No Spark No Start 78 with HEI...Help!!
Thread Starter
8th Gear
Joined: Jan 2007
Posts: 8
Likes: 0
From: Cumming GA
No Spark No Start 78 with HEI...Help!!
Help!! Were getting no spark at the plugs in our 1978 Corvette with HEI Ignition. We have changed the coil, had the module tested at Autozone (passed), tested the cap, rotor and pickup per manual; all with no luck.
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
Le Mans Master
Joined: Oct 2005
Posts: 9,429
Likes: 44
From: Macon, GA
Too weird of a scenario to start guessing. I would have guessed the module crapped out, but you said you tested it. Just a thought here - When you put the coil in ....you did put the spring loaded button on the bottom that touches the rotor right? Any chance you didn't reassemble everything under the cap correctly?
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Help!! Were getting no spark at the plugs in our 1978 Corvette with HEI Ignition. We have changed the coil, had the module tested at Autozone (passed), tested the cap, rotor and pickup per manual; all with no luck.
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
Ground strap on the coil?
Jim
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Move vac. advance while checking the pick up coil. Many say the pickup coils do not fail. The movement of the vac. advance can cause the leads to break internally- may not be noticeable looking at them.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
110%don't trust module tester ... 'specially operator. Modules are cheap & easy. In addition to ohming out pickup, also check the pu with meter on AC volts ... look for small, brief AC signal at you spin gear by hand.
-edit ... just a week ago my buddy's son's HEI failed ... both of em are very good mechanics ... took quite a while to find the cap had a tiny, tiny hole burned in it ... checked everything ... finally tried an old cap & away it went. Also check for water/condensate/schmutz UNDER coil. Caps are cheap & easy too!
Last edited by jackson; May 21, 2007 at 12:48 PM.
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
A pick up coil has two wires coming out of it that are always moving, then they break and might touch sometime and start the car again once.
People don't like to change them because you have to take the whole dist apart.
it is the problem most of the time.
I like to take the dist apart so I can clean it up and make sure everything else is OK or upgrade parts.
People don't like to change them because you have to take the whole dist apart.
it is the problem most of the time.
I like to take the dist apart so I can clean it up and make sure everything else is OK or upgrade parts.
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Advanced
Joined: Dec 2005
Posts: 64
Likes: 0
For what it's worth is the distributor turning? I had the same problem with mine awhile back. Ran great the night before. Went to start it the next day and no spark. Broke the pin that holds the gear on the distributor shaft.
Melting Slicks
Joined: Apr 2004
Posts: 2,083
Likes: 2
From: Montreal Qc.
This happened to me last week, turned out to be the module. Two mechanic-types told me it was 50% chance of being module 50% chance of being the pick-up coil.
Both of them also told me that changing out the pick-up coil was a 15 minute job, despite all the fuss about "taking the distributor apart". (Find an old-school mechanic who is older than 40 that works at a gas station and he's probably done it hundreds of times)
Both of them also told me that changing out the pick-up coil was a 15 minute job, despite all the fuss about "taking the distributor apart". (Find an old-school mechanic who is older than 40 that works at a gas station and he's probably done it hundreds of times)
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Help!! Were getting no spark at the plugs in our 1978 Corvette with HEI Ignition. We have changed the coil, had the module tested at Autozone (passed), tested the cap, rotor and pickup per manual; all with no luck.
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
It turns over strong, just NO spark. We did just change out the window switches (removed center console). The car did start a couple of times after this but now nothing. Please!! Any suggestions? The car is sitting in the middle of the drive and I need to get it going.
THANKS,
Brian and Richard
Update from Digital Vette forum
-Checked 12V at Bat terminal while cranking car, holds 12Volts (does drop due to starter load)
-No change if tack plugged in or not, still no spark
(my tach filter has been unpluged, not sure why)
It looks like the dizzy is totally self contained and should be firing if I have a ground and 12 volts at Bat (which I do) So it must be:
-Coil-new
-Module-bench test pass (at Autozone)
-Magnetic Pickup -Ohm meter tested/passed
-Cap -Ohm meter tested/passed
-Rotor -Ohm meter tested/passed
-Anything else I missed?
ps I did confirm it is spinning
Another goose chase to stimulate the number of posts? Ohm meter test on the rotor?
