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1980 chevy k10 shuts off on own and wont fire

  
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1980 chevy k10 shuts off on own and wont fire

 
bschevyk10 bschevyk10
New User | Posts: 21 | Joined: 07/12
Posted: 04/11/13
10:08 AM

I have a 1980 chevy k10 silverado with a 355 in it. I just got it back from the shop getting the timing done on it. Last weekend I drove it for maybe 15 mins and it just shut off and wouldny start back up. It would crank over but not fire. Then couple days ago I decided to see if it would start and it fired right up. I let it run and less than 10 mins it died again. It fired back up but within 30 seconds it died again. It did that a couple times then it would start anymore. Any ideas? Thank you so much.  

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 04/11/13
10:39 AM

does it have an additional wiring harness that comes out the side of the distributer and connects to the main harness or goes inside ???

there were electronic spark control modules on some K5s...   they look like an ECM .. either under the dash or under the front seats...  when the modules fail.. and they do.. the truck won't run...

you can disconnect the 4 wire connector from the side of the distributer...  not the one that plugs into the cap.. this goes elsewhere..

you can use a scotch tap to connect the black and the green wires together.. the truck should run again.. but the timing will be advanced about 10 degrees..  you will have to have the timing reset..

this is the EST distributer...

86Estchevydistributer

note that the module has 5 pins...   not 4.. not 7..

the harness i am talking about plugs into the yellow 3 pin connector.. its not shown  on this reman..


if you are good at soldering.. you might want to remove and open the spark control module .. look for damaged solder joints...

this is a honda relay.. but the solder joints have similar failure patterns..

i fix a LOT of things now that i learned about bad solder joints..

Hondamainrelaycircuitboard


if using the scotch tap to connect the black and the green wire does not work.. i have more tests..

like removing the coil cover..   sticking a test light into the RED Wire connection from the coil...

Heibigcap

Heicoilproblemat4k



turning the key from off to on.. to cranking and back to run.. does it have a constant light.. ignitions switches have failed also..

Ignitionswitchwornoutcontact

note the center contact.. this is off a 73. but the same ignition switch type was used up thru the mid 90s..  

68scott385 68scott385
Guru | Posts: 1990 | Joined: 10/09
Posted: 04/11/13
10:39 AM

Sounds like the HEI module to me. Have you tried to see if it is firing while cranking by holding one of the plug wire close to a good ground source while the motor is cranking?  
68scott385 68scott385 68scott385

68scott385 68scott385
Guru | Posts: 1990 | Joined: 10/09
Posted: 04/11/13
10:40 AM

OHhh, Wayne with the hole shot.  
68scott385 68scott385 68scott385

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 04/11/13
10:49 AM

shutting off after a few minutes does indicate a lack of dielectric grease under the ignition module to  transfer the massive amount of heat from the power transistor to the housing..  this will damage the module and ruin it.. even thou it may work for a few minutes...

you can get modules tested at some parts chains for free. have them run the test at least 6 times in a row.. see if the failure is thermal..

i have seen more failures on K5s of the spark timing module under the front seat or in the dash board than other failures...

jumping the black and green wires with that harness unplugged will restore spark control to the module..

Bigsmile  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 04/11/13
04:59 PM

Just go to the Tach lead connection on the HEI distributor Cap. itself

With a test light, Get the tach lead, and have a helper crank the engine.

If the test light stays on, the Ignition Module is NO Good.

If the test light Pulses, the Ignition module needs further testing. IE wait til the engine quites, and redo the test. If the test light stays on the ignition module is No Good....

Bob  

bschevyk10 bschevyk10
New User | Posts: 21 | Joined: 07/12
Posted: 04/12/13
04:57 PM

Thanks everyone for the advice. I figured it was the distributor. Now next question. I dont want to go through the hassle of fixin the distributor because its old and I want to switch to a msd. Now can I just pull the old one out and note how everything was when it came out and drop a msd in the same way and it work without worrying about timing and all that?  

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 04/13/13
09:05 AM

before Yanking out the old dead distributer....  

pull the distributer cap....  figure out where the #1 spark plug wire connects to the cap..

either use a remote starter button or a 15/16" socket on the alternator pulley nut to rotate the engine till the rotor is pointing toward the number 1 wire position... now..pull the rotor..

rotate the engine till the TEETH of the Reluctor and the teeth of the pick up coil are properly lined up..   then look at your damper timing marks...   the last movement of the crank should be in the normal direction of rotation to eliminate the slack from the timing chain...

you may now remove  the distributer... and install the new one.. .. you should be able to get the rotor pointing in the proper rotation.  once you get it to drop all the way onto the oil pump shaft and verify its down..         you may have to remove the distributer several times and turn the oil pump shaft with a LONG screw driver.  so the distributer will drop onto it..

once you have it in.. and the rotor is pointing in the proper direction .. you can turn the housing to align the tips of the pickup coil and the reluctor..  this will position the housing  so you can lock it down with the clamp... when you have reassembled everything else.. it should start...

if everything else is working..

please verify the electrical power supply ... and if its a 5 pin module like is shown above.. connect the dark green and black wire going into the distributer.. it will fix the NO SPARK issue.. i have been here before with the K5 issue.

one last thing.. if you live in an area where the truck has to be smog tested... keep your old distributer... and anything else.. so you can easily restore it to emission testing legal..