skunksmash]

Ok I will check for spark with one of the plug wires. I will also check out the pickup coil, as I believe they are pretty cheap items anyway.

I did manage to test the ignition coil though, (just the regular coil that a little plug wire goes to, not the pickup coil) and that came back good. I took it to autozone where they will test them, and the guy said that it was within spec. So then I took it to oreilly's and had them test it, and the guy said it was in spec. So I guess we can rule that out.

[Irish_Alley]

the icm will be on top of the pick up coil so you might as well take that in also

[jaredts]

Coil that a little plug wire goes to?  You have an external ignition coil on an '87?

[Irish_Alley]

yes 87 did have an external coil

[Skunksmash]

Ok I am getting spark at the plugs. I don't have another distributor to check the pickup coil with though.

However, it seems to have changed symptoms again. Now it has decided that it will start when I crank it up. But it will only run for about 5 seconds before it dies. Unless I keep my foot on the gas pedal, and keep the RPM's up. Then, once it warms up, it will go ahead and stay running at idle, and when I let my foot off the gas. But unless I sit there and warm it up, it will never stay running. And even when it warms up, when I am driving around I notice that it idles rough. Like when I come to a stop light or something.

Kind of a strange problem really.