Strange engine problems

[twincamman]

this is a good time to put an electric fuel pump in the trunk ??.ed

[Heuer]

Gravity or pressure fed, the result will likely be the same. If the pump is not "pumping" then fuel is not been passed to the carbs. My main concern is having passed pressurised fuel (via Mity-vac) to the carbs the engine still ran badly. Plugs are sparking and the timing, even if thereabouts, should allow it to run at least. Maybe the timing is varing as the engine is churned?

Jack shaft seems to be the common denominator.

[Chancer]

You seem to be looking for the worst problem when you probably just have a very simple one.

Apologies if you have already mentioned this, I am too tired to look back through all the postings, when you filled the carbs by the Mityvac did you take off the covers and check the float levels were both correct?

[Heuer]

Nope! But they are Stromberg's and work on demand. The pump fuel bowl is empty so I assume back pressure is preventing more fuel from being delivered. Unfortunately I can't separate one from the other - fuel not being pumped, engine not firing and requiring fuel.

[Chancer]

Well its been repeated enough times, myself included, you really must run the carbs using a small gravity tank or an electric pump before letting your imagination run riot regarding broken or slipped jackshaft, not saying it v=cant be that, others have suffered it but it could be as simple as an air leak on the suction line.

You can operate a fule pump using your hand to get it to suck up from a jam jar of fuel.

I hadnt realised that you have Strombergs, they cough and splutter just like Webers when starved of fuel, they will work just fine with a small gravity tank only slightly higher than them, thats just how I run mine every few years when I do an engine flush and o?l change.

[Heuer]

The Mity-vac holds eight litres of fuel and can be easily switched from suction to pump. When set to pump along with a couple of strokes of the handle it delivers fuel under pressure which is what I did
This immediately filled the fuel bowl and the engine fired but ran very badly as though it was running on two cylinders.

I then released the pressure from the Mity-vac and turned the engine over to see if fuel was now being drawn into the clear tubing by the fuel pump alone. - it was not. So my method was the equivalent of using an electric pump or having a gravity feed as basically I was forcing fuel into the carbs (at about 5psi) and then with everything primed seeing if the pump would draw. It would not.

Bit of a double whammy where the fuel pump is not operating and when I supply fuel by other means the engine runs erratically or not at all.

[oldchieft]

If the engine has been running like a bag of Bu**ers then it needs to a be given a good run.

Sort the fuel feed, check the ignition timing and plugs, then give it a good thrash in mid gear and hard load.

Just don't jump to worst conclusion.

Jon the Chief

[Heuer]

The engine was running beautifully until the last time I took it out. Misfires, backfires and cut-out. I would love nothing better than to take it for an "Italian Tuneup" but I can't even summon up enough power to reverse it out of the garage even if I installed a gravity or electric fuel pump. Pump does not work, timing is erratic and occasionally there is no oil pressure. My best guess is still the jack shaft but I am having the car taken to Paul Matty to get their diagnosis.

[Chancer]

Just don't jump to worst conclusion.

He seems determined to, I hope he is wrong.

The only definitive thing that I have read is that the fuel pump does not function and the engine misfires, seeing the rotor in a strange position when withdrawing the distributor does not mean erratic timing.

No discernable o?l pressure at cranking speed often occurs.

One carb could have a stuck or blocked needle valve, after priming the carbs or quite possibly just the one carb I would not expect to see the fuel pump drawing until the engine had been run for a few minutes and the float level(s) dropped.

Take the top off the pump and crank the engine and you will see if the jackshaft is turning and actioning the pump lever.

[twincamman]

It looks like panic has overcome reason ?.[.my money is on timing from the whim whammy CD distributor halls effect unit ]?..ed

[Heuer]

No panic here.Just tried removing the pump outlet pipe (to carbs) and cranked the engine for a total of about a minute (coil disconnected) and no fuel is appearing. Pumped fuel manually through the pipe and fuel appeared. So whatever other problem may be there it is fairly academic until the fuel supply problem is sorted.

Two pumps, one new, one overhauled by Brian Buckland, both fitted correctly and neither are drawing fuel. Where next?

Dizzy is standard unit with contact breaker.

[richardcox_lotus]

Try a third pump. Wil be cheaper.

[Orsom Weels]

Gent's, it sounds like the car was running fine, & had been for 6000 miles, then something went awry. The symptoms seem to be, if I've read through all this correctly, that the fuel pump stopped pumping fuel, the ignition timing is erratic & it may have no oil pressure, the one common denominator in that lot is the jack shaft, why are you giving David such a hard time for his reasoning? Seems perfectly logical to me. If the original pump stopped working, Brian Buckland declared it perfectly serviceable, but fitted new valves anyway, still didn't work, fitted new pump from Matty, that doesn't work either, suggests a problem with pump actuation. What needs to be confirmed is if the ignition timing did move & is it still moving after being re-set? Shouldn't be too difficult to ascertain. If it is discovered that all is good in that area, then we can try to figure out why two pumps suddenly wont work & what is causing the erratic running, but it sounds like lack of fuel has been disproved. I hope David doesn't get put off keeping us posted on what Matty's workshop finds.

[oldchieft]

Two pumps, one new, one overhauled by Brian Buckland, both fitted correctly and neither are drawing fuel. Where next?

IT IS SUCKING AIR

Jon the Chief

[Mick6186]

Different posts seem to be concentrating separately on each item but it appears that all of the faults, no fuel pump activation, intermittent oil pressure & changing timing all seemed to have happened at the same time. The only thing that can affect all three simultaneously is a jack shaft problem. My money's still on that item having a loose sprocket or a break. Sorry!
Mick.