QuestionQUESTION: Hello. I have a 1962 Standard Vanguard with a four cylinder 2088 cc engine. It will only start with much cranking at full choke, and once running it will barely run above idle, and then only with the choke in and the throttle fully open. It started this very suddenly; I drove to town with no issues, then after filling up this began. I have believe I have eliminated the carb as the source by swapping it for a spare with no change, same for the spark plug wires. The cap was new in the spring, and the previous owner had rebuilt the distributor as well. The plugs get very black and sooty every time I do get it running.
Any insight you can provide would be great, I'm very much at my wits end with this problem. Thank you.
ANSWER: So the engine was turned off at the filling station and the next turn of the key it needed full choke?
Or did it happen over a few hours or something.
Give a FULL rundown of everything that happened that day with the car, so I know one way or the other.
What fuel do you run it on?
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Things to check - fouling of the rotor arm and distributor contacts - this can happen (or get much worse) suddenly.
Bad Ht leads are a possibility, including (and I'm very wary of it) the main HT lead.
Check the low tension wiring also, make sure the coil is getting good power and also check the spark from the main HT lead to chassis when cranking, it should be regular and strong.
(but do go through exactly what happened with the good->bad running)
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I was worried you could have contaminated fuel... there's no chance the tank has been sugared or you have filled with the wrong fuel?
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QUESTION: Hello Christian. I had abbreviated what happened that day, below is a more exact accounting. I left at approximately 8 AM, drove to a car show approximately 8 km away. I had no problems, the car started with half choke immediately and required no choke within two minutes. I drove the car in a parade at 1pm. Car started immediately with no choke, ran smooth with no problems. Ambient temperature was very warm, approximately 29C. Parade was roughly half hour, walking pace. Temperature gauge came close to boiling, but not over, and no evidence of steam. Car ran fine, but surged a bit at the end. Pulled into the gas station, filled up with regular unleaded fuel. I use this same station all the time for all my vehicles, have never had any problem. Car would not start, I attributed this to vapor lock. Pushed the car back to where it was parked (roughly 100 feet) and left it to cool off with the hood open. Tried to start it roughly four hours later. Needed full choke and 20 seconds of cranking before it started. It then stalled three or four times, it started again each time but stalled as soon as the throttle was let up a bit. It would stall immediately if the choke was put in, regardless of throttle position. Towed it home, left it two days to cool off. Problem is still the same.
I checked the HT leads earlier this afternoon, the main lead from the coil has a nice fat blue spark, the rest spark nice and even. The rotor and distributor contacts are nice and clean. I don't see anything that looks loose or like it has rubbed and is grounding. Like I mentioned earlier, I changed the carb as I saw fuel leaking out of the choke mechanism. The leak stopped, but nothing else changed. Just to be sure, I checked and the float is bobbing merrily away and everything moves freely, but beyond that I wouldn't know what to check. I can't say for sure that there was no contaminants introduced into the tank, but the cap is fiddly, and will only go on if you know how to line it up and twist it just so. It didn't appear messed with, and I ran my finger down the neck and found no residue that would indicate pop or some other foreign substance being introduced.
Hope this helps gives you something else to work with, thanks again for your time.
ANSWER: The heat the engine was subjected to, I'm wondering it hasnt finished off a gasket, inlet manifold gasket - check it for leaks.
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And you say you have tried another carburettor and the problem is exactly the same.
So down to ignition: and the spark is strong and regular at all leads.
So timing..
Now, does this engine have mechanical or vacuum advance, I'm sure it has a "modern" distributor.. the vacuum lines can perish quickly in the heat and crack, causing timing to be retarded - this usually ends up with the engine sounding very asthmatic, gasping for more air at the end of each stroke.
Vacuum Leak.
Let me know if that's the problem.
Otherwise... a stuck valve? -
Can you do a compression test to verify this?
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QUESTION: Hi Christian. I've checked most of the things you mentioned. There were no HT leaks after running it in the dark. The vacuum line from the carb to the distributor is metal, but I removed it and blew through it, it appears clear. I checked for gasket leaks by spraying carb cleaner along the edges of the inlet manifold on the head and below the carb; I thought I would see it sucked dry immediately if it was drawn into a leak, but they appear tight.
One new breakthrough though. Instead of running the car for a few seconds and letting it die, I persisted in feathering the throttle as I racked my brains on the problem. Over six to eight minutes the RPMs very gradually increased. As the RPMs increased, the engine gradually smoothed out. Suddenly, it revved up nicely (sorry I don't have a tach to give a proper readout) and ran beautifully. I gradually let the engine return to idle; after dropping smoothly a bit, it ran rough as before and died almost immediately.
A co-worker who builds hot rods thinks this may be due to a faulty vacuum advance; I really didn't understand the theory behind it, but thought I'd ask your opinion before I pursue it.
I'm also going to check the compression on your advice, but the person with the equipment isn't available until the weekend. So if you think the vacuum unit on the distributor is a reasonable possibility I'll work on it in the meantime. Thanks, Doug
AnswerI'm thinking its the fault of a clogged idle jet, If it will rev properly but wont idle that's the only thing I can think of - If it will rev past say 1500Rpm all the way up but when returned to Idle chugs and splutters then clogged Idle jet is all I think it will be.
I think the slow running in the parade left the carb running through the Idle jet for a long time, and with the extra heat likely dislodged something from the fuel line near the carb and it's gone straight into the jet..
with the very slow fuel-flow there was a chance for a fair bit of sediment to collect in the float chamber or thereabouts, the next time the engine was started this sediment was shook up and dragged through the jets.
I conferred with a friend and we both think it's a blocked Idle jet.
