Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
09-17-2012, 08:06 PM
Post: #1
1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
OK, so I bought a 1990 Chevy Silverado with a 5.7L (350) TBI off Craigslist. I knew I'd have to do a lot to get it into shape, but now its kicking my behind. It was running a little rough and had very little power, so I changed the distributor cap and rotor. All good, but no real improvement.
So the next weekend I thought I'd change the spark plugs and wires. I gapped all plugs at .035 (as per specs), and replaced the plugs/wires one at a time so there was no chance of crossed wire confusion. Finished the job up and started the engine. It started normally and ran fine for about 1-2 minutes, then sputtered and died (almost like it ran out of gas). - I think I was reattaching the air cleaner at the time. Now it turns over, but that's it. It just won't start.

I did find a bad ground wire from the frame to body. I replaced the ground and cleaned all connections on ground and battery terminal wires. I also put a new starter and ignition switch in (with the broken ground wire, starter wouldn't fully turn over.)



I've checked the obvious.

•I have power to the coil
•I have spark (only checked at #1 plug wire, because I am working alone).
•I have good fuel flow through the injectors
•I have checked all fuses (that I know of - box under dash and on passenger side firewall under hood).
•I have set the engine to top dead center (by crankshaft mark) and verified that rotor is pointing to plug wire #1.


I know I have to be missing something fairly easy. Someone please throw me a bone. I'm trying to get this thing running before my wife has it towed to the shop and I have to admit I made a bad purchase. Any help would be appreciated.

Thanks,

TJ
Find all posts by this user
Quote this message in a reply
09-17-2012, 09:12 PM
Post: #2
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
try removing the exhaust manifolds from the engine and try starting it that way.... what im getting at is that your cat may be clogged or restricted.... if it is clogged then your vehicle will not run properly
Find all posts by this user
Quote this message in a reply
09-18-2012, 12:02 AM
Post: #3
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
I'll throw you another bone...

There's a ground wire (recalling from memory) on one of the bolts to the t-stat housing. If the ground is bad and not making a good connection there will be no injector pulse. If that bolt is frozen then cut / extend the wire to the alt or AC bracket with a fresh crimp connector.

Hint... try a shot of starting fluid and if it kicks for a few seconds that you know you have no fuel (not enough fuel?) reaching the intake via the injectors.

If you can verify injector pulse with a test light or "noid light" you may still have a low flow / pressure problem so have a look at the fuel filter before jumping to a weak fuel pump.

BTW, be careful with those plastic connectors on top of the injectors. Last I looked they are no longer available from GM if you break one. You'd have to make a trip to a bone yard and cut one out of another vehicle. Any GM TBI will fit from that vintage so just clip the harness back to where it's not brittle and splice it in.
Find all posts by this user
Quote this message in a reply
09-18-2012, 10:37 AM
Post: #4
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
OK, so I looked again at the injectors and they seem to be putting out the same quality of spray as when it was running last week. I went ahead and gave it a shot of starter fluid, with no change. The fuel filter is only a couple of months old so it should be good..

As for the ground, I think I'll go ahead and replace all of the grounds that I can find. I never knew something so simple could wreak so much havoc, but with the ground strap from the frame to the body broken, I couldn't get the starter to turn over fully and I was getting smoke from the steering wheel/column. (I did tear it down after fixing the ground and couldn't find where the smoke came from. No burned wires, no melted plastic, no signs of hot spot. But, no more smoke now that my grounds are good.)

Thanks for the tip on the injector connectors. That would really suck to have to chase down scraps, but I may grab a set just in case the next time I do visit the boneyard.
Find all posts by this user
Quote this message in a reply
09-18-2012, 10:50 AM
Post: #5
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
BTW, a bad ground to the engine under heavy load (starter?) will look for another path. Typically this will be either the speedo cable or the shift linkage so look closely for damage.

Seeing as you say there's spark and fuel I can only guess those are not in the right amount or the right time. You may want to double check your work and also look at possible fouled plugs. (flooded?) You may want to do a compression test while the plugs are out again. Not that this vintage suffers from jumped timing chains, but anything is possible at that age so take a deep breath and go back to basics. Maybe put a trickle charger on it over night so you get good cranking speed too. I have chased that dog once or twice in my time!
Find all posts by this user
Quote this message in a reply
09-19-2012, 04:35 PM
Post: #6
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
IT'S ALIVE!!! finally up and running again. Still a little rough, but I can work on that (more posts to come, I'm sure).

So it appears that even though I had spark, it wasn't good quality spark. I replaced the coil (no change), then the ignition control module (success).

Thanks for the input guys. I look forward to picking your brains again soon.
Find all posts by this user
Quote this message in a reply
09-20-2012, 12:43 AM
Post: #7
RE: 1990 Chevy Silverado - engine turns over, but won't start - I've checked the obvious
Glad to hear it!

Keep us posted on any other issues.
Find all posts by this user
Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)