Help! 1.9 petrol misfire/no power/cutting out = misery!

[busengineer]

I have an annoying problem with the bus, first off its a 1985 1.9 petrol watercooled

Weve had here about 4 months and she did North Wales and back a month and a half ago absolutely fine (300mile trip), since then I renewed the dizzy cap and rotor arm (local motorfactors) and tidied up the some wiring at the coil as it had been bodged before! So last weekend we headed off to Shrewsbury for the weekend and heres where the problems started!

After about 20 miles she started hesitating under light throttle openings, this then got progressively worse! She misfires on throttle and then feels like theres no throttle at all, it doesnt matter what i do with the pedal theres no response and most of the time she'd cut out, usually restarting after a couple of attempts. Anyway I limped her to the campsite had a great weekend and had her towed back. The breakdown guy said he thought it was the carb gummed up.

So I ordered some parts off Brickwerks and this week Ive replaced the plugs and leads, air filter, fuel filter and stripped and rebuilt the carb (which is a Peirburg), replaced brake vacumn hose and bolted it all back together this morning and fired her up, took her for a blast round the block and she drove ok, still a hesitation/misfire as you first press the throttle. Anyway got her home and she misbehaving again....

Misfire on most throttle openings unless reved very hard seems ok higher in the rev range(4k plus)

So I swapped the rotor arm and dizzy cap back and re did the wiring at the coil as these were the parts changed before the problem, still the same, misfire and poor running when up to temperature

So has anyone any ideas as im supposed to be going to South Wales in her on Friday and shes undriveable as she is

[busengineer]

My next best guess is fuel pump and pushrod, but it is a guess so im after good advice rather than me just throw money at it

[Mickyfin]

Is your exhaust blowing at all anywhere? This caused my WBX to randomly stall/cut out. Strange but true.

Also it could well be your fuel pump, and, or pushrod, the pushrod on mine had worn down a couple of mm, and renewing it really helped with my fuel starvation issue I had a while back.

[busengineer]

And did the fuel starvation issue cause misfiring and a lack of throttle/pulling power??

[kevtherev]

Ah!
Backfiring is classic weak mixture

Most likely caused by air leaking into the inlet side.. vac hose, servo hose, choke pull down unit, gaskets,
or fuel filter blocked (carb and Tank)
fuel pump and or pump pushrod

[busengineer]

Ive replaced the tank filter and cleaned out the carb filter when it was in bits

Wheres most likely for inlet side leaks??

Wheres best to get a pump and pushrod quickly?? GSF?

And its a misfire more than backfire, it does sound poppy at times so perhaps it is backfiring

[Mickyfin]

JustKampers sell the pushrod.

[VERAT25]

had this very problem.....................traced to vac hose and blowing exhaust........

all sorted

new s/s exhaust sweet

verat25

[REGGAJ]

Ignition module on its way out would give these symptoms.

[busengineer]

I was under the impression from research on here that the ignition module wouldnt do this, it either works or completely fails

Im thinking i'll try fuel pump and pushrod tomorrow, is it only showing up when up to temperature because the auto choke is masking the fuel starvation from the pump?? Just trying to get my head round it

[kevtherev]

yes your getting your head around fine.
but remember there's fuel starvation and fuel dilution.

[busengineer]

Right then . . . . the plot thickens!!!

Checked a few things this morning, just that vac hoses were in place etc, all seemed ok, so fired her up

Ive been out twice now probably about 7-8 miles in total and she's behaved perfectly!! So im now not suspecting fuel and im starting to think ignition, bear with me here!!

Im back on the original dizzy cap and rotor arm at the moment (i was yesterday tho when it was misbehaving so its not directly that). I replaced these as they look badly scorched/burned on the tip of the rotor arm and the points in the cap. So I had a look at the new ones id fitted (Intermotor) that i had run on the way to Shrewsbury and these were starting to scorch in the same way, so any idea why this may be?? And is it the coil or ignition module that are causing this and my running problems??

[REGGAJ]

http://www.brickwerks.co.uk/shop?page=s ... ory_id=122" onclick="window.open(this.href);return false;

All it does is read the signal from the Hall sensor in the distributor and amplify it to a level that the ignition coil can use.
They often fail, sometimes they give warning they are going with misfires and the like.

[busengineer]

Cheers for that, Im going to take the plunge and order a coil and ignition module for peace of mind as much as anything. They wont be here for tomorrow so im going to risk South Wales as shes been faultless today!! Strange!

[busengineer]

Well I'm sat in a lay by in the middle of Wales and its started playing up again!!!

I'm 25miles from my destination so I'm letting it cool and then il try again.

So I'm going to say its not fuel!! Or air leak as surely it would have done it before now, I'm stabbing in the dark and saying ignition coil or module breaking down. What are people's opinions because I need answers?

Anybody live near Abergavenny??