• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

fuel starving or electrics?

Share this page

CanberraBJ8

CanberraBJ8

Jedi Trainee
Offline
Hey guys. I fired up the BJ8 today after some months of work. To begin I couldn't get it to fire - but that just turned out to be the lead from the coil to the dizzy not being on far enough. Once i pushed it on hard she fired up straight away. What a glorious sound (esp. with the tiny side exhaust its fitted with currently!). However.... as soon as I lift the rpm over 1000 it starts a strange pulsing - as though I am pumping the throttle rapidly. A quick brrrraapppp! and then nothing before another brrrapp! on about a second cycle. If I give it a good push on the throttle it will lift to 2000+ first, but the same thing then happens.

I have fitted a new fuel line under the car - what they call bundy tube here (steel line copper coated) and turned the electric (modern) fuel pump from horizontal to vertical (to clear the new telescopic shocks).

Also I removed the wires from the coil while I was dong some electrical work (LED lights) and 'think' I put the wires back on the right terminals...

And the exhaust pipe has been cut down to a side exit. So it has a small 13"x8"x4" muffler and then about 10" of tail pipe.

So My thoughts so far are;

-Fuel pump suffering from the different position and not supplying fuel.

- Fuel bowl floats sticking.

-Something to do with the wiring?

I guess the fuel bowls shouldn't be the issue as surely only one would stick and it shouldn't have such a dramatic effect?

My car is negative earth (with alternator). The battery cut-off switch is not connected. The wire that normally would go to the cut-off switch is not connected to anything. what effect does (should) this have with the wiring positions on the coil? Currently the white/black wire is on the -ve terminal of the coil, and the white wire seems not to affect anything regardless of which side of the coil its one - still get the generator light on the dash either way with the ignition on...

Any ideas?
 
Though most carburetor problems are electrical...

... it does sound as though the fuel is the problem. Disconnect the fuel line from the carbs and let it pump out into a coffee can to verify the volume of flow. You can also lift the tops off the float bowls to see if the level is high (normal).
 
Suspect your fuel pump position might be the problem because that has been changed.

If it's a Putzke shock kit, if I recall correctly, for BJ8s he supplies a fuel pump mount that requires rotating the pump, but not mounting it vertically.

In computer troubleshooting there used to be a saying that with a problem "it's either broken or something's changed - what have you changed recently?"
 
I agree it can be any of the above, but my thought would be to look into the ignition electrical. I believe you said that the wire from the distributor or coil (i forget which) that goes back to the cut-off switch is not connected. But is it dangling there and making intermitten contact. Also check that all your connections from the ignition switch on thru to the distributor are in good shape. Intermitten contact somewhere could be causing this. (points, condenser, etc).
 
Thanks guys for the suggestions. Randy - do you mean checking the fuel bowls while the car is running?
My suspicion is that it's something to do with the pump (how I've set it up). First up I think I'll add a length of fuel line so I can turn the pump back to horizontal and see if it will run better. If that turns out to solve things I'll need to think about whether I can position it well on the body like that, or look for another pump that fits the space better...
I'm about to do the above, so I'll report back in a little while.
Cheers
 
CanberraBJ8 said:
Thanks guys for the suggestions. Randy - do you mean checking the fuel bowls while the car is running?
My suspicion is that it's something to do with the pump (how I've set it up). First up I think I'll add a length of fuel line so I can turn the pump back to horizontal and see if it will run better. If that turns out to solve things I'll need to think about whether I can position it well on the body like that, or look for another pump that fits the space better...
I'm about to do the above, so I'll report back in a little while.
Cheers
Click to expand...
That would be a good trick, wouldn't it? If it was me, I'd run the engine again, duplicating the fault as you described it, then check the level in both float bowls immediately after shutting the engine off. It's not so time-sensitive as say, reading the temperatures across the tire's tread after a good run, but you'll want to hurry along before heat-soak promotes evaporation.

