Hot Rod Forum banner

small block chevy cold start problem

4K views 6 replies 4 participants last post by  docvette 
#1 ·
I have a early 80's 305 Chev that I adapted to a Land Cruiser. I have a Edlebrock 15XX on top and new spark plugs and wires. My problem is that when I try to start the motor using the key .. it will not start. I have an optima battery and can crank a long time. I smell fuel after a few cranks and a touch of the gas. The motor is getting air and fuel .. but not sure on spark at start up.
Here's the deal.. if I turn the key to the run position and tow the crusier 20' feet in gear she will start right up.
Seems like I'm not getting a hot spark at the starter position . Does anyone have a simple wiring diagram how the wiring should be from the distributor to the key and starter?
I'm a little weak on wiring.. any help appreciated...
 
#2 ·
On your starter there should be two small posts on the solenoid. The inner one (closest to the engine) is for the starter circuit (to make the starter work), the other post supplies power while in the start position. You can run a wire from that post to the distributor/coil and it'll have power while cranking.
 
#3 ·
Doc here, :pimp:

BSTMECH and JMARK hit it right on the head..

You are missing your secondary Ignition..This is the wire that runs from the "R" terminal on the solenoid (closest to the fenderwell) to the Coil +

Early GM Ignitions had a single contact Ignition switch for coil power, Consequently when "Start" was selected, the contacts rotated off the "run" position killing power to the coil and car..To overcome this "Catch 22 " they went to the secondary Ignition..

When the solenoid is energized , a contact shoe inside the solenoid is contacted between the main battery post, the starter motor, and the "R" terminal which energizes the coil during cranking cycles.

Later model GM's went to a duel set of contacts in the Ignition switch to provide power to both functions , not requiring the need for the secondary Ignition..If you look at the schematic for a later model General Mystery Ignition switch, It will show what appears to be 2 switches , (hot at all times, Run, Start..) or 1 configured differently for one application..It can be confusing, But in reality it is the wiring for BOTH sets of contacts from one switch..

In a Land Crusher, I couldn't tell you what type of switch you have, (but pretty sure it is single contact) hooking up the secondary Ignition wire will hurt nothing and just may cure the problem.

If you want to test the theory , just run a test jumper wire from your battery to the + side of the coil and crank it over..If it starts .. you found your problem...run the secondary Ignition wire..you will have to disconnect the test lead to shut it off , It is bypassing the key when testing)

Doc :pimp:
 
#4 · (Edited)
docvette said:
Doc here, :pimp:


If you want to test the theory , just run a test jumper wire from your battery to the + side of the coil and crank it over..If it starts .. you found your problem...run the secondary Ignition wire..you will have to disconnect the test lead to shut it off , It is bypassing the key when testing)

Doc :pimp:
I should have mentioned I ahve a HEI system with the internal coil.

how do I test that? ........I have one larger wire coming from dizzy going to a relay and the other clip wire is not connected. I think it was the tach wire...
 
#5 ·
Is it possible that you may need the smaller wire attached, beside the thick power red wire? Sometimes labeled as tach? at the distributor junction block at the dist cap...In my E type Jag series 1 1/2 ...all ignition went through the tach...if it didn't work...no start...but it wouldn't run....I just thought of something else...make sure you're getting a full 12 volts when you are cranking over...not 8 or 9 volt...have seen GM hotrodders with that problem...not enough power to the coil when cranking...Just some thoughts...hope you get it running...Cheers! :thumbup:
 
#7 ·
Doc here, :pimp:

To test an HEI coil, Get your DVOM out and set it for Ohms, R X 1 Scale, Calibrated to 000, Measure the primary, Put your probes on the BATT terminal and the TACH terminal, It should read less than an ohm, but more than 000, Out of that range, toss the coil..

Next measure the secondary , with your Ohm scale set for R X 10K , place your probes on the BATT terminal, and the carbon element for the rotor pickup, (inside the cap) ,It will measure between 6000 and 30,000 Ohms..outside of that range toss the coil.

To wire that coil, since it's out of an 80 car, you only need the BATT terminal hooked up to the Ignition switch and the secondary Ignition..

The Tach wire can be used for an aftermarket tach, just plug it in (on most) ..

On the Stock car that terminal went to a filter / Buffer and had a split white wire, one to the Tach and one to a CCC or CCCC Computer..you don't have that so don't sweat that.

Be sure your Ignition power is supplying a full 12 volts, and is not hooked to a ballast resistor..If it has one remove it and jump around the wire..

Don't know if Land Crusher's had ballasts stock or not , so you need to check.

Doc :pimp:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top