Trouble with engine start after reassembly
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Junior Member
Joined: Sep 2004
Posts: 60
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From: Guetersloh, D
Car: 1982 Chevrolet Camaro Z28,
Engine: 5,0l
Transmission: TH 350
Trouble with engine start after reassembly
I got my car for about 3 years. After I bought it I put some new heads, a new intake, new cam and new headers on it. Between that, there were a long period where I wasn't able to work on the car. So it was standing about a year.
Since a few weeks I'm back again, last week was the first time I tried to fire it up, but it does not work the way I want it to ;-).
So I just wanted to get some "ideas" where to start searching.
I got still the Q-Jet on it, when starting there a 3 "options" of what happens.
1. flames out of the headers
2. a big bang and then smoke out of the intake
or 3. nothing. Depends on how I turn the ignition.
On the carb I adjusted nothing until now. distributer and ignition coil are the old ones.
Last thing strange to me is, that when I turn the key in starting position, the minus-cable coming from the firewall and going to the engine gets very hot and smokes a bit.
so now i'm hopin' for some nice "input" from you guys.
thx a lot.
Since a few weeks I'm back again, last week was the first time I tried to fire it up, but it does not work the way I want it to ;-).
So I just wanted to get some "ideas" where to start searching.
I got still the Q-Jet on it, when starting there a 3 "options" of what happens.
1. flames out of the headers
2. a big bang and then smoke out of the intake
or 3. nothing. Depends on how I turn the ignition.
On the carb I adjusted nothing until now. distributer and ignition coil are the old ones.
Last thing strange to me is, that when I turn the key in starting position, the minus-cable coming from the firewall and going to the engine gets very hot and smokes a bit.
so now i'm hopin' for some nice "input" from you guys.
thx a lot.
Junior Member
Joined: Apr 2005
Posts: 55
Likes: 1
From: Kansas City, MO
Car: 92 Firebird vert
Engine: 388ci
Transmission: 700r4
Axle/Gears: 3.23 open
Re: Trouble with engine start after reassembly
Sounds like the distributor is in wrong. Recheck timing. either out 180 degrees or off a tooth or so one way.
Joined: Sep 2005
Posts: 27,881
Likes: 2,434
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Trouble with engine start after reassembly
Exactly....
It's probably 180° off.
Remember, there are 2 instances of #1 TDC during a complete engine cycle; but ONLY ONE of those occurs at firing. The other instance occurs at the end of the exhaust stroke and the beginning of the intake storke. That other #1 TDC occurrence is #6 firing (4 cyls, i.e. ½ of an engine cycle) away from #1 in the firing order).
When the engine is assembled with the timing set "dot to dot" as one would normally do, then it is at #6 firing, NOT #1 firing. #1 firing occurs 1 full crank revolution, and ½ of a cam revolution from there, when both dots are at 12:00.
So, the best solution is probably to find #1 firing by way of compression in that cyl, lift the dist out far enough to clear the cam gear, turn the shaft 180°, and drop it back in. It'll "work" if you just move the plug wires around, but they probably won't fit and will end up looking like a giant bird's nest even if they do, so it's better to just do it right.
Pull the #1 spark plug; put a piece of hose in the hole; bump the starter in the smallest possible increments until you start to hear compression escaping through the hose; continue to turn the engine by hand until the timing mark is just barely onto the timing tab; and check that the dist rotor is pointing to the #1 spark plug which should be the one just to the driver's side of straight ahead. Lift it and re-install it at that point if it's not.
It's probably 180° off.
Remember, there are 2 instances of #1 TDC during a complete engine cycle; but ONLY ONE of those occurs at firing. The other instance occurs at the end of the exhaust stroke and the beginning of the intake storke. That other #1 TDC occurrence is #6 firing (4 cyls, i.e. ½ of an engine cycle) away from #1 in the firing order).
When the engine is assembled with the timing set "dot to dot" as one would normally do, then it is at #6 firing, NOT #1 firing. #1 firing occurs 1 full crank revolution, and ½ of a cam revolution from there, when both dots are at 12:00.
So, the best solution is probably to find #1 firing by way of compression in that cyl, lift the dist out far enough to clear the cam gear, turn the shaft 180°, and drop it back in. It'll "work" if you just move the plug wires around, but they probably won't fit and will end up looking like a giant bird's nest even if they do, so it's better to just do it right.
Pull the #1 spark plug; put a piece of hose in the hole; bump the starter in the smallest possible increments until you start to hear compression escaping through the hose; continue to turn the engine by hand until the timing mark is just barely onto the timing tab; and check that the dist rotor is pointing to the #1 spark plug which should be the one just to the driver's side of straight ahead. Lift it and re-install it at that point if it's not.
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Joined: Jul 2004
Posts: 10,763
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Re: Trouble with engine start after reassembly
I'd put money on the 180* off too, however
That worries me. This is the ground from firewall to the back of the cylinder head? I'd replace it. It's just a ground strap, it might have most of its wires cut. That gives a schwack of resistance, especially if you notice it's getting hot. That's a voltage loss for any large draing *cough* starter *cough*
That's a $4 part that i'd throw in at the earliest convenience.
Last thing strange to me is, that when I turn the key in starting position, the minus-cable coming from the firewall and going to the engine gets very hot and smokes a bit.
That's a $4 part that i'd throw in at the earliest convenience.
Senior Member
Joined: Jun 2002
Posts: 744
Likes: 1
From: England UK
Car: 85 Z28
Engine: LG4 modified
Transmission: 700R4
Re: Trouble with engine start after reassembly
Mine did this on the first couple of turns. My initial timing was way too far advanced, and coupled with new piston rings etc the starter was working against a lot of resistance. Definitely renew the earth straps with heavy duty items, but you'll probably find once the timing is correct it'll be fine.
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Joined: Jan 2000
Posts: 20,981
Likes: 11
From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Trouble with engine start after reassembly
How many other grounds do you have connected to the engine?
Joined: Sep 2005
Posts: 27,881
Likes: 2,434
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Trouble with engine start after reassembly
Current shouldn't be flowing through that ground strap, regardless. It's not the CAUSE of the problem, it's the VICTIM of a problem that actually resides elsewhere.
Check the negative battery cable and make sure it's connected firmly to its mounting point, with a clean, rust-free connection. That's the REAL problem.
Check the negative battery cable and make sure it's connected firmly to its mounting point, with a clean, rust-free connection. That's the REAL problem.
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