Sharing story - Solving issue of starving for fuel after running for 10 minutes

[cpbol]

I'm a new owner of an old Healey 3000 BJ8. When I took possession, it started and ran okay, but hadn't been freshened up in 10+ years. After a few short test rides, I discovered that the engine would sputter and nearly cut out after driving around town for about 10 minutes. It would run smooth as silk at first, which told me the carbs were tuned (well enough), but then after a few longer pulls through the gears, it would start to sputter and lose power, as if it were running out of gas. Long story long, this was repeatable many, many times. The fuel was fresh and I had plenty of fuel in the tank through all this.

1. My initial thought was to change the plug wires since they were old, and I could see visible corrosion under the 1 plug cap. Didn't fix the sputter.
2. Next, research showed that a bad coil can cause the symptoms. Easy to replace. Didn't fix the sputter.
3. Next I changed both fuel filters. One was before the fuel pump and the other was before the carbs. The one before the pump was packed full of crap. With clean filters, it didn't fix the sputter.
4. Next I cleaned out all 3 float bowls real well. Didn't fix the sputter.
5. Next, research showed the tank could be vacuum locked, so I loosened the gas cap when the sputter started. Didn't fix the sputter.
6. Next I changed the plugs, even though they weren't in bad shape. Didn't fix the sputter.
7. Next I checked the points. They were adjusted to the correct gap and were in really good condition.

Through all this I noticed that the fuel pump would pump away more frequently than I expected. My expectation was to hear it click maybe once every few seconds. There are times when I can hear it clicking steady and repeatedly - click, click, click, click. This weekend I discovered that I was able to keep it running fine by driving around like a Sunday driver - never really revving it up much in any gear. I have arrived to the conclusion that I must have a weak fuel pump. It clearly works well enough to stay running, but if I drive it any faster than an old lady drives, the fuel consumption seems to outrun the output of the pump, and it starts sputtering really bad. I have a new fuel pump on order that I will install later this week. My only other idea is an air leak somewhere. I checked the fitting at the tank and at both ports on the pump. There does not appear to be an air leak.

Am I missing any easy fixes?

 

[Bob_Spidell]

Air leak on the inlet side of the pump. We had erratic pump operation on our BN2, and spent a lot of time and effort--and a couple pumps--trying to track down the problem. Finally, my dad cut the outlet pipe out of the used tank we'd bought and sealed; turns out there was a pinhole leak in the pipe inside the tank. There was a lot of corrosion around the pipe where it exited the tank; my dad speculated that the flux used to solder the pipe had caused excessive corrosion. New, repop tank--not the very best quality, but serviceable--solved the problem.

 

[Patrick67BJ8]

Air leak on the inlet side of the pump. We had erratic pump operation on our BN2, and spent a lot of time and effort--and a couple pumps--trying to track down the problem. Finally, my dad cut the outlet pipe out of the used tank we'd bought and sealed; turns out there was a pinhole leak in the pipe inside the tank. There was a lot of corrosion around the pipe where it exited the tank; my dad speculated that the flux used to solder the pipe had caused excessive corrosion. New, repop tank--not the very best quality, but serviceable--solved the problem.

I had Fuel delivery problems where the pump checked out good twice but I knew the engine wasn't getting enough fuel. The first time it was a plugged sump/pick up in the tank and was fixed by taking an air hose to the outlet tube to the tank and giving it a burst of air. The second time it happened it was a clogged line between the tank and the fuel pump. This time I disconnected the fuel lines and blew them all out. Nasty stuff came out of the lines and problems gone.

 

[Bob_Spidell]

Dunno if you can put enough of a load on the engine sitting still, but you might try running a line from the inlet side of the pump into a bucket of clean gas (leave your cigars in the house). If the sputtering abates you're probably on the right track.

 

[RAC68]

Hi CPBOL and welcome.

