Suburban runs, only with key in start position

[Yerboogieman]

So my Suburban was having problems a few months ago, so I fixed my Saturn and just drove that while the Suburban sat in the garage.

Well, the Saturn finally blew the trans completely so this is my only other vehicle.

The problem goes like this, I can turn on the key and get all the accessories, then when I go to start it, it will start for a second and turn off. But if I keep it in the start position, it will keep running. If I put a wire from the battery straight to the coil, it will start and run just fine. What could this be? I've been searching for shorts, I cleaned up the connections in the fuse box, and replaced the coil wire, and the wire to the starter, but still nothing. It has an HEI conversion.

Thanks guys.

[LockDoc]

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Man, if you treated me like that I wouldn't run either.....j/k

I'm not real good at explaining the electrical stuff but it sounds like it could be the switch, resistor wire or firewall connector. If you run it too much with the coil connected directly to the battery you will burn the points in the dist.

LockDoc

[Yerboogieman]

Originally Posted by LockDoc

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Man, if you treated me like that I wouldn't run either.....j/k

I'm not real good at explaining the electrical stuff but it sounds like it could be the switch, resistor wire or firewall connector. If you run it too much with the coil connected directly to the battery you will burn the points in the dist.

LockDoc

I have HEI.

[DesertCat]

to fix this run a wire from the HEI batt terminal (where the HEI gets 12 volts to operate) to the unfused IGN on your fuse block. That should do it for good!

[Yerboogieman]

Originally Posted by DesertCat

to fix this run a wire from the HEI batt terminal (where the HEI gets 12 volts to operate) to the unfused IGN on your fuse block. That should do it for good!

I've been told that, but I still want to know the problem. I want to fix it to work like normal.

[DesertCat]

Originally Posted by Yerboogieman

I've been told that, but I still want to know the problem. I want to fix it to work like normal.

That is a very good way to wire in a HEI, many many guys run exactly like that. I didn't go into troubleshooting what you have because unless your ignition switch is bad, this will be a proper fix.

If not, get your DMM out and start checking for power. Bottom line is - whoever put the HEI in your truck had to modify your wiring to work properly. There are a number of ways to do that and you didn't say how it was done.

My solution simply gets it fixed fast and correctly. Your mileage may vary...

[LockDoc]

Originally Posted by Yerboogieman

I have HEI.

I guess it would have helped if you had mentioned that in the first place. I don't think an HEI has a coil wire it would be the power wire to the distributor.

LockDoc

[Yerboogieman]

Originally Posted by LockDoc

I guess it would have helped if you had mentioned that in the first place. I don't think an HEI has a coil wire it would be the power wire to the distributor.

LockDoc

I did, right at the end.

[LockDoc]

Originally Posted by Yerboogieman

I did, right at the end.

Sorry, I completely missed that. I'll crawl back under my rock now...

LockDoc

[80SPORT]

Turn the key to the on position and check for 12v at the hei plug

If you do not have power it is your ign switch or the wire to the hei

The hei draws a high current for a short time and should have a 10 ga feed wire...much heavier than the points ignition required.

The reason yours will run with the key in the start position is the points type ignition has an extra circuit from the starter to the ignition that bypassed the ballast during cranking.

[Yerboogieman]

Originally Posted by DesertCat

That is a very good way to wire in a HEI, many many guys run exactly like that. I didn't go into troubleshooting what you have because unless your ignition switch is bad, this will be a proper fix.

If not, get your DMM out and start checking for power. Bottom line is - whoever put the HEI in your truck had to modify your wiring to work properly. There are a number of ways to do that and you didn't say how it was done.

My solution simply gets it fixed fast and correctly. Your mileage may vary...

It's the one that goes from the ignition, splices into the starter wire, and then goes to the distributor. I'll just do the fuse box thing. I'm tired of dealing with it.

[Yerboogieman]

Originally Posted by 80SPORT

Turn the key to the on position and check for 12v at the hei plug

If you do not have power it is your ign switch or the wire to the hei

The hei draws a high current for a short time and should have a 10 ga feed wire...much heavier than the points ignition required.

The reason yours will run with the key in the start position is the points type ignition has an extra circuit from the starter to the ignition that bypassed the ballast during cranking.

I replaced the ignition switch and wire to the HEI. And what you said is exactly right. I have literally gone through this whole truck. Do I need to just go through it again?

[LockDoc]

Originally Posted by Yerboogieman

I replaced the ignition switch and wire to the HEI. And what you said is exactly right. I have literally gone through this whole truck. Do I need to just go through it again?

The yellow wire on the starter solenoid is one of the wires that you remove when you do the HEI conversion. I wired mine like DesertCat suggested. New red wire from Bat on dist connector to one of the IGN UNFUSED terminals in the fuse box. No other wires to the HEI. Mine works great.

LockDoc

[Yerboogieman]

Okay, so I hooked it to the "unfused" and unhooked the yellow wire from the starter. It does the same exact thing. Completely stumped.

[LockDoc]

Originally Posted by Yerboogieman

Okay, so I hooked it to the "unfused" and unhooked the yellow wire from the starter. It does the same exact thing. Completely stumped.

I don't know if you have tried this or not... Unhook the power wire from the HEI. Turn the ignition switch to the "ON" position. Using either a circuit tester or multimeter see if the wire you unplugged from the HEI is hot. If it is, I see no reason the truck shouldn't run, unless the ignition module is bad. If it isn't hot then there is either a problem with the switch or the wire between the switch and the "Ign Unfused" terminals in the fuse box.

LockDoc

[AzDon]

The original wiring scheme for GM vehicles with points has a resistor wire running from the keyswitch to coil+ side providing less than 12 volts (nine I think) Another wire fastens on the coil+ terminal that comes from the starter solenoid to provide full voltage while starting.
HEI requires full voltage while running, so the fix of running a 12 gauge non-resistance wire from "ignition unfused" at your fuseblock to the HEI terminal should have solved the problem.
I'd next check to see if twelve volts is constant at "ignition unfused" ,then at the HEI connector with the key turned on to the run position.
I suspect the keyswitch, but if you have power all the way to the HEI plug, then the problem is the distributor.

[Yerboogieman]

Originally Posted by AzDon

The original wiring scheme for GM vehicles with points has a resistor wire running from the keyswitch to coil+ side providing less than 12 volts (nine I think) Another wire fastens on the coil+ terminal that comes from the starter solenoid to provide full voltage while starting.
HEI requires full voltage while running, so the fix of running a 12 gauge non-resistance wire from "ignition unfused" at your fuseblock to the HEI terminal should have solved the problem.
I'd next check to see if twelve volts is constant at "ignition unfused" ,then at the HEI connector with the key turned on to the run position.
I suspect the keyswitch, but if you have power all the way to the HEI plug, then the problem is the distributor.

Mine doesn't have the resistor wire. I'm not getting voltage at the unfused plugs. I changed the ignition switch, cause I broke it getting out.

[AzDon]

Okay... The actual correct fix would be to run a new 12 gauge wire from the "ignition" lug on the keyswitch directly to the HEI AFTER checking for voltage there with the key in the run position..... I'm kinda mystified why there wouldnt be voltage at "unfused" with the key on, but that's not really the correct source for your HEI anyway...