exhausted all adjustments to get car to run right - resolved

[croute]

Hi - and help - I've been reading and reading and trying and trying to get my 71 Ghia to run properly.

- It was parked for 30+ years, a compression test shows 140 for all 4 cylinders
- I put a rebuilt dual vac distributor on - I could not get it to work at 5 atdc (set static) I plugged the retard vac and just set it to 7 btdc. the advance is 30 max
- I have a new EMPI carb, base lined both adjusting screws (2.5 turns out) and adjusted the accelerator pump. The choke is working properly and the fast idle screw is set right.
- New cap, wires and condenser and plugs (NKG BR6HS gapped right) and the valves are all adjusted properly. The points are gapped correctly and the dwell is 50.
- I sprayed starter fluid on the carb and manifold while running and there is no vac/ air leak

The problem: It will not rev without stumbling - I can get it to idle smoothly (I have to screw OUT the volume screw quite a bit). If you rev it quick in the garage it totally stumbles and tries to die and is not smooth at all. Driving - it will hesitate. If you floor it - it's very zippy and has power...
It really feels like it's too lean, if I turn the volume screw in (to make it richer) it starts to idle rough and also stumble and burble...and want to die...

OK, sorry an update - It looks like I had the accelerator pump adjusted to deliver TOO much fuel, It doesn't stumble and die, BUT it 'almost' runs smoothly, I still get a very slight hesitation as mid-throttle...

what am I doing wrong? any thoughts? thank you, Chuck

[dingerjunkie]

I have an older truck that did the same thing, and was especially bad under load or higher revs.
The source ended up being a weak/failing coil. I saw spark at the plugs outside the engine, and compression at idle (lower than a full-open carb) allowed it to idle just fine. Hit the gas or load up a hill and the misfires got waaaay out of control.
There was not enough output from the coil to cause a spark jump at full compression.

[croute]

Thanks for response DingerJ, I forgot to mention I have a new blue coil on it, and the older black coil seemed okay but I had the new one handy.

I re-timed it, again could not get any decent response with the retard vac line attached, so just plugged it and got it so the advance is maxed around 29/30 (I had to add that mark as my pulley has only a TDC and a 5 ATDC.

I it running about 90% now, good pull but still every so slight hesitation...

[Era Vulgaris]

If you're using a DVDA dizzy with an EMPI 34pict3, it will not run right. The DVDA dizzy will only work correctly with certain German Solex 34pict3 carbs that it was paired with at the factory. These special 34pict3 have a larger hole in the throttle butterfly than the ones designed to be used with an SVDA, to account for the different idle timing, and are identified by a unique number stamped on the base flange. See chart below.

Using an SVDA carb with a DVDA dizzy will create problems, as will using a DVDA carb with an SVDA dizzy.

The EMPI carbs in general aren't highly regarded. If you can swing it, I'd recommend a rebuilt original from Tim at Volkzbitz

_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD

Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue

[croute]

very interesting, thank you for the info. the car had a Bocar carb on it (assume not original) that had worn throttle bushings...I plugged the retard vac line on my DVDA (timed to an SVDA) and it is running much better now but not 100%, a bit too lean - I did look at the Volkzblitz carb and I can't quite afford it.

Is my plugged DVDA essentially an SVDA? Or are there other differences? And if so would a 'real' SVDA work better with the EMPI carb?

Thanks, Chuck

[kingkarmann]

If you have a mechanical fuel pump have you made sure working properly and putting out 2 - 2.5 psi ?

[croute]

I do have a mechanical pump, I have not tested the PSI. I can do that...thanks for the tip

[Era Vulgaris]

[tasb]

If he’s short on bread for a restored carburetor he’s not going to be able to afford a restored German 034. What’s your distributor part number and carburetor flange number?
_________________
Roads Scholar
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

Member# 2059

[croute]

thanks for responses, My distributor is Bosch 0 231 167 049 and the EMPI has a 24091 stamped on the base. It idles very well, and I do have some slight hesitation and it's running lean...so almost there...I was told also that changing my idle jet to a 60 could help.

The prices for a German 034 are about $200 and to replace my carb would be a lot more...

Thanks, Chuck

[tasb]

That $200 price tag is overly optimistic, if you can find one that is properly restored. They are highly sought after.

For the purpose of the table above your Bosch#167 049 translates to a VW # 113 905 205 AJ. That’s the first one in the table and is a DVDA. IF the Empi carburetor was copied from an SVDA engineered carburetor then you have a mismatch.
_________________
Roads Scholar
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

Member# 2059

[croute]

I get it - so I need a carb #279-1...thanks for the great info. This is quite a challenge, bringing something back to life that has parts changed and, of course, my lack of knowledge.

Now I know - I can work on a plan - the distributor IS correct for the year /car (my car is a 71), it makes sense to get the correct carb eventually, the car runs pretty well for now, while I replace the top and all the 100 other things I need to do.

thank you all. Chuck

[tasb]

The issue is the size of the hole in the throttle plate. All other things dialed in you would be left with a slight hesitation which is where you are at, so nice work. Not being a carburetor guy I don’t recall wether you just need to enlarge the hole or wether it’s already too big.
_________________
Roads Scholar
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

Member# 2059

[rcooled]

[croute]

I did see that 'fix' - it turns out that my new EMPI was flawed. The choke plate was not machined properly and was jamming in the throat of the carb, it wasn't moving...I am returning and will spend the money and find the correct carb for the car/distributor...thanks for all the input. C

[croute]

resolution: I sprung for a Volkzbitz carb and spent some time adjusting and fine tuning using the DVDA with both vac hoses connected and the car runs great. I did discover that the car really needs to be warmed up properly...but Idles perfectly with no hesitation, very smooth.

Thank you for your help. Chuck

[carmangary]

I rebuilt my carb recently and it would stumble whenever I gave it gas. I finally found I put the spring on the wrong side of the accelerator pump diaphragm. Once I put it together correctly it ran well.