Diagnostic help please.....

[wagonwheelers]

Hi all. We have an 1986 1.9 petrol.
I'll give you the symptoms first;
When driving engine suddenly looses power and then regains. Starts to kangaroo in other words.
If I down the throttle all the way while parked up, it will rev up and sometimes backfire.
If only half way, its very lumpy.
Will stall when idling.
Very little power. (Have to keep foot hard down to get up a hill when normally she'd fly up.)

Started a few days back, and we assumed a petrol problem. filled it up and she was fine. We did 200ish miles. Then it started again today.
There is plenty of petrol in.

Today I got the feeling it was an electrical fault, so I cleaned the rotor arm and dizzy cap. It fixed it... for half hour.
I also changed the plugs tonight. The old ones were beige in colour and looked ok. This made no difference and the engine increasingly still runs poor.
I was just about to give up tonight when I noticed the engine seemed to be rather hot. I checked the water and it was empty. Only checked it a few days back, not long before all the trouble started. I cant see a leak and the new water seems to be keeping its level, although its too late to check it for long. I'll have another look tomorrow.
Oh and the temp gauge hasn't given any indication of a problem.
In the quick run she had up our street after I put water in, she felt ok. Although, it wasn't really a long enough to test.
Anyway, Do any of the symptoms weigh up with over heating, or does the electrics seem right. The guy from the AA who had to help us limp home tonight thought electrical.
Any thoughts would be appreciated.
Paul.

[mike_gee32]

Have you replaced the fuel filter yet? I had similar symptoms (but without the backfire when revving) a few years ago and the fuel filter was completely blocked with crud. There should only be one filter on a carb engined van - right next to the fuel tank on the drivers side.

It could also be an air leak, if the vacuum pipes going from dizzy and air box to carb are shot that can cause difficulty starting and no power.

[wagonwheelers]

Have you replaced the fuel filter yet?

I haven't. I'll put it on the list thanks.
And the vacuum pipes seem ok.

[Ian Hulley]

My money's on the filter but if the filler neck or it's rubber gasket has decayed then water in the tank is also a likely option.

Ian

[Pootle]

There is a little gauze filter on the fuel inlet to the carb too - check that. Also the carb float bowl.

The backfiring and lack of power when going up a hill can sometimes indicate poor timing so I would check that with a strobe. On my T25 the diapraghm inside the vacuum advance thingummy rusted and the timing advance then became intermittent, which was a pig to diagnose.

[Ian Hulley]

The backfiring and lack of power when going up a hill can sometimes indicate poor timing so I would check that with a strobe.

Timing doesn't tend to move about once correctly set ... same as the 'strip the carb down brigade' . You need to look for what's changed ..... for example it's been wet the past few days.

[wagonwheelers]

Well, I changed the filter at lunch time, and gave it a quick run up the road. It was bad on the way up, but better on the way back. Didn't get time to give it a good run. I'll do that come home time. It did want changing regardless. It was full of crap.

[austen smith]

I had a similar issue (miss firing, low on power, revs OK out of gear etc) and turned out to be the coil!

[kevtherev]

Fuel pump, fuel filters and any vacuum operated unit or pipe is suspect here...like brake servo hose, pull down unit, distributor, gasket,

or anything that will weaken the mixture...even water in the tank

[wagonwheelers]

Thanks for all the suggestions. All much appreciated.
The van seems fine now. Looks like it was the fuel filter. The old one was pretty crudded up, and since fitting the new one, shes done a good test run up and down our local hills. Sounds smooth as a chutterbug again

[Ian Hulley]

Good to have the feedback

Ian

[Mickyfin]

Where did you get your fuel filter from mate? I need one, and Brickwerks only list one for the injection models. I'm guessing I can use one of these on my carb engine 1.9wbx?

[Mocki]

you cant use the injection one!!

you should be able to get one from any motor factors.
just a inline petrol filter.
from gsf they are about two quid , but i realise thats no help to you over there!!!

[Mickyfin]

Cheers Steve, Im sure I will track one down locally, there is an helpful motor-factors here who the last time I was looking for parts came out with a thick catalogue, and even brought up my Syncro part list on their computer

[Ian Hulley]

Here you go ... http://www.brickwerks.co.uk/shop?page=s ... gory_id=72 under Service Parts

Ian