See, the "reservoir" of fuel in the bowls should allow the engine to reach maximum revs, however briefly, so either the fuel pump is really struggling to put fuel in the carbs, or something else is wrong. Troubleshooting is a process of elimination, and since you altered the pump orientation, start by eliminating that as a possibility.

Then next stop will be to see if your carb problems really are electrical...
 
Well I've found there is no spark at the plugs. I cleaned up the terminals on the coil and it started. Thought I'd fixed it. It even revved up ok. So I backed it out of the garage for a run up the street and back, and before leaving the garage I revved it a few times again. It died and hasnt started again. I checked that there is power getting to the coil from the white wire - yes 12volts. And so I thought maybe the coil was on its way out. Just replaced it and still no spark.

So this is heading to the distributor isnt it?
 
Oh, before getting the new coil i realised i couldnt hear the pump running anymore. So I thought it had failed. I removed it again... and tested it on the battery. Runs. must have just filled the bowls and couldnt pump any more fuel up?
 
If you fill the float bowls and the car still won't run...suggest replacing the condenser and rotor and static timing the engine. If the rotor is the type with the brass rivet it may be cracked. Try rotating the the rotor on the shaft by hand - if it moves past the weights, the drive pin is sheared.

You don't say whether you're running a Pertronix - you may have fried it. You can tell a fried Pertronix by the bubbles on the label.
 
Not running EI. There is voltage at the coil - just no spark at the plugs. Pump does run.

I'll look at the fuel bowls today. Are the points for a Healey (and the condenser) generic, or will I have to order them from a Healey specialist? That is, there aren't Healey specialists in Canberra, so I'm wondering where I'd go to source some without ordering them in from out of town... The local Auto warehouses (SupaCheap, Auto Barn etc) arent much help these days. I had to go to 3 before I found a coil yesterday!
 
CanberraBJ8 said:
Not running EI. There is voltage at the coil - just no spark at the plugs. Pump does run.

I'll look at the fuel bowls today. Are the points for a Healey (and the condenser) generic, or will I have to order them from a Healey specialist? That is, there aren't Healey specialists in Canberra, so I'm wondering where I'd go to source some without ordering them in from out of town... The local Auto warehouses (SupaCheap, Auto Barn etc) arent much help these days. I had to go to 3 before I found a coil yesterday!
Click to expand...

Just a SWAG: if you have a known good (distributor) rotor pop it in. Usually, these fail outright but you might have one shorting out at higher RPMs.
 
So With a little help via phone messages from a school friend who was a mechanic, I traced the problem...

It turned out to be the wire from the points to the spade connector attached to the outside of the dizzy. It looked fine, but ended up falling apart in my hand. I've soldered a new wire in. She fired right up after that!

https://i1349.photobucket.com/albums/p744/356fair/IMG_1840_zpsfb4f77c5.jpg
 
Note this (and the ground wire) is a special very fine grain, ultra-flexible wire - normal wire is too stiff and may affect the spark advance as well as break after a while.
These wires are available from Healey parts sources.
 
Ah, so thats why its such a fine wire! Thanks Steve. And thanks for the suggestions in the PM.
 
Yep, Glad you found it.
 
Interesting. We had a car have the exact same problem on a tour we lead at Rendezvous to Virginia City. We had 24 cars with all kinds of spares but no one had a low tension wire. The car had to be towed back to Tahoe.
TH
 
I'm going to order a low tension wire set, but its driving ok with the piece of standard 3mm wire (including plastic insulation) I soldered in...
 
Tahoe Healey. There is no problem rigging up a normal wire in the distributor if it is just to get you home. I run with one in mine for a couple of weeks before I got the very fine wire replacement fitted.
 
It wasn't my call. I carry regular wire with me but nothing that flexible or the wire from my spare condenser might have worked. As you stated it could have made a temporary fix. They just wanted it fixed.
I will now try to carry a low tension wire in with my spares. Apparently a bit more common of a problem than I thought although I never heard of one self-destructing before.
 
Back
Top