5.3 on TH350. Starter jamming on flexplate
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Could wiring be a cause? There's a hot wire wired bad, I haven't tracked it down, someone towards the front of the engine. I'll get very little smoke when turning the key over. Waiting on a buddy to come over so he can turn it while I locate the smoke when its turning. There's no sparks, just a very small amount of smoke that you can barely see.
Now this is what I've been suspecting all along. Let me see if we can understand what you mean by 'dish going towards the engine'.
So, imagine the flexplate is off the engine and sitting on the concrete floor. The flange that bolts to the end of the crank is on the concrete, so that if it were a solid vessel, it would hold water. THAT is the orientation that should bolt to the crankshaft. The flange that is touching the concrete should bolt to the crank and the 'cup'/'dish' should face the transmission.
So, imagine the flexplate is off the engine and sitting on the concrete floor. The flange that bolts to the end of the crank is on the concrete, so that if it were a solid vessel, it would hold water. THAT is the orientation that should bolt to the crankshaft. The flange that is touching the concrete should bolt to the crank and the 'cup'/'dish' should face the transmission.
What starter bolts are you using? You would be amazed how often this happens from not using the OEM bolts. Slightest difference in these bolts makes them hang up.
Also, to the earlier point, think of the flexplateblike a bowl. The milk holding part should be towards the trans.
Also, to the earlier point, think of the flexplateblike a bowl. The milk holding part should be towards the trans.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Now this is what I've been suspecting all along. Let me see if we can understand what you mean by 'dish going towards the engine'.
So, imagine the flexplate is off the engine and sitting on the concrete floor. The flange that bolts to the end of the crank is on the concrete, so that if it were a solid vessel, it would hold water. THAT is the orientation that should bolt to the crankshaft. The flange that is touching the concrete should bolt to the crank and the 'cup'/'dish' should face the transmission.
So, imagine the flexplate is off the engine and sitting on the concrete floor. The flange that bolts to the end of the crank is on the concrete, so that if it were a solid vessel, it would hold water. THAT is the orientation that should bolt to the crankshaft. The flange that is touching the concrete should bolt to the crank and the 'cup'/'dish' should face the transmission.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
What starter bolts are you using? You would be amazed how often this happens from not using the OEM bolts. Slightest difference in these bolts makes them hang up.
Also, to the earlier point, think of the flexplateblike a bowl. The milk holding part should be towards the trans.
Also, to the earlier point, think of the flexplateblike a bowl. The milk holding part should be towards the trans.
Here's a drawing of the flexplate. Every picture I could find online showed the curve going in towards the engine.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
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Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Sounds like its not getting enough current to the starter to keep it cranking the flexplate.
Last edited by moe4541; Sep 8, 2017 at 01:56 PM.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
I have 3 grounds on my harness, you're saying put one on the passenger head and one on frame?
and block to frame
and battery to frame
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Intake gets pretty warm after turning it over a few times. This is thr smoke I was seeing and didn't know where it was coming from..........any ideal of what's causing this?
Last night I decided to buy a PSI wiring harness. The current one was reworked. I think its an electrical issue that I'm stumped on. It's probably something simple or a wrong wire somewhere. The $600 new harness is cheaper then taking it to a shop.
yeah there are 2 engine harness grounds that go to the rear of the passenger head. Should be a bolt hole right near the cam sensor. I think some harnesses had another ground near the front of that same head.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Some updates........the smoke I was told was just fuel vapor. I mounted the coils on the frame, the driver side coil pack wasn't facing the correct way so the plugs were reversed. I haven't cranked it since this discovery. Hopefully this is the fix........others mentioned the timing, base tune (timing), wrong crank sensor. I'll update this afternoon.
TECH Junkie
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Restricted User
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From: Ohio
Your starter teeth shouldn't be touching the flexplate like that. There is a plunger in the starter that pushes the teeth outward to engage the flexplate. If your starter teeth are touching the flexplate when you install it, then something is wrong right there.
To get an accurate commpression ready u need to turn it over steady to u get the highest reading. Have u tried turning engine over by hand? Like stated above the starter gear should kick out once ingaged. Yours looks to be stuck outward already. At this point u might be better off pulling trans and starting over with a fresh install.
Thread Starter
Staging Lane
Joined: Apr 2017
Posts: 84
Likes: 1
From: Dallas Tx
Yea I turned it over 3-4 times straight, I didn't record it.
I checked the pushrod length they were good, it seems like the valves are staying open. I'm taking the front of the engine apart to check timing and TDC.
I checked the pushrod length they were good, it seems like the valves are staying open. I'm taking the front of the engine apart to check timing and TDC.
