Bronco is stalling...............AGAIN!!!

[BNC04]

I'm not anywhere near most on this board from a technical perspective but your gas cap venting statements have me confused. I would think a vented cap would be designed to prevent a vacuum within the tank from occurring, much like a vent on a gas can. when the vent is open, the fuel will flow more freely because air is being let into the gas can to equalize the pressure and remove the vacuum effect. Can you try replicating the failure with the cap removed or at least loose to the point where your sure it is not creating a seal and thus a vacuum in your system which would prevent fuel from flowing freely during driving conditions?

Brett

[Eck]

I'm not anywhere near most on this board from a technical perspective but your gas cap venting statements have me confused. I would think a vented cap would be designed to prevent a vacuum within the tank from occurring, much like a vent on a gas can. when the vent is open, the fuel will flow more freely because air is being let into the gas can to equalize the pressure and remove the vacuum effect. Can you try replicating the failure with the cap removed or at least loose to the point where your sure it is not creating a seal and thus a vacuum in your system which would prevent fuel from flowing freely during driving conditions?

Brett

I just drove it without a gas cap and was able to replicate the same thing happening. I am not really sure how to tinker and check the float levels with the carb. Do I need to completely remove it and open it up?

It is strange. The engine will sometimes not die out until I push the clutch in and then it is suppose to go back to idle but will just die. As soon as I start it back up and give it a couple pumps of fuel, it will idle fine. Also, the fuel pressure guage was climbing up to 4-5psi this morning when I started it up fresh. When I checked the pressure after the first time it stalled-- it was at 0psi. Clearly there is a problem there but I can't tell what...

[Eck]

I checked the float level and it seems to be fine where it is.

The fuel pressure is what is really bothering me at this point. I just let it run in my driveway for about 15 minutes idling. It started out at about 3psi and was slowly climbing and then 10 minutes later, I go out to check it and it is just sitting at 0psi. From my understanding, the CARTER should be running the system at 6psi. Does this mean I have a leak somewhere? I checked to make sure all of the fittings were tight, there are no fuel leaks anywhere.. but not sure air is getting in to the system to cause ZERO psi?! The one thing I did not do was flare the steel lines where they connect to the rubber lines. Would that cause this?

I am reaching the end of my rope. I have not been able to drive this damn thing now for months...

[BNC04]

Can you possibly run a line from your pump into an external gas tank? This will either point to crud in the tank being sucked up or remove it from the equation.

Brett

[Eck]

Can you possibly run a line from your pump into an external gas tank? This will either point to crud in the tank being sucked up or remove it from the equation.

Brett

I could-- wouldn't I see this "crud" in the fuel filter before it even gets to the pump though?

[BNC04]

Not if it is blocking the screen around your pickup tube in the tank or if there is some issue with the pickup tube. I'm just suggesting things that might help isolate without tearing stuff apart yet. The next thing I would think about is then running a piece of hose from the external tank to the carb bypassing all your connections. If it still did it then, you know it is not fuel line leak related but it could still be your pump with your pressure dropping to zero, It seems doubtful it would be anything else if it fails from another tank and a continuous line to the carb. I'm sure there are easier ways to test but thats what I'd try.
Brett

[Viperwolf1]

Can you possibly run a line from your pump into an external gas tank? This will either point to crud in the tank being sucked up or remove it from the equation.

Brett

Sounds like a good plan.

[Eck]

The problem is that I can't really replicate the stalling just revving the engine in the driveway. I think I'm just going to suck it up and drop the tank, try to flush it out real good and see if I can at least eliminate that. I was not having this many issues with the stock tank so I'm really hoping the new tank is the source of the problem.

[ZOSO]

No cat. I have not tried a new coil because when testing the current one, it shows it's good. Not sure if it could test good but still be a bad coil?

When your testing to coil it's cold and your just measuring the resistance. When the coil gets warm ie:running it will get warmer and the resistance will rise.

[Viperwolf1]

The problem is that I can't really replicate the stalling just revving the engine in the driveway. I think I'm just going to suck it up and drop the tank, try to flush it out real good and see if I can at least eliminate that. I was not having this many issues with the stock tank so I'm really hoping the new tank is the source of the problem.

If the fuel pressure is dropping to zero you've found the problem. Now you just need to find out why it's doing it.

[ZOSO]

The problem is that I can't really replicate the stalling just revving the engine in the driveway. I think I'm just going to suck it up and drop the tank, try to flush it out real good and see if I can at least eliminate that. I was not having this many issues with the stock tank so I'm really hoping the new tank is the source of the problem.

