Ever get the feeling of de javu?

[saabfast]

Bad valve clearances may be a little noisier at idle but will affect the performance under load at higher revs. Very easy to take the carb pistons out and clean with SU's, just 3 set screws around the top, remove it and the piston lifts out with the needle.

[Polly-Red7]

Saabfest,
Cheers for the heads up re Beans' method for the manifold. The carbs have been cleaned and rise and fall together. The needles look ok with the naked eye and have the bias as indicated the manual I have for setting up SU's. The floats/chamber have also been cleaned too.

[dursleyman]

Have you checked the fuel pick up on the end of the fuel gauge sender inside the tank. There is a filter on it that can get blocked if something is floating about in the tank.

[Cobber]

Normally in order to determine fuel starvation you would check both fuel pressure and fuel flow rate.
Pressure, you test with a fuel pressure test gauge..... should be no less than 2 psi. The manual states 2.5 to 3.5 psi, though practice suggests that figure is too high.

Flow rate, you measure how much fuel the pump delivers over a set period of time.
The problem here is that British Playland. in their infinite wisdom, have not provided fuel flow figures
Maybe someone here might have them.

[Polly-Red7]

Well whisper it quietly but the problems seems to have cleared!? And to be honest I'm not sure what I've done to rectify it? I've methodically gone through peoples suggestions and today was all things fuel. Apart from checking everything out I replaced the inline filter (although it didn't look too bad). And cleaned the carbs again. So which one of these seems to have solved it is anyone's guess? Thank you once again to everyone who contributed. Fingers crossed this ones put to bed!

[busheytrader]

Hi Chris,

I wouldn't be surprised if you cut open the in line filter and find that the orange paper element (it's nearly always orange) is coated in orange crud.

Good to hear that it's sorted.

[Tamas Petrunin]

I had fuel starvation on another car causing it to die when you booted it, eventually tracked the cause down to the inline fuel filter collapsing under the higher fuel flow so it temporarily blocked the flow only for it to pop back into shape by the time you lifted the bonnet to investigate. That caused a fair bit of hair to be pulled out.

[Polly-Red7]

Bushey trader and Tamas, although I haven't dissected the filter yet on closer inspection some of the vanes (for want of a better word) do look as though they are being sucked? together. I can only concluded this was the problem after all the heartache! I've marked the new one up with the date and will look to change in a couple of months. Another successful trouble free drive today so a may risk a commute this weekend (52 mile round trip) Again thanks to all for your help and expertise. Chris

[Hasbeen]

About 14 years ago, just before my fuel tank rusted through from the inside, I could not get 150 kilometres from a new in line filter, before fuel starvation would make driving impossible.

I had installed the filter after the pump, as the fine rust silt did not worry it.

When starvation stopped the car, I was caught a couple of times with no replacement, having not replaced it. I found if I removed the filter from the supply hose from the pump, held it vertical, & let the petrol in the pipe up to the carbs drain back through the filter, it would remove enough of the silt to give me another 20 or more kilometres to get to a parts shop to buy a couple.

I mention this as it is an emergency repair that can get you home.

With one of my parents mid 80s cars I had a similar problem. More than half throttle produced just coughing & spluttering. On inspection I discovered the in line filter was about 7/8Th full of water. Emptying the water did not help much, as the water soaked part of the element did not like passing fuel at all.

Hasbeen

[busheytrader]

Good to hear you're up and running again.

Fuel goes through my inline filter before making its way through the electric fuel pump and Holley carb. You would think this provides all the protection you need but orange rust dust is so fine some of it had passed through it and was collected by the pump's integral filter and then more appeared in the bottom of the carbs fuel bowls.

Hopefully your in line filter is easy to get to, mine is close to the fuel pump so tucked up between the tank and the rear bulkhead, not an easy roadside fix.

[Beans]

Good to see the problem looks solved. Make sure you use decent quality fuel filters in future.
I use a fairly large generic Bosch fuel injection filter, which fits in a Bosch coil bracket.
This bracket in turn fits perfectly to the studs BL forgot to delete when they moved the coil to the wing on later cars ...



You hinted to it in your first post that the rubber mounts might have perished.
Always good to check their condition. Spray some start pilot over the with the engine running.
If the revs rise they need replacing. Don''t use new aftermarket ones as they are rubbish.
Heavy duty cable ties (as Hasbeen hinted) can help as a temporary repair.
Sadly that part of my weblog is still waiting to be repaired after Photobucket pulled the plug a few months ago.

As for the mounts alloy ones are available, or you can make them yourself when you have access to the correct tools.
More reading in here: http://tr7beans.blogspot.nl/search/label/SU

[Polly-Red7]

Thanks for the heads up Beans, will have a study at your blog. I like your filter set up; can you let me have some specifications of the filter and I'll try and get hold of one? The carb mounts are passed their best to be sure. Looking at replacing asap with either decent old stock/secondhand ones or I did wonder about the aluminum ones? I would have to buy those as I don't have access to mill my own.

[Polly-Red7]

So another false dawn and my problem is back! Admittedly it is now an intermittent problem. Sometimes the car feels and behaves like new and other times it behaves like a pig! Its all getting me very frustrated and down!

To try an add to what I've posted before I fitted a new fuel filter which I've relocated to the engine bay as the original was by the tank and hard to see. Should this filter be full of fuel because it isnt? Also at times I can see air bubbles in the filter bowl, is this normal? I've checked the tank breather which seems fine although unscrewing the cap you can hear a hiss of air? Help me Obi Wan Wedgeheads your my only hope!

[dursleyman]

I wouldn't worry about bubbles in the filter, mine usually has quite a big air gap at the top but it doesn't cause any problems.

[Polly-Red7]

Wow dursleyman I think I know my problem now! My filter is lucky if it has an 1/8th of what yours has in! Will try and post a picture of my set up