I think Bob and Patrick have it right and an air leak on the inlet side of your SU pump would cause rapidly ticking and not deliver sufficient fuel. However, how plugged was the dirty filter removed and is the new filter showing any signs of dirt. If so, the pump is, or was, drawing fuel and you may have to thoroughly clean your tank.

All the best,
Ray(64BJ8P1)

 

[bob hughes]

When I had fuel problems (turned out to be a blocked fuel line to the jet from the bowl on HS6 Carbs) I disconnected the fuel supply to the carbs and put the end in a large bottle and used the pump to pass several litres through and timed it to get a feel for the pump out put. It does sound as if it is in the supply between tank and carbs.



Bob

 

[Michael Oritt]

Here's another possibility: Several people, me being one of them, have had similar experiences caused by debris in the tank being pulled against the fuel pickup by fuel suction, esp. under full throttle. When the engine is turned off, or in some cases when the car is operated at moderate speeds, the item causing the clog falls away from the pickup and everything is fine until it is again pulled against the pickup, ad nauseum.

It doesn't take much stuff for this to happen and given the age of our cars it is no surprise that debris, whether from fuel or whatever, has made its way into the tank. The solution usually is to remove and clean out the tank but I was able to see and fish the offending item out via the fuel sender hole. I pulled out the skeletal remains of a large leaf, quite confounding given that a 100's fuel filler is in the boot. Nevertheless once I pulled the leaf out the problem stopped.

 

[British_Recovery]

Change the condenser. It can heat up after use and fail, only to recover after cooling down.
Bob

 

[RAC68]

A Lack of pump output, in both volume and pressure, could definitely lead to fuel starvation at speed and acceleration.

Reading Dave's document shows how the SU pumps will overheat and burn the solenoid swamp resistors when a blocked input prevents the pump from going through a complete cycle with power on. Although the pump will stop, if filter blockage had caused resistor damage but did not completely burn both swamp resistors (wounded but not killed the pump), I would expect the pump to pump but at a much lower output pressure and volume.

Additionally, since your pump is performing but it is not uncommon for the diaphragm to need adjustment after a long storage period. A misadjusted diaphragm could lower pump operation and volume/pressure output. I would first perform a pump maintenance, then test volume and pressure per Bob/Patrick, to determine if pump performance is up to spec.

Ray(64BJ8P1)

 

[CaptRandy]

When I purchased car it ran fine. Would take it for a 30 minute ride with full tank of fuel, never missed a beat. Took it for a ride of about 2 1/2 hr and it seemed to run out of fuel even though tank had been full when I left. Would pull over and sit about 5 minutes and it would start back up fine and run about 15 minutes and cut off again. Irritating to say the least. Got car home and into garage. This happened repeatedly so something wrong. Pump would click like crazy when engine died. Pulled the fuel gauge plate and looked inside. What I found was that the tank had been coated with a rubber type stuff and strings of it would float around still attached to the tank. The strings were enough to clog the baffle points in the tank and impede the flow of fuel to the pickup point. Changed tank-problem solved.

 

[RestoreThemAll]

I have a curious question. You mentioned that you cleaned out all three float bowls. Is this a tri carb? Do BJ8s have three carbs? Maybe some do but I'm not aware. Has something been modified? What model carbs? I'm not sure any of my questions help but I am curious.

 

[blueskies]

It does sound as if the problem lies somewhere on the tank side of the pump. You may want to look there next.

 

[John Turney]

The fuel pump should have a screen on the inlet. Considering that the filter ahead of the pump was full, maybe the screen is blocked.

You mentioned that the fuel pump clicks more frequently than you expected ("every few seconds"). I recall mine clicks about once a second at idle from looking at the ammeter, but I can't hear it at speed (side exhaust). Maybe others can hear theirs.

 

[cpbol]

Thanks for all the responses everyone. My first thought is gratitude for all the suggestions. My second thought is CRAP, I thought I was going to bolt on the new pump and solve my problem, but now I feel like making sure it's not one of these other items first.

