Running getting worse

[Robbie693]

Thanks Alan for going through this, it's very useful to have someone else's perspective on my efforts and findings. I've been lurching back and forth from fuel to ignition being the culprit and it's easy to lose the plot especially as I don't know the causes of some symptoms; the weak mixture causing spitting explanation is a good clue. And yes - the plugs do look clean.

What's the best way to check the pump pressure? I don't have a gauge so is there any other way to do this? I was presuming the pump is ok as I bought it, rebuilt, from Brian Buckland but I will check if I can.

The carbs were rebuilt by a retired fuel systems development engineer (mostly with Zenith carbs) and I do have faith in him that he did it correctly. I know he has a good track record anyway. He did say that the only thing that was not quite right was the floats which looked, he said, to have been messed about with a bit but he apparently managed to get them looking ok. Having taken them out recently they looked fine to me although I have nothing to compare them too.. I looked into getting some new ones but Dellorto no longer sell the 10g ones as fitted to my carbs.

I'm going to try re-setting the floats to 15mm and 25mm droop (which I didn't check before) and check the remaining ignition bits that people have mentioned recently. Then I'll be hassling Brian!

Thanks again

Robbie

[Spyder fan]

Robbie,

This is the item you need, choose the 0-15 psi version http://www.demon-tweeks.co.uk/Product.do?method=view&n=1539&g=9004&utm_source=Google&utm_medium=Base&utm_campaign=Motorsport A standard mechanical pump on a twin cam should produce between 2 and 4 pounds of pressure. This will check that the pump is actually working but won't be able to measure the flow.
An easy way to check that sufficient fuel flow is getting to the carbs is to disconnect the coil (safety first) remove the spark plugs (to make the engine easy to turn over) then remove the fuel line feed from the carbs and place it in a suitable glass container (a well supported milk bottle is fine). Then simply crank the engine with the starter and you should get a pretty fast flow of fuel into the container, it may come out pretty fast at first but then slow to a dribble, this means there is debris in the top of the fuel line near the tank. If it just dribbles it's probably the pump or debris near the pump. If all is well then move on to suspect the carburettors.

hope you can solve it this weekend.

Regards

[collins_dan]

If it was the pump, would running the car affect it? It sounds like the problem is made worse by running and getting up to temp. I agree that it could be fuel related, but I'm thinking carbs. I had a similar issue and it was resolved by making some adjustments to my strombergs and timing. Good Luck. This must be making you crazy. Dan

[Robbie693]

Thanks Alan. Will test out the pump asap. Unfortunately probably not this weekend as I have a Mini to fix too! Maybe in the week though hopefully.

This must be making you crazy. Dan

I'll say it is!

Thanks Dan, I hope as with yours it'll be adjustments that is needed as buying expensive stuff is going to be difficult at the moment. As far as fuel starvation and the problem appearing when hot I'm thinking, in my very amateur way, that the heat is causing evaporation to the (possibly) low fuel delivery. Is that feasible?

Cheers both

Robbie

[collins_dan]

I don't know enough to even have an opinion on that. With mine, it was a fuel mix issue. I needed to get to a mix that wasn't too lean at high rpms, while avoiding getting too rich at low rpms. I ended up changing to a different needle that was better shaped for how my engine had been set up. Timing had to be adjusted a little as well. I don't know how difficult it is to adjust the mixture on your carbs, but if not too hard, try making it slightly richer, keeping track of the change so that you can reverse it if it doesn't help. Good Luck. Dan

[Spyder fan]

[quote="Robbie693"]Thanks Alan. Will test out the pump asap. Unfortunately probably not this weekend as I have a Mini to fix too! Maybe in the week though hopefully.


Mini's are for whimps, James Martin the chef has one and I WOULDN'T DRIVE ANYTHING THAT GUY HAS TRIED TO FIX!

