73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 74chev4x4 on April 06, 2010, 01:59:56 pm
-
1974 chevy 3/4 ton 4x4 454 with turbo 400. I recently pulled my motor out to change the rear main, oil pan gasket and to clean and paint the block. I put it in a week ago and have been slowly working on getting everything back together. Today I bolted the flexplate to the torque convertor and put the starter on. The exhaust is not hooked up to the exhaust manifolds yet and I have 3 of the 6 trans bolts in, but I just wanted to start it before I went any further. Anyway went to start it today and it will only crank short cranks(2-3 seconds) and then it sounds like it has trouble turning over, pulled the starter and tried it and it spins fine. It hasn't fired yet, backfired a few times, but no real start. I know I can figure it out, but just worried about it having trouble turning over. What would it be binding on, I rotated the motor as I put the bolts in the flexplate to the convertor and it moved without much trouble so I'm not sure. Hopefully I haven't screwed anything up? Any help would be great!
-
Maybe get your starter tested and double check your connections. If you're worried about something more mechanical you might try again rotating the motor by hand all the way through 360 degrees and make sure it moves smoothly. My bet would be that its not mechanical, but who knows. A starter spinning fine with no load is really no test at all.
-
Do you have a good battery? What is the condition of the starter? It it binding like it cannot turn over?
-
Throw those other 3 bolts in and finish your exhaust. If your running without exhaust, you will have a harder time hearing if something is wrong.
When you pulled the motor, you didnt do anything else besides the rear seal, pan gasket, and paint? Make sure your battery is FULLY charged as well. Never know. Did you take out your dizzy?
-
nope left the dizzy in, battery has 12.2 volts. It seemed to turned over fine when I was rotating it to put in the flexplate to torque convertor bolts, starter seemed fine before this. Not sure what this could be. I did take off all the plug wires and put them back on, could have mixed them up, but this doesn't explain the binding?
-
also I did nothing mechanical to the engine besides replacing gaskets and cleaning it up.
-
Double check the starter is shimmed properly and the bolts are tight. There should be a specific gap between the flywheel and starter teeth.
-
Yeah starter is in exctly like it was before, I will try charging the battery!
-
Is the flexplate on backwards?
-
pretty sure I put it on the way it came off, would it bind if it was on backwards?
-
just a guess but what about timing, sound like its too advanced. i know it will slow down the rotation of the engine when warm but not sure about cold and your back fire kind of backs this ideal up. did it back fire out of the carb or pipes. carb means too advanced and pipes mean to retarded
-
12.2 volts isn't much voltage, I think like 12.7 is closer to fully charged?
-
update: Ok so I had the battery on the charger all night, came out this morning to start it and it cranked more than before, but still no fire, then it would barely crank. So I had jumper cables going from my other truck to the chevy and tried to crank it and it would barely turn over. Then it kept cranking even after I took the key out and smoke started coming from under the motor and filled the engine bay. So now I have a burnt up starter and to make matters worse I noticed that oil was running off the back of the motor near the rear main seal that I just replaced. So I am a little mad at that thing right now, I think I will just keep the truck and sell that motor and put in a small block like I orginally wanted to rather than figure out why it is leaking oil again. I know I will still have the same electrical issue to deal with, but I hate that 454 everything I do to that thing goes wrong and I am pretty good with motors, no expert, but not bad.
-
Sounds like either the starter is bad or the ignition switch.
-
starter was new like 5 months ago and worked great before I pulled the motor? I will go through and check everything, going to pull all the plugs and make sure it is still turning over smoothly, not sure why it wouldn't? The torque convertor was spinning freely before I bolted it to the flexplate so I don't know what the deal is?
-
so I got underneath and found I fried the wires to the starter, cleaned them up and spliced in some new wire and connectors to the starter and bought a new starter. Now I have power inside the cab again, fan is running wipers work. Hooked up the new starter and have it on the ground to see if it works and nothing? Checked all fuese I could find and none are blown, is there another fuse I should check or something else anyone can think of, I don't think its the new starter cause the old one wouldn't do anything after I fixed the wires so I went and bought a new one.
-
Two of the wires to the starter are fusable links, were they the ones fried? If they were replaced with full-size wire and the cause has not been found then your truck might catch fire. I recommend you disconnect the battery until this is sorted out.
-
Where is the fusible link at on these wires? Yea the one going to the battery was cooked!