Yes, although it is a BJ8, it was converted to the tricarb setup in 1968. A new cam was added at the same time (which will be the subject of another post in the future). The previous owner had the car for 47 years so there is a lot of history that says the carb setup is fine as long as there isn't a contamination of supply issue.

I peaked in the tank to see how it looked. There was not any chunks of anything floating around. There was only a small amount of pink slime? looking stuff like you would see at the bottom of a toilet in the guest bathroom that doesn't get used much. I couldn't see the pickup for the fuel line because there was a baffle blocking the view. Any tips on how to get to the other side of the baffle? I did the trick to blow air back through the intake line to clear the inlet screen in the tank. When I did that, a nice clean stream of fuel squirted out when I removed the air line. That indicated to me that the pickup was clear. With that said, I guess I can't say that with 100% certainty. I also checked the screen in the pump and it was clean as a whistle.

Are there any other takers on a bad condenser? I have heard that suggestion before.

In summary, an air leak on the inlet or a blockage at the pickup in the tank make the most sense. Those options aside, has anyone replaced a suspect pump and solved the problem?

 

[RestoreThemAll]

Absolutely change out the condenser. Very common in this car. Your symptoms are a good indication. Put it on your list of items to carry in the trunk.

 

[CLEAH]

has anyone replaced a suspect pump and solved the problem?

Yes, I have, on my Sprite. It was doing something similar to your car--the pump was dying and did not operate consistently (the car would run for a while and then sputter out). I changed it out, but I also tightened up various clamps on the fuel line because it was sucking air (there were air bubbles evident in the clear fuel filter near the carbs). The main problem was the pump, though, because it would stop clicking altogether. Since your car sat for so long, it might be a good idea to change out the fuel tank too instead of trying to clean it. It is just a tin can, and they are not terribly expensive.

Your car sounds like a beast with the tri-carb set up. Very cool. Please tell us more about it! Welcome to the forum, and greetings from Cleveland Heights!

 

[bob hughes]

Just one more idea into the mix.

My car would run for a few miles then cut out after a short period of time, I guess around 10 - 15 mins. it would start up and go for a few more miles then cut out again. I traced the fault to a faulty low tension connection from the coil to the dizzy, the old black and white wire had been cut by A. N. Other and a home made wire ran direct from the coil to the dizzy - the connector to the dizzy was hanging on by a thread and the insulation. I made up a new one and all was rosie again.



Bob

 

[steveg]

Inside the distributor, the ultra-flexible ground wire between the foot of the condenser and the base plate, sometimes frays inside the insulation or has been replaced by a PO with a stiffer wire which eventually breaks inside the insulation. The wire can then make intermittent contact and cause failure to run.

The main cutoff switch in the trunk can fail after heating up and cause the problem. The black and white wire is the grounding wire from the switch. Disconnect it from the distributor to troubleshoot.

 

[Randy Harris]

My BJ8 had the identical problem with the exact same symptoms. After a number of crazy and costly "fixes" I decided to pull the tank and have it properly cleaned. Sure enough out came a small metal washer that had dropped into the tank when the prior owner had replaced the original gas cap with a spring loaded racing style cap. I'm guessing some of the metal parts had fallen into the tankwhen the cap was removed. Thanks Moss! The washer was sucked up against the pump inlet under acceleration. As soon as the car sat for even a minute or two the washer would drop away and the problem disappeared, and then reappeared down the road. Carefully check your gas tank. I'd bet a weeks pay you have an obstruction.

 

[cpbol]

Update: I changed the condenser and it didn't fix it. I removed the fuel filter between the tank and pump to eliminate several air leak possibilities, but that didn't fix it. After several more test drives I discovered that I can drive it for close to an hour without any problems, then suddenly BAM - sputtering and cutting out. It seems to happen around the time I turn the engine off and then back on again.

I'm down to it being a tank obstruction or a bad fuel pump. How are you guys cleaning out the tank? Just dropping the drain plug?