1.9DG dies off on acceleration

[Bigface]

So I know this topic has been covered time and again - believe me I feel like I've read them all - but I'm at the end of my rope here. 

Revs die off on acceleration, then there's a lag where the engine appears to die before they pick up and the van accelerates almost normally, usually with a few misfires on the way. It does it in neutral on the drive, but it's WAY worse when pulling away in 2nd and 3rd. Daughter in the car behind says it stinks of fuel, plugs were black and plenty of exhaust smoke.

Started after I removed/refitted the gearbox, and I know for a fact some cables were stretched in that front right corner of the engine bay, but the cables are a mess in there after 35 years or so of 'maintenance', and I can't make head or tail of the wiring drawings. There's at least one wire snapped at a temp sensor below the thermostat housing, but someone's linked it to another wire in the past...

So far it's had:

New plugs, leads, distributor including cap and rotor arm, coil and ignition amp. No change. It's had a replacement (known working) carb. New fuel filter(s), tank removed and cleaned out and fresh E5 fuel. Air filter is new-ish and the problem remains with the air housing off. I've checked for air leaks with the carb cleaner spray, and replaced a perished brake servo hose. Idle cut off valve has been checked. Wiring continuity checked between ignition amp and dissy. Timing checked by local garage. 

I haven't yet checked the fuel pump as I'm waiting for a capable assistant to turn it over for me while I watch the output.....

Reaching out here for some ideas here please as I'm just about done. It used to run really nicely prior to this issue.

[Bigface]

UPDATE - checked fuel pump flow by starting the van with the outlet hose into a pop bottle - seems to be healthy, good flow, rapid strong spurts. 

[TONYT25T25]

Have a look at thiz link as a similar problem was raised
viewtopic.php?t=176663

[Bigface]

Thanks for that - 

I think mine differs in that it does it from cold (is slightly better when hot), and I think I've covered all the issues raised in that thread - shame they never came back with the ultimate solution to theirs though......

[TONYT25T25]

I did drop a hint in the reference post, updates are easily missed by members sometimes.

[Bigface]

Anyone got any other suggestions? Or can point me at the correct wiring diagram in the Bentley manual? 

[diabolov]

I would of said look at accelerator pump or float height on the carb, but as you have changed the carb then that p#sses on that...
what about the auto choke? Does that work ok?
 

[tobydog]

Something to do with the distributor vacuum advance??

[Bigface]

I would of said look at accelerator pump or float height on the carb, but as you have changed the carb then that p#sses on that...
what about the auto choke? Does that work ok?
 

Well it works in as much as it starts and idles from cold, and the same from warm…. I’m not sure what else to check on it. I will say I re - replaced the carb today, new gaskets etc and cleaned the pancake seal, and I also re-made the brake servo hose with new jubilee clips and put a fresh end connection on the carb end of the vac advance tube and it seems to have improved things. It’s got me wondering if I had/have an air leak which is undetectable by the carb cleaner spray trick. Intention is to lock down ALL air connection points with jubilee clips tomorrow.

[Bigface]

Something to do with the distributor vacuum advance??

Appears to work OK - like I say I remade the carb end of the tube today as it wasn’t the greatest and along with other bits things appear to have improved…..

[keynsham1]

My DG starets fine but the engine will stall before it is properly warmed up when the throttle is pressed, unless you give it a little bit of a rev before letting the clutch out. I have always assumed it is to do with the automatic choke. It is fine once warmed up properly so I have never worried too much about it.

[diabolov]

How about that bakelite/whatever block under the carb? How's that looking?

[Bigface]

All good - gave it a good clean when I swapped the carbs back yesterday. New gaskets too.