Crosflow powered 7 - won't start
Discussion
I spent all morning cleaning out the carbs and the fuel filters. I also removed all the spark plugs and cleaned them up.
Still no joy.
I then decided to see if I could see fuel being sprayed into the carbs when I manipulated the throttle control springs. I imagine I should be able to see the spray through the chamber where the fuel filters are located. I could see nothing.
Would this be indicative of a fuel pump issue?
The one thing I didn't do was remove and check the distributor. On a twin Weber Crossflow the distributor is located directly behind the front carb and this really needs to be removed in order to get at the distributor. I just don't have the confidence to remove a whole carb and, more importantly, be sure I could put it back on correctly.
Still no joy.
I then decided to see if I could see fuel being sprayed into the carbs when I manipulated the throttle control springs. I imagine I should be able to see the spray through the chamber where the fuel filters are located. I could see nothing.
Would this be indicative of a fuel pump issue?
The one thing I didn't do was remove and check the distributor. On a twin Weber Crossflow the distributor is located directly behind the front carb and this really needs to be removed in order to get at the distributor. I just don't have the confidence to remove a whole carb and, more importantly, be sure I could put it back on correctly.
Equus said:
Were the float chambers of the carbs full of fuel when you took the tops off to clean them out? The carburettors have floats in them, with a valve that acts like the ball valve on your toilet cistern. Provided the fuel is getting to the carbs, and the float valves haven't stuck, the float chamber of the carburettor should be swimming in petrol... you can't miss it! If the float chambers are not full of petrol, then clearly the petrol isn't reaching them from the fuel tank.
Are you on a mechanical or electric fuel pump?
Very basic faultfinding:
First, are you sure there's fuel in the tank?
Disconnect the fuel pipe where it enters the carb (direct it into a bottle or something to catch the fuel, and also disconnect the low tension leads from the coil, so you don't have a spark is a good idea!), then switch the ignition on. If you have an electric pump, you'll hear it operating, and fuel should start coming through the pipe and collecting in the bottle. If a mechanical pump, you'll need to actually turn the engine over using the starter motor.
If fuel isn't coming out of the pipe by this point, you have a fuel supply problem (no fuel, blocked fuel pipe, non-functional fuel pump).
Second: do you have a spark?:
Take a spark plug out and rest it on top of the exhaust manifold. Turn the engine over on the starter. You should see the spark plug sparking. If it isn't you have an ignition problem.
If you have fuel getting to the carburettors and a nice, strong spark getting to the plugs, then the problem is most likely to be with the carburettors (blocked jets) or stale fuel.
The fuel tank is about 1/4 full. It is registering on the dash fuel meter.Are you on a mechanical or electric fuel pump?
Very basic faultfinding:
First, are you sure there's fuel in the tank?
Disconnect the fuel pipe where it enters the carb (direct it into a bottle or something to catch the fuel, and also disconnect the low tension leads from the coil, so you don't have a spark is a good idea!), then switch the ignition on. If you have an electric pump, you'll hear it operating, and fuel should start coming through the pipe and collecting in the bottle. If a mechanical pump, you'll need to actually turn the engine over using the starter motor.
If fuel isn't coming out of the pipe by this point, you have a fuel supply problem (no fuel, blocked fuel pipe, non-functional fuel pump).
Second: do you have a spark?:
Take a spark plug out and rest it on top of the exhaust manifold. Turn the engine over on the starter. You should see the spark plug sparking. If it isn't you have an ignition problem.
If you have fuel getting to the carburettors and a nice, strong spark getting to the plugs, then the problem is most likely to be with the carburettors (blocked jets) or stale fuel.
I think the fuel pump on the 1600 Crossflow with twin carbs is mechanical.
The engine is turning over on the starter motor. It just won't fire up.
I can't really rest a plug on the exhaust manifold AND turn the ignition over at the same as my arms aren't long enough
Equus said:
Your arms shouldn't be anywhere near the plug (or the plug lead) - that's the idea of resting it on top of the exhaust manifold!
If you're holding it at the time, you might well get a big enough belt of electricity (especially for an old bugger like you, and especially if you have electronic ignition fitted) to kill you!!
So long as you can see the electrode of the spark plug as you're turning the engine over, and the metal body (not electrode!) of the plug is in contact with some bare metal part of the engine, you should be able to see the spark as you stand beside the cockpit and turn the car over on the starter. In fact you'll probably hear it, too, if you have your hearing aid turned on - it sounds like the piezo electric clicking of the spark on a gas cooker hob.
No disrespect, but if you need to be asking these questions, I'm inclined to suggest that you need to get someone in who knows what they're doing.
That's exactly why I'm asking. If I knew what I was doing, I wouldn't be asking.If you're holding it at the time, you might well get a big enough belt of electricity (especially for an old bugger like you, and especially if you have electronic ignition fitted) to kill you!!
So long as you can see the electrode of the spark plug as you're turning the engine over, and the metal body (not electrode!) of the plug is in contact with some bare metal part of the engine, you should be able to see the spark as you stand beside the cockpit and turn the car over on the starter. In fact you'll probably hear it, too, if you have your hearing aid turned on - it sounds like the piezo electric clicking of the spark on a gas cooker hob.
No disrespect, but if you need to be asking these questions, I'm inclined to suggest that you need to get someone in who knows what they're doing.
You don't need to be rude about it.
I will be getting a garage to look at it now as I recognise what I can and can't do.
Equus said:
Sorry - I didn't realise you were asking: there was no question mark on the end of your statement that your arms weren't long enough to reach.
Not intending to be rude, but whilst the basic faultfinding is really simple (if you've got a spark and petrol, it should run, so it's just a matter of finding out which is missing, and where), it involves playing with flammable liquids and very high voltages, so if you're likely to do silly things like holding a spark plug in your hand as the live ignition system tries to fire it, you're best not touching anything and getting someone in.
If I'd known what to do, I wouldn't have opened the thread in the first place. Although I'm no mechanic and freely admit it, I have taken part in car maintenance and repair courses, including one that was for a whole year. At no point was I ever advised to carry out any sort of test using spark plugs lying on exhaust manifolds - probably because the teachers would not have been silly enough to advise such a tactic.Not intending to be rude, but whilst the basic faultfinding is really simple (if you've got a spark and petrol, it should run, so it's just a matter of finding out which is missing, and where), it involves playing with flammable liquids and very high voltages, so if you're likely to do silly things like holding a spark plug in your hand as the live ignition system tries to fire it, you're best not touching anything and getting someone in.
As it is, I had no intention of doing this because, in the back of my mind, it did seem not quite "right".
Many thanks to Mike for popping over last night and checking out my car. We are pretty sure the fault has been identified - a broken distributor cap. So, a new cap and rotor arm will be on order today.
Thanks also to all who have suggested various theories over the past few fays
I'll let you know if and when everything is sorted.
GO PISTONHEADS.
Thanks also to all who have suggested various theories over the past few fays
I'll let you know if and when everything is sorted.
GO PISTONHEADS.
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