2stroke1971

My son borrowed my FB the other day because his car had a flat. He drove it on the highway a bit further than I usually do when i take it out.

It died on him after about 10 miles, and then restarted a few minutes later.

We had this a year ago or so...dumping some fuel in the carb would ALWAYS start it when it was doing this, though it did not always stay running....

It would crap out....you could kill the battery trying to crank it up, then 30 minutes later, it would fire right up...run 10 miles and die again.

I replaced the fuel filter....some of the lines to the pump as well since they were kinked.
We've taken long trips since then, but here it is again cropping up.


So something is still buggy with the fuel delivery.

Any ideas? Could the relay fail intermittently? Fuel pump perhaps? Its got an aftermarket one on it....not sure what it is though.

For that matter what is a good aftermarket pump? Its a stock car, I dont need anymore pressure then what is needed....

Thanks in advance!

Cookboy

iTrader: (10)

Have you looked at the fuel pickup in the tank? That's what mine was. I was amazed any gas got through.

2stroke1971

No, I haven't...Do you have to drop the tank to check that out?

Thanks,
Neil

t_g_farrell

iTrader: (1)

Another thing to consider is that it may not be fuel but the ignition. Ignitors tend to fail only
when heated up. They will get progressively worse over time until it just won't start anymore.

I replaced a fuel pump thinking like you are but it turned out to be ignition all along. Thats when
I did the DFIS using TFI coils linked in my signature.

Cookboy

iTrader: (10)

Given Mr. Farrell's reply, try swapping the leading and trailing ignitors. See what that gets you. Dropping the tank is necessary to inspect pickup, but affords the opportunity to replace old fuel lines and put a new sock on pickup if all else is well. And it only takes 30 minutes each way, down and up.

2stroke1971

I will check into that.

The previous owner had some sort of ignition problem ,he had replaced the whole distributor with another unit. I don;t really understand the ignition on this car all that well at this point to be honest.

So the direct fire deal eliminates the ignitors, and you keep the original distributor?

Ive got some pick it yourself junkyards around here as well. I always thought a pair of super stock accels would work nice in there....

I think I have to drop the tank either way. I am spread so thin Im not sure when I will get to doing it though. Too many indulgences and not enough time or money.

What should swapping the leading and trailing ignitors get me? I take it the trailing unit is not as critical since some people leave them out of the direct fire deal right? So perhaps if the trailing unit is more functional than the leading unit i may see an improvement...is that the logic?

Thanks again!
Neil

Cookboy

iTrader: (10)

Yes, if the trailing ignitor is good and leading not, swapping them will let you know. There is no big upside to swapping in 'performance' coils.
There is a big upside to direct fire, even using stock coils. Direct fire still needs an ignitor, 2 actually, unless a 2nd gen coil is used.
I use an msd box where an ignitor would be with my 2nd gen coil dfis.
Anyway, for now just swap your ignitors and see what you get. Quick, easy, and no harm if it doesn't solve the problem. They can remain swapped, they're the same part.

WJM ROTARIES

Sounds like tank breather / vent is blocked and casing vacuum on tank and you let sit for a while will re start

2stroke1971

ok, so why "direct fire"...what is being bypassed? The old ignitors? With other ignitors? Is there a difference in how the stock and a modded system work or is it just to get more reliable ignitors/better spark?

Cookboy

iTrader: (10)

The distributor, or more precisely, the cap and rotor are bypassed. One coil fires directly to one leading plug. Each coil still requires an ignitor, a j-109 or gm hei, or you can use an msd box in place of an ignitor.
The upside is a much stronger spark. Better combustion, easier starting. In everyday driving I don't really notice the difference, power wise, but it's there. I could tell when I first did it by a difference in exhaust tone.
That's the experience of a non mechanic non technical cook.

2stroke1971

Well, I dropped the tank today. It was nice and clean inside. A few black specks...nothing like rust inside at all...the pickup/screen was pristine. I drained the gas out anyway.

The vent line form the tank goes to this valve looking thing on the underside of the car, just up from the tank. I am assuming this is some sort of vent valve.

I was telling my son about the vent thing and he mentioned that after it had cut out on him and restarted a bit later, he went to a gas station to put a few bucks in it just in case..when he unscrewed the gas cap it sucked ALOT of air in.

It's making me think, WJM, that it may be what you are describing. So am I right, is that thing a vent valve? The line from the tank went into it, then a line went up front...and there was a third port on it, and it just has about 6 inches of hose just hanging there.

Down on the tank itself, the larger bore line from the tank would be the out and the smaller one is the return...then theres the vent. Im thinking of just running a line for the vent port up and out of the way somewhere, rather then into that valve. The tank is still out, Im gonna replace the fuel lines on it.

I probably wont get to working on it until next weekend. One good thing though...with the tank out and having it jacked up, I got a good look at the undercarriage. Its got better bones than I thought originally. It has that typical rear fender well rust issue on the drivers side, and the rear quarter on that side is rusty, but other than that, the frame rails and the rest of the unibody look pretty good. I used to think that this one would not be worth rebuilding the engine on, but I can see doing that at some point now.

Thanks for the replies about the direct fire ignition! I will consider that in the future.

WJM ROTARIES

Yes that is a vent valve and they can get blocked ,See if you can dismantle it and get it working, it is important for the hole system to work. also check the vent hose goes up to the carbon canister [under hood ] it or the canister could be blocked also

2stroke1971

the carbon can?
'Hmmm...
I think that is not connected, and the two metal lines that went to it are hooked to themselves or blocked off.....i wil have to check that out.

Thanks again!

WJM ROTARIES

If the pipe from the tank is blocked off you have no vent to your tank

2stroke1971

Heh heh. Yep, the charcoal can is long gone. I plugged those lines off not too long ago when I pulled the carb to reverse the mechanical seondary thing. .so no vent.

Now the tank is venting out of the smaller metal line on the passenger side under the hood. No can though.

I spent alot of time replacing fuel lines under there. The fuel pump was not stock, and donesnt fit in the recess well. A real pain to route all the hose so they do not crimp. Need to get some generic line with a u bend in it if they do not make specific hoses....


I drove it around the block a few times, so far so good....I wont think its fixed until I take it for a long drive though. Ive got alot more to do.