Crossflow won't fire

[Klunk]

To check if the pump jets are working, remove the air filter.  Looking down the trumpets to the butterfly plates (torch may be required), open the throttle quickly a few times by hand then let it shut.  You should see the butterflies get wet and a pool of fuel at the bottom near the bottom of each butterfly.  

[OliverSedlacek]

I disagree with Klunk, the jets are behind the butterflies so they don't wet them. It's possible but quite hard to see the pump spray by looking down thethrottles with a torch. I also think it's unlikely tha all 4 pumps are buggered.

You could also take all the plugs out and crank the engine on full throttle as you should then easily see a fuel/air spray mix coming out of the plug holes.

Careful with naked lights though.

[Klunk]

I beg to differ Oliver.   The pump jets are just in front of the butterflies, and depending on the size of your chokes, visible.  Pump jet is No. 13 here

I do, however, agree that it is unlikely that these are the issue.  

 

[Roger King]

On the face of it this does seem like a carburettor issue.

Firstly do what Klunk suggests by looking to see if the pump jets are working. If not, you need to look at the jets to be sure they're not blocked and you also need to check that the mechanism is working.

You should also remove the slow run jets and check that they're not blocked. It is highly unlikely that the main jets will have blocked and even if they have the engine will run just fine on light throttle.

You could also remove the covers over the progression holes and blast some carburettor cleaner back up the passageway to the slow run jets preferably while the jets themselves are removed. Make sure that you get a can of carburettor cleaner that has a "straw" that can be attached to the aerosol outlet; this will allow you to direct the cleaner accurately up the passageway.

You can sometimes get a reluctant engine to fire by laying a teaspoonful of fuel (at your own risk) in each induction tract as near to the butterflies as possible. Easy start does a similar job and I note that it ran briefly like this so ignition problems can be ruled out.

[scorcher]

Longer vigorous pumping, freshly charged battery and bingo we're off and running ! Sun is shining too so good luck Terry. Thank you all for help in this.

[Terry Field]

AH! Longer vigorous pumping  -- I knew I was getting something wrong . Now what about the car?

 

Terry

 

[andy_h]

I had a carb problem (leaking fuel) which I think was stuck floats but I  rebuilt the carbs anyway thinking it could have been warn needle valves also. Anyway, I took the carb tops off  recently to re-check floats and I found some crystals in the carb around the gasket/corners. I suspect these formed over the winter and may be the cause of your blocked jets.

 

 

 

 

[Terry Field]

Right, I've followed all the good advice; cleaned all the jets by taking them out and blasting them with a shot of compressed air from a can, including the progression holes and accelerator pumps. Everything looked clean and fine.

I filled up the carbs with fresh fuel and turned it over. It gave me the benefit of two or three rather apologetic coughs (progress indeed!), so it looks as though the fresh fuel in the carbs was starting to be effective. After that it just churned over without firing at all. Checked the plugs and they were all wet, so the fuel is getting through.

So it seems that I am left with just a stale fuel problem, depite adding 10 litres of fresh. I guess the next step is to drain the tank and pipes and refill it.

Thanks for all the advice so far.

 

Terry

[john g]

I'm loving this thread, I know Terry probably isn't, it's like a drama unfolding with all the xflow stars taking part including Roger the oscar winner. I had an issue a couple of years ago after a winter lay up. Not running well tried everything but a chap I know was convinced it was the plugs. No way, I thought, I had replaced them the year before so they had only done a couple of thousand miles and had a good spark. However I changed them and hey presto. Terry, are you using new plugs? Just a thought.

Oh yes and not a laptop or ECU in sight.

[Drumster]

Terry, I've never been entirely convinced by the stale fuel theory as once I got the Zetec started it ran perfectly happily on 7 months old fuel......

[Terry Field]

Hi John,

Glad to offer the entertainment 

From what you say, and from Chris's last comment, I think I will change the plugs - at least it is the easier option. Although I can still get it to fire on the easy start!

One of the frustrations is that I have never had this problem over the winter before, so I can see where Chris is coming from.

It really is a case of elimination at this stage, so plugs it is for the next step.

More entertainment tomorrow no doubt

 

Terry

[SM25T]

Change the HT leads while you are at it. Modern carbon conductor leads don't like being messed about with.

[Terry Field]

I think that's the next step after the plugs, Ian.

 

Terry

[Jonathan Kay]

I've never been entirely convinced by the stale fuel theory

Nor me, for petrol in car tanks for a few months. But in this case I'd still change it as Terry proposes.

Jonathan

[Nigel Riches]

Battery, get a new one, from somewhere.

My take on this is the battery is on the "edge"  of serviceability, ok, it cranks the engine but there's sweet FA for the ignition system, easy start is sending you  a hoax, this stuff is pretty much ether, so will ignite at the least sign of a spark. 

Did you have the battery on a conditioner over winter, how are the cell electrolyte levels?

