Fuel Starvation?

[kevh]

Hi All,

I am getting very near the end of a long and sometimes frustrating 1935 12 restoration and have hit upon another problem.
I have fitted a new electronic fuel pump and all associated fuel lines, the car starts first time on the button and will run and rev all day when not moving but when driving the car it repeatedly loses power and stalls. It starts up again immediatley and will tick over and rev as though all is ok but as soon as it comes under load again it tries to stall. The fuel pump is not constantly ticking and the bowl is filling so I assume everything on that side of the carburettor is fine.
What do you suggest could be the cause?

[luli]

Marginal needle valve?

[kevh]

Thanks luli, can you expand on that please, your advice is always greatly appreciated.

[luli]

|f the needle valve is sticky it can reduce the fuel flow when the carburetor heats up. I guess your car is using an SU. The needle valve is in the top cover of the float chamber.
What is the general condition of the carburetor? In the WSM you can find detailed instructions how to diagnose it.

[RobHomewood]

Luli is probably right but how instantly does the engine die when put under load? If the problem is dirt in the carb jets being pulled into a position where it blocks the flow say, the effect would be almost instant. If however the needle valve is sticking the engine would presumably have a whole bowl full of fuel to use before cutting out. My fuel pump is at the rear of the car so if the problem was in the pump it would take several more seconds for the effect to get to the carb and then the engine. A problem with the pickup in the tank would take even longer to show. If you can estimate the timelag between throttle open and cutting out that might make it more obvious where the problem is.
Best of luck
Rob

[TonyG]

Hi Kevin,

This is a puzzle and I suspect the solution is within the suggestions already made with regard to fuel starvation. The challenge is identifying which bit is at fault? A garage would substitute bits until the fault disappeared but you probably don’t have luxury of spare pumps, carbs filters etc.

I’d suggest running a pipe from the tank side of the pump into a can of fresh petrol, thereby ruling out a blockage or debris in the tank or fuel line, which is very common on these old Rovers. Easy and cheap to do.

Ensure all the filters are clear- if you have an SU pump this has a small filter similar to the one in the input to the carb float chamber. When the engine cuts out, switch off the ignition to stop the pump and check to see if the float chamber is full. If not, check the needle valve and the possibility that the pump isn’t working. If it is full, the only place for a fuel blockage is the feed through the carb. Assuming that is ok, the only other cause might be fuel vaporisation if the fuel is getting too hot in the engine bay but it doesn’t really sound like that as the car starts up straight away.

Let us know what you find but my guess would be a blockage in the fuel supply or the pump playing up.

Do you have any pics of your car? Always nice to see old Rovers coming to life!

Tony.

[SHyslop]

From your description of the difficulty my suggestion would be that the problem, on nearly any other car, would be a leak in the inlet manifold at one of the joints, drawing air and thereby weakening the mixture, the problem being not a lack of petrol but a surfeit of air which the petrol requires in the right quantity to produce the power required to drive the car rather than just run the engine. If you can hear a whistle or groan when the engine is running, that can be a guide by following where it is coming from as to where a leak may be. The noise a pinhole makes is quite disproportionate to its size and they are often on the underneath or hard to reach faces of a joint.

However, the complicating factor is the downdraught SU. When not being under the load of moving the car, the carburettor can act with apparent correctness, the needle rising and falling with enough small movement to give the appearance of correct operation. However, under load the piston rising is dependent on enough depression in the inlet manifold to draw the piston upwards and if there is something causing the piston to stay down or an insufficient amount of manifold depression due to the points in the first paragraph, there won't be any torque as opposed to revs.

There is another pair of possibilities, not on the fuel side, should all appear well with the above. Both are easily checked. The first is that the points are at the right gap. Some newer points have cams which are of poor material and if this has failed or the screws weren't tight enough, the engine may run but again be powerless. Lastly, a failing condenser. Not failed, but failing, Again, the engine may run but not have any go. The test is to substitute another, any make, any type, but preferably with a bracket with a hole in it and a lead. Connect a crocodile clip to the hole in the bracket and another to the lead. Now place one clip on the distributor LT terminal and the other on a convenient earth and run the engine. If it works as it should, the condenser in the distributor is at fault. If it doesn't, the condenser is ok and you have a handy to fit spare when the right one does fail, as it will.

If it were my car, those are the places I would look at first.

[kevh]

Thanks all for the suggestions.
I was unable to find anything which looked like it may be the cause so I went back a few steps.
I removed the carburettor and inlet manifold, all gaskets have recently been renewed so I refitted these but this time added a smear of Hylomar red to remedy any unseen surface imperfections.
I dismantled the carb and thoroughly cleaned it, a small amount of dirt did come out, I had done this previously so maybe this dirt had been dislodged while working on the car.
Put it all back together and it seems to be cured, although the vehicle gates to the industrial estate where I have my lock up were closed so I couldn't go far to thoroughly test it and the weather is lousy today, I drove it beyond the point where the issue started previously and it was fine.
I just have some paint remedials to take care of, some micro blistering has appeared as a result of previous paint not being applied correctly, and I think I am just about done with the restoration.
Question is now do I sell or keep? the market for pre-war cars seems to be on it's backside at the moment, but realistically with two e-types along side it how often will I use it?

[TonyG]

Kevin,

Thanks for the picture, your car looks excellent! A really smart colour combination. From the registration number your Rover must have started life in the same part of the country as the Tourer used in ‘All Creatures Great and Small’.

It’s a great shame that pre-War cars don’t command the value they deserve. The effort and cost involved in the restoration is similar to more valuable classic cars but the return certainly is not. I’m in the final stages of getting my P2 on the road and, having had the enjoyment of rebuilding it, I am also debating whether to keep it or try to recover some of the cost. The sensible thing to do is probably to drive it and get some use, also affording the opportunity to show it and maybe attract a new owner. These are good old cars and well sorted ones represent an excellent vehicle for anyone wanting to get involved in classic car ownership. The important thing is that you have saved your Rover so well done for doing such a fine job.

Tony.

[kevh]

Hi Tony,

You are correct they are undervalued to such an extent that it makes no financial sense to restore such a vehicle as you will never recoup the outlay.

Its not just pre war-cars either, recently I was speaking to a Riley enthusiast who told me that most Riley RMA's and RMB's in need of more than a mild restoration are currently being scrapped as nobody is prepared to invest the time and money when the price of a good car is so low, I suppose the same applies to many other marques, which is a shame as many restorable cars will be lost.

I bought the Rover on a whim unseen via an online auction (never do that!!), it was described as fully restored but nothing could have been further from the truth, it had been subjected to an engine rebuild and the timber frame had been sorted but that was in the early 1990's and had hardly moved since.

I have thoroughly enjoyed the restoration but have often wondered why I am bothering when compared to the e type roadster I am currently restoring which requires similar man hours, purchase price £40k, restoration cost £15-20k, restored value £90k+.

Still, life would be pretty dull if everything was about financial justification

Good luck with your P2.