If the fuel pressure is dropping to zero you've found the problem. Now you just need to find out why it's doing it.

Thats not entirely true. Every mechanical and electric pump I've had on my bronco does the same thing. When idling hot the fuel pressure drops to zero. And i've never had an issue either. The engine idling hardly uses any fuel. I can take my regulator and crank it all the way up and let the pump run free and i'll still show "0psi". Once i get out on the road and start using it is when the pressure comes back up.

[ZOSO]

It's one of 2 things. ignition or fuel. Only under load and when warm do you have this issue. I would look into the coil as 1 spot. then give the fuel system a once over again. Go out and drive it, get it to stumble and quit. touch the coil and see if it's hot. and do the same to the fuel pump. The pump may be weak and it shows when it gets hot. same with the coil. Heat does mess with all sorts of things.

[hockeydad4-22]

Here is a thought looking down a different path.

Way back in high school I had a 76 olds cutlass with a 350 and Rochester 4 barrel carb that was behaving similarly. I pulled that carb and rebuilt it, replaced filters and fuel pumps till I was ready to set the car on fire. Nothing worked. At the time I was working at a full service gas station and asked the head mechanic to take a look at it, he took the dist cap off and replaced the module in it, said it was cracked. When the car would get good and warm (or hot - considering the way I actually drove it) it would expand and separate. Never had an issue again. I searched and searched, I spent hours and hours, but I never fixed a damn thing... he spent about 7 minutes under the hood and charged me 35 bucks but fixed the issue.

I do not know if this is even possible in your situation but if so, it would be a pretty easy fix. Take a look.

[landshark]

sounds like bad fuel pump or clogged filter in tank/pump line to me... i had a new pump in my other bronco that would start failing after it ran for a bit and caused the Fuel Pressure to drop and then of course the engine would stumble and quit eventually.. i would re-check the pump and filter..

[Eck]

So lots of ideas. Trying to put a plan together to get it figures out.

First drive it until it stalls, check the coil to see if it's hot. If so, replace the coil. If not, check the pump to see if it's hot.

It is a brand new pump and I've heard from everyone that the Carter is suppose to be rock solid. What's the easiest/best way to check the pump.

I've already replaced the fuel filter, so it would have to be coming from the tank itself. Last step would be to drop the tank and clean it out of any potential gunk.

HockeyDad- I've already replaced the cap and rotor on the dizzy. Is that what you were referring to?

How does the fuel pump placement look? Someone on CB said it needs to be lower than the tank and that the fuel filter not being completely full is an indication it can't pull the fuel. There isn't anywhere that I could mount it any lower...

[Gunnibronco]

Hockey Dad is referring to the "trigger" or module inside the dizzy. I think it sends a signal to the Duraspark box for each revolution. I replaced the cap, rotor, etc only to have the module in my MSD fail, heat induced & intermittently like you, that same year. I don't know how exactly your dizzy or Duraspark works but someone will speak up. Sorry I can't be more specific regarding where the module is or how to replace it.

[Viperwolf1]

It's going to be difficult to determine the condition of the coil or fuel pump by heat. They normally get pretty warm. I'd say if it dies that's the time to check for spark and fuel in the carb. Should be able to rule at least one of those out.

The pump location is fine. I use 2 of those mounted on the frame like that and don't have problems.

The fuel filter is a little suspicious looking. Is that a replaceable filter element? If so it could be leaking air in where the filter screws together. Easier to pump air than fuel.

[Eck]

Replaceable filter element? It's a new $3 filter that is about 2 miles old.

[Viperwolf1]

Replaceable filter element? It's a new $3 filter that is about 2 miles old.

Ok. It looks like one of those that comes apart so you can replace the filter element.

[Eck]

I feel like I'm just throwing darts at a wall. There seems to be at least 5 things people are saying it could be and I really am not sure where to start or how to check those things. Sorry, not trying to sound like a whiner.

Two questions. Would anyone be available Friday during the day to help me check a few of the things?

Secondly, I'm seriously debating taking this to a mechanic-- any good suggestions in north Denver?

[Justin]

First drive it until it stalls, check the coil to see if it's hot. If so, replace the coil. If not, check the pump to see if it's hot.

It is a brand new pump and I've heard from everyone that the Carter is suppose to be rock solid. What's the easiest/best way to check the pump.

