Running Problem 2.8 Granada - Real Head Scratcher

[GrannieTwoEight]

Hi Guys/Gals

Just joined up, short term - to post about the problem with my car; long term - for banter I suppose!

Ok down to the nitty gritty:

Restoration project 2.8 MK2 grannie - C plate

Basically have fully rebuilt the engine including, rings, rocker shafts, tappets, gaskets; ancillary stuff: fuel tank, sender, pump, coil, carb and all the rest, including OE stuff where possible, and for the life of me I cannot get it to tick over.

Now I had done the rebuild a few years ago and granted the car has remained static, and stored, as I have been doing some bodywork on it and also other projects. But since then always have ran it and moved it regularly while working on it or doing other stuff.

I noticed last year it started running gruff and so I figured maybe as it had been dormant over winter that maybe it could do with fresh fuel, nope never worked, and done all the usual checked timing, plugs, leads, mixture, filters (I have inline filter instead of that rotten thing in the tank).

I then discovered the tank and sender were absolutely rotten inside so replaced tank and sender with new ones, flushed out all the lines changed the filter, still no success. Then as usual was back to checking pipes, hoses, looking for leaks, putting 4 point plugs in, which improved the running a little bit but not much. I noticed that the plugs were sooting up quite easily so I plummed and got a new weber 38 DGAS carb and replaced the wheezy solex (which by the way was quite new all the same, so couldn't really understand the running problem).

So got the weber, fitted it and viola was running great, for about a month (takes deep breath) but then it started again, chugging and then cutting out.

I ended up taking a can of fuel from under the car straight up to the pump to see if this made any difference, trying to eliminate the tank and pipes in case any blockages - no luck, tried resetting the mixture screws to about 1 and a half turns each side - no luck. New carb flange mounting gaskets - no luck, plugs checked/cleaned (one more time) - no luck. Checked compression (about 11 bar on each)

So the point I am at now is after renewing basically everything and trying my best to go through the whole thing logically I am still no further forward. From my investigations over the weekend what I do now know though is these 3 things:

1) that when it is cold it seems to start & run fine and when it starts warming up it starts loosing it, the revs start collapsing slowly then down down until thump it cuts out. Trying to restart it will start after some gassing and then will hunt up and down.

2) When it is hunting if I put my hand over the carb throats, not fully, just leaving a small air gap, the revs recover and it ticks over smoothly. Although eventually it will give in and cut out.

3) If after cutting out and leave for a while it will start and run ok for a bit then lose it again - pretty much the scenario from cold starting.

Now I was thinking maybe the Weber needs a bigger tick over jet or whatever it is but then why does it tick over good sometimes then cut out? This leads me to think it isn't that. It's like someone is clamping shut the fuel pipe, however fuel is gushing out the delivery pipe when I crank it, even after cutting out.

To me number 2 is the biggest indicator of what might be the problem, but it is the "what" that I still cannot determine.

Maybe some of you guys can have a stab at some suggestions as I think this really needs a 2nd pair of eyes on it!!

Thanks ever so much

Andy

[Skyedriver]

Need a bit of time over this but does the dgas have an auto choke
Hunting normally means running rich.
Choke on when its cold wont switch off, over fuel, stall. Leave, cools, starts, repeat
I'll get back to you, but in the meanwhile do you want to sort out my mini?

[chrisr29]

Sounds like there was a bit of crap left in the fuel lines that's possibly worked its way into the carb jets. Pull the carb apart and check for crap in the jets. Do you have a filter directly before the carb?

[V8 FOU]

Sounds like an inlet manifold gasket leak to me. If holding your hand partially over the carb helps then you are richening up the mixture. An air leak of this nature would tend to be worse when hot.
Best bet is to get it on a gas analyser to look for excess O2 and HC.
Other problem with these is the distributor, it can often break down when hot. Had one of these brought in years ago which actually cut out when hot. Took ages to find, but replacing the distributor cured it.

[GrannieTwoEight]

Hi

I had an in line filter in the fuel pipe then changed as it was looking quite manky so that was replaced too. The filter is just before the pump in the fuel line. The choke - auto choke from coolant always turns off quite quickly, that's when the problem seems to start.

Andy

[GrannieTwoEight]

V8 FOU said:

Sounds like an inlet manifold gasket leak to me. If holding your hand partially over the carb helps then you are richening up the mixture. An air leak of this nature would tend to be worse when hot.
Best bet is to get it on a gas analyser to look for excess O2 and HC.
Other problem with these is the distributor, it can often break down when hot. Had one of these brought in years ago which actually cut out when hot. Took ages to find, but replacing the distributor cured it.

That's the one thing I aint replaced is the dizzy although I never thought it would be a heat related thing. So you think more along the lines of an air leak? It certainly does seem like that with the sound the engine is making, it hunts - higher revs and seems smoother then drops and is rough, then back up again, then eventually dies.


