if not dirt in fuel, what else?

pasenah · Post by **pasenah** » Mon May 05, 2014 4:46 pm

I've had running issues ever since I discovered a rusty filler neck. That's been replaced, tank cleaned out, new inline filters replaced and also new swirl pot. I've taken the Weber off and cleaned as best I can without exposing the float chamber (I attempted it then got scared and put it back together and sprayed every hole with carb cleaner, Inc removing the 4 jets across the center)
I just can't seem to solve it. It will drive ok then start to judder, like its starved of fuel, and I check the filtrers, ( inline and tank lifter) and they are clear.

Its got new plugs but could a warn dizzy cap and rotor arm cause these symptoms?

Post by **MRMENDER** » Mon May 05, 2014 6:59 pm

Remove the fuel tank sender cover under seat.
Disconnect both hoses, go to engine bay do same to fuel hoses (Pump inlet & return) blow them through with compressed air. Check what comes out. If there is a lot of crud, it could be the cause. Also check the filter in the suction line in the tank (Remove the gauge sender unit to do this)

pasenah · Post by **pasenah** » Mon May 05, 2014 7:26 pm

I've checked the sender filter and that's always clear.

So even dirt in the return fuel line could cause this?

Nate · Post by **Nate** » Mon May 05, 2014 9:59 pm

inlet filter on the carb? still got water in the fuel? (look in tank, if yes, suck it out with some small pipe - it will sink to the bottom of the fuel - then treat with wynns dryfuel) carb needs setting up after it's been messed with, or needs properly stripping and cleaning. are you sure it isn't an ignition problem?

pasenah · Post by **pasenah** » Tue May 06, 2014 2:15 am

Inlet filter changed.
Wynn's Dry Fuel added last week.

Think I need to get the carb float chambers exposed so I can replace the inner jet for the new one in the kit, then a lest I can tick that off the list.

I'm getting a good spark from each lead so I'm assuming they are ok and its had new plugs.
After a carb strip I guess I'll try a new dizzy cap and rotor arm but it all points to a fuel issue at the moment.

Post by **the edmundator** » Tue May 06, 2014 8:10 am

Once you are certain it's not a fuel/dirt problem, you could try the ignition amplifier (easy to test if you have a spare or can borrow one). If it only happens after driving for a while, once the car is warmed up a bit, this could well be the problem. I had a duff one on one of my mk2s, and the symptoms are very similar to blocked fuel supply.

pasenah · Post by **pasenah** » Tue May 06, 2014 9:09 am

If ignition amplifier, could that be ok for a couple days then play up, then play up for one day, then be fine again?
Cause that's the random problem I'm getting?

pasenah · Post by **pasenah** » Tue May 06, 2014 9:14 am

Actually I've just discovered a possible cause. It looks like I've been tricked and the carb is jetted for a 1.6?
The sizes I've got are
155-F30-120
155-F25-125

Am I right? Could this cause these symptoms?

Post by **the edmundator** » Tue May 06, 2014 6:51 pm

pasenah wrote:If ignition amplifier, could that be ok for a couple days then play up, then play up for one day, then be fine again?
Cause that's the random problem I'm getting?

Yes, quite possibly. When mine went, it started stuttering while driving, then cut out completely. Then it restarted ok but stuttered and cut out again. This carried on for a bit until it also wouldn't start. It started only doing it after having driven for a while, but the time needed before it happened got shorter and the poor running got worse.

I don't know about the jet sizes for the carb, but under load you won't be getting enough fuel if it's jetted for a 1.6 and you have a 1.8.

marcus · Post by **marcus** » Tue May 06, 2014 7:39 pm

Before my ignition module packed in, the car was getting increasingly difficult to start but ran fine, ultimately culminating from one day to the next in it not starting at all because of a total lack of spark. I replaced the module and initially this didn't cure my problem but I subsequently discovered this was due to poor connections between the module connector and the module and between the smaller plug on the other end and the distributor body.

pasenah · Post by **pasenah** » Tue May 06, 2014 9:23 pm

Have you got a link to an ignition amplifier/module, so I'm looking at the right thing I think you mean?

Post by **the edmundator** » Tue May 06, 2014 9:42 pm

It's under the plastic rain-tray at the windscreen end of the engine bay, on the passenger side. Small, black, rectangular device on a piece of metal with a multi-pin cable attached to it.

Like this:

There are various different types and places like Eurocarparts/GSF will invariably send you the wrong one - best to take it into a shop (or see if someone on here has a good 2nd hand one you can try).

pasenah · Post by **pasenah** » Tue May 06, 2014 9:47 pm

Cool, as I thought, thanks. I'll replace the jets and check the needle valve, then move onto electrics if no joy.

go-for-it1 · Post by **go-for-it1** » Fri May 09, 2014 9:44 am

Have you replaced the rubber fuel hoses in the engine bay between the fuel lines and pump and pump and carb as these can collapse internally without giving any signs externally. They cause a restriction in the line resulting in starvation.

pasenah · Post by **pasenah** » Fri May 09, 2014 3:09 pm

No not looked at those fuel lines, but will now, thanks.
I've stripped the carb fully now and still have issues, so have ordered the ignition module, £30, to see if that does anything.
It seems to only happen when its warmed and possibly even caused by the fan starting???

Scirocco Register

Scirocco Register

if not dirt in fuel, what else?

if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?

Re: if not dirt in fuel, what else?