Weber behaviour opinions?

Subydoug · Post by **Subydoug** » Thu Jul 04, 2013 6:25 pm

Hey fella's,

Got an issue of late with the ol'faithful wagon. Issue is that randomly, at all temps, though usually during the first heating up period, the motor will be idling beautifully, afr's around 13, then stall. Start it back up, fires straight away and carry's on idling perfectly. I've ruled out fuel pressure, fuel flow, carby is whistle clean, manifold vacuum seems normal, jets all clear and what not, filters are clear. I hedged towards spark, but today it happened bad while I was driving along, boom "lights out". Pumping the accelerator trying to get it going again yeilded some spluttering and coughing. Afr at this point was off the chart lean. Seems like if its coughing like that then the sparkers are arking. Hmmm, so I pull up, check fuel pressure, good. whip the top off the weber, bowl has fuel, verify the float valve is working correctly. Used some fuel line to blow thru the Venturi's and they pulled fuel up from the main jets fine. Rrrrrrrrrrrr. Check spark anyway, good. Jump back in, fire it up and continue off to work

.

Any idea's fella's? I'm going to treat the fuel for water, other then that I'm fresh out.

Regards

Doug

Post by **TOONGA** » Thu Jul 04, 2013 9:00 pm

please tell me you took off the phenolic spacer AKA water leakage device.

it sits on the manifold between the manifold and the factory carby.

the spacer cracks with age and leaks when it wants.

TOONGA

Subydoug · Post by **Subydoug** » Thu Jul 04, 2013 9:51 pm

Yeah mate, that craps gone

Just gaskets. Manifold vac is good. Ran perfectly on the way home tonight. Not one, hiccup, fart or hiss at all. Motor ran good to

. Gave it a good thrashing too for a change. Pulling WOT to 5k before changing, solid 13-14 on the lambda gauge.......Hyundai excel in the mirrors

. Not one miss

. Nothing worse then an intermittent fault.

Anyway, current theory on the matter, given its splendid performance in the afternoon and its common tendency to play up on the way to work, I think Im getting condensation on the carby, inside the airbox, etc. When it all starts to heat up, it drips down into the carby and is blocking the jets enough to conk out at idle. When I fire it back up the block has already cleared and it carry's on running. As to why thismorning it resulted in no fuel for a long period of time I have no idea on that part yet.

That's where you fella's come in....No pressure

Doug

steptoe · Post by **steptoe** » Fri Jul 05, 2013 7:51 am

It's always on the way to work, never on the way home when less pressure on you

My 465 Holley used to do similar to me, though not have AFRs to go with it. It always meant time for a new genuine coated metering block to body gasket to fix the problem.
I didn't have EGR valve to cause issue. What if your PCV valve gave some relief and stuck open? That's go lean - depending on how fumey yer crank case is

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 8:54 am

Yeah I thought about that Steptoe, but the vac gauge didn't drop off at all. Il take the vortex into work today and tomorrow, Il give it a sprinkle around the carb, just to be 100% sure its not pulling air in there at all. Maybe its something to do with thermal expansion of the carby/manifold and the current gasket isn't cutting the mustard.

Regards

Doug

BRAT87 · Post by **BRAT87** » Fri Jul 05, 2013 9:56 am

Hey,

Yep my 87 Brumby was having the same issue with the Webber Carby. Died on me 2 weeks ago on Maroondah High way in Melbourne on a saturday night at 5pm in 10 degree cold. lol Couldn't get it going again. got a tow truck, got it home and it was running rough as. So I sent it off to the mechanic and they sent the carby off to a carby specialist. Supposedly, well what I was told was part of the problem were the jets that come with the webber were wrong for the EA81 It was getting too much fuel and hence why it was stalling. The other issue was the silicon the previous owner used to seal the carby to the manifold. I have gaskets for it now and it runs great. Not sure if this helps you or not.

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 10:17 am

Ive been running the weber for the last 20 odd thousand km's. Been on there for over a year and never done this.

If it helps you out, Im running a 55 primary idle, a 50 secondary idle, annnd.....bugger, cant remember the mains, Il check for you.

Regards

Doug

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 10:27 am

mainjets, primary 155 and secondary 150. The primary with a 150 is better, bit leaner, but I just haven't been bothered to swap it back around again.

Can get away with a 50 on the primary idle but you will need to wind your mixture screw out around 5-6 turns. With the 55 Im sitting at around 2 1/4 turns out on the mixture and about 3-4 turns in on the idle stop. 1000rpm idle and AFR of around 13.

Regards

Doug

Post by **TOONGA** » Fri Jul 05, 2013 6:09 pm

Why do you have a 155 primary?

I have pulled carbys off of 4.1 litre fords and the primary is either a 135 or 140

my weber has a 135 primary and a 150 secondary and Im thinking of taking the 150 down to a 140.

TOONGA

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 8:06 pm

Mine came with a 145/140 combo, which gave me white plugs and an ash coating in my headers

. When I first put the lambda gauge on it was around the 16-1 mark under load. 150/150 is whats best for me, I put the 155 primary in when I started messing around with the supercharger.

