Technical SBC keeps dieing

The engine is a '74 350 block in a '60 suburban. I got her back together about 2 months ago and I've put about 500 miles on the engine and drivetrain since that time. I rewired pretty much everything on the engine side and have had zero issues that I've noticed with that, but I do seem to have something draining the battery, so I installed a marine grade battery switch between the battery and the junction block. She's been down the last week due to a brake line issue...it was getting pinched between the exhaust and the tail pipe. I couldn't find a 45 or 90 fitting to install on the T, where the line from the front T's off to the rear wheels, so I cut the exhaust pipe off on the p***enger side at the muffler. That muffler is shot anyway and I figured, I'd just take it to muffler shop and have them re-route the exhaust pipe. I'm seriously doubting this has any bearing on anything, but it's the only change I've made.

Last night after hooking the brake line back up, after cutting the tail pipe (true dual exhaust setup) on the p***enger side I took her for a spin to check things out. All was good for about 5 minutes, then she just died. I coasted onto a side street and tried to start and she cranked and cranked for a minute and again nothing, so I called my wife to come get me so I could grab a gas can and fill her up. I'm running the original fuel tank, but it started leaking, so I patched it. I haven't had any issues or signs of leaks since, but wondered if maybe I missed something with her sitting for a week. I have a new tank to install, but there's some mods that need to happen so with no current leak, it got shoved to back burner and thus never hooked up the gauge to the original tank....I had just filled her up a few day before parking her when the brake line gave out, so I figure she should have at least 8-10 gallons of fuel. While on the phone with wife after sitting for a minute, she fired up and ran good for a few blocks, before repeating....again I coasted to the side of street. I crawled under and looked at the rear fuel filter and there is a mix of fuel and a large air bubble in the filter....also a bit of rust from the tank. The fuel looks clean and at first I thought, maybe she is running low, but again, I cranked and again she started and I was able to drive her home. I crawled under and my wife pushed on the bumper and the fuel line isn't getting pinched and I'm sure I heard gas sloshing around.

Online searches seem to point to electrical issue maybe. What do I look for? I've had to temporarily add an extra key and key fob to my keys, because I've been driving another one of our cars more lately. I'm curious if the extra weight is too much for the ignition switch....I plan on later trying to start it to see. When I re-wired everything I cleaned up the wires on the switch under the dash at the ignition as well. Everything is soldered and heat shrunk I believe and all wires in engine bay for the most part are the same and then I wrapped them in fabric automotive tape to clean things up. I figure later in the day I'll go out, start her up and see if I can re-create the issue by messing with the wires while she's running. My concern is if it's the HEI, cutting out....is there an easy way to figure that out? Should she run if the battery terminal is loose OR if the alt wires are loose....I know they say newer cars won't run if the you unhook either and when I was testing my previous alt on this, if I unhooked the battery, the truck died. I bought a new, larger alt very recently and it's showing 14amps while the truck runs.

***FWIW, I think the drain is in the lighting circuit, which is slated to be re-wired as I work down the list, but for now they work and turning the battery off at night with the switch seems to keep me good. Maybe this is related though.

 

The next time it acts up, have a can of starting fluid at the ready and if it fires then you know its a fuel issues which could be very likely with an old fuel system. If it doesn't fire than its likely an ignition issue and you can proceed down that road.

 

Hard to follow all the details in your post, but you said you cut off the exhaust pipe at the muffler just before this problem came up. So, is the exhaust being directed at the fuel line coming from the tank, and causing vapor lock? That would go along with your description of the failure, i.e. it ran find, then died after some time of driving, then after sitting for awhile it fired back up.

 

That is kind of the thing, at this point, by the time I open the hood, remove the air cleaner, it would have already had time to re-fire apparently. I never sat more than a minute or two when this happened yesterday. The first time, I tried to immediately crank and it just cranked and cranked for maybe 15 seconds and figured she was out of fuel, so I called my wife and then tried again and she fired. The 2nd time, I immediately got out, crawled under to investigate the clear fuel filter. Besides the tank, which is obviously a big part of fuel system, everything else is brand new. All new lines, filters, pickup, pump, carb rebuild, etc.

 

HEI issues can also behave like that, ie quit then start again after sitting a little bit.

I'm not a fan of starting fluid, I'd rather look at the carb and see if it has fuel. But I'm also not a fan of clear fuel filters, they're a bit too fragile for my liking.

 

...I had a problem like your saying,....it turned out to be a gas tank that was rotting from the inside,rust etc was clogging the lines and fuel pump,....changed tank ,pump and lines works great....miller

 

You follow correctly, I probably should have proofed my post. Yes, that muffler could potentially be blowing hot air at the fuel line. There is a fuel line that runs very close to where the brake line that got pinched, maybe 6" away. I was worried maybe without the tail pipe to limit suspension travel maybe the fuel line was getting pinched now, but after crawling under and having wife bounce the rear of the truck, it looks clear. I'll see if there is a way to angle the exhaust g***es off the line. That could make perfect sense....idling in the drive the exhaust would just float everywhere, but driving it would tend to move right over that area now. Hmmm...

 

post some pics, of the engine, fuel routing, etc, so we can see the other problems that you didn't notice.

 

The first clear filter leaked, it was gl***, the next one was a fram (I believe) and it's a solid design, seems much better and maybe not a perfect solution, but wanted to watch this old tank after cleaning it. I really wanted to salvage it if I could, but it's obvious that isn't possible. Was hoping to limp the tank through the summer.

The amount of 'rust' in the filter though more than I'd like to see, doesn't really seem to be enough to clog the filter or the lines in my opinion, but the sock on the pickup, could be a different story. The filter element doesn't have any sediment on it.

