Trouble starting - 302

[jonmelton]

Hey guys, I'm having trouble getting my bronco started and wonder if anyone has any ideas. Here is A LOT of back story, but I'm a detailed guy.

I have a 1975 with a stock 302. I haven't been able to get it to pass emissions and have been slowly doing work to get it to pass. When I bought it a year ago, it ran fine. Since I bought it I haven't done anything major to the engine, I've replaced the distributor cap, 2150 Autolite carb, and spark plug wires. But, a few months ago I pulled it in the garage to work on the heater and change the C-bushings. The hoses to the heater had been disconnected by the PO, so I flushed the radiator, put on a new pair of hoses to the heater, and rebuilt the heater box under the dash. I don't think any of this has anything to do with it not starting, but now you know.

After I finished the bushing install, and the heater rebuild I started it back up. It was running really rough, but I just thought it was due to the freezing cold weather and that it had been sitting for a couple months. I drove it around a bit and it never really cleared up, but from the bushing install my alignment was way off and every time I hit the breaks it pulled scary hard to the right, so I didn't drive it over 30 mph. On my second trip out it died at a stop light. I kept trying to restart it, and at one point it restarted but it was acting like I was flooring it so I killed it. After that it wouldn't start again.

I got it back to my house and started troubleshooting. I would put gas in the carb and it would turn over and run really rough for a few seconds then die. I made sure I had gas, checked my fuel lines, checked my fuel switch, and just figured it was my fuel pump. So today I replaced my manual fuel pump, and I still can't get it to start. Still when I put fuel in the carb, it turns over and runs really rough then dies.

Any ideas?

 

[suthernboy]

I'd start by checking out the choke.

 

[blubuckaroo]

So you know it's not getting fuel.
Disconnect the carb and replace the short piece of fuel hose with one long enough to reach a bottle or can. Crank it to see if it's pumping.

 

[galen1970b]

check your wires to make sure they are in the right firing order....you could have a 351 cam...which has a different firing order..instead of 15426378, it might be 13726548...that would make it really hard to start...and run bad...it happened to me once a long time ago....did a tune up then the truck ran horribly. After rebuilding heads...installing electronic ignition(it had points..) new carb etc...it sat for a couple months until a buddy dropped by and mention the firing order thing....I swapped 4 plug wires...5 and 3, 4 and 7...and it fired up without skipping a beat. we were doing donuts at the local fred meyers parking lot 10 min later...

 

[WheelHorse]

You bought it a year ago running fine.

Because it did not pass emissions you decided to install new wires and a cap and rotor despite it otherwise running fine?

What brand of cap/rotor/wires did you use. A lot of stuff from the parts store is junk! Do you still have the originals that ran fine a year ago?

Also, a reman carb was installed?

It could be something as simple as inferior electrical parts, to a stuck float, to a power valve eaten by ethanol.

 

[jckkys]

The correct firing order is cast on the top of the intake manifold right behind the distributor, a Ford better idea. If you still have the original Motorcraft 2150 try putting it back on the engine. After all the engine ran "fine". When you replace multiple parts without running the engine after each part is installed it's hard to know what caused the problem, or in some cases the improvement. I've made that mistake many times.

 

[Aptosgrown]

I may have missed something or someone saying, but did you check replace your fuel filters. I know mine has three. A metal one attached directly to the carb, a see through one on top of the intake manifold and another mounted to the frame before my fuel pump. It could be possible when you jacked it up any particles in your tank may have gone to the pick up and sucked up a bunch of crud. Could have clogged a jet as well.

It might not run perfect when fuel is dumped straight in the carb and same thing with straight Carb Cleaner. In addition if when you were messing around with hoses and heater install you knocked a vacuum hose or plug off that would get an engine to easily run very rough.

 

[jonmelton]

I'd start by checking out the choke.

I've poked around the carb, it has an electric choke, but it doesn't have any power going to it. I don't know if this is THE problem or not because I did run the Bronco fine with the new carb on it for about 3 months.

Any suggestions on how to mess with the choke without the Bronco running?

 

[jonmelton]

You bought it a year ago running fine.

Because it did not pass emissions you decided to install new wires and a cap and rotor despite it otherwise running fine?

Yep

What brand of cap/rotor/wires did you use. A lot of stuff from the parts store is junk! Do you still have the originals that ran fine a year ago?

Yeah, probably just bought cheap AutoZone crap. I don't remember. Checked all the plugs and wires and they all look like they are in good shape. Cap still looks brand new.

Also, a reman carb was installed?

Yeah, got it from National Carburetors. Ran great for about 3 months.

It could be something as simple as inferior electrical parts, to a stuck float, to a power valve eaten by ethanol.

I feel like it has to be something electrical. Like not enough power getting to the spark plug wires.

 

[jonmelton]

I may have missed something or someone saying, but did you check replace your fuel filters.

I only see two. One going into the carb and the other going into the fuel pump. I removed the one going into the fuel pump to see if that helped (it was pretty dirty) but still nothing.

I just bought the one going into the carb when I replaced the carb.

 

[suthernboy]

I've poked around the carb, it has an electric choke, but it doesn't have any power going to it. I don't know if this is THE problem or not because I did run the Bronco fine with the new carb on it for about 3 months.

Any suggestions on how to mess with the choke without the Bronco running?

What made me think choke was your statement about restarting it at a stoplight and it acted like you were flooring it. The choke plate on the carb is opening isn't it? If not, disconnect the link from the choke thermostat or hold the choke open with a piece of wire and try it.

 

[galen1970b]

when you try and start it does it backfire through the carb?

 

[jonmelton]

when you try and start it does it backfire through the carb?

Yep, not consistently. But it has done it 3-4 times.

 

[galen1970b]

check your spark plug wires, for both firing orders...you might have a wire hooked up wrong

 

[WheelHorse]

Open up your distributor and make sure your vacuum advance arm is still hooked onto the rod.

I had one come off on me, which it super retarded the timing and ran like you have described. It just did it out of the blue as well.

 

[blubuckaroo]

I only see two. One going into the carb and the other going into the fuel pump. I removed the one going into the fuel pump to see if that helped (it was pretty dirty) but still nothing.

I just bought the one going into the carb when I replaced the carb.

It sounds like you may have a plugged tank pickup.
If you have access to an air compressor, you could try disconnecting the fuel pump suction hose and put a little air pressure into the tank. You should get a good stream of fuel out of the suction hose.

 

[69red]

it ran great for 3 months on a new built carb with a new filter. but now it does not.

if your gas is really dirty, 3 months is plenty of time to plug up a new filter.

id check that filter out too.

 

[jonmelton]

Open up your distributor and make sure your vacuum advance arm is still hooked onto the rod.

I had one come off on me, which it super retarded the timing and ran like you have described. It just did it out of the blue as well.

I checked the vacuum advance arm. It feels snug and in place.

 

[jonmelton]

it ran great for 3 months on a new built carb with a new filter. but now it does not.

if your gas is really dirty, 3 months is plenty of time to plug up a new filter.

id check that filter out too.

Checked the filter and gas was passing through.

 

[jonmelton]

It sounds like you may have a plugged tank pickup.
If you have access to an air compressor, you could try disconnecting the fuel pump suction hose and put a little air pressure into the tank. You should get a good stream of fuel out of the suction hose.

Pulled the hose from the fuel pump, sprayed some air in and fuel poured out.