When a rotor starts arcing through the cap directly into the shaft only leaves a small black dot at best.A resistance test will still show it to be good.Have you tried testing for spark with the cap off and and flipped upside down with the harness still connected?
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
If they're talkin' 'bout C3 large, coil-in-cap HEI ... Both of em are mistaken. PU coil for above is a small, continuous wound coil that completely encircles shaft. Cannot get it past mech advance asmbly/rotor mount. Dist has to come out of motor ... gear off shaft .. shaft out of dist ... pu out ... new pu back in ... shaft back in ... gear back on ... dist back in motor ... retime it. ... I guess a really fast amped up leprechaun can do it in 15m ... I wouldn't wanna try it that quick. If I could bet against em tryin' it in person within 15m ... I'd probably take the $.
R&I "ignition" coil is a 15 min job ... not pu coil.
Le Mans Master
Joined: Apr 2005
Posts: 6,363
Likes: 429
From: Seattle Area WA
I had something similar happen with my old Suburban. I had rebuild the distributor and used a generic pickup coil. After a few weeks I was having starting problems. What I found out is that the contacts on the pickup coil would make intermittent contact. When it was cold, no spark, when it was hot out it fired right up. I swapped it out with a GM piece and no problem since.
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
Before spending money replacing everything and the time to do it, just get a new performance distributar for Skip White performance of Ebay for $50, I have two of them and they are just fine!
Cruising
Joined: Feb 2018
Posts: 14
Likes: 0
From: Dracut Ma
Looking for help. Been working on a 75 vette. She sat for 7 years. I got her to start in the garage and noticed she was leaking gas and all other fluids. Started the rebuilding process of the front end. Finished with a new fan radiator from Dewitt and when completed she would not start. She has no spark. Distributor look ok but a little dirty. Replaced it with a new one and still no spark. I do have 12 volts to the battery line to the distributor and even tried jumping it to the alternator. I have read many post and can not seem to find the answer. Anyone out there with any advice would be greatly appreciated.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Looking for help. Been working on a 75 vette. She sat for 7 years. I got her to start in the garage and noticed she was leaking gas and all other fluids. Started the rebuilding process of the front end. Finished with a new fan radiator from Dewitt and when completed she would not start. She has no spark. Distributor look ok but a little dirty. Replaced it with a new one and still no spark. I do have 12 volts to the battery line to the distributor and even tried jumping it to the alternator. I have read many post and can not seem to find the answer. Anyone out there with any advice would be greatly appreciated.
are you sure you have the power wire to the correct terminal on the distributor.....i seem to recall there are two spade terminals one for the tach output and one for the power coming in....
Last edited by bobs77vet; Jun 26, 2018 at 10:30 AM.
Cruising
Joined: Feb 2018
Posts: 14
Likes: 0
From: Dracut Ma
you replaced the distributor with a new one? what about the distributor cap/rotor and spark plug wires? do you have good clean ground wires from the battery to frame and frame to engine?
are you sure you have the power wire to the correct terminal on the distributor.....i seem to recall there are two spade terminals one for the tach output and one for the power coming in....
are you sure you have the power wire to the correct terminal on the distributor.....i seem to recall there are two spade terminals one for the tach output and one for the power coming in....
Thanks for the reply. I made a connection to the new Distributor with the alarm wires by mistake. This was the way the old one was hooked up. The car started before I started working on it. So I took it for granted they belonged. I cut the wires off and hooked it straight. She fired up. Had to adjust timing but she seems to be OK.,
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
excellent....I think you have to have the perspective that everything that was done previously is suspect and take very little for granted. make sure you independently verify things with the manual. good luck and keep up the good work. bob
