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Intermittent starting issue.

cuervo

cuervo

Runn'n down a dream!
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83 carbed 305 auto HEI.

Has gas, fuel filter is full, press pedal the acc pump squirts fuel.

No spark, sometimes other times fires right up. Died a few times, no spark.

Change wires, plugs, ignition module, rotor, cap, and even the coil. At one point I did the HEI coil test and it tested bad, replaced.

Strange to say the least. Will go months without an issue then not start for 3 days. Do nothing to the truck go out after 3 days fires right up.

Has only died twice while driving but would not fire for couple of days after towing it home.

ugh! There are no kill switches, tachs or anthing non factory wired to the ignition.

Lemme see ideas, please. :bow:
 
how are your battery cables? If they are even remotely questionable then replace them or at least clean the terminals.
 
It's been awhile since I tore into a HEi Distributor. Isn't there a pick up assembly in the distributor? Thats the first place I would look.
 
thorguy57 said:
It's been awhile since I tore into a HEi Distributor. Isn't there a pick up assembly in the distributor? Thats the first place I would look.
Click to expand...

Yup, the ignition module. It was my first guess the first time it happened so I replaced it at the same time I replaced the coil.
 
something possibly loose or corroded in the ignition switch. When you are turning the key, it could be effecting something. the next time it doesnt start, put a test light on the wire feed that goes from the ignition to your coil. while your turning the key to start, that wire should be supplying you power at the ignition module/ coil.
 
Updating this. It's a 1983 305 HEI carb motor, no computer of course.

Well, it is no longer intermittent. The truck wont start at all.


I have 12 volts to the distributer coming in on the pink wire from the ignition for sure. Stays above 10 volts while cranking.

I tested the coil, ignition modual, cap, rotor, and replaced the pickup coil because it had some strange numbers.

I used this diagnosis page here, http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=261539 to test everything.

Yet after doing all of this I still don't have spark to the plugs.

There is no tach or tach wire grounding out so I'm completely stumped on it now. :mad:

Any other ideas?
 
cuervo said:
Updating this. It's a 1983 305 HEI carb motor, no computer of course.

Well, it is no longer intermittent. The truck wont start at all.


I have 12 volts to the distributer coming in on the pink wire from the ignition for sure. Stays above 10 volts while cranking.

I tested the coil, ignition modual, cap, rotor, and replaced the pickup coil because it had some strange numbers.

I used this diagnosis page here, http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=261539 to test everything.

Yet after doing all of this I still don't have spark to the plugs.

There is no tach or tach wire grounding out so I'm completely stumped on it now. :mad:

Any other ideas?
Click to expand...

There actually should be a computer...it's only function is to adjust the timing on the distributor. It was to help with detonation problems on 305s.

Check and see if there is another connector on the distributor at the back next to the firewall; it has 4 wires. There is a knock sensor that the computer uses to know how much to adjust the timing.

About 5 years ago my 83 K5 had this same exact problem. I got rid of the computer and used a non-computer distributor and no problems ever again.
 
Last edited:
djtejas said:
There actually should be a computer...it's only function is to adjust the timing on the distributor. It was to help with detonation problems on 305s.

Check and see if there is another connector on the distributor at the back next to the firewall; it has 4 wires. There is a knock sensor that the computer uses to know how much to adjust the timing.

About 5 years ago my 83 K5 had this same exact problem. I got rid of the computer and used a non-computer distributor and no problems ever again.
Click to expand...


I had this problems with this as well. There is a way to bypass the (ESC) I believe it's called.You simply bridge some wires at the 4 prong connector.I am 300+ miles away from my K5 and I don't remember which wires. I'll try and find the write-up on this for u. Yeah it like to drove me crazy,mine would bog down and run like @#$$%%! Replaced everything from carb to dist.
 
I had a problem with my 86 C20 305-H engine. It could start and run fine and just suddenly die out, sometimes start right back up or take a couple hours to get restarted. After several weeks of this nonsense (and getting very good at getting those half turn dist. cap latches off), I did some checking. There is a power feed to the spark control unit under the dash that comes off of the pink (hot) wire to the distributor. The pink wire clips into the connector for the feed, which in turn clips into the dist. cap. What had happened was the feed for the Spark Control was shorting out somewhere, killing the spark. I talked to some Chevy mechanics at my dealer about this and they told me how to bypass the spark control computer and keep the original distributor, something they claim is done quite often.
[SIZE=-1]First thing to do is unhook the spark control computer lead from the pink wire and hook the pink wire directly to the dist. cap. Make sure you plug it into the cap at the BAT terminal. The second thing is to locate the 4 wire connector that feeds into the ignition module. There's a brown (D), green (C), white (B), and black (A) wire there. The letters in () are on the black clip that the wires come out of. You cut the green (C) and black (A) wires between this clip and where they go into the distributor. Then all you need to do is solder the 2 cut leads from the dist/ignition module together, i.e. the green and black ones, (make sure to tape the exposed wires) and now your HEI distributor will function just as a pre ESC model does. I did this and it has been running fine for well over a year now.[/SIZE]
[SIZE=-1]Dan[/SIZE]
[SIZE=-1]Note: Here is a photo I made of the plug which goes to the ESC control and feeds the ignition, which Dan mentioned above. I labeled the wires which need to be cut and showed which wires are A, B, C and D.[/SIZE]





