Powerless, No power under load Options

[Carlitos Way]

I've got a 1.7 block, warmed up to a 2.0 with dual weber carbs. The carbs were jetted per Aircooled.Net specs, and they were just rebuilt by a reputable local carb shop.

When I accelerate, I get absolutely no power. I've replaced the distributor, coil, gas lines, gas pump and made sure the carbs are synchronized.

Car idles like a champ. I can stomp on the gas and it revs up nicely. As soon as I put load to it (i.e. let off the clutch), the car bogs down and sputters.

Any thoughts/ideas?

[So.Cal.914]

It still thinks it's a 1.7?

Check timing, points and condenser.

[Carlitos Way]

Thanks for the quick response. Actually, I forgot to mention, that I just replaced the distributor with a new (Brazilian?) 009. New pts and condenser. Also tried a second COIL, just in case this one was flaking out.

[r_towle]

Dirty idle jets.
broken/torn accel pump gasket.
From what I remember (a blatant disclaimer) the main jet does nothing till 2500-3k rpms...something like that...the point being, off the line, you are using the idle jet...and again (memory) there is an additional fuel squirter that shoot fuel in at the top of the venturi...just for take off need...so you get a little extra squirt to go from 0-10 mph...
Look and check the ignition...then look down the carbs (in the venturi) make sure each barrel is squirting the extra fuel...
If the accel gasket os torn, the carbs will still sync up at idle...
If you get stuck...test the carbs at 3000 rpms..

Or ignition.

Rich

[Toast]

Do you have the correct size venturies and/or are they possibley pluged. Pull each one out and blow into it (watch for the gas!) and make sure there isn't some microship-sized debree blocking airflow.


Actually, dont really have a clue. I just remember doing that to the dual webbers on the VW and it seemed to help with load power.

[rhodyguy]

carbs...40, 44...? what size are the venturis'? do you know off hand what the jetting specs were? if the venturis' are too large you may experience some off idle stumble. when the revs get up there it will want spin like crazy.

k

[ClayPerrine]

I would also suggest that you do a "float test" on that distributor.

Float Test: Throw it in the lake and see if it floats.


The 009 distributor was designed for a VW air cooled industrial engine It does NOT have the proper advance for a automobile engine. I would suggest locating a 050 distributor, or even the stock distributor from a 1.8L 914. Both have a better advance curve than the 009.

[r_towle]

I worked with the aircooled.net guys on a beetle...they are cool, they have a datbase, you tell them the motor and the carb, they tell you what works..
I asked them how they got this databse....its from customers that have BTDT and it works...

they are really cool about swapping venturis and jets till you get it right...

Just a great company...

I agree though, if the venturis are to large, or the air,main,or idle jets are wrong...youll never get it...

but...make sure the ignition is perfect before you go to far with it...
40mm on a 1.7 ......with 28mm vents, F11 tubes, 200 air, 125 mains and 50 idles.
That works on a superbeetle, 1.6 liter...
that took trial an error to find, and I worked with aircooled.net...

rich

[rhodyguy]

enough with the 009 jokes!! we all know they are not the optimum dist for our T-4 engines. i will tell you this...my car ran FINE for about 3 years with one in it. the run to campbell for the 04'. too many trips to portland and further south to count. i drive/drove my car all of the time. i didn't have to take any crap (performance wise) from the 2.0s with djet locally. the ONLY reason i changed mine out was due to the fact that i sourced a mallory at an offer i couldn't refuse. carbs can be daunting at first. knowing what the "changeables" are goes quite a ways in suggesting some changes that might be of some help. personally, i don't think it is the dist "itself", that is the problem.

k

[obscurity]

I had the same thing happen on my 1.7 FI.

Turns out I needed new shift bushings cause I was actually in 3rd gear. You may have already checked this but...

[Pompano Beach 914V8]

Sure sounds like an ignition problem.