Try to jump start from another vehicle, with the engine thereof running, and a good healthy charge from that alternator. 

When the battery in my diesel Land Cruiser quit it cranked fine, but the ecu had a nervous breakdown, all sorts of trouble, new battery, problem gone. 

Just my Saturday evening input. 

Hope you get it sorted soon, with the spring weather improving. 

Regards, Nigel. 

[Golf Juliet Tango]

Having experienced starting problems with both the Crossflow in the Seven and the K Series in the 21 I understand how you feel.

This experience tells me it is a combination of things, each of which would not impede you but with two or three less than optimal conditions the car will just refuse to start no matter which one you tackle first. In the situation the analysis seems odd. You get sparks, you find fuel, but it will not fire.

[elie boone]

Any possebility that the balance on the carbs is way out ?

[Jonathan Kay]

Following Nigel and GJT's thoughts... measure the battery voltage at rest and during cranking. I'm generally rather keen on doing this early (!) in the diagnostic process. I'd bet against voltage deficiency in this case (no ECU and the appropriate ignition on ether) but it's quick and easy to do.

Jonathan

[Terry Field]

Now I really am confused!

But first to answer the latest comments - I don't have a meter but I am happy that the battery is OK. It is a 2 year old Powervamp which is alaways kept on a conditioner. Engine is turning over long and fast and the spark is good.

                                                                   -I haven't tried a jump start yet for the reasons above

                                                                  - The balance on the carbs has not been touched - so no reason why they should be way out.

I fitted new plugs, pumped the carbs by hand about 10 -12 times and then again for about 12 times on the loud pedal, opened the throttle wide and tried to start it, but nothing. I took out the new plugs, only to find that they were bone dry!! (easy to tell on new plugs).

Checked the fuel pump again, fuel is reaching the carbs; took the top of the carbs, reservoirs are full, floats seem to be OK.

Took the plugs out and turned it over, with a torch and my nose down the plug holes - absolutely no sign of fuel and a distinct smell of fresh air being pumped out. There didn't even seem to be any vapour in the bores.

I'm really not sure where to go next. The tempation is to contact one of the old car restorers in the area, on the basis that they might be familiar with Webers, or at least will know a mechanic who is, and let them have a go.

Cheers

Terry

[Molecular--Bob]

Are you getting fuel from the pump jets when you hand opperate the throttle? If you look at this vid https://www.youtube.com/watch?v=ut7_ONJwTbw you can see the amount of fuel that should be coming out. keep the butterfly open and you should see the residual fuel comming out of the jets which are behind the throttle plate.

If you are not getting fuel then youhave a carb issue. If you are then it should start and I would put the new plugs back in and try the cold start spray again and see if you can keep it running on the idle / main jets. 

[Roger King]

I really can only reiterate my comments from 10/03/15. If you don't carry out these procedures you will get nowhere in eliminating the (quite likely) possibility of a carburettor problem.

[Terry Field]

Hi Roger

 I followed your advice - March 12th above - and removed and blew through all the jets using a 'straw', including the progression holes (albeit with compressed air and not carb cleaner - would that make much difference?). I also removed and looked at the accelerator pumps.

I will try Klunks suggestion again - it is a little difficult to see because of the position of the clam shells blocking the view, but I'll have another go. If there is no fuel at the butterflies, where do we go from there?

Thanks

Terry

[Terry Field]

I've just tried pumping the throttles, but I can see no fuel at any of the butterflies. It is a bit difficult to see, but there was nothing obvious, no smell, and I even pushed a piece of kitchen roll down one of the trumpets to see if it absorbed anything - but again it was dry.

I then poured a couple of teaspoons of fuel straight into the trumpets - it fired instantly and ran for a couple of seconds (much popping and banging!)

So it really does look as if there is some form of blockage or malfunction on the carbs (but why both of them?)

Terry

[virden]

Terry,

Is it possible that the flow of fuel to the carbs is so slow, that once you have pumped the throttle a few times you have in the process emptied your float chambers?  Place one of the bango connections into a jar and turn  the engine on the starter the jar should fill very rapidly.  Disconnect the coil before doing this!

Another but remote possibility is that the Orings between the carbs and the manifold are leakig big time. 

Good luck

[Roger King]

The fact that it runs for a few seconds with fuel placed manually in the inlet tracts pretty much proves that the problem lies in the throttle pump system. If this is not functioning it is not possible to get any fuel into the engine to start it initially.

You need to remove the pump jets and check they are clear and after replacingthem, check the mechanism is working OK. For this you will need to remove the tops of the carburettors.

When the throttle is shut the pump rods (one per carburettor) should be sitting high, but when you hold open the throttle they should fall gently. It is this action that sends fuel to the pump jets. If they don't fall, the pump jets won't pump.

You can often free them off with a bit of gentle waggling - don't force. If this doesn't work (it usually does) you will need more in-depth work done.