I've already replaced the fuel filter, so it would have to be coming from the tank itself. Last step would be to drop the tank and clean it out of any potential gunk.

HockeyDad- I've already replaced the cap and rotor on the dizzy. Is that what you were referring to?

How does the fuel pump placement look? Someone on CB said it needs to be lower than the tank and that the fuel filter not being completely full is an indication it can't pull the fuel. There isn't anywhere that I could mount it any lower...

I'd be surprised if the pump was bad, but it isn't unheard of. Your placement looks OK to me, but I'm no pump wizard. It's pretty much where I plan to mount mine. I'm not sure how you could mount it lower than the pickup. The order I'd diagnose in is:

1. Unhook the fuel line from the carb and run it to a clean 5 gallon bucket. I've got zillions of them for my aquarium if you want to borrow some-they'll need cleaning if you want to re-use the fuel. Run the fuel into the bucked by turning on your ignition, see if it slows down after 5 or 10 gallons. This may eliminate the pump as the issue.
2. Drop the tank and check for crap or leaky hoses. As Viper mentioned, air flows better than gas, could be something inside the tank.
3. Replace the coil. I'd probably have done that anyway, just because it's a pretty basic tune-up item.
4. I'm not familiar with the Duraspark distributors, but there should be some sort of trigger mechanism inside it. I'd replace that.

No idea about a north metro mechanic, but I'd be happy to take a look at it. I'll likely be working late, so I'm not sure that'll work, but I can make some time another day. Might be able to do Thursday morning or possibly this weekend.

[Eck]

Thanks Justin. I'm out of town Thursday and have a wedding this weekend. I'm planning to be around all next week though so maybe there would be a time that works next week too?

I might get a new coil since they are pretty inexpensive. I can also pump the fuel out but I'd imagine I wouldn't see much of an issue. Maybe run the engine to temp until I see the pressure drop below 2psi and then disconnect the line and pump to a bucket. What's the best way to get rid of old dirty fuel?

If none of that works, I'll drop the tank(this is where I could use some help).

[Eck]

I was looking at Oreillys to figure out which coil to buy. Does it matter? They don't have a duraspark one so wasn't sure what the differences were and if I could use a different brand. I was also looking for the dizzy trigger or module and couldn't figure out what that was per HD and Gunni's previous comments. Anybody care to elaborate on what it is or if it's called something different?

[ZOSO]

http://shop.advanceautoparts.com/webapp ... tor+pickup

[kchaser]

I would suggest just filling a gas can and putting the fuel line in it so you can isolate the possibility of a tank issue. Then put a piece of clear hose onto the carb fitting. Maybe a foot or two. Maybe you can see if it is starving for fuel or if it's a carb issue. I would also try a different carb to eliminate that possible issue. But that's just me.

[Eck]

I would suggest just filling a gas can and putting the fuel line in it so you can isolate the possibility of a tank issue. Then put a piece of clear hose onto the carb fitting. Maybe a foot or two. Maybe you can see if it is starving for fuel or if it's a carb issue. I would also try a different carb to eliminate that possible issue. But that's just me.

The problem is that I can't replicate the problem in my driveway so it won't help much to pump from a gas can. I would also think replacing the carb is the LAST thing I'll do since that's the most expensive. Even when the pressure is idling at 0psi, it doesn't die in my driveway. Thank you for the suggestions though.

Thanks for the link ZOSO. It seems like BSD brand is interchangeable with the duraspark brand. Even their ignition module looks to be the same.

[Justin]

Thanks Justin. I'm out of town Thursday and have a wedding this weekend. I'm planning to be around all next week though so maybe there would be a time that works next week too?

Yup, I should have some time next week.

[plumbdoctor]

Wtf! Fix it!! JK, did you ever secure the coil after the ps install? So it only happens under load, bouncing down the street?

Lost my thought... Still mad Melancon gave up the bomb to Adams... I will remember shortly??

[plumbdoctor]

Does the filter fill up when running?

[Eck]

Waiting on you to offer and come over and fix it Keith!!! We fixed the coil location about 3 weeks ago so it's been bouncing around since May. Replacing the coil on Friday and hoping that helps.

Didn't they end up winning that game that Melancin gave up the bomb? I'm pretty sick of the Cardinals and wish the Pirates could've pulled that one out.

By the way, stop by Friday- I've got a fuel pressure guage and a t-shirt for you. While you're here, you can help me fix me rig!