[Cap'n Krusty]

The car should have adequate power, even with the fishing weight 009. The timing should be set to 30 or 32 degrees at 3000 RPM. If you set it to TDC static, then you're only getting 17 degrees or so of total advance, making your car a dog undrer load. Think BASICS. Recheck the dwell while you're at it. The Cap'n

[Carlitos Way]

Cap'n...

Assuming I was doing the static timing (I was)... and the impeller has the wrong timing mark since it's a 1.7 impeller rather than the 2.0. Should the timing mark then be at the left or the right of the original timing mark, as I face forward from the back of the car?

Thanks,

[Cap'n Krusty]

Cap'n...

Assuming I was doing the static timing (I was)... and the impeller has the wrong timing mark since it's a 1.7 impeller rather than the 2.0. Should the timing mark then be at the left or the right of the original timing mark, as I face forward from the back of the car?

Thanks,

The timing marks are the SAME for ALL the T4 D-jet cars, 1.7 and 2 litre. Get a good timing light, and set the timing at 3000 RPM. There is no 12 degree BTDC mark.

The Cap'n

[Aaron Cox]

what size mains??? does it make lots of intake noise, but just doesnt move?? could be rich???

you need the weber book by bob tomlinson at cbperformance.com.....

[tesserra]

Fuel flow
Pump? Filter?

If it was injected this would be the problem,..... carbed maybe.

Good luck, just remember it will run right some time soon.

[Carlitos Way]

Well, I took the darn thing to a local mechanic... and he's made no better progress than I did on my own.

Once again, here are the symptoms: Car idles fine. When I rev up the engine, without load, I can get it to rev up nicely without any problem up to 4k-5k RPM. Sounds nice and even. However, when I sit in the driver's seat and try to pull away from a dead stop I get no power. Hardly enough to move the car forward.

Revisiting what was done before I took it in:

1) I had replaced the distributor with a stock 1.8 per recommendations from other members. Still no change. Tried a 009 aftermarket replica distributor. No change.
2) Had carbs rebuilt by a reputable carb shop.
3) Changed Fuel pump. Increased fuel pressure up to 3.5 lbs, rather than 2.5
4) Replaced hoses coming out of the fuel tank.

What the mechanic has done:

1) Replaced the 009 dizzy with a "new" unit (I'm assuming one of the Brazilian units, not an original 009).
2) Changed the orientation of the carb linkage (I had it in the front of the engine. he relocated it to the rear).
3) Changed fuel hoses to remove minor kink coming out of the fuel tank.
4) Changed fuel pump because he didn't like the one I had installed.
5) Checked compression. Compression "acceptable (I didn't get the numbers for all cylinders) but he didn't feel the compression was low enough to keep the motor from running, and it was fairly even across all cylinders, albeit lower on the passenger side than the driver's side).
6) Synchronized Carbs to even fuel flow across both banks.

End result:

Problem persists. Mechanic is suspecting one of the following:

1) Bad (flattened) cam
2) Bad Carbs
3) Bad Ignition Cables
4) Blowby so extreme that it is bogging down the engine. Mechanic wants to do a leak-down test to see if this might be the cause of the problem.

My dilemma is, I've spent close to an additional $600 on this mechanic after all is said and done... and the problem prevails.

Other suggestions people have made, but I have yet to check:

1) Uneven fuel hose lengths after the the T separating the fuel to the 2 carbs.
2) Poor timing setup, based on using wrong timing mark.

I welcome any suggestions at this point.

Thanks!

[drewvw]

oh man...somebody in cali take a look at his poor car!

[r_towle]

You can waste more money if you want.

Find out the specs on the carbs.
If they were rebuilt, ask the rebuilder what the specs are.
You need,
main jets
Venutris
Air jet
Idle jet
Emulsion tubes.

Please find out that before you spend any more money.
If you need help to figure out what is in there, PM me and I can wlk you through how to find out.

Once you have that information, and the ignition is set properly, we can diagnose it.
If the cam is flattnened, or you have severe blowby, there are tests for that as well.

Rich

[TravisNeff]

Dizzy 180 degrees out? easy to do and it will run, it will throw fits under load.