View Full Version : intermittent ignition problem on '77 350

04-08-2000, 06:23 AM
My son has been using my old 77 3/4 ton Chevy Pickup. It has a 350ci motor and automatic transmission. Usually it works fine, however lately has been giving us trouble.<p>It acts like it is flooded, at first that is <br>what I thought the problem was, we waited<br>a few hours and it started ok and ran fine.<br>However after a few days it started doing <br>it more often and it takes longer before it will start, once started it runs fine.<p>The engine turns over well, although we usually end up putting a charger on the battery because we keep running the starter.<p>My son says he thinks it has something to do with night driving, as once started it works all day but when he drives it home at night<br>the lights and voltage some times drop down and then will jump back up - much like a bad connection in the electrical system. The next<br>day, it won't start, turns over well, stinks of gas but won't start. It's as though it is not getting any spark, doesn't even try to start, just spins - then, after much waiting and trying it will start like nothing is wrong - we can immediately **** it off and it will start ok and do so for the rest of the day.<p>Are these symptomatic of anything easily fixed? If so, what?<p><br>thanks in advance,<p><br>joe<p>PS: you can e-mail me with suggestions and or comments about this problem at 77chevytruck@linuxfan.com

04-09-2000, 04:24 PM
I have seen an Ignition module cause the no start problem. but not the same as you have explained it. I would check the spark output when starting it the first time in the morning. Motor manuals has an easy to follow test for the ignition system. Try your library for the manual. I would also check the body grounds from the battery and the engine block. I have seen alot of problems like you have discribed cause by bad grounds.<br>Good Luck

04-09-2000, 05:50 PM
I have a very similar problem, actually, I just fixed mine, maybe my symptoms will sound very similar to yours maybe not but i think they sound awful close.....<br>start ok sometimes then dies takes 30sec to 1 min of starter then fires up and runs as if nothing had been wrong.....<p>i had my carb rebuilt, problem is gone, and there is a bit more spunk in the engine too, i have the ol quadra-puke, ran me 145.00 here in san antonio, and that included a flow test and a 1 yr warranty.<p>-after i picked up the carb he said it looked to him like my float was the original, i agreed that it was as my dad is the orig owner and he has never had any carb work done on it, 140000 miles on it at rebuild time. <p>also as was stated earlier, you voltage thing check your grounds, i think you have 2 different problems going simultameously.<p>-have you replaced your coil? Have heard that people with their older chevys have coil problems until coil gets warm?????<br>dont know about that one first hand but do know that coils run about 15 bucks at the parts house<p>-abe

04-10-2000, 06:35 PM
I have a '77 with a 350 also and have had<br>a similar problem. The engine started right<br>up in the morning as long as I drove the <br>truck everyday. Recently I did some bodywork<br>on my truck and didn't run it for a few days.<br>It wouldn't start, It sounded flooded and I<br>ended up pulling out the spark plugs to dry<br>them out, the plugs were soaked, I cleaned <br>them and reinstalled them and the engine <br>started. The next day I purchased a new set<br>of plugs and a set of MSD ignition wires and <br>installed them. Now even if I don't start the<br>truck for a few days it'll still fire up. I<br>also suspect the factory coil isn't putting out enough voltage, I'm gonna try a new coil soon. I also have a Quadrajet carb and a few<br>people have told me that they leak internally<br>and that could be the cause of the flooding and the longer the truck sits the more it leaks. I think the carb and bad ignition <br>components, including the trucks age, play a<br>factor, or may even compound, starting problems.

04-10-2000, 06:52 PM
Hey again, If the choke on your carb<br>is sticking that could also be adding <br>to your problem, I hope this helps you<br>out, it's just my personal experience<br>and opinion.<br>4LOW

04-11-2000, 10:36 PM
Check the ignition rotor, they can get a small perforation that leaks spark to ground.<p>Also, I'm not sure if the HEI system has a voltage dropping resistor in the line or not. If there is one you ned a connetion to the starter solenoid to feed full 12 volts to the coil during cranking. I've ssne start failures that were caused by that. Try hooking a jumper from your battery to the coil input terminal and try starting it. if it fires right up add a line from the solenoid trigger termial to the coil input.

04-12-2000, 07:15 PM
If you put on a new carb try an Eldebrock, they are far better than the factory carb.<p>----------<br>Get Amsoil Products at WHOLESALE!<br>www.synthetic-motor-oil.com

04-13-2000, 06:13 PM
Well, last evening I tried starting it again- nothing, just would spin - no effort to start. I then removed the distributor cap and looked at the rotor etc. <p>To me it didn't look too bad but did have a little carbon on it, so I wiped it off with my finger. I also bent the spring like conductor up a little to make sure it is making good contact. I replaced the distributor cap and tried starting it again, It spit a few times and started.<p>I left it run for several minutes and parked it in the garage. When I shut it off, it kept turing over like they do when they are over heated, but it wasn't too hot. This morning it started right up, and after work this evening it start immediately as well.<p>I don't feel comfortable using it, still not sure what was wrong of if it is fixed. I do believe it has something to do with the ignition as opposed to the carburation.<p>I hate to take it to a garage if it really doesn't need a tune up or anything like that.<p>thanks for the help, I will keep reading an looking for more suggestions. <p>I did find a manual on &quot;Ebay&quot; and was high bidder, but so far the seller has not responded to any of my emails to find out where/who to send the money order. I haven't bought many things from Ebay, but so far this is the longest it took for the seller to reply, the others replied within the first 24 hours.<br>technically he has 3 business days, so I must wait a little longer before I look for another manual.<p><p><br>

04-13-2000, 08:33 PM
if it is still deseling after you shut it off your timing is out<br>this means a trip to your local garage to have the engine turned would probably solve your problem. Also they would be able to tell you if your carb was in good shape and the condition of the ignition system. A tune up shouldnt run you more than 50 plus parts<br>-abe<br>

04-13-2000, 09:03 PM
I had a similar problem with my 78 camper special. It was the coil pick up mounted under the rotor. It is about 1.5&quot; wide and tapers in on bpth sides with an electricle connector. Once changed I never had another problem.<br>Dino

04-14-2000, 05:43 PM
It really sounds like you have a bad coil. I have seen one vehicle do this. It was a bad coil. <br>When you changed the Distributor cap. How was the ground strap in the distributor?<br>all so, is your distributor loose? if not than your timing is probably ok. unless it has a problem with the timing chain.<br>You can take the truck in to a garage and just have the problem diagnosed. We would normaly charge one hour labor for this. $60.00 <br>PS. I check the coil that was causing the problem just like you have. It passed all the tests I ran on it with a DVOM. only an ignition scope would have shown the problem. low output voltage. Coils are cheap. and easy to install. maybe you should try one.

04-15-2000, 05:00 AM
The distributor seems tight, the truck has been starting every time now - it usually only takes a few seconds, really fast! I think it wants out of the garage and knows it has to be good before I let it out &lt;G&gt;.<p>I plan on trying a new coil, but it may be another week before I can get to doing that.<br>If it happens again, I will definitely send it to the repair shop and let them go over it.<p>thanks again<p><br>joe