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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: autofreak on April 25, 2012, 09:51:07 AM
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lets go back to the begining. i have an 86 k10 350 4spd. i was late for work, dead batt so i swaped in a diff battery, i didnt lock it down hit a bump battery fell out and shorted out. i had to replace the fuseable links on the starter to get power back to everything. i replaced the ignition moduale,cap, rotor, coil, plugs, wires. i checked the timing. it trys to start, but it just will not start. i am compleatly stumped. any help would be apriciated
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Sounds like your timing is off. You say it tries to start, so I assume it fires every now and then. How did you check your timing?
You could start by bringing the motor around to cylinder #1 compression stroke and stop your balancer at the 10-12 degree BTC. Remove the distributor cap and turn the body of the distributor so the rotor is pointing directly at the #1 terminal. It helps to make a mark on the body of the distributor where the #1 terminal is, so when you remove the cap you know where to point the rotor.
You may have already done this, but I would check again and then maybe look at the ignition module.
Also check your spark plug wires and make sure they are in the correct order.
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fireing order is 1-8-4-3-6-5-7-2 (dont let wire numbers 5 and 7 touch....they fire right after another and side by side...it being a 86 is it throttle body or computer controlled carb....something could be messed up in there
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It sounds like you "replaced" the ignition because it wouldn't start. Is this assumption correct? ???
BEFORE you go changing settings, throwing more parts at it, fueling frustration, and generally adding to your grief, take a deep breath and think. :o Review the basics.
1) How did the engine start and run BEFORE the battery fell out?
2) What have you systematically verified?
3) After replacing the plug wires, did you verify #1 and the firing order?
3) Forget the timing for a moment, does it have spark?
4) Does it have fuel?
5) If the answer is "NO" to 3 or 4, you have a definite starting point and direction to persue.
6) If the answer is "YES" to 3 and 4, check timing chain wear before getting exotic in your thinking. And, so on....
Keep your approach systematic and focused. Be methodical, not random, in your diagnosis. Do one thing at a time and carry it through to completion, before going to the next item. Make some observations, take some measurements and tell us what you find, so we can better assist you. :D
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He stated it "wants to start" so checking timing is the easiest thing to do. Check you plug wires, making sure they are in the proper firing order and your distributor timing after that.
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He stated it "wants to start" so checking timing is the easiest thing to do. Check you plug wires, making sure they are in the proper firing order and your distributor timing after that.
Why would you assume that the timing is off when he did not move the dist. only replace module and cap,rotor, coil and wires ? The battery falling out and shorting out the electrical system, and autofreak stating that he had to replace the fuseable link to get power to starter again suggest electrical issues right off the bat.
bd has 2 excellent points. #1 - people get frustrated and start to overlook simple things that should be in order in any diagnostic situation. #2 - checking for spark first and fuel second is the correct diagnostic order for this situation.
While checking for spark make sure as stated the spark plug wires got put back in proper order.
The statement "wants to start" can mean many different things to different people. Just because it cranks over and turns does not mean it is sparking and getting firing of the spark plugs. Some people can not tell this by just cranking over an engine.
My suggestion would be along the lines of what bd said, then carefully exaiming everything you changed to see if 1-it is all put back together right. 2-Since you got the fuseable link at the starter and we know the one on the firewall is working because the switch itself is working, "the easiest things" would be to check the stuff you replaced first, because it got replaced before diagnostic's were performed to see what actually failed. If I read his statement correctly.
One more point to ask, I understand you were late for work, but do you know why the battery was dead ? Did you leave your lights on or was it running great and all of a sudden one day the battery was dead ?
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first off i would like to say THANK YOU to every one for taking time to help. ok the motor is basicly brand new i rebuilt it last summer, with a double roller timing chain and it ran great. it was a computer controled carb truck but now it has a holley and older dist out of an 83, so the computer is non issue. I work in an auto parts store so i took the module to work and tested it, and it was bad, so i replaced it. plugs and wires got replaced because i burned a wire on the header. i went to a platnum plug, so i just upgarded the coil to a higher voltage one. when i checked the timing i brought no 1 to tdc, and made sure the rotor was pointing at no1 on the cap. the wires are in the correct order. as for the batt being dead it was cold and snowing that day and it was an ol crappy battery to start with, so it got replaced. i does try to fire every now and then, it has fuel. i hope this info does help, cause i am truley stumped.
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im thinking i will just bite the bullet and drop in a new dist today and see what that does.
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Check for spark first. Pull a plug, connect the plug wire, lay the plug on a ground and have someone turn the engine over.then look at plug and watch for spark at the gap. No need to buy a new distributor if you have good spark
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when you broght it to TDC the exhoust valve has to be open and going to close and then put the damper mark on ether 0 8 or 10 and the dis should be pointing at number 1....when you time it pull the vac. advance hose off...try that
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Autofreak, since you work at an auto parts store, pick up a spark test tool that looks like a spark plug with a ground clip attached to it and use that to check for spark. They work well. ;)
If no spark, verify ignition power and ground to the distributor.
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yeah i tried the spark checker, it has spark but only every now and then, so im thinking the pickup coil is bad. i got a good deal on a msd dist, so im going to drop that in, which is what i think i should have done to start with. but once again thanks for the help everyone, and ill let you guys know how this round turns out
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I have seen new electrical parts be bad right opf the box.
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Cool let us know. I to am going to get a msd dizzy one with an ajustable vac advance. Let us know how it goes. That sounds like your problem.:)
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yeah i tried the spark checker, it has spark but only every now and then, so im thinking the pickup coil is bad. i got a good deal on a msd dist, so im going to drop that in, which is what i think i should have done to start with. but once again thanks for the help everyone, and ill let you guys know how this round turns out
My vote, then let us know what happens.
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ok guys, i put the msd diizzy in and it fired right up. runs better than it did before. i noticed better throttle responce and faster starting. thank you guys for the help, but the battle is finaly over
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ok guys, i put the msd diizzy in and it fired right up. runs better than it did before. i noticed better throttle responce and faster starting. thank you guys for the help, but the battle is finaly over
Well thats good news...
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Congrats!! Another epic repair challenge conquered! ;D
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ok guys, i put the msd diizzy in and it fired right up. runs better than it did before. i noticed better throttle responce and faster starting. thank you guys for the help, but the battle is finaly over
Awsome! witch msd part# did you get?
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ok guys, i put the msd diizzy in and it fired right up. runs better than it did before. i noticed better throttle responce and faster starting. thank you guys for the help, but the battle is finaly over
Now you can pass on that knowledge the next time someone says their battery fell out and shorted the truck out.