Larger Engine capacity doesn't always lead to bigger jets Toonga, its more to do with pressures and velocity's inside the venturi of the carby. For instance, if I pull 1 litre of air thru a carby at a fixed rate and it gives me a lambda reading of 15-1. If I then pull 2 litres of air thru the carby at the same fixed rate, Im still going to have a lambda of 15-1. Now, say if I was to get that same litre of air and draw it thru the carby at a slower rate, maybe in half the time, Im going to draw less fuel, therefore the lambda will be leaner. In that scenario Id need to go to a bigger jet to let more fuel in. This is because the carby regulates the fuel as the air flows thru the carby. So a big engine with a small carby may need to run smaller jets then a small engine with a big carby because the air velocity thru the carby is faster on the big engine then the smaller one.

Sorry about the ramble there. 135/150 is an odd combo, is that in a 32/36 or something different? I thought that generally the secondary jet is smaller then the primary in progressive carbs?

Regards

Doug

steptoe · Post by **steptoe** » Fri Jul 05, 2013 8:09 pm

Will one of you two make a sticky for Weber on EA81 / EA82 - sit back and watch the counter

Post by **TOONGA** » Fri Jul 05, 2013 9:23 pm

Doug Im using an ADM34 weber off a 4.1 motor both butterflys are 34 and the carby is progressive. when I first got it the primary was a 140 and the secondary was a 210, the idle jets were both 60 it was fun to drive but I drove everywhere in a cloud of black smoke

I now have idle jets of 50 and as stated 135 main and 150 secondary.

A very responsive carby on a 2.2 litre motor.

TOONGA

BRAT87 · Post by **BRAT87** » Fri Jul 05, 2013 10:04 pm

Thanks for that SubyDoug! I don't know much about Carbys or jets so that knowledge is helpful!

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 10:14 pm

Progressive 34's, sounds like a beast! She must bark when you crack the secondary open. My 32/36 has a momentary lean spike when The secondary opens. I suspect lifting the secondary idle jet one size would fix it. Eh, I rarely even have the secondary open. Don't need to in the city.

Have you monitored your o2 before?

Regards

Doug

Subydoug · Post by **Subydoug** » Fri Jul 05, 2013 10:19 pm

No worries mate, any dramas just pipe up and someone on here should be able to help you out.

Regards

Doug

Subydoug · Post by **Subydoug** » Sun Jul 07, 2013 11:09 pm

Just some follow up,

Been driving the wagon around during the weekend. I installed my redline Fuel pressure reg, set to 3.5psi and treated the fuel for water on Friday arvo. Saturday morning I fired it up early in the cold and let it warm up, not one problem. Rechecked everything for vac leaks with the hose, all seems fine. Went fine all day Saturday. Get in it this morning feeling pretty confident, blast off down GF freeway and into the Northbridge tunnel where it decided to have a hissy fit

. Once again lost all power and started slowing down. The friggin odds of it happening in the tunnel, I donno, but it did. Anyway, kept a cool head and decided to utilize the moment to figure out what the hell was going on. Looked down at the tacho, yep still showing rpm. Probably means the points are still working as they should. Look up at the wideband gauge, off the chart lean. Put the two together in my head and assumed I had a fuel issue, so what to do.....
Tried pumping the accelerator, few coughs, that's it. Held it WOT, nothing but induction noise. By now Id slowed down to around 60km'h, so I slammed it into 3rd to get some rpm back. Still nothing. What the hell, into second and WOT. BAM! Tell ya what, that surge of power coming back was pretty satisfying

. Cant remember how hard it revved but it was satisfying, and I didn't have another issue all day.

I think what Im going to do is treat this more as a spark issue. I just cant see how all the jets, idle, mains can all stop working at precisely the same time. Seems near on impossible to me unless the carby itself is getting starved of fuel. I just don't believe that's whats happening given that the car runs perfectly most of the time. May run a temporary fuel pressure gauge up onto the bonnet so I can see what its doing. Also might throw my ecu back in and modify it to monitor the ignition leads so if it happens it'll spew out info for me to see.

In the mean time I might just spray all the connectors with wd40 in the mornings before heading off to work.

Last question then Im off, If a car was to be running, and then have its ignition killed, what do you think a wideband sensor would read? My hunch was rich, but on second thought, if Im not burning the air maybe there would be more in the exhaust charge indicating lean? thoughts or practical tests?

Regards

Doug

steptoe · Post by **steptoe** » Mon Jul 08, 2013 7:45 am

second new coil fitted up to swap in case next time ?

Subydoug · Post by **Subydoug** » Mon Jul 08, 2013 10:15 pm

I replaced the coil around 2k ago to an MSD blaster 2. Engine has been running beautifully since then. I got a whole spare distributor, may just chuck a timing wheel inside it and be done with it. Took the vortex today so no extra knowledge on the subject.

Regards

Doug

Subydoug · Post by **Subydoug** » Sat Jul 13, 2013 7:58 pm

Hey fella's,

Think I've found my Gremlin. Took the wagon out again today, no issues at all until I was about 500m from home when she cut out. Pulled over, cranked and started fine. When I got home I turned it off, tried to start it again and It wouldn't fire. I popped the top off the disty and measured the point gaps. Around 1mm. Meant to be 0.2 to 0.4

Reset it and, adjusted the timing and now she purring again

. Was it the real issue...donno, but it probably wasn't helping. I was pretty confident that the tacho was still showing rpm the other day but maybe it was just getting enough to give a tach signal but not enough to discharge the coil fully.

Regards

Doug