Here you go!
 
johnathan said:
I had a problem with my 86 C20 305-H engine. It could start and run fine and just suddenly die out, sometimes start right back up or take a couple hours to get restarted. After several weeks of this nonsense (and getting very good at getting those half turn dist. cap latches off), I did some checking. There is a power feed to the spark control unit under the dash that comes off of the pink (hot) wire to the distributor. The pink wire clips into the connector for the feed, which in turn clips into the dist. cap. What had happened was the feed for the Spark Control was shorting out somewhere, killing the spark. I talked to some Chevy mechanics at my dealer about this and they told me how to bypass the spark control computer and keep the original distributor, something they claim is done quite often.
[SIZE=-1]First thing to do is unhook the spark control computer lead from the pink wire and hook the pink wire directly to the dist. cap. Make sure you plug it into the cap at the BAT terminal. The second thing is to locate the 4 wire connector that feeds into the ignition module. There's a brown (D), green (C), white (B), and black (A) wire there. The letters in () are on the black clip that the wires come out of. You cut the green (C) and black (A) wires between this clip and where they go into the distributor. Then all you need to do is solder the 2 cut leads from the dist/ignition module together, i.e. the green and black ones, (make sure to tape the exposed wires) and now your HEI distributor will function just as a pre ESC model does. I did this and it has been running fine for well over a year now.[/SIZE]
[SIZE=-1]Dan[/SIZE]
[SIZE=-1]Note: Here is a photo I made of the plug which goes to the ESC control and feeds the ignition, which Dan mentioned above. I labeled the wires which need to be cut and showed which wires are A, B, C and D.[/SIZE]





Here you go!
Click to expand...

I found out about this too...I just went ahead with the non-computer distributor because I planned to do upgrades in the future and eventually did...built a complete new motor (350 instead of 305) two years ago...
 
Awesome info guys. I guess I'll have to check for the "computer" as I just figured there would not be on 305 carb with a manual 700r4.

I'll first have to trace the pink wire back and see if I can find this clip as I could not before. It seemed to dead end in the fuse block on the firewall.
 
You DO have a pick up coil AND an ignition module in an HEI--the module is the boomerang shaped unit with 4 or more prongs on it,the pick up coil is a doughnut looking plastic covered coil of wire that is sitting in the base of the distributor,two of the wires from it plug onto the module--to remove it you must pull the distributor out,remove the roll pin from the drive gear,and pull the shaft out from the rotor side,then after removing a c-clip or snap ring,the coil can be removed and replaced..

...tests can be made using an ohm meter,but I have had some act "normal" and test "good" one day and crap put intermittently,replacing one IS a pain in the butt,but thats the only way to be sure if its "good"..many guys just toss in a known "good" distributor or buy a rebilt/new one,seeing it needs to come out anyhow,and taking the shaft out can be "fun" when it seizes up in the housing sometimes..
 
diesel4me said:
You DO have a pick up coil AND an ignition module in an HEI--the module is the boomerang shaped unit with 4 or more prongs on it,the pick up coil is a doughnut looking plastic covered coil of wire that is sitting in the base of the distributor,two of the wires from it plug onto the module--to remove it you must pull the distributor out,remove the roll pin from the drive gear,and pull the shaft out from the rotor side,then after removing a c-clip or snap ring,the coil can be removed and replaced..

...tests can be made using an ohm meter,but I have had some act "normal" and test "good" one day and crap put intermittently,replacing one IS a pain in the butt,but thats the only way to be sure if its "good"..many guys just toss in a known "good" distributor or buy a rebilt/new one,seeing it needs to come out anyhow,and taking the shaft out can be "fun" when it seizes up in the housing sometimes..
Click to expand...


I replaced both the pick up coil and the module.


I did go out and look behind the glove box this morning and bigger then crap there is computer in the damn thing!!

I'm going to price the computer before I do the other backyard fix.
 
Well, get this. I call the parts store to get a price on the ECC and the manager says to make sure the knock sensor is not grounding out. I never heard of a knock sensor killing spark before.


Any I chase the lead down and could not find a place where it was ground out but I did give the connector a twist. I also open the glove box and pushed on the ECC connector and tugged on the wire loom.

The damn thing has spark now!!! WTF? Gotta get a timing light on it since I pulled the distributor to replace the coil pick up.

So, at best I'm back to intermittant spark I guess. :D
 
I put a timing light on the the damn thing and it runs better then it's run in a over a year!!!

So now what? New computer, cut the wires and jump it. Let it be until it dies again?

Grrrr!
 
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