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Power Loss

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mgtf328

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My BJ8 suffered a loss of power the other day. Just driving along it backfired a few times the engine became "lumpy" and refused to accelerate but didn't die completely. I stopped and managed to keep the engine running by "blipping", the throttle and it gradualy came back to life and I just drove on with no further problems. I did a further journey the day after with no problems so I don't think it's a carb or timing issue and I've never experienced fuel vapourisation even on the hottest of days.

However, I started it this morning and the same thing happened. The engine dies and runs roughly as though it needs more choke and doesn't pick up. Justs as though it needs to warm up and doesn't pick up when the throttle is pressed. Sounds and feels like it's overchoked or starved of fuel.

So in this order I'm going to check it out tomorrow:-
1 I'll check the fuel filters and look for loose/broken wire connections and plug leads.
2 I'll try and bypass the isolating/imobilising switch in the boot which I understand can be very unreliable. I'm not sure how to do this yet, I never use it. I have a "screw down" battery isolator fitted to the battery terminal that I use for imobilising the car rather than the switch, I'll check that too.
3 It has electronic ignition - I have some points and a condensor but am not sure how to they fit. If anyone has an image of a BJ8 dizzy with the cap off I'd be greatful for a copy.
4 Fuel pump - seems to work ok, the usual fast tick switching ignition on which slows down and stops when the bowls are full. If necessary I'll take the pump off and check it if 1- 3 above doesn't sort it.
5 I'll buy a new coil!
6 New plugs(?) but I think this is getting desperate!

Any more suggestions would be greatfully received.

Thanks
AJ
 
Is the inside of your fuel tank coated with something that has come off and is now sloshing around in the tank blocking the pick up line ?
 
Thanks, The tank is aluminium and has no coating as far as I know. It's in pretty good condition, at least on the outside!
There's an after market in-line fuel filter in the engine bay before the carbs that looks OK so the filters in the carbs must be clean. I suppose it could be the filter in the pump, I'll check. Don't think there's a filter in the tank. It's my gut feeling the pump is on it's way out but it could be the electronic ignition module. I'm not sure which make it is and there's nothing written on it that I can see. It's probably an earlier model that doesn't like the ignition switched on without the engine running. I'm always conscious of that when I wait for the pump to finish clicking when I start from cold.
I guess the only way to find out is by trial and error fitting new parts. The cheapest order to test seems to be, fitting points, new coil, new pump.

AJ
 
Check that the distributor is properly clamped tight. I agree with Danny, it's ignition. I had a coil do a similar thing to me once.
 
Just been out for a trial run. It behaved very well for the first 10 miles then stopped. It just died slowly and stopped. I sat there for a short while and tried starting the engine. It fired first time and off I went. Got all the way home but it did falter now and again so I slowed down and it was OK. So I reckon it's the fuel pump. I've got a coil on order I'll order a new pump. Don't think it's the ignition, I'm told that when a petronix goes it usually fails completely.

Still not figured out how the points fit in the dizzy though!! An image would help a lot if anyone has one handy.
Thanks

AJ
 
mgtf328 said:
Just been out for a trial run. It behaved very well for the first 10 miles then stopped. It just died slowly and stopped. I sat there for a short while and tried starting the engine. It fired first time and off I went. Got all the way home but it did falter now and again so I slowed down and it was OK. So I reckon it's the fuel pump. I've got a coil on order I'll order a new pump. Don't think it's the ignition, I'm told that when a petronix goes it usually fails completely.

Still not figured out how the points fit in the dizzy though!! An image would help a lot if anyone has one handy.
Thanks

AJ
Click to expand...
Try blowing out your fuel lines from tank to carbs. Disconnect lines at tank, pump, and carbs when doing it!
 
Feel the coil, if hot to the touch, replace.
 
Well I fitted a new electronic SU pump and it does the same thing. Engine cuts out with one or two small backfires and it coasts to a stop. Wait a few seconds and it'll start again and runs for a while longer before the same thing happens. I've found that it runs ok as long as I go slowly and don't speed up and starts on the button.

The electronic pump is much noisier than the old one I can hear it rattling away all the time I'm going down the road. The old one didn't do that.