 

Here are some pics. If you need more let me know. I was trying for a hard steel line off the eddy filter, but couldn't get it bent and settled on the stainless. It routes very close to alt and block, but touches no where and is about 1/2" off any surface at minimum. The rubber from pump is temp zip tied to battery cable just to keep cable inline until I get it wrapped up with harness tape....have just been waiting to insure I'm happy with everything before making it more permanent.

The rest of the line is 3/8" steel line basically bent to follow factory lines. Only exception on this is where a bend got tricky, so I cut the line and used that spot to install the rear filter. That filter is more towards front end of muffler, so I don't think that's the point of issue. If you look the the picture with the rear of muffler, you can easily see the flex brake line, which led to T that was tight at issue with tail pipe. In this picture you can also see the steel fuel line transition to rubber, where it goes to top side of tank. I suppose very easy for great to sit right there.

 

Rest of pics

 

In interest of getting this on road long enough to get to muffler shop AND to see if issue is in fact vapor lock. Any chance I could reinstall the tail pipe, might be able to dent it where it rubbed on brake line to help with that, then use metal foil tape to sort of reattach it to the muffler? My thought is the foil tape might allow me to somewhat reposition it a bit and keep it less solid so it doesn't smack the brake line as hard. Might even be able to cut open pop can for backing under the tape.

 

You're doing better than I would have. My wife woulda laughed her *** off for a bit and then come and rescued me. Then I'd never hear the end of it.

 

My Hudson with a 350 had a similar problem would run for two block and sometime several miles, then it would act a lot like vapor lock. In line filters showed very little rust or anything else. The pickup in the tank was getting clogged with all the junk in the tank. Cleaned up the tank and all has been good for years. I would look closer at the condition of the tank.


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My neighbor said when growing up they had an intentional harvester pickup that vapor locked and they would put wooden cloathes pins on the lines and that was enough to dissipate the heat. I'm betting it is a vapor lock due to the non existent tail pipe so I'll try to re add that tomorrow and see. If not I'll replace the tank and if necessary blow out the fuel lines.

 

When it dies, look down tbe carb and see if the accelerator pump squirts fuel when you move the throttle linkage. If so, you need to check for spark. It sounds like you are losing one of these two. Intermittent electrical issues can be a real pain to specifically identify sometimes. Get a manual to help troubleshoot your problem, the wice will get tired of coming to you rescue eventually. Wife, that is.

 

Also, while driving the exhaust temps would increase and so would the engine's fuel demand.

 

Take your air hose and blow through the fuel line back towards the tank. That will usually blow a hole in the sock if there is one left and it hasn't rusted off. I would drop the tank and either take it to a radiator shop and have it boiled out or at least take a pressure washer and soap and clean it as best you can. Then use one of the gas tank products that seal the inside of the tank.
You have eliminated one problem that is going to be a constant headache, plugged fuel filters can ruin your day or night . I just did a Torino that had been setting and It was amazing the **** that came out of the tank.
I don't think you have vapor lock.
The pickup in the dist could be going out . Getting hot and coming back when it cools off.

 

I had the same problem with my 53 Buick special. It would **** up rust in the filter {from the gas tank}and die. I would let it sit a few minutes and it would start again and down the road a ways it would stall again. I finally sent the tank out to be boiled out and cleaned. If its not electrical and your not getting fuel I would check your gas tank. Get it patched and cleaned at the same time. Mine was so bad I would carry 4 fitlers with me. When the car stalled I could roll under the car and have the filter changed in 2 minutes but I was going thru too many filters. It was easier to have the tank cleaned.LOL. Bruce.

 

When I was 16 I drove home from my job at a textile mill 1/4 mile at a time. It took me several hours to get home. The problem was where the gas line changed from steel to hose before the fuel pump. It had deteriorated and was not leaking but let the pump **** air. When I stopped the pump would gravity fill and let it run until it ****ed enough air to die again.

 

I did everything to clean this tank and was going to seal it, but right before it got a pin hole leak.so I used the two part epoxy and patched and ordered a new tank. The pickup and sock were brand new. I installed the original tank anyway as I needed to get the truck registered and on road while I searched for the tank.

That all said, I patched the tale pipe back on with a tin can and it was definitely better, drive a few miles and all was good, UNTIL I pulled into the drive and waited on wife for five minutes and it stalled out. When I checked the carb it was spraying gas, but it was a few minutes later as I checked other stuff first. I'll try again tomorrow....

 

Sounds to me like the ignition control module in the distributor....it gets hot and quits working, cools down after a few minutes and starts working again....has happened to me in the past...$20 and 20 minutes is worth a shot...

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Don't have your fuel line zip tied to the battery cable by the fuel pump.....I was lucky when mine caught fire and got it out before the fuel line burned through!!!

 

Regarding the ign control module, I'll have to check that out. The dist isn't that old, realize everything can fail, wonder if my old dist I've is worth a try.

Regarding the cable, I know I need to get that changed.

 

Chinese HEI, suspect the worse.

 

Regarding HEI failures, check out this thread I did on missing ground straps inside the HEI.

https://www.jalopyjournal.com/forum/threads/stupid-hei-tech-for-dummies.950499/

 

Bad HEI modules can produce many annoying problems. I had one that would **** out after 5 minutes of running, wait 2 minutes and it might start again, rinse-repeat. My last one as long as the car kept running it was fine, shut it off for less than 15 minutes, guaranteed to start, let it sit 20... had to let it sit 2 hours to cool down.

 

Yep, they are so cheap that they've become a disposable wear item.

There are a few ways to trouble shoot a module. But this one will p*** the test - while its running. It will fail the test when it won't start. So the trouble shooting needs to be done while its in "the no start" condition. On the last line of the trouble shooting chart for the module it will say " subs***ute with a known good unit" and repeat the test drive.

 

Any update?