77 Chevy 350 - Occasional No Spark

Jim Rieschl · 03-13-2008, 10:44 AM

I have a 77 Chev pickup with the standard 350 engine. Occasionally after sitting overnight or after work the truck will crank over but not start. Once it does start the truck runs fine. This same problem happened last year and I replaced the cap and rotor along with the coil. At that time I decided that the coil was the problem because I noticed the insulation was burned off one of the wires in the connector area of the cap.

This morning the starting problem happened again. I was running late and just took a screw driver and rapped the top of the distributor. The truck started right up.

This same problem surfaces about every 6 - 8 months. I basically end up replacing the cap and rotor and the problem is gone.

Any thoughts on a possible cause??

stumpuller454 · 03-13-2008, 09:10 PM

i`m scratching my head but I think there might be an ignition module under the rotor?(mounted to distributor) i`ve had to replace mine in my ole 80, did weird things for me too.

Jim Rieschl · 03-14-2008, 10:50 AM

I figured it out yesterday. The original coil in the truck had 3 leads coming out of the coil. Red (Power) and yellow (tach) and a black ground for ground. All 3 went into the connector block on the distributor.

For some reason the new coils you buy also have 3 leads but one goes to ground the coil on one of the coil mounting bolts, and the other two red and yellow fit into the distributor cap.

What I missed when I installed the new coils is a little ground strap that fits under the coil and extends out to the middle slot on the distributor. The instructions specifically say to have this secondary ground in place or the coil will burn up.

Next time I will have to bother reading the directions. $160.00 later for the two burned up coils and lesson learned.

Jim

stumpuller454 · 03-14-2008, 04:32 PM

dang, some times those instructions come to bite yuh, been there,...

Jim Rieschl · 04-07-2008, 07:33 AM

Well it happened again this morning - Went to start the truck and no spark. I had a 79 Caddy that had a problem with spark when it warmed up, ended up being the pickup coil. Maybe this truck is having the same issue when cold - I think I will try that next????

Last year I replaced the module.

Jim

stumpuller454 · 04-07-2008, 05:11 PM

check all connections and wires for ignition system, maybe they are rubbed or loose somewere,....

Jim Rieschl · 04-08-2008, 11:21 AM

Last night I removed the distributor and replaced the pickup coil.
The truck started but still needs some minor timing adjustments.
Where can I find the correct timming for a 77 chev 350? I think it should be 8 degs BTDC.

Chevy_Finatic79 · 04-08-2008, 11:45 AM

I think I read for that era late 70's it's 8*BTDC for auto trans anf 4*BTDC for manual. for me personally that is still too much (retard) I advance mine til she runs smooth and idles high then turn down the idle a little and adjust from there. make sure you disconnect the vacuum advance while setting the timing. But to each his own

03-13-2008, 10:44 AM	#1
Jim Rieschl Junior Member Join Date: Mar 2008 Posts: 4	77 Chevy 350 - Occasional No Spark I have a 77 Chev pickup with the standard 350 engine. Occasionally after sitting overnight or after work the truck will crank over but not start. Once it does start the truck runs fine. This same problem happened last year and I replaced the cap and rotor along with the coil. At that time I decided that the coil was the problem because I noticed the insulation was burned off one of the wires in the connector area of the cap. This morning the starting problem happened again. I was running late and just took a screw driver and rapped the top of the distributor. The truck started right up. This same problem surfaces about every 6 - 8 months. I basically end up replacing the cap and rotor and the problem is gone. Any thoughts on a possible cause??

04-08-2008, 11:45 AM	#8
Chevy_Finatic79 Senior Member Join Date: Mar 2008 Location: Lincoln NE Posts: 442	I think I read for that era late 70's it's 8BTDC for auto trans anf 4BTDC for manual. for me personally that is still too much (retard) I advance mine til she runs smooth and idles high then turn down the idle a little and adjust from there. make sure you disconnect the vacuum advance while setting the timing. But to each his own __________________ "She's gonna Freak when she see's my wheels" 85' Chevy C-10 Longbox (Rat) TBI 5.7 Liter/THM350 90' Chevy Suburban 4x4 TBI 350 Cu.In./700R4 http://www.truckforum.org/forums/truck-pictures-176.htm

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
E3 spark plugs	gmtech	Chevy Truck Forum	5	07-03-2008 06:49 AM
spark plug gap	smokensteve	Chevy Truck Forum	7	01-26-2008 09:56 PM
Spark Plugs	MI0706	Chevy Truck Forum	3	12-31-2007 10:17 AM
92 5.7 350 spark problem	cplnorton	GMC Truck Forum	2	11-06-2007 05:23 AM
Spark Plugs 2000 Chevy	TLing56	Chevy Truck Forum	5	08-01-2007 11:10 AM

03-13-2008, 09:10 PM	#2
stumpuller454 Senior Member Join Date: Dec 2007 Location: Really FAR NORTH! Posts: 1,029	i`m scratching my head but I think there might be an ignition module under the rotor?(mounted to distributor) i`ve had to replace mine in my ole 80, did weird things for me too.

03-14-2008, 10:50 AM	#3
Jim Rieschl Junior Member Join Date: Mar 2008 Posts: 4	I figured it out yesterday. The original coil in the truck had 3 leads coming out of the coil. Red (Power) and yellow (tach) and a black ground for ground. All 3 went into the connector block on the distributor. For some reason the new coils you buy also have 3 leads but one goes to ground the coil on one of the coil mounting bolts, and the other two red and yellow fit into the distributor cap. What I missed when I installed the new coils is a little ground strap that fits under the coil and extends out to the middle slot on the distributor. The instructions specifically say to have this secondary ground in place or the coil will burn up. Next time I will have to bother reading the directions. $160.00 later for the two burned up coils and lesson learned. Jim

03-14-2008, 04:32 PM	#4
stumpuller454 Senior Member Join Date: Dec 2007 Location: Really FAR NORTH! Posts: 1,029	dang, some times those instructions come to bite yuh, been there,...

04-07-2008, 07:33 AM	#5
Jim Rieschl Junior Member Join Date: Mar 2008 Posts: 4	Well it happened again this morning - Went to start the truck and no spark. I had a 79 Caddy that had a problem with spark when it warmed up, ended up being the pickup coil. Maybe this truck is having the same issue when cold - I think I will try that next???? Last year I replaced the module. Jim

04-07-2008, 05:11 PM	#6
stumpuller454 Senior Member Join Date: Dec 2007 Location: Really FAR NORTH! Posts: 1,029	check all connections and wires for ignition system, maybe they are rubbed or loose somewere,....

04-08-2008, 11:21 AM	#7
Jim Rieschl Junior Member Join Date: Mar 2008 Posts: 4	Last night I removed the distributor and replaced the pickup coil. The truck started but still needs some minor timing adjustments. Where can I find the correct timming for a 77 chev 350? I think it should be 8 degs BTDC.