Checked the tank and by my reckoning there's 10 litres or 2.5 US gallons. I measured it with a stick and there's an inch of fuel in the tank. Is this enough!! Is it just sucking air I guess this would make the pump noisy? Don't want to put any more fuel in than I have to as I'm thinking there's a filter in the tank that may be blocked and I may have to drain the tank. Not sure how to get at the tank filter, can it be done with the tank it situ. Is there even a filter in the tank?

Checked the timing and it's spot on. I don't think the tank is drawing a vacuum and the coil stays cold. It definitely seems like a fuel problem to me.

Any ideas would be welcome right now as I'm stumped and going off Healey's fast!

Thanks
AJ
 
Gas cap vent open/clear? Description sounds like possibly poor venting, creating a vacuum in the tank preventing fuel flow - vacuum disappears quickly when pump stops and then you can restart and run until vacuum forms again. Driving slowly uses less fuel, creating less vacuum potential in tank so it runs better. You can try blowing thru the vent hole or try putting a different cap on it and go for a drive. I know it's a stretch but you seem to have exhausted other options.

I've never had an aluminum tank, but I've never heard of a in-tank filter in a Healey.

If not fuel related, I agree with others, try changing the coil.

Dave
 
Is the coil getting hot? Woulld load up and die on the way to work. Shut down for a couple minutes, then drive on to work. Come home the same. One car hot coil, replaced. Second car coil connections at nuts somewhat loose.
 
When the engine dies how does the fuel pump sound ……if it’s clicking really fast then you have fuel starvation issues .
once the float bowls are full with the engine idling you should hear a steady tick every few seconds . If the pump is rattling away constantly then either fuel is puking out all over the place somewhere or the pump is being starved of fuel .
 
I went through an issue with the car running fine, then suddenly losing power and barely running at idle if at all. It would happen at random. After pulling the tank, swapping out fuel pumps, coil, distributor, plugs, etc., turns out I had kinked the braided fuel line connected to the carb feed pipe. Removed and repositioned it and no more issues. It was allowing just enough fuel through to idle, but not much more.
 
Take a longish drive and when you experience the loss of power stop the car and remove the petrol cap. If you hear a rush of air you have been pulling a vacumn, which could be due to the cap not venting correctly. I had this problem with an after market cap.
 
I put a new pump in, but that didn't work. A lot of stopping and starting to get home again mainly on busy junctions, (twice!). Why does that always happen? I found out it was drawing air in by disconnecting at the carbs and turning the pump on.

I noticed that the new banjo washers I got from AH Spares are slightly too big and don't fit in the recess in the banjo fitting. I thought that they would get pressed in when I tightened the fitting up. Ah, no! The one on the inlet obviously got mangled up letting air in first time round. I now cover them with a piece of flat wood and gently tap them in place before assembling the fitting. But that didn't work! Back to the stopping and starting.

In desperation I've fitted a new coil although the old one didn't seem to get hot. Maybe I've got a spare now. How do I test the old one?

I then decided to have another look at the pipe connections. I was going to replace the hose completely, but I couldn't get the hose off the pipe fitting on the tank and was afraid I was going to damage it if I twisted it too much. It's a long reach to the fitting if you haven't got a lift and I'm too old to crawl underneath. Well not true, it's getting back out is the problem and I don't trust the wife enough now to help me get back out. The garage door would mysteriously close by itself!

So I shortened the hose between the pump and the tank a little and blew it thru. The hose seemed to be in pretty good shape so I put it back together. I used a bicycle pump as I don't have a compressor. But the line seemed to be clear and I could hear the air bubbling thru in the tank. I did the same thing for the pipe to the carbs. There's no sign of twisted pipes and I think the lines are all clear. Still don't know if there's a filter in the tank. AH Spares have a video on their website of a tank being manufactured, but it doesn't show the delivery pipe. I'm going to call them Tuesday to find out.

The pump now rattles when I start the ignition and slowly comes to a stop. Good sign, right!

I'm sure the electronic ignition module is OK because it starts after sitting for a minute or two and I do manage to get back to the garage albeit rather slowly.

Would really like to take a longish drive to test the fuel cap, but 2 miles is the most I've achieved. Seriously, there's no sign of air rushing in when the fuel cap is removed and I've driven it down the road with the fuel cap off.

I'm dreading having to go out in it again to see if it's OK. It's a holiday weekend here and there's loads of traffic around. I've been saved by the rain!

AJ
PS. Anyone want to buy a really cheap Healey? Looks good sitting in the garage, just don't plan any long weekend trips!
 
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