Another no start problem - any ideas? Tried all I know...

[TimQ]

I just left my '86 sitting in the local Wal-Mart parking lot because it wouldn't start. I'm looking for some ideas on what I can try when I go back in the morning before giving in and calling a tow truck.

A little history. It's a v6 with a 1-year old rebuilt q-jet. Just about 90k original miles. Automatic.

I had an intermittant stalling and starting issue a year ago. After replacing ignition modules, coils, plugs, cap, rotor, wires, fuel pump, fuel filter, and, in the end, the entire distributor, I finally tracked it down to a faulty ESC module (the box up behind the dashboard that messes with the timing based on engine knock). Once I figured that out m(as in, bypassed it), the truck has run perfectly since. That is, till the last few days.

For the last week or so, the truck won't start intermittantly. For example, on Friday, I drove a few miles to pick up a chair at a local shop. Came out, and no start. Decided to walk up the street and grab lunch at the local pizza shop...came back and it fired right up.

On Sunday, I took my father-in-law to look at computers at the mall. Come out, truck won't start. Got some starter fluid and sprayed some into the carb but nothing. We decide to have lunch. Come back...starts up.

Tonight, I decided to take a spin for a good 90 minutes or so. On the way in from my normal loop, I decided to stop at Wal-Mart. Come out...no start. Figuring the battery might be giving in (just got really cold here the last week and the cranking speed was a tad slow), I went back in and bought a new one. Put the new battery in and crank it. Cranking speed is way better but still no start. I decided to see if I just needed to wait. So, I go in the store and poke around...come back out 40 minutes later (you know...about how long it takes for lunch). Still nothing. Perhaps the truck knows I didn't actually eat this time??

So my wife comes to pick me up and I figure, why not try and jump it...maybe the new battery isn't fully charged. Still nothing.

My guess is, I will go back in the AM and it will start right up.

Here's what I know. I have spark to the plugs. I have at least 12volts or so at the wire going to the dizzy. I can hear fuel squirting in when I manually move the throttle.

Also, after the first incident of a starting problem last week, I put new plugs and wires on it, checked the dizzy to make sure all was in order, and even checked the fuel filter. I checked for voltage loss between the battery and the wire coming into the dizzy. That was fine.

So, I'm at a loss.

The truck is running great otherwise. After hitting it with some seafoam a few months back, it doesn't smoke on start up anymore, or hesitate when punching the throttle. I used to have to add a bit of oil every second time I filled the gas tank. I've gone 5 or 6 tanks since the last oil change (1000 miles at least) and I've not had to add any oil. I'm getting 12 mpg or so and thats with fairly agressive and fast driving. So I would think the engine is in reasonable shape. When I had the problem with the ESC and replaced the dizzy, I had the shop set the timing. So I'm pretty sure that is right.

So...what gives? Any ideas? Especially those I can try in the AM to get my truck out of the parking lot at Wal-Mart?

Thanks.
Tim Q

[Dru]

Are you getting fire to the plugs? Unplug a wire, and either stick a screwdriver in it, and have someone crank it over, while holding it close to a metal bracket, or just grab ahold of it, and get shocked a few times..if you are, I actually use the latter method more than the other. There is a neat tester light for this, but I'm also cheap with some things.

It could be the HEI module, sometimes the cheap China replacements don't last, and the heat was getting to it before it failed.

Been a long time mechanic, but I'm still pretty old school when it comes to electronics under the hood.

[ol'red77]

check for any broken wires to the starter,dist,alt,fusable links,etc etc etc, bad connectors or connections, a bad connection will send you in a tail spin and make you say stuff you normally wouldn't say on sunday at church lol!!! it can be a real pain in the rear. I had a similar kinda problem you had and it was a broken wire hanging on by one strand going to the hot side of the dist and when the motor was running it was fine then when i went to go start it it wouldnt run at all cause of a bad or no connection.......

Hope that helps somewhat...TTYL Richie

[Allensracing]

there are four things needed for a carbureted 4 stroke engine to run. fuel, air, compression, and spark.
you certainly have air and compression. your missing fuel or spark.
could there be contaminated fuel? water in the fuel? but if starter fluid doesnt help, you have eliminated that also
that leaves spark.
weak spark from an intermittent electrical problem?