Andy

[Skyedriver]

Inlet manifold leak seems feasible.
Choke compensates when cold, when off you need to apply a hand to choke it and richen mixture. It's your term hunting that puzzles me now, if its running lean it wouldn't hunt.

[chrisr29]

GrannieTwoEight said:

Hi

I had an in line filter in the fuel pipe then changed as it was looking quite manky so that was replaced too. The filter is just before the pump in the fuel line. The choke - auto choke from coolant always turns off quite quickly, that's when the problem seems to start.

Andy

Could be crap left between the pump and the carb that's worked its way in, blocked jet will weaken the mixture, hand over the choke will richen it up again.

Just seems odd that you say it ran fine for a month after replacing carb then began to degrade again. I'd try cleaning jets first - after all it will cost you nothing.

Had the same issue on a Polo years ago, turned out to be crap in the line between the pump and the carb. Cleaned the carb and fitted the filter just in front of it - problem solved.

I do a lot of work on old cars with carbs and issues usually revolve around dirty jets.

[madjules]

I remember my dad had a very similar problem with his Grannie (78 Mk11 2.8 Estate on carbs) back in the day.

Sadly he’s not around to ask anymore, but my vague memory is that after weeks of problems it was something to do with the anti-stalling device or possibly vacuum supply associated with the autobox.
As I said, sorry it vague, but may help.

[rallyspit]

It certainly sounds like fuel starvation. Have you checked the fuel tank breather? Try running without the fuel cap on to eliminate.

[guru_1071]

rallyspit said:

It certainly sounds like fuel starvation. Have you checked the fuel tank breather? Try running without the fuel cap on to eliminate.

i would suggest this, the fact it starts great, then dies, then starts if you left it stand.

if the tank cannot vent, it vacuumes as the fuel is used, then the vacuum defeats the pump.

if it runs ok with no cap on, check the fuel tank breather

[anonymous-user]

Either not enough and erratic fuel supply or too much air via an inlet manifold leak would be my guesses. Try testing for an inlet manifold leak by getting it running and then spraying WD40 along the joints. If it's sucking in air somewhere the WD should give some nice smoke out of the exhaust pipe.

[GrannieTwoEight]

Thanks for all the suggestions. I have just put a new tank and sender in and am sure the breather is fine, also never hear any pressure when I take cap off but i'll check again. The pipe goes up from tank into the filler neck and vents there by the looks of it. I've also eliminated the tank anyway by running directly from a 5 litre tank of fuel directly onto the pump.

Stange how you get some cars absolutely filthy, no fuel filter, or old filter with old fuel and they run great then this - really strange. I'm also wondering if the jets are not the right one for the car.

As I said and a few others here have mentioned the hand over the carb is a tell tale sign of something, or is leading me to the path of the problem. Eventually though even doing this it will stall out but it takes a lot longer.

I think this narrows it down to air leak, jets dirt or dizzy. Will try and have a look at the jets but unsure what ones to take out or exactly where they are. Just thought i'd mention too that the mixture screws are about 1.5 turns out, I also tried at about 3 turns out and not much difference.

Andy

[windy1]

Get some brake cleaner and spray a bit round the inlet manifold gasket area whilst it is running. If you note a change in engine speed then this is the likely source of the leak.

[rumple]

And lastly, post some pictures of it

[davepoth]

Is it the original coil?

[Ray Luxury-Yacht]

I'm thinking air leak somewhere?

[rallycross]

rumple said:

And lastly, post some pictures of it

Hope you get it running with something simple like an inlet manifold leek, but get some photos up anyway - You never see them on the road these days but noticed one just the other day, a 2.8 Ghia 2.8-X estate and it looked very nice, they used to look huge but it looked quite small now.

[kev b]

A few shots in the dark - is there a blocked filter gauze in the carb where the fuel pipe union screws in?
Is the float height correct and the float free to move?
Is there a split diaphragm in the vacuum advance capsule or the kickdown actuator on the autobox?

[GrannieTwoEight]

Hi

Regarding comments above the coil is brand new, the auto box is brand new and the carb (weber 38DGAS) is brand new!

Tonight I plummed the fuel feed pipe right onto the pump, pulled off the old filter (well nearly new actually) and put a new filter between outlet of pump and inlet to carb, then set the mixture screws up to 3, still no luck really but holding my hand over the top of carb it ran a bit longer than usual, so I plummed for turning the mixture screws up to 6 turns and then it ran without cutting out.

However, although you can't hear it when tick over, when you hold revs about 2k you can hear it jump and then splutter a bit (like someone is pulling a plug lead off and on) but not quite as bad as before, I don't know if the mixture screws need turned up a bit more but 6 to me is well enough, the recommendation for the old solex is about 1.5 - 3 turns, but turning up certainly improved things but not completely out of the woods yet.

I also tried turning the timing a little bit clockwise and vice versa - this only made things worse so the timing was ok where it was.

I don't know if the higher mixture setting is going in the right direction or it is masking something else?

Andy