Poor running - Bad idle / stalling

Phil Robson

Phil Robson

Well-Known Member
My V8S stalled in normal driving recently & I had to get the AA man out. That was bad enough, but the problem was no fuel coming through which the chap had a hand pump for. The engine was not warm (definately not vapour lock) and the car then ran OK back home.

Starting a few days later was instant but the engine has run like a tractor at low revs ever since & will not idle. I have changed the (mechanical) pump for a decent low-use one but nothing has changed. There have been no other changes. I have checked the n/s carb which was spotless (tho' a little worn) & for good measure the plugs all seem to be firing OK & the distributor cap is fine.

It sounds like it's not running on all cylinders but I can't find the logic! Any help would be greatly appreciated. Thanks.
 
Fuel pump problems are usually more evident at high rpm/load
The fuel pump on my TC came loose once, and the engine started to misfire at 70ish, gradually reducing until I couldn't go above 60. At that point I checked the pump and found it loose, tightened it up and all was fine.

More likely in your case would be some muck or something in the fuel / carb. Or a problem with the float valves in the carbs. Was the tank particularly low at the time ?

How hard do you drive ?, might be worth giving it a real blast, full throttle, to help clear out the carbs.

Richard
 
Always difficult to diagnose a problem like this over distance but it does sound like fuel pipe blockage / dirt in carbs.
Spinning engine on starter motor with fuel pipe disconnected (disconnect HT lead first and aim fuel in to bucket!) should produce a healthy flow of fuel - if not suspect blockage. If o.k. plan B is detach floats from carbs and clean.
Hope this helps.
Regards, John.
 
Another track to go down.
I had a problem with my car stalling (usually at traffic lights, sods law !), and then not starting for 10 mins, also occasional weak pickup at low revs. It ended up being a ignition problem, the condenser in the distributer was faulty.
 
Ron,
Yes, I usually check ignition side before fuel but in this case as fuel seemed to be the initial problem I think I would investigate this side firstly.
As I say, it's always difficult to diagnose at a distance as so many variables need checking / eliminating.
Regards, John.
 
John

Your probably right, on re-reading Phils mail, he did mention the lack of petrol coming out of the pipe.
I was'nt meaning to infere your diagnosis to be wrong.

However it is possible that this is a ignition fault and this had not been raised in the thread as an alternative road to go down. If all else fails Phil has now got a plan B to think about.
Keep up the good work
 
Gentlemen,

Thank-you for your interesting responses. I was low on fuel beforehand so dirt is a possibility - I'll check the other carb as soon as I can. I do drive reasonably hard and the problem seems to becoming more intermittent.

Also, the condenser route is certainly worth persuing - I'll change that and see if it helps.

Thanks again
 
Hello, it's me again. I'm still having running problems with my V8. I've done everything I can think of & am getting complaints from the neighbours who don't seem to appreciate nightly tuning!

The consistent problem now is that the car sounds like a tractor to around 2500 revs in any gear, then takes off dramatically. I've changed one carb, set the mixture ('colortune' plug), balanced them, put on a new coil, dizzy cap, points, rotor arm, condenser, the leads are recent as are the plugs (which appear to look the correct colour having checked the front one of each side). I've also changed the clutch which I know has little bearing, but was slipping which made the above syptoms difficult to detect.

Any ideas ?? Please help !!

Thanks again,

Phil (Hull & E. Yorks RO)
 
Less frustrated than yesterday......I got my friendly mechanic to check things over. Apparently the off-side carb still wasn't working, stuck needle or similar.

So the "Rocket" is back! It's been a long few weeks, & absence does make the heart grow fonder!

The only other comment before I finish is that there seems to be no damage as yet (if there is to be at all) to the heads from running on neat super unleaded. The engine is an early 'S', ie: a high compression, & it's now done 22,000 miles of hardish driving on this alone. Long may it last!

Thanks for reading,

Phil.
 
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