[bitchin85]

my guess would be the ignition module. i got a cheap-o when i re did my motor about a year ago and it went out in just a few months. and had to get a third one just the other day> and theyll fry in no time if you dont put that thermal whatever grease(forgot whats called, it transfers the heat out of it to the base of the dizzy). that would be my first thing. hope it helps and good luck

[xrcr]

Verify spark (or not) if none X2 on the ign. module.However I have never had one slowly go bad it worked or it didn't

[TimQ]

Thanks for all the tips.

Yes, I am getting spark. That's what's driving me crazy about this. When I had the ESC problem, when it wouldn't start, there would be no spark. Then it would spark and it would be fine for a while. I even have a consistent 12+v to the ignition wire coming into the ignition.

Any other thoughts? One thought I have is that the battery is strong enough to crank the engine but not strong enough to create the spark needed to fire the engine. Anyone have any idea how many volts I need while cranking in order for the spark to be strong enough to fire the engine?

Of course that wouldn't explain why it doesn't work when jumping it.

Grrrr.

[tucsonjwt]

A V6 is unlikely to have a starter heat soak issue, but if you can, the next time it won't start when hot try jump starting the truck. You might be able to start it with one of those jump start packs instead of another vehicle. If that gets the vehicle started quickly, then it could be a starter/solenoid issue, or an upper steering column issue.
As you know now, these old trucks can have a lot of problems - fix one problem and another pops up. Also, there is no guarantee that fixing one problem will fix your intermittent no start issue - I had that with my 83 big block and it took several years and many experienced ASE mechanics (and $$$) to finally fix the problem. In my opinion, auto repair still involves a lot of guesswork - even for the "professionals", and there are very few really good mechanics in the business - those that will guarantee a fix, regardless of what they say.

[tucsonjwt]

Sorry, I just caught your last post about not starting when jumping it - so disregard my last post - I assume you have had the parts store check your charging system with the battery in the truck.

[motornut]

you might wana check enough gas
pour it down the carb when it no start
check tank sending unit for crack etc
this should narrow down the issue

[TimQ]

Well, true to form...had a friend drive me over this morning to get the truck and it started right up. Not even a blink...just roared to life. Drive about a mile to get gas. Fired up again no problem. Drive half an hour and went home. Shoveled the driveway and she still fired up fine.

Damn trucks.

So it appears to be a problem starting when warm but not always.
When it doesn't start, it still has spark and it cranks...just no fire.

Suggestions welcome.

[Allensracing]

when you say it has spark... how are you testing it? are you pulling a plug wire and arcing it to ground? are you hooking up a spark plug and watching it spark?
I am voting on electrical problem.
if the engine is cranking, the problem is not a main battery cable.
what else is going on when it is not starting? are your lights flickering or anything like that?
the more details about what happens when it doesnt start, the easier it makes the troubleshooting

[TimQ]

I test spark by pulling a plug wire and either putting another plug into it and holding it by the frame or, if I am alone, I shove a piece of wire up in the plug wire and ground that to the frame by the door. Either way I get spark (which was not the case when I had the ESC problem).

The only other thing that I've seen...and I'm not sure this is consistent...but on some occassions (last night included) when it doesn't start, it does seems to fire for just a split second the first time I crank it and then nothing after that until I just walk away and come back many hours later or he next day.

Been reading the forum and other sites on the web and I wonder if it's a choke problem (staying closed even when warm) and maybe getting flooded after that. But, you'd think 40 minutes or an hour on a night when its 20 degrees would be enough to cool the engine down.

[Allensracing]

if its flooded you should be able to smell it when you open the hood. also, running with the choke on tends to make it run rich, and it might kill it but it shouldnt take hours to recover.
what do your plugs look like when it does this? if its a choke problem your plugs would be black.
have you pulled a couple plugs and checked them when its not starting?

[TimQ]

I have noticed a slight gas smell at times. But not overwhelming and it seems to go away pretty quickly. I didn't check this time but last week when it happened, the plugs seemed fine. Certainly not black (though I put new AC Delco ones in then just in case).