-
just thought of this this morning, could it be the coil?
-
pulled the coil out and one of the wires was a little fried, replaced it and still nothing, good God did I mess up the distrbuor also. What else would give power to the starter?
-
In the case your in now i suggest you replace the harness.Just from the firewall forward .There not expensive and be a great insurance policy in this case...
thanks
pat
-
where would I find the harness from the firewall forward? I wish I knew what blew cause I hate to keep throwing parts at it. not sure what else to check. It did smoke from the block on the firewall above the motor where the power wires connect with the ring connectors, not sure if that is a fuse thing or not?
-
One more thing to consider. Did you get the ground wire hooked back up correctly after you reinstalled the engine? I did not put mine back correctly after I rebuilt my engine and I had sparks jumping off my transmission linkage! I reconnected the ground wire to the a :)lternator bracket and everything worked fine then. Just thinking... :)
-
which ground wire, from the starter? I might not have, I will check for it.
-
which ground wire, from the starter? I might not have, I will check for it.
No, From the block to the cab.
The fusible links are on two of the small wires (12ga??) at the starter, insulation is softer and the are 2ga smaller but the insulation is thicker and are meant to burn before the harness fries.
-
I have one from the block to the cab, nice new big strap. Yea the wire melted right at the starter and I replaced it, but it still doesn't want to kick on, when you turn the key the fan, radio stops like it is going to start, but the starter does nothing? I hate electrical issues!
-
Do not bolt the flexplate to the converter until the bellhousing bolts are ALL in and torqued. Your wires at the B+ terminal on the starter solenoid are fusible links and need to be replaced with fusible links not regular wire.
See here http://forum.73-87chevytrucks.com/smforum/index.php?topic=11972.0
Make sure before you repair them that the wires are not pinched in the bellhousing or chafed and rubbing on anything. Reinstall them on the same B+ terminal as the battery cable and be sure it's routed correctly away from the exhaust. Your negative battery cable should be going directly to the cylinder block with a clean tight connection.
Check your fusible links at the alternator and junction block also.
-
VileZambonie, I already bolted it up to the convertor so what did I screw up by doing this. Should I just run new wires(fusible links) to the starter and to the fuse block? I really screwed this thing up!
-
OK tested the wires going to the starter and I have voltage on the two going to the larger terminal on the starter and the smaller wire going to the smaller bolt on the starter has no voltage of course I was by myself so I couldn't test it while I was turning the key. I have a 4th wire coming down near the starter that has 12 volts going through it, but I cant remember if this goes to the starter or not? Should there be three wires of four? Is there another fuse or silinoid that could be blown that is not allowing it to start? Thanks guys I know its getting a little long winded just trying to get her running again!
-
Which wire do you have going to the alternator post?
-
The wire from the alternator is going to the larger post on the starter along with the cable from the pos on the battery, the other two wires(not sure where they are coming from ignition I guess) I have going to the smaller post on the starter the one with the small s next to it. That is how I beleive the old one was set up. I believe it must still be some kind of fuse in the ignition or a bad wire from the ignition, still not sure? Thanks.
-
The wire from the alternator is going to the larger post on the starter along with the cable from the pos on the battery, the other two wires(not sure where they are coming from ignition I guess) I have going to the smaller post on the starter the one with the small s next to it. That is how I beleive the old one was set up. I believe it must still be some kind of fuse in the ignition or a bad wire from the ignition, still not sure? Thanks.
recheck your wiring... I don't think that's right.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=11766.0 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=11766.0)
-
(http://i6.photobucket.com/albums/y228/Sabaka454/charge.gif)
-
Sorry it took me so long to get back. i was refering to the big ground wire from the battery. It goes to the alternator bracket. If it's grounded to the frame it can make some crazy stuff happen.
-
Mine neg. bat is grounded to that bracket, too. Consensus among users on this site is that the block is the best place.
-
This may be way out there but....AND keep in mind I am NOT a re-builder
There is some crankshaft endplay on big blocks
You changed the rear main, so you changed the way the crank is sitting in the block?
Like I said, way out there.
Crank is binding?
Did you hand crank as posted above? Rotate it more than once through 360, like many times.
Keep in mind that when you activate the starter, the crank will move as it spins and Just Maybe your worn internals are causing binding whereas it worked fine before with the worn parts. Plus, endplay may have caused the rear leak initially.