Regards

Alan (former riley elf owner)

[Robbie693]

Mini's are for whimps,

Alan (former riley elf owner)

And Lady-friends!

Robbie

[Mr.Gale]

A number of years ago I had a similar problem with an E-Type and the problem turned out to be a dirty inline fuel filter. At high RPM's and WOT, the filter was restricting the fuel flow, replaced the filter, problem went away.
Just a thought.
Gale

[pauljones]

Robbie and Gale,
If you have a look at my recent posts,you will see I had the same problem.It could be fuel,it could be ignition were the answers from the forum members.To eliminate the ignition problem,I got an Aldon ignitor 2 module with flame thrower coil,as a matched set from Aldon directly.I also got a set of leads,8mm NGK's.As Ive said in my post,a bit pricey but it works and well,As for the fuel issue.I ended up taking of the carbs(dcoe type) and the braided fuel line just to get to the pump and clean out the fine mesh filter.The pump was bogging,I ended up cleaning it with a tooth brush and some chrome cleaner.No wonder it tasted funny in the morning.The carbs were stripped and cleaned out.I had a bit of fun as I had no manual just a spare set if it all went wrong...Brave I know.
The end result is a plus 2 that now runs like a sewing machine,picks up revs and starts on the button.A combination of a bit of money,some time which thankfully was free and some good advice from the forum.

Based on my very recent experience and that yours sounds like mine was,Id sugest trying the same.The price was worth the piece of mind and a good upgrade for the ignition too.

Paul

[Robbie693]

Thanks all for the new replys.

Dan - sorry I missed your post earlier. Yes the mixtures are easy to change on the Dellorto's - getting them right though is a different matter! I was wondering if the slight stumble off idle would be improved by a slightly richer mix too.

Gale - I don't have a fuel filter, apart from the ones in the carbs and the pump, but I take your point on potential blockages and this backs up what Alan was saying also.

Paul - Glad you got it sorted, sounds like your problems were more severe than mine as I get the impression that yours wouldn't rev at all, rather than just when hot? Replacing the distributor again will be a last resort as the one I have is almost new and from Aldon also. I will bear your experiences in mind though

Thanks again

Robbie

[Robbie693]

I just had a thought..

The charging system wouldn't cause my problems would it?

The battery has always been sluggish from cold and the charge light doesn't go out from a cold start until I reach just over 2000rpm. It's fine on re-starting, just the first cold start of the day.

I can't see it but would this effect high speed rev's?

Cheers

Robbie

[Spyder fan]

I think you are clutching at straws. Stop messing around with fixing Mini's and get your head under the elan bonnet to check for the fuel line blockage that you almost certainly have.

Do the checks I mentioned by cranking the engine to work the pump, it will only take a few minutes to do that. Once established that there is a blockage, remove the carbs and then remove the fuel pump. Get an airline on the fuel line and blow it back to the tank, check that petrol is literally pi++ing out, then reconnect to your cleaned and checked fuel pump. Consider fitting a filter at the tank end.
Problem will be solved.

Btw I'm feeling a bit grumpy today.......
.

[Robbie693]

I think you are clutching at straws. Stop messing around with fixing Mini's and get your head under the elan bonnet to check for the fuel line blockage that you almost certainly have.
.

I'm good at straw clutching!

Btw I'm feeling a bit grumpy today.......
.

Me too - I'm doing armchair diagnoses as I'm stuck at work when I'd rather be playing with cars. I've not checked the tank/lines yet as I've got a full tank of fuel so I'm waiting till I've burned it off a bit..

Regards

Robbie

[neilsjuke]

Ign W/L faults can be caused by faulty ignition switches causing a high resistance have you hot wired it yet.
Neil

[Robbie693]

Interesting.. maybe there's a connection (excuse the pun) either way it would be good to sort that at the same time.

No, not yet Neil. Haven't had chance to do anything with the car for over a week now - hopefully this weekend though. I'll report back with findings when I do.

Cheers

Robbie